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Kalman Filtering for Navigation and Target Tracking:

U.S. Navy Submarine applications related to Kalman filtering 

We have prior experience for over 40+ years in a variety of defense areas including Submarine Inertial Navigation (compare the prior hyperlink to our clearer discussion below) [and an understanding and a facility with the underlying navigation error models constituting a psi-angle analysis of an Inertial Navigation System (INS) consisting of accelerometers and gyroscopes in an integrated whole]; Air Force Aircraft Navigation and Radio Multi-lateration Relative Navigation (JTIDS RelNav) and communication (JTIDS/MUFBARS/ICNIA); Sonobuoy DIFAR/LOFAR target tracking; Search and Screening; Antenna Radar Cross-Section Detectability; NavSat (a.k.a. Transit), LORAN-C (both hyperbolic and phase-shift rho-rho circular), Bathymetry (bottom sounding sonar map-matching) and GPS analysis and usage on Submarines; and GPS analysis and usage in test aircraft (along with test plans and procedures for many of the above); and Early Warning Radar Target tracking considerations relating to the target tracking filters and estimation concerns (and the underlying mathematical models of all of the above and more). Thanks to John Rommelfanger (MITRE, retired), we have a copy of Modern Navigation Systems, a short course by (the late) Walter R. Fried (Hughes Aircraft Company), 10-12 June 1992. Of course, we at TeK Associates already had both editions of Walter R. Frieds book but having access to his slide-based concise summary is priceless. Thomas Kerr III knew Walter Fried personally and when Tom last saw him in 1994, based on Tom’s rather aggressive questions and comments from the audience, Walter Fried seemed pleased that Tom had evidently become a watchdog for navigation since they had first met back in 1980, when Tom made his first technical Navigation presentation at Position, Location, and Navigation Symposium (PLANS) in Atlantic City and Walter Fried was there as his session chairman. Tom received a written a accommodation certificate for his work and presentation there [9], [8], [10]. (Please see next image below for verification of this claim.)

Familiarity with historical application constraints and specs for many platforms (especially including C-3 Poseidon, C-4 Poseidon-back-fit [which, in those days, used multiple Univac CP-890/YUK computers in the Navigation Room], and similarly outfitted D-1 Trident SSBN\SSN submarine mission objectives, scenarios, and countermeasures). We have had first hand shipboard experience in San Diego in the 1980s and earlier weapons system and fire control training in the 1970s (regarding numbers and mixes of RVs) at Dam Neck, VA. We have also been aboard the Compass Island (sister ship of Cobra Judy used for strategic radar target tracking) in the 1970s, where components being planned for use within the SSBN Navigation Room are tested beforehand (in a Navigation Room that was identical to but bass-ackwards from how it is oriented within actual SSBNs). The U.S.S. Compass Island was replaced in this role in the late 1970s by the U.S.S. Vanguard (as obtained from NASA). We are aware of vintage 1970s vibration tests for submarine INS components using Big Bertha and the Little Chipperson the deck above it. Present day barge tests with submerged C-4 plastic explosives emulating depth charges and use of 300 pound swinging hammers, capable of impacting at up to 100 gs, now reveal weaknesses or non-compliance of electronics within the expected dangerous environments is just as important today (even if their names are no longer as colorful). We have also performed GPS testing, both dockside and at sea, onboard the SSN-701 LaJolla in the early 1980s at the San Diego, CA submarine base (for NADC and for NOSC).

We have participated in several Independent Verification and Validation (IV&V) programs for sonar\sonobuoy target tracking (PTA and LOFAR/DIFAR and LAMPS), and in analysis and development programs for integrated augmented INS navigation for Submarines (SSBNs) and in Joint Tactical Information and Distribution System (JTIDS) Relative Navigation (RelNav),  and in Development Testing and Evaluation for Operational Readiness [DT&E(OR)] for GPS navigation aboard submarines (SSNs). (To see a high level overview slide show on current status of GPS, please click here to obtain the main executable file stpete.exe. In order to view the slideshow, user must first download this associated .DLL file, then this .DLL file, then this VBX file, all to the same location in one folder on their local computer. Our Website host requires temporary conversion to exclusively lower case spellings. A constraint in running it is that a Windows host Operating System is required. Those typical OSs that allow this are Windows 9X/2000/NT/Millenium/XP and Vista and likely on Windows 7/10. It also runs on older OSs like Windows 3.1 and 3.11 For Workgroups.) 

“Escape Velocity” from a Linkedin discussion: I agree with what everyone said except for:
(1) when Hugo Jiménez-Pérez said that eccentricity e = 0 for a parabolic orbit (properly corrected by THK: e = 0 for a circular orbit, 0 < e < 1 for an elliptical orbit; e = 1 for a parabolic orbit; e > 1 for a hyperbolic orbit).
(2) when David Elm said that at 4 earth radii, the sun becomes a bigger factor (properly corrected by THK: the moon becomes a bigger factor first since it is nearer and has a greater effect on earth tides than the sun). Don't forget all the (i.e., 5) Libation points of three body problems (also called Lagrangian points): being L1, to L5. (these are totally unrelated to GPS frequencies of the same name designations)
(3) when Carlos Antonio Campos Nogueira said one needed to assume an idealized Earth (a perfectly homogeneous, uniform, and smooth sphere of mass M). Properly corrected by THK: one can assume a prolate ellipsoid with J2 accounted for but treat all the mass M as though it were all concentrated at the earths centroid or center of mass.
Escape velocity is aptly explained in: http://en.wikipedia.org/wiki/Escape_velocity 
Recall historical precedent: RPIs Murray R. Spiegel. Applied Differential Equations 1963 edition, with a fully worked out section: From Earth to Moon, which properly accounted for mass decrease as rocket fuel was consumed.

Other interesting precedents (to set the stage):

Lest we forget, Emeritus Prof. Ronald L. Klein (UWV) published many articles on estimation Theory using Gaussian Quadrature formulas [in order to improve the accuracy of the Propagate Step integration of the system dynamics within an EKF]. Here and in what follows below, Thomas H. Kerr III’s comments and annotations are in a different color font to make it easier for readers to distinguish (and, perhaps, to ignore).

Emeritus Prof. Thomas Kailath (Stanford Univ.) alerted the estimation community to a precedent by some Japanese researchers that posed linear estimation within a “Krein Space” instead of within a Hilbert Space and apparently obtained faster convergence as a consequence. While Matrix Positive definiteness plays a prominent role within all the analytic proofs supporting the usual Hilbert Space-based derivation of Kalman filters, the Krein Space approach frequently involves matrices that are indefinite (but, perhaps, the difference of two positive definite matrices). The tool in common is still  projections onto linear subspaces.
-Hassibi, B., Ali H. Sayed, A. H., and Kailath, T., “Linear Estimation in Krein Spaces-Part I: Theory,” IEEE Trans. on Automatic Control, Vol. 41, No. 1, pp. 18-33, Jan. 1996.

-Sayed, A. H., and Kailath, T., “A State Space Approach to Adaptive RLS Filtering,” IEEE Signal Processing Magazine, Vol. 11, No. 3, pp. 18-60, July 1994. (Here they demonstrate that most of the myriad of RLS filters are merely simplified variants of a Linear Kalman filter.)

In the early 1970’s, many researchers from Washington University in St. Louis, MO (e.g., Alfred S. Gilman, K-P. Dunn, Prof. Ian B. Rhodes) investigated approximate nonlinear estimation in the presence of so-called “Cone-Bounded” nonlinearities so that the resulting mechanizations are still fairly tractable. Dunn and Gilman went to work at Lincoln Laboratory after obtaining their Ph.D.'s but, unfortunately, these nice results apparently were not deemed directly relevant to EWR target tracking at that time.

An additional caution by Dr. James L. Farrell (VIGIL, Inc.) in specialized topics related to Integrated Avionics in order to reach their fullest potential (as an update to the most recent version of his book on Integrated Avionics). 

Please click the following: to learn about developing ISR Applications using MatLab and Simulink 

Please click the following:TeK Associates experience looking into SLAM (Simultaneous Localization and Mapping) and other possibly non-GPS technologies for airborne navigation (appearing in the open literature)

For situations involving imaging and optics that have zero mean Poisson Process White noise (as the formal derivative of a Centered Poisson Process with independent increments just as Gaussian white noise is the formal derivative of a Brownian motion process [a.k.a., a Weiner process] with independent increments),  please see: (1) Donald L. Snyder, Random Point Processes in Time and Space, Springer Texts in Electrical Engineering, 2nd Ed. 1991 (1st Ed. from John Wiley and Sons, NY, 1975). Prof. Donald L. Snyder (Washington University in St. Louis, MO); (2) Fishman, P., Snyder, D. L., “The statistical analysis of space-time point processes,” IEEE Trans. on Information Theory, Vol. 22, No. 3, pp. 257-274, May 1976; (3) Snyder, D. L., and Fishman, P., “How to Track a Swarm of Fireflies by Observing Their Flashes,” IEEE Trans. on Information Theory, Vol. 21, No. 6, pp. 692-695, Nov. 1975; (4) Salimpour, Y., Soltanian-Zadeh, H., Abolhassani, M. D., “Extended Kalman Filtering of Point Process Observations,” Conf. Proc. IEEE Eng. Med. Biol. Soc., Buenos Aires, Argentina, 6670-3, Conference Dates: 31 Aug.-4 Sept. 2010. Alse see [233] to [240]. My speculations: The above technologies  could be of interest to SBIRS-high or SIBRS-low to detect and track Russia’s Avangard Hypersonic glide missiles, capable of traveling 20 times the speed of sound (i.e., 767 mph) and of performing maneuvers in taking an evasive zigzagged path as it speeds towards its designated target (and to, ostensibly, be deployed by Russia in 2019 and so far contained within a UR-100N UTTKh missile [designated in NATO terminology as the SS-19 Stiletto] first stage used to carry the glider up into the atmosphere but eventually to be replaced in this role by a new first stage missile that Russia is currently developing in 2019). It was test fired in 2018 from a silo in the Dombarovsky missile base in Orenburg Oblast, in the southern Ural Mountains and traveling more than 3,000 miles to Kura training ground in the Kamchatka region in Russia’s far northeast) and, perhaps, aim lasers toward them as potential targets of interest. [The U.S. and China are currently jointly working on a Hypersonic missile too, according to Jane’s Defense in late December 2018.]  https://www.flightglobal.com/news/articles/dod-keeps-eye-on-hypersonic-missiles-and-manoeuvring-425086/  https://news.usni.org/2019/02/01/40831?_lrsc=a801f315-b3d7-4987-b0c7-78717bd0b9e9  


Simulation of hypersonic aircraft radar and other characteristics, as seen by different sensors (click here to get this unclassified 5MB pdf on this subject): 

      Also see: https://journals.sagepub.com/doi/abs/10.1177/002072097401100415  
A Ball-Balancing System for Demonstration of Basic Concepts in the State-Space Control Theory
by V. Jørgensen First Published October 1, 1974 Research Article
The Ball-balancing Systems is intended to demonstrate the basic concepts in the state-space control theory for graduate education. The physical properties of the system are stated and the mathematical model is evaluated. Conditions of stability are discussed.

1.Jorgensen, Kjeld , The Multivariable approach in Theory and Practise (in Danish), M.Sc. Thesis, Technical University of Denmark (1971).
2.Elgard, Olle, I., Control Systems Theory, McGraw-Hill (1967).

      For a modern application of Elgard's theory above, please see: http://www.ijeei.org/docs-5184432705c6a43e405da8.pdf   
Pushpa Gaur1, Nirmala Soren1, and Debashish Bhowmik, Secondary Frequency Regulation of Multi-area Interconnected Hybrid Power System with Electric Vehicle, 
International Journal on Electrical Engineering and Informatics - Volume 10, Number 4, pp. 738-752, December 2018.
Reference list contains 25 references. The first five are:
[1]. O. I. Elgard, Electric energy systems theory, McGraw Hill, New York, 1982, pp. 299-362.
[2]. O. I. Elgerd, C. Fosha, “Optimum megawatt frequency control of multi-area electric energy systems”, IEEE Trans. Power Appl. Syst., Vol. PAS-89, No. 4, pp. 556-563, 1970.
[3]. P. Kundur, Power system stability and control, McGraw Hill, New York, 1994.
[4]. R.J. Abraham, D. Das, A. Patra, “Damping oscillations in tie power and area frequencies in a thermal power system with SMES-TCPS combination”, J Electr. Syst, Vol. 7, No. 1, pp. 71–80, 2011.
[5]. K. C. Divya, P. S. N. Rao, “A simulation model for AGC studies of hydro–hydro systems”, Int. J. Elec. Power and Energy Syst., Vol. 27, pp. 335–342, 2005.  



Bulut, Yalcin, "Applied kalman filter theory" (2011). Civil Engineering Ph.D. Dissertation:


Samra Harkat, Malika Boukharrouba, Douaoui Abdelkader, "Multi-site modeling and prediction of annual and monthly precipitation in the watershed of Cheliff (Algeria)," in Desalination and water treatment:


A fix for previous timing problems experienced by Patriot Missile:

Defeating Hypersonic Missile Threats:

Raytheon Hypersonic Contract:

U.S. X60A Hypersonic Test aircraft in 2019:

The Air Force Research Laboratory, Aerospace Systems Directorate, High Speed Systems Division, in partnership with Generation Orbit Launch Services, Inc., is developing the X-60A vehicle. It is an air-dropped liquid rocket specifically designed for hypersonic flight research. X-60A program completed its Critical Design Review, a major milestone in the program in 2019. The program now moves into the fabrication phase. The initial flight of the vehicle, scheduled in about a year, is based out of Cecil Spaceport in Jacksonville, Florida.

Hypersonics: DoD Wants ‘Hundreds of Weapons’ ASAP:



USAF Kicks Off Early Study For Hypersonic Cruise Missile:

After the shutdown of the ESA/CNES launch base in Kourou, French Guiana, and despite the initial statements by the US space industry, COVID-19 starts creating negative impacts on on-going programs.
It is a reality to face. Space programs, being long term, might suffer less (apart from delays and induced cost impacts) than other industrial sectors, but it is indubitable that 2020 will see an overall contraction of the space economy in terms of revenues, as compared to very optimistic forecasts of several hundreds of million in US dollars. This is the time when governments should keep their support to the space industry, resisting the temptation of short-sighted "savings". One example: we still want to go back to the Moon!
US Space Force Delays GPS III Launch in Response to COVID-19 - Via Satellite:

The Space Force recently launched its sixth and final Advanced EHF satellite from the Cape March 26. But other national security-related launches have already been delayed as the COVID-19 pandemic spreads across the globe: Rocket Lab announced in March that it has temporarily halted launch preparations for its “Don’t Stop Me Now” mission, which includes three National Reconnaissance Office (NRO) payloads and was scheduled to launch in late March from the company’s Launch Complex 1 in New Zealand.

GeekWire | Stratolaunch resurrects its hypersonic rocket vehicle under a new name: Talon-A:

The Future of Laser Missile Defense:
What can catch a missile moving many times the speed of sound? An interceptor that's as fast as light. See how we're hurtling toward lasers that can stop hypersonic missiles: https://rtn.co/2WMIscv 

What can catch a missile moving many times the speed of sound? An interceptor that’s as fast as light. See how we’re hurtling toward lasers that can stop hypersonic missiles: https://rtn.co/2WMIscv  :

(Dec. 2020) General Atomics And Boeing’s New Liquid Laser Could Win High-Energy Weapon Race:
Keep an eye on this partnership. Boeing and General Atomics, two of the best at high-energy laser technology, will deliver advanced capabilities for America's air and missile defense systems. Our troops will also enjoy another layer of protection.https://www.forbes.com/sites/davidhambling/2020/10/30/general-atomics-liquid-laser-could-win-high-energy-weapon-race/?sh=1a30db665b3e 

Hypersonic missile tests: https://www.navy.mil/submit/display.asp?story_id=112406  

Raytheon, Lockheed Martin sign teaming agreement to pursue contract to modernize surveillance and air traffic control radar systems:

U.S. Army, Raytheon complete preliminary design review of DeepStrike missile:

Space Fence SST radar operational! A huge leap ahead in space surveillance!
Looking forward to seeing the increase in the number of objects monitored and in the orbital accuracies:


Missile Defense Agency Advances Laser-Blasting UAVs:

Lasers: Beyond The Power Problem:

Directed Energy: The Time for Laser Weapon Systems has Come:


Air Force Releases Video of New Combat Drone, the XQ-58A Valkyie in 2019:

U.S. Army to Buy $39.6 Million Worth of Pocket-Sized Drones:

NASA Dream Chaser:

There are a lot of advantages to attacking signals vice satellites:
-It is a lot easier to do
-It can be easily undone if you don't want to do it any more
-It probably isn't an act of war
-and (sic, consider) the power you would have available from a nuclear reactor...!

An interesting bit from the article:
"...the deployment of EW [electronic warfare] platforms in orbit would be in accordance with a policy for Russia’s electronic warfare program until 2020 approved by the Russian government in January 2012. A summary of this policy indeed mentions space-based electronic warfare as one of the objectives to be accomplished in the period before 2025. More specifically, it talks about the need to deploy “multifunctional space-based EW complexes for reconnaissance and suppression of radio-electronic systems used by radar, navigation and communications systems.”
Ekipazh: Russia’s top-secret nuclear-powered satellite:


Kazakhstan uses drones to patrol capital during COVID-19 lockdown:


Invisibility Technology Takes Big Leaps That Can Be Seen:

https://now.northropgrumman.com/invisibility-technology-takes-big-leaps-that-can-be-seen/    (Dr. Eli Brookner, Raytheon [retired] has published plenty in keeping track of the status of meta-materials for radar, optics, and acoustics.)

U.S. Air Force to transfer 23 units to the Space Force:


Remembering a bit of history pertaining to the Cold War and the U.S.’s successful race to the moon:

NASA’s Original Apollo Moon Landing Guidance Computer Is Being Restored:


Thousands of Hours of Newly Released Audio Tell the Backstage Story of Apollo 11 Moon Mission:


Apollo 12 in Pictures: Photos from NASA’s Pinpoint Moon Landing Mission:


Also in the 1980’s from the Air Force Institute of Technology (AFIT) and elsewhere: (1) Maybeck, Peter S., and Rogers, Steven K., “Adaptive Tracking of Multiple Hot-Spot Target IR Images,” IEEE Trans. on Automatic Control, Vol. 28, No. 10, pp. 937-943, May 1983; (2) Maybeck, Peter S., and Hentz, Karl P., “Investigations of Moving-Bank Multiple Model Adaptive Algorithms,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 10, No. 1, pp. 90-96, Jan. -Feb. 1987; (3) Tobin, David M., and Maybeck, Peter S., “Enhancements to a Multiple Model Adaptive Estimator/Adpative Image-Tracker,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 24, No. 4, pp. 417-426, July 1988. A hot time in the old town tonight!  Maybeck, P. S., Stochastic Models, Estimation and Control, Vol. 1, Academic Press, NY, 1979 (and Vols. 2 and 3 published in the 1980’s.)

Also see: Special Issue of IEEE Transactions of Automatic Control, Vol. 28, No. 3, 1983 devoted to nonstandard applications of Kalman Filters. For more standard applications of Kalman filters, please see 1982 NATO AGARDograph No. 256 and Feb. 1970, No. 139 (Noordhoff International Publishing, Lieden).

A good book by: Bruce P. Gibbs (and contributed to by many of Thomas H. Kerr III's  prior TASC cohorts from the 1970’s and by other illustrious contemporaries): Advanced Kalman Filtering, Least-Squares and Modeling: A Practical Handbook, John Wiley & Sons, 23 February 2011:  http://onlinelibrary.wiley.com/doi/10.1002/9780470890042.fmatter/pdf  [They joke in the introduction that they could show pictures of famous mathematicians of yesteryear too (My words: instead of pertinent content such as: What?, How?, and Why?) but they refrain from doing so in their book. However, they do so on the cover.]

Click here to obtain a detailed 128Kilobyte resume for Thomas H. Kerr III emphasizing only his Navigation experience.

Click here to download a 214KByte pdf file which conveys our view on the problems with Covariance Intersection

Click here to obtain a detailed 266Kilobyte resume for Thomas H. Kerr III emphasizing only Target Tracking for strategic Updated Early Warning Radar (UEWR).

Also see or click on: https://archive.org/details/DTIC_ADP011192/page/n7/mode/2up to view: Satz, H. S., Kerr, T. H., “Comparison of Batch and Kalman Filtering for Radar Tracking,” Proceedings of 10th Annual AIAA/BMDO Conference, Williamsburg, VA, 25 July 2001.

Click here to view our abstract for GNC Challenges for Miniature Autonomous Systems Workshop, 26-28 October 2009 to occur at Fort Walton Beach,.FL.

Click here to download a 1.56MByte pdf file that demonstrates our Navigation familiarity by our pioneering new developments in using Inertial Navigation Systems and GPS in support of airborne platforms performing terrain mapping, which is a slide presentation corresponding to: Kerr, T. H., Use of GPS\INS in the Design of Airborne Multisensor Data Collection Missions (for Tuning NN-based ATR algorithms),Institute of Navigation Proceedings of GPS-94, pp. 1173-1188, 20-23 Sept. 1994.  Click here to download a 4.40MByte pdf file that conveys the entire report. (Thomas H. Kerr III became a senior member of AIAA via the required endorsements by running this specific report by Richard Battin [Draper Laboratory and MIT Aero. & Astro.] and by Wally Vander Velde [MIT Aero. & Astro.].)

Click here to see a 160 KByte quantitative analyses of the relative pointing accuracy associated with each of several alternative candidate INS platforms of varying gyro drift-rate quality (and cost) by using high quality GPS external position and velocity fix alternatives: (1) P(Y)-code, (2) differential mode, or (3) kinematic mode at  higher rates to enhance the INS with frequent updates to compensate for gyro drift degradations that otherwise adversely increase in magnitude and severity to the system as time elapses.  Click here to obtain the corresponding 1.40 MByte PowerPoint presentation.

Click here to view our recent short comment submitted to the Institute of Navigation for publication in their Journal and already published.

Please click here for information on jamming vulnerability of STAP.

Key Benefits:

·       On a more positive note, the late Prof. Itzhack Bar-Itzhack proved the observability and controllability of the linear error models that represent navigation systems:

1. Drora Goshen, I.Y. Bar-Itzhack, "Observability Analysis of Piece-Wise Constant Systems-Part 1: Theory," IEEE Transactions on Aerospace and Electronic Systems, Vol.28, No.4, pp. 1056-67, Oct. 1992.

2. Drora Goshen, I. Y. Bar-Itzhack, "Observability analysis of piece-wise constant systems II: Application to inertial navigation in-flight alignment (military applications)," IEEE Transactions on Aerospace and Electronic Systems, Vol. 28, No. 4, pp. 1068-1075, Oct. 1992.

3. Drora Goshen, I. Y. Bar-Itzhack, "On the Connection Between Estimability and Observability," IEEE Transactions on Automatic Control, Vol. 37, No. 8, pp. 1225-1226, Aug. 1992. 
It is shown that when a linear dynamic system is stochastically autonomous (that is, when the system is not excited by a random signal), its estimability property as defined by Y. Baram and T. Kailath (ibid., vol.33, p.1116-21, Dec. 1988) reduces to the classical observability property.

4. Itzhack Y. Bar-Itzhack, Drora Goshen, "Unified approach to inertial navigation system error modeling," AIAA Journal of Guidance, Control, and Dynamics, Vol. 15, No. 3, pp. 648-654, May-June 1992. 
Several inertial navigation system error models have been developed and used in the literature. Most of the models are ad hoc models which were needed to solve certain particular problems and were developed for that purpose only. Consequently, the relationship, correspondence, and equivalence between the various models is not evident. This paper provides...

5. I. Y. Bar-Itzhack, Y. Vitek, "The enigma of false bias detection in a strapdown system during transfer alignment," AIAA Journal of Guidance, Control, and Dynamics, Vol. 8, No. 2, pp. 175-180, March-April 1985.
This work describes a phenomenon discovered during in-flight transfer alignment of a strapdown inertial navigation system. The phenomenon, which has not been reported in the literature before, is that of false longitudinal accelerometer bias estimation by the Kalman filter employed in the transfer alignment. Reference data timing error is suggested...

6. Itzhack Y. Bar-Itzhack, "Modeling of certain strapdown heading-sensitive errors in INS error models," AIAA Journal of Guidance, Control, and Dynamics, Vol. 8, No. 1, p. 142 ff, Jan.-Feb. 1985.
Self-alignment of a gimbaled inertial navigation system (INS) results in a platform tilt which cancels the effect of the level accelerometer biases. The same cancellation takes place in strapdown INS too; however, unlike gimbaled INS, in a strapdown system, this cancellation is perturbed once the INS changes heading. This note shows that the standalone...
so Kalman filtering may be rigorously applied in this application domain. (It had already been successfully applied to navigation for more than 10 years without these analytical niceties having been supplied to shore up the hole in the analysis that everyone recognized was present but just had not bothered to clean up since they were busy actually implementing Navigation solutions using Kalman filtering in a somewhat cavalier fashion without this rigorous analytical stepping stone yet officially being in place.) Others worked on this aspect too: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5375725/ 

7. Bar-Itzhack, I. Y., Mallove, E. F., "Accurate INS Transfer Alignment Using a Monitor Gyro and External Navigation Measurements," IEEE Trans. on Aerospace and Electronics Systems, Vol. 16, No. 1, pp. 53-65, Jan. 1990.

8. Bar-Itzhack, I. Y., "In-Flight Alignment of Inertial Navigation Systems," in Control and Dynamic Systems: Advances in Theory and Applications, C. T. Leondes (Ed.), Vol. 38, Advances in Aeronautical Systems, Academic Press, pp. 369-396, 1990.

(It is, perhaps, worth noting that both Prof. Itzhack Bar-Itzhack and John "Jack" Bortz, Ph.D. were two of Thomas H. Kerr III's coworkers at TASC in the early to late 1970's.)

For Additional Perspective: (The Late) Prof. Itzhack Y. Bar-Itzhack (Technion) hosted (the late) Richard "Dick" Battin (of Draper Laboratory and MIT Aero. & Astro. Dept.) when Dick Battin visited Israel. (Prof. Bar-Itzhack died within a year after his beloved wide died.)

Also see:

-William S. Widnall, Stability of Alternate Designs for Rate-Aiding of Non-Coherent Mode of a GPS Receiver, Intermetrics Report No. IR-302, 25 Sept. 1978.
-Boris Danik, "A Low-Cost Velocity Reference System for Rapid Alignment of Aircraft Inertial Platforms on a Moving Base," Proceedings of the IEEE 1980 National Aerospace and Electronics Conference (NAECON), pp. 608-615, 1980.
-Gelb, A., Course Notes Marine Inertial Navigation, The Analytic Sciences Corporation (TASC), TASC TR-119-1, Reading, MA, January 1967. (Handles Monitor Gyro in alignment procedure for SINS/ESGM)

-John E. Bortz, Micron Analysis, Vol. 1. MESGA Attitude Readout Error, The Analytic Sciences Corporation (TASC), Technical Report AFAL-TR-72-228, Air Force Avionics Laboratory, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio 45433, August 1972.

"Coning and Sculling" are issues usually associated or encountered with use of "strap-down" INS mechanizations (https://resources.inertiallabs.com/en-us/knowledge-base/coning-and-sculling-integration-methods, http://files.microstrain.com/TN-I0019_3DM-GX3-25__Coning_And_Sculling.pdf, https://www.researchgate.net/publication/260629899_Approach_to_direct_coningsculling_error_compensation_based_on_the_sinusoidal_modelling_of_IMU_signal, and https://arc.aiaa.org/doi/10.2514/6.2020-0599), where the accelerometers and gyros of the " strap-down INS" are bolted directly to the "platform frame". Modern insights into how to handle strap-down INS mechanizations with finesse, insight, and with less hassle are discussed in Farrell, J. L., “Strapdown at the Crossroads,” Navigation, Journal of the ION, Vol. 51, No. 4, pp. 249-257, Winter 2004 [Correction in Vol. 52, No. 1, page iii, Spring 2005] (also see Kerr, T. H., Novel Variations on Old Architectures/Mechanizations for New Miniature Autonomous Systems,” Web-Based Proceedings of GNC Challenges of Miniature Autonomous Systems Workshop, Session E1: Controlling Miniature Autonomous Systems, sponsored by Institute of Navigation (ION), Fort Walton Beach, FL, 26-28 October 2009. Web-Based Proceedings of GNC Challenges of Miniature Autonomous Systems Workshop, Session E1: Controlling Miniature Autonomous Systems, sponsored by Institute of Navigation (ION), Fort Walton Beach, FL, 26-28 October 2009). 

-"In this post, we review the integration of "deep learning" in classical Inertial Navigation System (INS) with Inertial Measurement Units (IMU’s) only to solve part of the problem mentioned above. First, we present some cutting edge architectures for improved 
speed estimation, noise reduction, zero-velocity detection, and attitude & position prediction. Secondly, the KITTI and OxIOD dataset are discussed. Lastly, schemes of pedestrian inertial navigation with deep learning are presented":

We are knowledgeable about various historical approaches, their assumptions, their derivation, and their evolution [such as the INS analysis conventions of Peter Grundy and William Widnall (Intermetrics, Inc.) vs. that of the late Kenneth Brittings (Northrop) and the missing minus sign in that of (the late) Prof. Itzhack Bar-Itzhacks (Technion Univ.)  vs. Don Bensons (Delco AC Electronics, TASC, Dynamics Research Corporation (DRC), and now at MITRE): Benson, D. O., `The Psi-Angle Error Equation in Strapdown Inertial Navigation Systems’, IEEE Trans. on Aerospace and Electronic Systems, Vol. 15, No. 1, pp. 168-170, Jan. 1979., where Donald Benson was correct all along; or on issues of intentionally and actively maintaining the small angle approximation for INS analysis to ensure (or enforce) the validity of the associated analysis that relies on this assumption being correct]. A sad commentary is that in one of Prof. Bar-Itzacks later publications, he notices that the underlying navigation coordinate systems appear to move in a direction opposite from what he previously expects but he still fails to recognize this quirk as merely a consequence of his prior failure to recognize and adhere to the sign convention that Don Benson tried unsuccessfully to alert him to 20 years earlier as being in error. It was rather sad and disappointing that no one from a recognized navigation analysis house (like C. S. Draper Laboratory [James Potter?], Rockwell International-Autonetics [James Lowery III?, J. S. Stambaugh?], Rockwell Collins, Singer-Kerfott [Dr. Bernard Friedland?], Honeywell, Northrop Grumman, Sperry Systems Management at Sperry Univac - Unisys [e.g., Dr. Hy Strell or the late Norman Zabb or the many other navigation analysts there], Magnavox, Motorola, TASC, General Dynamics, Teledyne Brown, JHU/APL, JPL, Air Force Institute of Technology (AFIT) [Peter S. Maybeck?], MIT Aeronautics & Astronautics [Prof. Wally VanderVelde or Prof. Richard Battin], Stanford Univ. [Prof. Arthur Bryson or Prof. Charles Hutchinson, who received his Ph.D. from Stanford Univ. and was a TASC navigation consultant at that time], Stanford Telecommunications, or anyone else from Dynamics Research Corporation [DRC] like Al Dushman? Al Kleinman? Herb Sanberg?) entered into the fray to back up Don Bensons view. At the ION 57th Annual Meeting & CIGTF 20th Biennial Guidance Test Symposium, 11-13 June  2001, Albuquerque, NM, Tom found out that Don faults Tom for not doing so back then since Tom described how he recognized the problem but did not say anything at the time (but Tom has always had to pick his battles carefully and wait his turn since Tom is frequently critical and does not want to be labeled as just another Nay Sayer) and, moreover, Tom was not yet a recognized authority in this particular area of specifying navigation error models from first principles even though Tom had seen it done and understood it, including its underlying principles and assumptions. Besides, at the time, Tom worked for TASC, which was a direct competitor of DRC (where Don Benson then worked), so it would have been extremely politically incorrect for Tom to have entered the fray back then and endorse our competition (especially since Itzhack Bar-Ithzach was working at TASC at the time). As the Happy Warrior, Tom certainly has not shied away from controversial technical battles. However, he can disagree without being disagreeable (most times, unless he has to return fire in like kind).
We are somewhat familiar with the historical HAD/HAP procedure, developed by the late William Zimmerman in the 1960s while he was at Dynamics Research Corporation (DRC), for computationally calibrating biases within the SSBN submarine Ships Inertial Navigation System (SINS), in those days consisting of only single-degree-of-freedom conventional gyros (but with two SINS present with one as a warm standby system with the other one being in the path of primary navigation reliance) with mechanical spinning rotator gyros. We also know about the Carousel navigation system INS that is constantly rotated to average out the adverse effect of the biases that are present (where William Zimmerman and Robert Ship [along with several others] hold a patent on this important concept). 
We have gone through the rigorous supporting mathematics, yet we summarize the results in a clear straightforward manner, expressed as simply as possible.
We are familiar with the application constraints associated with utilizing these algorithms and are aware of what application constraints are usually actively in force.

TeK Associates Capabilities:

Knowledge of operational principles and behavior of INS gyros and accelerometers and likewise for GPS: Familiar with their underlying state variable error models and INS calibration procedures and typical failure modes and interactions. 

A clear simple overview (that appeared on the Internet on 1 January 2019) that offers an understanding of INS concerns is available here by clicking on it.  

The future of GPS and  GNSS that appeared on the Internet is provided here by clicking on it. 



--The first satellite in the new GPS III constellation blasted off in late December 2018 on a SpaceX Falcon 9 rocket at Cape Canaveral – Harris technology is on board, as it has been on every launch for the last 40 years. 

--Lockheed Martin provides the satellite, and Harris navigation technology generates the GPS signal that billions of people depend on everyday. Harris technology has been on more than 70 GPS satellite payloads, including the 31 GPS satellites moving through space today. Harris says that they are looking forward to a continued partnership on future GPS III satellite launches. 

--Harris congratulates the United States Air Force, Lockheed Martin, and SpaceX on the successful GPS III launch. “Special thanks go to the dedicated Harris employees at their Clifton, NJ facility who develop this amazing technology. Learn more about Harris’ role in the GPS mission here:



Map of GPS Control Segment: https://www.gps.gov/multimedia/images/GPS-control-segment-map.pdf                                                     

Satellites being reported in view, as seen from the GPS Project Office, at a fixed location within CONUS (as the earth rotates and as the satellites move in their respective 6 orbital planes).

Realistically, the GPS receiver can move and the platform upon which it is based can move also (like a person with a GPS-equipped cell phone on a ferry boat sailing from Manhattan, NY to Staten Island). 

GPS interference:


Space Command Calls Out Russia for Anti-Satellite Test:

Air Force’s Joint Forces Space Component Command Missions to Move to U.S. Space Command.

GPS interference Solutions:


Sophisticated Spoofing of GPS: 








New GPS ‘circle spoofing’ moves ship locations thousands of miles:




GPS jamming on agenda as Russian defence delegation sat down for talks in Oslo:


Size of GPS Jammer markets: https://www.transparencymarketresearch.com/signal-jammer-market.html 


Power of THOR ready to down enemy drones - GPS World:
The Air Force Research Laboratory (AFRL) developed a counter-swarm high-power weapon to deter enemy drones — THOR

Learn more about the weapon, which provides non-kinetic defeat of multiple targets. (Photo: AFRL) #AFRL weapon  #drone 


Please click on the link to see: 7 Deadly Sins of Innovation in the Age of AI

3 Things You Need to Know About Artificial Intelligence:

Public-private partnership to launch eLORAN technology to back-up and accompany GPS - Intelligent Aerospace:


International Civil Aviation Org Issues Advisory on GNSS Disruption (Finally!)
In September, 2019, it was reported how airline and pilot groups had raised the issue of GNSS disruption to the UN's International Civil Aviation Organization (ICAO).

The body decided it was an urgent issue (since airplanes have almost crashed because of GNSS disruption, after all) and they decided to act promptly.

The result was a letter to member states published today:
A few thoughts before you get too discouraged about why it took so long for ICAO to act:

ICAO is an international body and they can't do anything quickly. The only real power ICAO has is to bring nations together to talk and provide them information. It can't do much more than merely inform. For things to happen, nations have to start changing the way they do business.
Most all the member states had all the information already. This is just nudging them to act in ways they already know that they should. The list of things ICAO recommends nations do is a pretty good one. If any nations pay attention and do some or all they will be better off than before.
When we do have a major air crash because of GNSS disruption this will be a list of good practices for people to look at and adopt to help prevent it happening again.

Editorial Advisory Board PNT Q&A: Opportunities with GNSS correction services - GPS World:

New players are offering GNSS correction services — pushing prices down and offering new business models. What opportunities does this open up?


GPS Disruptions Varied, Widespread - Reports to the US Government:

RNTF Report:

Very few people know how to report problems with GPS reception. And few of those take the trouble to do it. So the listing that the US government maintains of GPS disruption reports really represents the tip of the iceberg. Likely only the most sophisticated and diligent users, often with the most persnickety problems, appear on the website.

We like to check in on the listing periodically and see what kinds of things have shown up. The reports so far in 2020 have been a varied collection.

There are always a number of problems that the government says are due to "user equipment." Interestingly, problems due to week rollover are still being reported, along with the usual number of receivers that needed updating or had another sort of problem.

In February and July of this year there were problems with the GPS ground control system that caused the information broadcast to contain minor errors. These was detected and reported by some sophisticated users and acknowledged by the Air Force's GPS Operations Center. The web page, which goes back as far as 2017, shows similar events in February and November of 2018, and in May of 2017.

The most interesting by far, though, are the ones the government categorizes as "unknown interference" or "insufficient information." Reading the information that is posted, it is not hard to imagine either a sloppy technician allowing their equipment to emit interference, or some sort of malicious actor with a jammer.

The site includes a number of reports from the Mediterranean and Middle East, which are never any surprise. US military commanders have called the area the most contested electronic warfare environment in the world.

A significant number of reports suggest persistent interference due to a device fixed in one place.

A persistent problem in Edmonton, Canada, that has been going on for quite some time.

In Lancaster, CA a ... permanent disruption of GPS reception noticed over 6 months, driving daily in early evening and late evening, and is detected by 2 separate models of Garmin automotive GPS units. There is no overhead signage that could cause a drop out. The drop out and loss of reception covers a span of approximately 200-300 yards centered on the Ave J overpass.

Boulder, CO reported ...Noticed irregular signal multiple times near the same block during weekdays.

From New Hampshire ...I have had a number of intermittent GPS issues within 1 mile of this location over the past year. GPS drops almost exactly 10 mph and the location plots diverge for approximately 1km parallel to the actual track. I took a picture of the GPS track showing the deviation. Contact me (Dana) if you would like a copy of the track picture. I had previous similar incidents in the same vicinity.

In Puerto Rico ...My GPS position is changing. Beginning on 1-14-2020 almost every day, why is that? I measure from the same point at my home.
There are also quite a few that could well be due to a mobile source, possibly someone with a "personal jammer":

Driving in San Francisco and across the Golden Gate bridge with ...a 1,000 foot offset to the west.
A US Coast Guard vessel in Atlantic Beach, FL reported ...losing both of the ship's GPS receivers during their mooring evolution. Unit verified with another USCG vessel, at the pier, who was experiencing the same issue. Unit restarted both GPS displays with no resolve. After waiting approximately 20 minutes GPS signal regained and seems to be working properly.

In Warrenville, IL I used GPS for a trip immediately prior to this anomaly, without issue. When I attempted to enter my next trip leg, I noted an anomaly. My GPS apps could not locate my vehicle correctly and could not plot a course to my destination. The map display spun around multiple times, and at times placed my vehicle at the end of nearby dead end roads and even in the middle of a nearby field. I restarted the apps, to no avail. I restarted my phone and the bizarre behavior continued. About fifteen minutes after first noting the problem, I restarted my phone again and my GPS apps began working correctly. I do not know if it was a device issue or a GPS system issue. As of this date, I have used GPS twice on this device, without issue.

A user in Medford, OR lost their whole network for a while. We use GPS timing servers across our network within the CONUS. Across our network at approximately the same time, the timing servers went into holdover. As this issue was seen in multiple places, we do not think there were any issues with the hardware or software. We are trying to understand if something impacted the GPS satellite systems ability to provide timing on March 16th, 2020. (there wasn't)

Near Dulles Airport in VA I was on Rt. 50 heading East near Avion Pkwy close to Dulles Airport. The GPS navigation in my vehicle stopped working. When I looked for more information in the GPS it displayed no bars for a GPS satellite signal. This outage continued until the end of my trip in Reston, VA. I made two attempts to turn off my vehicle and restart the navigation during the trip, but this did not work to restart my GPS navigation. It was when I stopped the vehicle, stopped the engine, and got out of my car for 10-15 minutes that the GPS system resumed activity. 

Rehoboth, MA - Position shown on maps was off by approximately 0.5 mile to the west. Also had same occurrence last night while in the same general area. When I noticed the issue on my Nav radio, I checked location on my iPhone and it was consistent with the radio in showing the wrong location.

Gibsonton, FL - I was driving following my GPS when all of sudden it lost GPS signal on the highway. I checked my vehicles GPS also and it could not lock onto me. It finally returned after about 20 mins but something must have knocked it out.
Quite the collection of reports!

If you would like to check them out yourself, feel free to visit the US Coast Guard Navigation Center website at:

Applanix introduces OEM solution for direct geo-referencing of airborne sensor data - GPS World

Applanix Corporation, a Trimble Inc. company, introduced the Trimble AP+ Air OEM solution for direct georeferencing of airborne sensor data. Learn more about the solution, which enables users to produce maps and 3D models without using ground control points.


Teardown: Mini GPS Jammer:

Read, meditate and do not imitate.
It is scaring to realize how easy is to jam GNSS signals.
This is the reason why we need a resilient, worldwide, integrated PNT infrastructure.


GPS World 30th Anniversary Timeline - GPS World:

GPS World’s 30th anniversary GNSS timeline provides highlights in both system and policy development and industry over the past three decades. Check it out now.

Downloads available for free for these wonderful historical posters.

Yup, we added the question mark to the headline. The Army's Mounted Alternative PNT System (MAPS) is certainly helping soldiers in challenging GPS environments, but it doesn't come close to what most would call an "alternative."


In the words of the Army program manager, MAPS 1 is helping with jamming and MAPS 2 is helping with spoofing. Lots of interesting capability in the package, including the eventual ability to use M-Code. There are IMUs involved and some other tech as you will see in the article, but not really what most folks would call an "alternative."

We also take issue with the quote "... will ensue soldiers know where they are even if GPS isn't working." We are going to bet that most soldiers would have a fair idea where they are regardless. This sounds like a power point sound bite in a budget brief (don't get us wrong - these kinds of programs should be much better funded).

The most interesting thing, with MAPS, in our opinion, is the C4ISR/EW Modular Open Suite of Standards, or CMOSS. This seems to be one realization of the DOD PNT Strategy's "Modular Open Architecture System" CMOS (everyone has to have their own name and acronym). The high level concept (which we have long espoused) is:

The best way to ensure you have PNT is to use a lot of diverse sources
This means you need to have a robust architecture
There are lots of diverse sources around right now and more could be brought on line with existing mature technology
When new sources become available, sophisticated users ought to be able to access them fairly easily
So a part of the critical path is figuring out a way for users to be able to access as many diverse sources (existing and future) as they can. Hence the modular, open architecture approach. This is not a trivial problem (authentication, fusion of diverse senors, prioritizing and 'voting,' to name a few) but it is an essential one..

Note - we also link to a second, related C4ISRNet article below.




Jens Hoxmark:
Solution provider for Mission Critical PNT, IoT and 5G Telecom Ctrl Cmd and Trusted Precise Wireless Timing, TPWiT.
Dana, yes, I read "army" and thought of people in close contact with Terra Firma. Doing 500kts makes it lot more challenging to shop at the local bakery, for sure.

But I came to think of the presentation by Dr. Aaron Canciani at the US Space Based Advisory Board meeting back in December 2018, where he presented the very interesting concept of "Magnetic Navigation" 


This has also been published in Inside GNSS 15th June 2020 https://insidegnss.com/183615-2/ 

It's a very promising concept in combination with inertial and compact atomic clocks to be an alternative for a system that can be applied for military application by looking at the presented results, either in relative or absolute mode.

Jens Hoxmark:
Solution provider for Mission Critical PNT, IoT and 5G Telecom Ctrl Cmd and Trusted Precise Wireless Timing, TPWiT.
The detection of natural variation of the magnetic field is also applied for seismic interpretation. Please check the information on the homepage of "Electromagnetic Geoservices" EMGS.


"The MT signal is measured using the same seafloor receivers as used for a conventional controlled source electromagnetic (CSEM) survey.

However, the MT (MagneTotelluric) signal strength depends on solar activity interacting with Earth’s magnetosphere. To ensure good data quality, the receivers are kept on the seafloor for several days, continuously measuring the natural variation of the electromagnetic fields.

Resistivity models from MT inversion images deep structures such as basement and delineates complex salt and volcanic structures."

So they actually make constructive use of the Solar Magnetospheric alterations, in close cooperation with various observatories like the one in Tromsoe that is continuously measuring the magnetic flux /field http://flux.phys.uit.no/Last24/Last24_tro2a.gif 

So there is definitely a magnetic "landscape" out there, that can be applied for navigation, even at 500 knots with present technology in pattern-recognition and fuzzy logic.

Tom Kerr:
In the 1970's and perhaps even before, (under Project: LINEAR CHAIR) the U.S. Navy was investigating just that above topic for external position fixes to compensate for deleterious gyro drift over time for U.S. submarines to avoid any "observables" exposure (of antennas or sonar bathymetric map-matching to any potential enemy surveillance). Such an endeavor was progressing back then and needed to utilize onboard Fluxgate magnetometers, which have recently greatly improved and reduced in size, as I learned at a recent 2018 series of IEEE Boston lectures on Optics-related topics. In the mid 1970's, there was a Kalman filter design planned for magnetic position fix "navaid" update to a submarine-borne INS that was called a "Schmidt Filter". (Not corresponding to Stanley Schmidt nor to George Schmidt at Draper Laboratory at that time, who were involved with novel use of Kalman filters of their own for navigation applications; but to another person named Schmidt.) For this approach to be useful, it was necessary for an accurate Earth's magnetic map to be available. People had speculated on trying to marry magnetic navigation with Gravity-based maps of the Earth since there are unique features of each that may be complementary. Specialized surface ship fleets would be needed to compile such maps of magnetic and gravity fields experienced at various depths.

GPS military code receives operational acceptance for early use - GPS World:

The Space and Missile Systems Center’s Production Corps achieved a major GPS milestone with the approval for Operational Acceptance of GPS Military-Code (M-Code) Early Use. Read more on the approval. 


Y. Jade Morton received the Johannes Kepler Award from the Institute of Navigation (ION). 

Read about the advances she's made in receiver technology, automated data collection, robust carrier phase tracking and remote sensing.:



GPS World celebrates 30 Years of leadership (7 Oct. 2020):


What would the world do without GPS?


GPS Program Updates and its role in the SMC Space Enterprise Architecture: as of 8 October 2020

GPS tracking devices industry to grow 12.2% CAGR by 2026:

According to a report by InForGrowth, the global GPS tracking devices market was valued at $1,567 million in 2018 and is expected to grow at a CAGR of 12.2% during the forecast period 2026. Find out what factors are driving that growth.


Planes continue to fly into a GPS dark hole over the Mediterranean, puzzling experts:



8 Examples of Artificial Intelligence in our Everyday Lives:



UK Getting National GNSS Disruption Monitoring System - GPS World:


GPS IIR/IIR-M satellite antenna patterns released for worldwide - GPS World:

Partnering with the U.S. Coast Guard Navigation Center (NAVCEN), U.S. Space Force and Lockheed Martin Space have released the GPS IIR/IIR-M satellite antenna patterns for worldwide public use. Learn more about the resources. (Diagram: NAVCEN/Lockheed Martin) #GPS #satellite #antenna


Justyna Redelkiewicz on how GSA is using Galileo to enable innovation:

This week, our colleague Justyna Redelkiewicz (Head of Section Consumer Solutions at the GSA) sat down with Ronan Leonard from the Irish Tech News Podcast to talk about #Galileo, #IoT, and #EUSpace��️ enabling innovation and entrepreneurship.
You can listen to the podcast here: https://lnkd.in/dBGy75p 



L5-only receiver designed for mobile phones:

GNSS receivers first reached the commercial domain in the early 1980s. Here's how receiver technology has advanced since then.


Safran Optics 1 Mission:

Delighted to be a part of the Safran Optics 1 team! See how our electro-optic and navigation systems solutions are making a difference in surveillance and reconnaissance missions for dismounted soldier, airborne, naval, and land vehicle operations.

https://lnkd.in/dqTaxTt                          https://lnkd.in/deebVXG 

GPS Dual Use:



ESA seeks proposals to demo 5G positioning, timing - GPS World:


High-Precision GNSS for Precision Agriculture & Farming:
With over 12 years of lean manufacturing experience, Hexagon | NovAtel provides excellent customer and technical support for #agriculture #OEM integrators.

See the broadest range of the highest precision #GNSS positioning products >> https://hxgn.biz/3fVtLgW 


Coral reef conservation technology wins Copernicus Masters 2020 competition:

Reef Support, an automatic warning system that uses artificial intelligence and satellite imagery to detect coral bleaching, algal blooms, sediment plumes and debris caused by humans, won the Copernicus Masters 2020 competition. Learn more about the system and how it works. :


ArcGIS web app incorporates datasets, NGS data layers for surveyors - GPS World:

Get an overview of an ArcGIS web application that incorporates various California-specific datasets and National Geodetic Survey (NGS) data layers to assist surveyors planning vertical control surveys.


We're launching the world's latest Earth-observing satellite to monitor sea levels & provide data for weather forecasting and climate models:

5 things to know about Sentinel-6/Michael Freilich, a historic U.S.-European partnership: https://lnkd.in/dX4cKEG 

Our Buyers Guide has a dedicated site that we’re continuously updating to ensure that you have the most accurate and complete resource available. With 100+ product categories and new ones added regularly, the GPS World Buyers Guide (gpsworldbuyersguide.com) is the No. 1 resource when making purchasing decisions for your company. For more information on our guide or getting your company listed, please contact Emily Adkins at eadkins@northcoastmedia.net

OneWeb LEO PNT: Progress or Risky Gamble? - Inside GNSS:



Under Attack – Receiver Response to Spoofing: Robustness vs. Resilience - Inside GNSS:




DHS PNT Conformance Framework - Important Step in "Toughening"​ Users:

Dana A. Goward's Blog Editor's Note: The community and government have long struggled to define "resilience" when it comes to GPS/GNSS receivers. While it does not provide the "procurement language" so many have called for, this is a huge step forward for the community. We will likely publish more on this in the coming weeks, but we wanted to ensure it was highlighted for our readers.


DoT Maritime Spoofing, Jamming Workshop Slides Posted:


GRIT - GNSS Resilience and Integrity Technology:

It takes GRIT to protect your position, navigation and timing measurements. Introducing the new #GNSS Resilience and Integrity Technology (GRIT), a commercial suite of firmware enabling trusted situational awareness and mitigation of possible interference and spoofing threats across applications and environments.

With spoofing detection, interference mitigation and time-tagged data snapshots of analog to digital samples to characterize your RF environment, GRIT protects your positioning solution no matter where it takes you.

Learn more >> https://hxgn.biz/32xOFhQ 

Triton Submarines — famous for underwater explorations including that of the Titanic — replaced large, outdated computers onboard with rugged tablets. 

Find out how the tablets have eased tracking and communication:


Solution to GPS Hacking:

To see unclassified commercial document that discusses a solution to GPS Hacking as the first main article, please click this link.

Unmanned survey vessel efficiently maps seabeds - GPS World:

In the busy Shizuoka harbor, Weichao Liu of CHC Navigation used the company’s Apache6 marine drone to take a bathymetric survey of a channel in preparation for dredging at a Shizuoka seaport. Here's how the survey was conducted.


GSA, Public Safety sign BroadGNSS agreement on critical infrastructure:


Europe seeks alternative PNT services, deadline Jan. 13 - GPS World:


GNSS Access is the Mainstay of Modern World - Geospatial World:


South Korea partners with broadcaster on eLoran and 10-cm GPS - GPS World:


Can I Trust These Signals? - Galileo's Proposed Authentication Services:
Dana Goward: "Authentication seems to be the challenge of the age. Can you trust information you find on line? What political "leaders" are saying? Or how about those signals from space?

The folks over at the EU's Galileo program are trying to do something about the signals from their satnav system, at least. They have plans for two authentication services. An open service available to all and a commercial, fee-based service.

Our colleague Logan Scott, of Logan Scott consulting (and one of the smartest guys we know) pointed out this blog post series about these services. Our readers with a technical background will find it interesting.

And here is a presentation about them that was given at the PNT Advisory Board meeting last December.

We note that, while the US government likes to call GPS "the gold standard" for GNSS, no such authentication service is planned. The USAF has been experimenting with Logan Scott's Chimera proposal, but we haven't seen any proposal to operationalize it.

All of these efforts are good, though they will require users to upgrade their recievers to take advantage. Even then, while receivers would be more resistant to jamming and spoofing, they wouldn't be immune.

A system of systems apporach is needed, including terrestrial signals such as those mandated by the National Timing Resilience and Security Act of 2018

Let's get those on line too as quickly as possible, so users only have to upgrade their equipment once."

https://berthub.eu/articles/posts/galileos-authentication-algorithm-part-1/  (blog services)

https://www.gps.gov/governance/advisory/meetings/2019-11/pozzobon.pdf  (pdf presentation about them)



3 Dec 2020 - U.S. DOT, MARAD Convene Panel on GPS Jamming and Spoofing - Maritime Executive:


China Research Paper on Differential eLoran - Sensors Journal:

Research on the eLoran Differential Timing Method:

Abstract: An enhanced long-range navigation (eLoran) system was selected as the backup of Global Navigation Satellite Systems (GNSS), and experts and scholars are committed to improving the accuracy of the eLoran system such that its accuracy is close to the GNSS system. A differential method called eLoran differential timing technology is applied to the eLoran system, which has been used in maritime applications of eLoran. In this study, an application of eLoran differential timing technology in a terrestrial medium is carried out. Based on the eLoran timing service error, the correlation of the timing service error is analyzed in theory quantitatively to obtain the range of the difference station in the ground. The results show that to satisfy the timing accuracy of 100 ns, the action range of eLoran difference station on the land needs to be less than 55 km. Therefore, the eLoran differential method is proposed, and in the difference station, the theoretical calculation is combined with the measurement of the signal delay to obtain the difference information, which is sent to the users to adjust the prediction delay and improve the eLoran timing precision. The experiment was carried out in the Guan Zhong Plain, and the timing error of the user decreased from 394.7287 ns (pre-difference) to 19.5890 ns (post-difference). The proposed method is found to effectively enhance the timing precision of the eLoran system within the scope of action.

Please click this link to see the unclassified pdf on eLoran Differential Timing Method 

U.S. Already 0-1 in Tech War With China - National Defense:
Blog Editor's (Dana A. Goward) Note: A disturbing Op-Ed discussing China's dominance in rare earths and progress on 5G, quickly suggesting that the score might already be 0-2. Or maybe 0-3 if you throw in AI.

However you are scoring, the U.S. is another point down to China in the tech war because of PNT.

And it's not merely that Bei Dou is newer than GPS

China has a Comprehensive PNT Plan announced at Stanford last year. And they are executing it. They have PNT at MEO and are putting it at LEO and GEO. And they are upgrading their Loran system to eLoran and expanding it into the less populated western region of the country. This for the express purpose of ensuring they have PNT independent of space and terrestrial location.


James Keissling, Systems architect and analyst: Commenting on recent late 2020 test intercept of potential enemy ICBM:
If you define a 'test' as having some representation of the underlying problem - then nope. Please consider the physical geometry of a real engagement - its effectively nose-on. As the shown diagram appears to be more a chase, its not clearly representative.
Ralph Savelsberg, Associate Professor at Netherlands Defense Academy:
I agree. One of the challenging aspects of intercepting an ICBM-like target is the larger closing velocity than when intercepting an IRBM. Assuming that the range at which the KV resolves its target doesn't change much, that leaves it with much less time to correct its trajectory and consequently it may run into the limit of its divert. So, if you want to reduce that risk you have to reduce the closing velocity and this is pretty much the geometry you'd pick for that. In the real world, however, it seems highly unlikely that you'd actually have this option. 
Also see:
Video: https://youtu.be/5nsafpZv5SM 

Russian and Chinese space weapons could plunge West into DARK AGES with crashed economy and mass blackouts, experts warn - The Sun:

Dana A. Goward's Blog Editor's Note: The Sun is a British tabloid known for its sensational take on most things. Sensationalism aside, we need to ask ourselves, what in this article is not true or likely true?
Debbie White, author
17 Dec 2020, 12:48
Updated: 17 Dec 2020, 15:05
RUSSIAN and Chinese space weapons could "unleash havoc" in a satellite attack which could cost the UK some £1billion a day, experts have warned.

It is feared an orbital onslaught could shut down hospitals, crash the economy, knock out communications, and cause mass blackouts.

Space tech is becoming a new arms race as nations roll out anti-satellite weapons, ground-based lasers and GPS jammers which experts say all pose a "significant threat" to the West.

Leading boffins painted a bleak picture to The Sun Online of a devastating attack involving these devices which have stepped from the pages of science fiction.

The warning comes as the US and UK yesterday accused Russia of launching another anti-satellite missile - the third of its kind in 2020.

And it follows China staking its claim to the stars by planting a flag on the moon as a spy chief warned: the Communist regime is the "greatest threat" facing the UK.


Galileo 6 Hour Outage 14 December - Update Posted

Dana A. Goward's Blog Editor's Note: We greatly admire the Galileo project, all they have achieved and are still achieving. As a civilian project focused on economic and public benefits, the system has been designed with features not available in older and military systems such as GPS and GLONASS.

Building and operating a GNSS is an incredibly difficult and complex task, involving many difficult and complex sub-tasks. For example, we just had a conversation with Dr. Marc Weiss yesterday about the many subtleties and difficulties of building an atomic clock (not to mention one that needs to go into space), which is just one component of a GNSS. You also need rocket science, Einstein's general AND special theories of relativity, and a whole lot more. 
Very glad to see Galileo up and running again.

GPS and GLONASS have have outages also. Bei Dou's turn will come. Good reminders that no human-created system is perfect. All are subject to a host of vulnerabilities and threats. 
The Galileo system was returned to its nominal state a few hours after the incident which occurred between 00:00 and 06:00 on Monday morning 14 December 2020.

This service incident is still under investigation. It is confirmed to be related to an abnormal behavior of a ground atomic clock in the time determination function of the system.

The time synchronisation and orbit determination algorithms immediately flagged the data as MARGINAL (SISA*=NAPA**) before it affected the quality of the measurements.

However, the incorrect data was still uploaded to the satellites.

User receivers that do not process the health and status flags, or that keep MARGINAL satellites as part of the position solution computation, may have experienced large positioning errors.
* SISA: Signal In Space Accuracy

** NAPA: No Accuracy Prediction Available

*** Estimation provided based on rapid truth products available to date with the corresponding limitations.

Media note: This feature can be republished without charge provided the European GNSS Agency (GSA) is acknowledged as the source at the top or the bottom of the story. You must request permission before you use any of the photographs on the site. If you republish, we would be grateful if you could link back to the GSA website (http://www.gsa.europa.eu).


Jamming - It's not just for GPS anymore!:

It is the professional car thief's jammer toolkit! it jams GPS/GNSS, Wifi/Bluetooth/2.4 GHz, Key fobs, and Lojack. Jamming Wifi disables the CCTV. It can also be used to stop a car from being unlocked or started near the scene of a crime. Even a police car.

(Jan. 2021) Blog Editor's (Dana A. Goward) Note: Admittedly, the below article has nothing to do with GPS, GNSS, or navigation. But it does show a vulnerability of wireless technologies, especially those with weak signals. 

And it adds to the overall national concern about resilience after we say so much far-flung damage to networks after the explosion outside an AT&T office in Nashville.

That's why we advocate in "A Resilient National Timing Architecture" for a PNT resilience triad of GNSS, fiber, and terrestrial low frequency, high power broadcasts. Three technologies that are as different from each other as possible.

BTW - we agree with the comment in the article - "It is not very sophisticated." Unfortunately, just about anybody can do this.


Thomas Kerr III's comment on the above: We are aware that 5G will be using phased array antennas, which can perform adaptive beam-steering and null-steering to thwart certain types of jammers, so they can do more with less power than before!

(Jan. 2021)Top 10 GPS Spoofing Events in History - Threat Technology:


Blog Editor's (Dana A. Goward) Note: It is kind of jarring to realize that this has been going on for so long that we can talk about "the history" of spoofing. One would have hoped that, given the potential dire implications, a serious effort to eliminate the problem would have mostly solved, or at least managed, it by now.

The above article is an interesting review. We are wondering if there were events even more interesting that would have made the top ten, but were never discovered or made public. 

What would you have included in the list? 

How about the Swiss auto show were the cars were spoofed to the UK and years into the future?

Or the time a military drone accidentally (we assume) spoofed a light aircraft over Los Angeles?

How about when a passenger aircraft nearly crashed into a mountain

Full disclosure, the author of the article below is employed by Regulus Cyber, a corporate supporter of the RNT Foundation.


(Jan. 2021) The new year is here and so are we — anytime you need our Buyers Guide, you can find it on its dedicated site, https://lnkd.in/eSK6qBs. And if your company is a manufacturer, service provider or distributor and you are not listed or need to update your listing, please contact Emily Adkins at: eadkins@northcoastmedia.net

Solar Flux at New High, GPS Problems Possible - Space Weather News (29 November 2020):

Last year saw the sun reach solar minimum, the period of the least amount of activity (sunspots, flares, coronal mass ejections), We are now heading toward solar maximum.

"Coronal Mass Ejections (CMEs) are large expulsions of plasma and magnetic field from the Sun’s corona. They can eject billions of tons of coronal material and carry an embedded magnetic field (frozen in flux) that is stronger than the background solar wind interplanetary magnetic field (IMF) strength." (NASA)

Particularly strong CMEs impacting the earth can disable or damage satellites and ionize the atmosphere preventing satellite signals from getting through.

The 1859 Carrington Event was so strong the "northern lights" were seen in the tropics and currents were induced in telegraph lines powerful enough to set some offices on fire. The same thing happened again in 1921 with the "New York Railway Storm," named after one of the offices that caught fire.

Earth narrowly missed being hit by a "solar super storm" in 2012. 

Last week's forecast warned GPS users of potential problems, particularly in areas with auroras and in low latitudes, over the next week or so.

Thanks to Marco Lisi for highlighting this report for us.

GNSS reflectometry measurements improved with COVID-19 pandemic - GPS World:

A study shows the quality of GNSS reflectometry measurements may have improved significantly during the COVID-19 pandemic with the lack of parked cars near the ground station. Learn more about the study, carried out by geodesists from the University of Bonn.


(Jan. 2021) ESA-funded GIDAS helps protect critical systems - GPS World:

In late 2020, the first GNSS Interference Detection and Analysis System monitoring stations were installed at the Czech airport in Brno. Learn more about the system.


Why Do We Need to Be Protecting Drone Operations from GPS Interference?:


FAA approves first fully-automated commercial drone flights - The Hill:

We hasten to point out that this FAA approval for BVLOS (beyond visual line of sight) operations comes with a wealth of restrictions on when and where these can take place. The restrictions will greatly reduce the chance of mishaps. And while the approval does not mention navigation or GPS, it does reference previous waivers that require not starting or ending operations if GPS signals and equipment are not 100%. 

That said, once operations are underway, GPS problems can arise that work against ending the flight and lead to an accident.


Solar Flux Hits New High & Big Flares Possible Now
Space Weather News 11.26.2020





The Biggest Solar Flare In Years Was Just Seen, With More Coming Soon:

Thank God, the solar flare was not oriented directly toward the Earth. However, impacts on radio communications and on GNSS signals are expected.

X-rays and UV radiation from the flare ionized the top of Earth’s atmosphere, producing a shortwave radio blackout over the South Atlantic….

Ham radio operators and mariners may have noticed strange propagation effects at frequencies below 20 MHz, with some transmissions below 10 MHz completely extinguished.


Our Sun Has Entered a New Cycle, And It Could Be One of The Strongest Ever Recorded:


The Sun may be in for a very busy time. According to new predictions, the next maximum in its activity cycles could be the one of the strongest we've seen.

This is in direct contradiction to the official solar weather forecast from NASA and the NOAA, but if it bears out, it could confirm a theory about solar activity cycles that scientists have been working on for years.
Much more below. Has good comments too!


Belgian company Seafar pioneers barge automation technology:

SEAFAR integrated Septentrio’s AsteRx-U dual-antenna, multi-frequency, multi-constellation receivers into its autonomous vessels to provide sub-meter positioning for navigation and control. Get more details on this tech integration.


Route Masters to build integrated public transport platform for African megacities - GPS World:

Route Masters signed up to the national SPRINT - SPace Research and Innovation Network for Technology business support program to develop an innovative transport management solution for African cities. Learn more about the project.


Looking ahead to 2021, we want you to know that we are here for you anytime you need help making purchasing decisions for your company with our dedicated Buyers Guide site (https://lnkd.in/eSK6qBs), where you 

can search for 250+ manufacturers/service providers, 100+ product/service categories, location and by keyword. 

For more information on the above, please contact Emily Adkins at eadkins@northcoastmedia.net.  

FlashbackFriday: 1976: This image features the first military GPS five-channel receiver built in one of several programs that studied the feasibility of GPS. The receiver weighed more than 270 pounds and had seats for two operators!

Today, Raytheon Technologies completed the acquisition of Blue Canyon Technologies, a leading provider of small satellites and spacecraft systems components. 

From sensing subsystems to mission systems integration and from launch and range support to on-orbit operations, Blue Canyon will further our ability to develop space capabilities faster than ever.

Welcome to Raytheon Intelligence & Space, Blue Canyon. We look forward to working with you to deliver disruptive technologies to support our customers’ success in space.


James Taiclet on LinkedIn: Lockheed Martin is acquiring Aerojet Rocketdyne. Learn more about 


Boeing test sees five AI-enabled jets teamed up:

We've just flown five surrogate jets powered by our autonomous technologies at Australia’s newest commercial drone flight test range.

The ground-breaking mission system technology was developed with the support of over 90 personnel from small-to-medium enterprises and the Queensland Government as part of the Advance Queensland project.

The technologies developed from the project will inform future autonomous aircraft. Watch the flight below!


Erika Armstrong, 428,232 Aviation Enthusiasts | A "Chick" in the Cockpit (her words, not mine) | ATP | Author | FRAeS | Keynote Speaker:

We've just flown five surrogate jets powered by our autonomous technologies at Australia’s newest commercial drone flight test range.

The ground-breaking mission system technology was developed with the support of over 90 personnel from small-to-medium enterprises and the Queensland Government as part of the Advance Queensland project.

The technologies developed from the project will inform future autonomous aircraft. Watch the flight below!
#aviation #achickinthecockpit #pilots #pilottraining #pilotlife #E6B

GPS satellite SVN-77/GPS III SV04 set healthy for use - GPS World:

The U.S. Coast Guard Navigation Center has issued a notice that GPS satellite SVN-77 (PRN-14) was set healthy for initial use. Get more details.


Joshua Cohen, Writer on national and international naval and defense issues:

The cheapest way to take out a carrier I know of:
1,900 crew of French aircraft carrier go into quarantine after Covid-19 outbreak!:


Congress hits fast-forward to field new capability to counter drones:
Congress wants to rapidly advance a joint program to develop and field a capability for countering drones, requiring the Pentagon to field a system as early as next fall and adding more than $47 million to fuel the effort, according to the fiscal 2021 National Defense Authorization Act.

“The executive agent of the Joint Counter-Small Unmanned Aircraft Systems (C-sUAS) Office, as designated by the Under Secretary of Defense for Acquisition and Sustainment, shall prioritize the objective of developing and executing a plan to develop, test, and begin production of a counter unmanned aircraft system that can be fielded as early as fiscal year 2021 to meet immediate operational needs in countering Group 1, 2 and 3 unmanned aircraft systems,” read the NDAA language released 3 Dec. 2020.

GPS Jamming & Spoofing, 2020 Year in Review - Spirent's Guy Buesnel:
Blog Editor's (Dana A. Goward) Note: This is a repost of Guy's excellent article on Linkedin. We are reposting on all our social media to help distribute this interesting item as broadly as we can.

We found his three predictions for 2021 particularly interesting.

Our thanks to Guy for his on-going insights and excellet observations in this area.

Guy is a member of RNTF's International Advisory Committee.

Full disclosure - Guy's employer, Spirent, is a corporate supporter of the foundation.

Thousands of GNSS jamming and spoofing incidents reported in 2020.
Published on December 2, 2020.

Guy Buesnel
PNT Security Technologist - with expertise in testing system robustness against GPS Interference and spoofing threats

48 articles

Disruptions to GNSS signals have been rife throughout the year, caused by everything from embattled pig farmers to regional conflicts. Here are some of the most notable events of 2020.

2020 has been a remarkable year in many ways. But while the coronavirus pandemic has upended operations worldwide, some global trends have continued uninterrupted.

One of them is our increasing reliance on satellite positioning, navigation and timing (PNT) services, now an integral part of everything from smartphones to driverless vehicles.

Another is the continued rise in instances of GNSS signal interference that put those services – and those who rely on them – at risk.

Thousands of disruption incidents have been reported throughout 2020, from China to California, and from the Arctic Circle to New Zealand. Here’s my roundup of the most significant events of the year, together with a few predictions for 2021:

December 2019: Intermittent GPS signal loss experienced by aircraft landing at Harbin airport in north-eastern China is traced to a jammer installed at a nearby pig farm.

The South China Morning Post reports that the jammer was meant to deter drones operated by criminal gangs, whose aim was to drop packets infected with swine fever on to the herd – forcing the farmers to sell the infected meat to them at lower prices.

An extraordinary story, and one that illustrates once again how the use of illegal jammers can have unintended – and potentially serious – consequences for civil aviation.

January: Mexico passes an anti-jammer law, having discovered that GPS jammers are used in 85% of cargo vehicle thefts in the country.

The use of ‘personal privacy devices’ (small GPS jammers that plug into a vehicle’s cigarette lighter) to aid cargo theft is so widespread that the Mexican government has made it illegal to manufacture, sell, buy, own, install or use PPDs in the country.

In many countries today, only the use of such jammers is illegal selling, buying and owning is OK. But with criminal use of jammers on the rise, will we see similar laws passed elsewhere?

February: An alarming report made by a light aircraft pilot to NASA’s Aviation Safety Reporting System suggests possible spoofing by a US Department of Defense (DoD) drone.

GPS World reports that the pilot noticed a DoD drone flying above them. At the same time, the aircraft’s Primary Flight Display (PFD) started to show a location in Utah, and then Montana, rather than its actual flight path to San Diego from Los Angeles.

Even more worryingly, the aircraft’s primary navigation system did not recover after the drone encounter, eventually forcing the pilot to make a visual landing in San Diego. If there had been poor visibility that day, this could have been a dangerous incident for the pilot.

While it’s unclear whether this incident was due to incidental jamming or deliberate spoofing, the wake-up call here is the lack of resilience on the part of the navigation system. As radio frequency (RF) interference becomes increasingly common, systems need to be able to recognise when they are being disrupted, and to recover after the disruption has occurred.

February: In France, a manufacturer of high-precision GNSS equipment complains of regular disruptions to GPS and Galileo signals at their factory.

The French Radio Frequency Agency (ANFR) investigates, and eventually tracks down the source of the interference… to a broadband router installed in the nearby apartment of an elderly lady. The defective router turns out to be emitting harmful interference centred on the 1581.15 MHz frequency, very close to GPS L1 and Galileo E1 signals centered on 1575.42 MHz.

It’s a clear illustration of the threat of in-band and adjacent-band interference to GNSS-dependent systems, though I do wonder what the lady in question must have thought when a team of ANFR investigators with a directional antenna turned up at her door!

March: ‘Circle-style’ GPS spoofing is reported in Iran’s capital, Tehran. A GPS user informs the US government that their (unspecified) device seems to be moving in a circle around the Iranian Army training college, when the device is in fact stationary.

GPS World follows up, finding that heatmaps from the Strava fitness app show the same circle pattern around the same building. It’s not the first time circle-style spoofing has been seen, but it’s the first outside of China, where similar patterns were observed in Shanghai in 2019.
The jury is still out as to what kind of spoofing equipment produces these circle effects (not to mention who’s doing it and why), but Spirent has had some limited success in attempting to replicate the effect in the lab, as this blog explains.

June: GPS jamming once again causes problems in the far north of Norway, close to the Russian border.

Local police have been reporting jamming incidents since 2017, affecting everything from ambulances to personal safety alarms. Norwegian authorities have identified Russia as the source of the jamming, but the attacks seem to be both unpredictable and unpreventable.

As Finnmark police chief Ellen Katrine Hætta told the High North News: “There is not much they can do about it. We as a society need to improve our systems." It’s a reminder that as civil reliance on GNSS grows, receivers must be protected against the effects of RF interference.

August: A drone crash in the UK highlights the safety risks posed by jamming and spoofing interference to uncrewed aerial vehicles (UAVs).

The 25lb survey drone lost GPS reception due to RF interference at the survey site. Although programmed to hover in place, it drifted with the wind, eventually crashing into a house and falling to the ground. Fortunately nobody was hurt, but serious injury could have resulted.

As drones are used for more tasks, manufacturers will need to ensure their receivers are robust and resilient, and that action taken by the drone on encountering RF interference doesn’t have unintended consequences.

August: A fleet of Chinese fishing vessels are accused of misreporting their location to mask illegal fishing activity.

The ships were reporting a location off New Zealand via the Automatic Identification System (AIS), an onboard system that reports a ship’s GPS co-ordinates. However, the Ecuador government said the ships were actually near the Galápagos Islands, where illegal fishing has occurred before.

This type of AIS ‘cloaking’ is just one of many ways that criminals use location spoofing of a GPS-dependent system to aid their nefarious activities.

September: The US Maritime Administration (MARAD) renews its advice to the maritime industry to be vigilant for GNSS disruptions worldwide.

It notes there have been multiple instances of interference in the Central and Eastern Mediterranean region, as well as the Persian Gulf and some Chinese ports, and encourages crews to report new instances to the US Coast Guard.

November: Echoing September’s MARAD warning, Fortune reports that GPS outages are now standard occurrences on commercial flight routes between the US, Europe and the Middle East.

Aviation association Eurocontrol says it received 3,500 reports of GPS disruption in 2019, an all-time high. Jamming is widespread across the central and Eastern Mediterranean, likely due to electronic warfare between conflicting factions in Syria, Libya and elsewhere in the region.

These reports are another reminder that RF interference is now commonly encountered in geo-politically sensitive hotspots, creating major disruption for commercial shipping and aviation.

Three predictions for 2021:

The events of 2020 show that satellite-based PNT is becoming ever more central to our lives – and consequently, that countering the many threats to GNSS has never been more critical.

Having closely observed the evolution of GNSS threats over many years, I’d like to make three predictions for the year ahead:

#1 Spoofing will become a greater threat to commercial users

GNSS Spoofing (broadcasting of a fake or delayed GNSS signal) has been a concern in the defence domain for many years, but it’s now starting to impact commercial and civilian users too. As more devices and autonomous systems rely on GNSS, and as spoofing know-how and equipment are now relatively easy to acquire, we’ll see more unprotected systems fall victim to spoofing attacks.

#2 Assured PNT testing will move off the laboratory bench and into the field

From drones to driverless cars, autonomous systems need assured PNT services to operate reliably. Manufacturers will need to assess the real-world performance, reliability and resilience of multi-sensor systems to check they’re functioning adequately for both safety- and liability-critical operations. For that reason, we’ll see performance and integrity testing of platforms expand from the laboratory and into the field.

#3 PNT vulnerabilities will be integrated into cybersecurity frameworks

Historically, GNSS receivers have been developed and tested as standalone systems. But today they’re increasingly one subsystem in a complex device with multiple ports, sensors and connections. To a hacker, the RF interface is just another attack vector, which means that increasingly, we are likely to see that the specific GNSS vulnerabilities in the RF domain are dealt with as part of an integrated cybersecurity framework, rather than treated in isolation.

Stay up to date with GNSS vulnerabilities.

Threats to GPS/GNSS are evolving all the time. To stay up to date with the latest news, events and incidents, join over 1,300 industry professionals in the GNSS Vulnerabilities LinkedIn group.


A pertinent comment by Allan Bradly: https://www.linkedin.com/posts/allan-bradley-59b0093a_trumpadministration-activity-6741050405935046656-Y-wx 

GPS Backup Finally Moving Closer - Aviation News from the Reason Foundation:



Google to improve urban GPS accuracy for apps:

The wrong-side-of-the-street position error in smartphones is caused by reflected GPS signals in cities (due to multipath of a particular GPS satellite signal to the receiver of essentially the same intensity so it isn't easily weeded out and distinguished from the primary signal), and Google employees embarked on an ambitious project to help solve this problem. Hear from Frank van Diggelen, principal engineer, and Jennifer Wang, product manager, Google, on how the team has worked to resolve this issue in Androids.


LDACS-NAV could guide global aviation:

GNSS is a critical single point of failure for navigation in the aviation industry. A new white paper published by Egis says it’s time for the industry to get rid of legacy navigation aids and catch up technologically with the rest of the communications industry.


GPS is Major Threat Vector in US Maritime Cyber Plan:

The National Maritime Cybersecurity Plan issued on the 2nd of December and recently made available joins a list of national strategies and plans addressing security for the 95% of all U.S. trade that depends on maritime. It outlines a number of challenges and threats the nation must address. None are trivial.

Challenges include a too-small workforce, confused federal-level governance, and information/intelligence sharing. Also, a highly varied set of commercial and other governmental stakeholders, many of which might find it difficult to establish a credible cybersecurity program.

Threats are many and varied to both Information Technology (IT), and Operational Technology (OT) systems. A category of threat is described as coming through electromagnetic spectrum system (EMS). Threats via EMS include communications systems and GPS.

At one point the plan describes how, in 2016, the Department of Homeland Security predicted that loss of GPS signals would bring port operations to a halt if a backup system wasn't available. This wasn't a difficult prediction because the U.S. Coast Guard had already seen it happen in 2014.

Elsewhere the plan describes jamming and spoofing navigation as significant problems. Also, how 14 maritime groups petitioned the U.S. Coast Guard Commandant to raise the issue at the International Maritime Organization (IMO). GNSS interference was later described by IMO as an urgent and safety of life issue.

It is good to see another national document including GPS disruption as a cyber issue. This is appropriate as disruptions:

Interfere with IT and OT systems' ability to communicate;
Interfere with end use devices (computers and equipment of all kinds) and Can insert false data into systems;

(Jan. 2021) New Appointee for Key National PNT Post:
President Biden has appointed Professor Robert Hampshire from the University of Michigan as Principal Deputy Assistant Secretary for Research and Technology at the U.S. Department of Transportation (DOT).

DOT is the federal lead for civil positioning, navigation, and timing (PNT) issues. Within the department, the Assistant Secretary for Research and Technology has this responsibility. This makes Professor Hampshire a critical player in national PNT community.

Here is a link to the University of Michigan's announcement about the appointment that includes a link to Prof. Robert Hampshire's bio:


HP names 3 new C-suite members — a chief technical officer, a chief legal officer and a chief strategy and incubation officer - Silicon Valley Business Journal:

Harvey Anderson, Esq. (Tom Kerr's cousin's son!) was mentioned in the above news article as now being the new Chief Legal officer at HP.

(Feb. 2021) Russian Electronic Warfare System Is Capable Of Neutralizing GPS, Galileo and BeiDou Systems - Sputnik International:

Blog Editor's (Dana A. Goward) Note: This article by Sputnik is interesting as it has some nuggets of information that haven't been widely known. For one, it reveals 
their spoofing capability exists simultaneously in hundreds of locations. Earlier analysis of Russian spoofing operations concluded there were only a few sets of 
equipment, and these were regularly relocated to follow VIP movements. We speculate this was the case at the time (2016 - 2019 or so) and more equipment has since been developed and deployed.

The article also says the system is called "Pole-21." This system, or one very like it, has long been used to spoof navigation receivers in Moscow, the Black Sea and 

Electronic warfare has long been a focus for Russian forces. It is seen as a way to neutralize the West's technology and turn it from an advantage into a disadvantage.

As examples, years ago Russia announced installation of GPS jammers on cell towers to disrupt cruise missile attacks on their homeland.

And a standing Russian boast has been that their electronic warfare capabilities (which are VERY impressive) make Western aircraft carriers useless

It is always good to be reminded of Russia's impressive abilities to neutralize our essential space-based PNT services. Also, of the West's critical vulnerability 
relative to others
Russia, China, South Korea, and Saudi Arabia are NOT nearly as vulnerable. They each have sovereign, terrestrial, high power, difficult-to-disrupt,
PNT systems for the express purpose of protecting themselves from interruptions of space-based signals.

Russian Electronic Warfare System IS Capable Of Neutralizing GPS, Galileo and BeiDou Systems
Sputnik International News

1 February 2021

Siberia and the Ural Mountains region will receive Pole-21 radio-electronic warfare systems designed to defend against drones and other weapons. In this way, the 
Pole-21 will become an impediment to satellite navigation systems, drones, allowing to avoid possible attacks by cruise missiles and weapons of high precision.

In addition to interfering with enemy communications, the system is also able to inject false coordinates into these communications in order to disorient the opponent.

According to the Russian Ministry of Defense, Izvestia told the portal, the systems will be installed in the Ural Mountains and Siberia later this year.

Unlike systems of the same type, the Pole-21 has hundreds of radio interference transmitters installed at a considerable distance from each other. Each of the transmitters 
can be controlled remotely, allowing electronic defense to operate over an area of hundreds of square kilometers.

Although the technical characteristics of the equipment are kept secret, it is known that the export version is capable of neutralizing the GPS satellite navigation
systems, of North American origin, European Galileo and Chinese BeiDou.

The area of action of a complex can reach 150 km². A single station on the Pole-21 is sufficient to interfere with communications from a GPS receiver over a distance 
of up to 25 km.
The global GPS positioning system is used, in addition to smartphones, also in military drones, and high-precision weapons.

In addition to being able to interrupt the enemy's satellite communications, the Pole-21 system also allows transmitting wrong coordinates to the opponent's 
technological platforms.
It is known that the Pole-21 entered service in 2016, having already been used in the Eastern Military District of Russia and at the 
country's 201st Base in Tajikistan.

Note: We are not able to provide a hyperlink to the original of this article. The text above was received from a highly trusted source and we are confident in its 
accuracy. It is also entirely consistent with other Russian press releases and announcements.

(Feb. 2021) This image features Gladys West, whose work helped develop the Global Positioning System. Learn more about her career in a March 2018 GPS World article:

(Feb. 2021) Army researchers detect broadest frequencies ever with quantum receiver:
A new quantum sensor can analyze the full spectrum of radio frequency and real-world signals, unleashing new potentials for Soldier communications, spectrum awareness 
and electronic warfare. U.S. Army researchers built the quantum sensor, which can sample the radio-frequency spectrum—from zero frequency up to 20 GHz—and detect AM and FM 
radio, Bluetooth, Wi-Fi and other communication signals:


(Feb. 2021) Sewage Plant Jams GPS Around Airport - AVWeb:
Blog Editor's (Dana A. Goward) Note: This problem impacted aircraft within 25 miles of the Wilmington, NC airport and had been documented since May 2020.

This long standing problem was finally resolved due to the persistence of the airport 's highly dedicated pilots association. They worked with the Airline Pilots Association, the Aircraft Owners and 

Pilots Association, the National Business Aviation Association, their local congressman, the Federal Aviation Administration, and the Federal Communications Commission to find the 

source of the problem

After several attempts over the course of three months, the FCC and the FAA finally located the problem as coming from the local sewage treatment plant. 
Good thing it wasn't a bad guy trying to not get caught.

Wireless Utility Controls Jammed GPS Near Airport:
by Russ Niles

January 31, 2021

Pilots using Wilmington Airport in North Carolina are hoping the mysterious and random interruptions in GPS service near the airport are a thing of the past after an FAA team tracked down 

the likely cause. The agency officials discovered signals coming from a utility company’s wireless control system were jamming GPS within a two-mile radius of the airport. Pilots had 

reported losing the signal in critical phases of flight including instrument approaches. The situation was serious enough that it prompted a 25-NM NOTAM around the airport warning pilots 

that they could lose GPS.

Authorities shut down 85 “emitters” used by the system within two miles of the airport and the outages stopped, according to the ILM Pilots Association newsletter.

(Feb. 2021) ‘It’s a safety issue.’ Questions raised about GPS-based landing systems at US airports following 7 Investigators'​ report - WXYZ:
Blog Editor's (Dana A. Goward) Note: In the1990's after the advent of GPS, the FAA planned to decommission its ground-based navigation aids and have aircraft rely entirely on space-based systems, 

essentially GPS and its augments. In 2001 a Volpe Transportation Systems Center report showed what a horribly bad idea that is. 
It also pointed out that it would be a bad idea for other parts of society to rely just on GPS for navigation and timing.

Aviation authorities in the the US and Europe, though, have never completely moved away from that idea. "Wouldn't it be great if we could get rid of those expensive ground-based systems," they think," 

and just use those incredibly expensive satellite systems, that are paid for by someone else!" So the 
ground-based aviation navigation beacon network continues to shrink and age. We understand the FAA has dozens of new VOR equipment in storage, for example, that they have no funds or plans to 

install (wouldn't you include the install funds with the purchase budget?).

And while some other nations are using new, much more capable and safer Instrument Landing Systems that could increase the safety, flow, and efficiency of major airports dramatically, we understand 

no efforts are underway to install them in the U.S. 


Report on Navy Laser, Railgun and Gun-Launched Guided Projectiles:


(Jan. 2021) Why Do We Need to Be Protecting Drone Operations from GPS Interference?:
Awesome article by Danielle Gagne at CommercialUAVNews (Commercial UAV Expo ) about our [infiniDome LTD (GPSDOME)] work with Easy Aerial Inc. creating a new 

resilient drone standard for #bvlos #borderpatrol #uavs #jamming


(Jan. 2021) FAA Files Reveal a Surprising Threat to Airline Safety: the U.S. Military's GPS Tests - IEEE Spectrum:
Blog Editor's (Dana A. Goward) Note: Perhaps the title of this article should have been "GPS Jamming Set to Crash Passenger Aircraft." 

One thing I learned in Aviation Safety Officer school is that aircraft accidents are not random. If you are paying attention, you can almost always see the indications and warnings well 

in advance. A host of minor problems, then some close calls. 

More close calls (called in aviation "near misses"), and then finally, an aircraft is lost and people die. 

The problem is that human beings often have difficulty acting to prevent bad things from happening. And for those who try to head off accidents, it is usually difficult to persuade others 

that the time, effort, and expense is necessary.

Until after a bunch of people are dead. Then it is often a bit easier. But not always.

We knew natural gas leaks were dangerous. But nothing was done to give it an odor until the New London, Texas school exploded. 295 children had to die before we took action.

We knew passengers in automobiles were dying because they were not restrained in crashes. Tens of thousands had to die before we had seat belts and mandatory use. 

We knew hardened cockpit doors would help prevent aircraft hijackings. 2,977 people had to die on 9/11 in a direct attack on the nation before better doors were installed.

We know GPS signals are vulnerable and need to be integrated with stronger terrestrial signals. How many will have to die before we do that? 


(Jan. 2021) America Has a GPS Problem - New York Times:
Blog Editor's (Dana A. Goward) Note: Great opinion piece by Kate Murphy of the NY Times. Not much new in here for our regular readers, but very good to see this in such a well 

respected and widely read outlet.

Note that she says the RNT Foundation "...advocates for an eLoran backup of GPS." We also advocate for all the other systems the government has said are needed to backup GPS.

The government has most recently said that a combination of fiber, UHF beacons, and Low Frequency (a la eLoran) is needed to make America safe. We are happy to and do advocate for that.

Our strongest advocacy is for the government to take action. So far, all we have seen (1) studies that focus solely on critical infrastructure, and (2) warnings to users to protect themselves.
Kate Murphy, a frequent contributor to The New York Times, is a commercial pilot and author of “You’re Not Listening: What You’re Missing and Why It Matters.”

Jan. 23, 2021, 11:00 a.m. ET
Time was when nobody knew, or even cared, exactly what time it was. The movement of the sun, phases of the moon and changing seasons were sufficient indicators. 

But since the Industrial Revolution, we’ve become increasingly dependent on knowing the time, and with increasing accuracy. 

Not only does the time tell us when to sleep, wake, eat, work and play; it tells automated systems when to execute financial transactions, bounce data between cellular towers and throttle 

power on the electrical grid.

Coordinated Universal Time, or U.T.C., the global reference for timekeeping, is beamed down to us from extremely precise atomic clocks aboard 

Global Positioning System (GPS) satellites. 

The time it takes for GPS signals to reach receivers is also used to calculate location for air, land and sea navigation.

Owned and operated by the U.S. government, GPS is likely the least recognized, and least appreciated, part of our critical infrastructure. Indeed, most of our critical infrastructure would 

cease to function without it.

The problem is that GPS signals are incredibly weak, due to the distance they have to travel from space, making them subject to interference and vulnerable to jamming and what is known 

as spoofing, in which another signal is passed off by hacking as the original. And the satellites themselves could easily be taken out by hurtling space junk or the sun coughing up a fireball. 

As intentional and unintentional GPS disruptions, respectively, are on the rise, experts warn that our over reliance on the technology is courting disaster, but they are divided on what to do 

about it.


(Jan. 2021) Robots emerge from stealth: Locata's PNT orbs provide port guidance - GPS World:
GPS World visited with officials at the Ports of Auckland, New Zealand and the Australian company Locata to reveal a revolutionary port automation system. 

Find out how this system could change the way containers are handled around the globe:


(Jan. 2021) US R&D Plan for Resilient PNT - At the very last minute:

One hour and fourteen minutes before its end, the Trump administration published the "National Research and Development Plan for PNT Resilience."

Does it matter? Many of those who authored it are no longer in a position to do anything about it.
But yes, it still matters for several reasons. First, R&D in any area, is almost always a good thing. Also, the folks who developed the plan provided a very nice 

outline of the many ways we need to improve our understanding of our PNT services. Also why and how they should be improved.
And a lot of the smart folks who contributed to it are still important players in the national PNT space.

Many see the last administration as preferring to continue admiring the problem rather than acting to solve it. "More study" was a relatively constant call 

as a way of deflecting the need for action.

But this is an R&D Plan. On its own, for what it is, it's a pretty great document.

We (i.e., Dana A. Goward) will likely write more about this in the coming weeks.

In the meanwhile, since the electronic archives at the White House are undergoing a transformation from the old administration to the new, you can find a copy 

of the plan on our website at the link below.


(Jan. 2021) DOT report: L-band, UHF, LF and fiber PNT needed to protect US - GPS World:
January 19, 2021 - By Dana Goward

In a long-anticipated report issued last week, the Department of Transportation (DOT) outlined the results of its GPS Backup Technology Demonstration project

As officials had previously projected, it called for a system-of-systems approach using multiple complementary technologies.

The report called for an architecture that included signals from space in the L band, terrestrial broadcasts in the Ultra High Frequency (UHF) and Low Frequency (LF

spectra, and a fiber backbone to synchronize and feed precise time to terrestrial transmitters.

The demonstration project and report were mandated by Congress in legislation passed in late 2017 and funded in early 2018

Delays within the administration resulted in the project beginning in early 2019.

The 437 page DOT report is filled to the brim with detailed information about the project, individual technologies, and demonstration results.

The Executive Summary says that...in addition to the findings from the DHS December 2018 effort (which, as mentioned above, don’t seem 

to be publicly available), 

the DOT demonstration had four key findings:

All TRL-qualified vendors offered showed PNT “performance of value” and one showed value in all scenarios.
Neither eLoran company succeeded in the Static Basement Timing scenario.
R-Mode ranging did not meet the minimum technical readiness level (TRL) of 6.
Deployment effort and coverage (infrastructure per unit area) are significant cost factors.
Addressing the needs of critical infrastructure owners and operators, the report concluded
the needed “…technologies are LF and UHF terrestrial and L-band satellite broadcasts for PNT functions with 

supporting fiber optic time services to transmitters/control segments.”




NOAA Contract for Prototype GPS-Denied Receiver:

Blog Editor's (Dana A. Goward) Note: We were interested to see this navigation sensor fusion effort sponsored by NOAA.

According to Jack Elston at Black Swift, the $400K contract will result in a prototype navigation receiver that will probably fly first on one of the company's drones.

Integrating other sources with GPS as a way of increasing resilience will likely be a burgeoning field.

The US Department of Defense is pursuing the holy grail of this with it's modular open systems approach (MOSA). The idea is to be able to integrate, prioritize, and 
use virtually all legacy and future P, N, and T sources with a simple "plug and play" box or algorithm.

Rather than re-describe Black Swift Technologies' project, we have reproduced their press release below.
18 Jan. 2021, NOAA Awards Black Swift Technologies Contract to Develop GPS-Denied Navigation
Posted at 14:34h in Uncategorized by Michael Irvin 

Enabling Beyond Visual Line-of-Sight (BVLOS) Operations for UAS in GNSS-Denied Environments

Boulder, CO – (January 18, 2021) – With nearly 95,000 miles of domestic coastline, NOAA’s National Geodetic Survey faces a daunting task. Under current FAA  

regulations, unmanned aircraft system (UAS) operators are required to keep their aircraft within visual line of sight, making coastline surveys time-consuming and 

arduous, having to tediously map 2-mile segments at a time, and then relocate to the next operating area. To address this challenge NOAA has selected Black Swift 

Technologies (BST) to develop commercially viable technology enabling GPS-denied navigation of UAS—technology critical in enabling long distance, beyond visual 

line-of-sight (BVLOS) flights.

“Enabling BVLOS operations in the National Airspace System is largely an issue of improved sensing,” states Jack Elston, Ph.D., CEO of Black Swift Technologies
“Operators, both government and commercial, are looking to perform missions over longer distances. These users represent a number of currently under-utilized 

applications for UAS due to capability and regulations—applications such as aerial imaging, environmental observation, precision agriculture, and infrastructure 

monitoring and inspection.”

Accurate aircraft position information is essential for safe UAS operations within the Unmanned Aircraft Systems Traffic Management (UTM) system. Unfortunately, the 

primary system that provides position information, GPS is a single point of failure in the system, subject to jamming and spoofing, along with on-board failure or poor 

signal quality in locations such as urban canyons, at high latitudes or at high altitudes.

BST aims to provide a robust, secondary navigation option through their diverse-source global positioning system (DS-GPS) that will provide accurate position updates 

to UAS in GPS denied areas through augmented sensor suites and advanced machine learning capabilities. This will be performed through the careful weighted fusion 

of advanced machine vision algorithms with the localization of the vehicle using triangulated signals of opportunity—essentially everything emitted within a set of frequencies 

from a non-moving source.

How it Works:

DS-GPS utilizes a standard GPS receiver augmented through the use of additional sensing capabilities to estimate inertial velocity and absolute position. This information 

allows for the vehicle to determine when the GPS signal is degraded either through spoofing or environmental effects. Other sensors, including cameras and a 

software-defined-radio, can then be used to replace the GPS as the primary navigational sensor providing position and velocity estimates from diverse sources.

“Black Swift Technologies has worked with NOAA in particular in the past to supply systems that can be used for both coastline work and atmospheric science,” 

Elston emphasizes. “The work in this SBIR is a natural extension of the machine learning based techniques BST has been developing for unmanned aircraft. One 

of the key technologies of this work is to use machine vision (both optical flow and SLAM) to allow continued safe flight of UAS in the event of loss of GPS. Work 

associated with coastline inspection and mapping would greatly benefit from BVLOS operations since this would significantly reduce the amount of time an operator 

has to spend in the field.”

(Jan. 2021) The drive to autonomy: Companies gear up with sensors, strategies - GPS World:
For the past decade, widespread deployment of autonomous vehicles (AV) has been just over the horizon. Check out some challenges car manufacturers are facing 

with AV development


(Jan. 2021) US Army heads into future tactical unmanned aircraft rodeo next month:

The U.S. Army is heading into a culminating event used to evaluate four different unmanned aircraft systems capable of replacing the service’s current tactical UAS — 

the Textron-made Shadow.The service will hold a “rodeo” at Fort Benning, Georgia, the last week of February through the first week of March where all five of the 

Brigade Combat Teams which spent the last year evaluating Future Tactical UAS systems will be represented, Brig. Gen. Wally Rugen, who is in charge of Army 

aviation modernization, told Defense News in a recent interview.

The Army selected four UAS in 2019 as candidates to replace the Shadow. Each candidate would undergo soldier assessments to help inform requirements for 

a FTUAS capability that would fit into a future vertical lift ecosystem to include new helicopters and other air-launched effects.

The service first selected two teams to provide systems for the soldier-led evaluation in March 2019: Martin's UAV and Textron’s AAI Corporation. Martin UAV 

teamed with Northrop Grumman to provide its V-Bat UAS. Textron offered its Aerosonde HQ.

(Jan. 2021) Norway Diplomacy Plan for GNSS Disruption Not Working:

The report was completed on the 19th of December 2019. With the speed of government, it was reviewed, approved and finally posted for public viewing on the 

18th of December 2020:
Titled "GNSS/GPS Disruptions in Aviation," the report by a Norwegian working group also offers some familiar comments on the essentiality of GNSS/GPS

as well as a number of insights into Norwegian and European thinking and plans for transportation.

It repeatedly discusses the criticality and vulnerability of GNSS services:

It has gradually been recognized that GNSS systems are vulnerable, with a high risk of serious consequences for society in the event of a signal outage...

A serious failure in the PNT services will spread to other parts of society and may cause problems in maintaining services on which the population depends. 

PNT system failures can occur for reasons including disruption of GNSS signals.

The report also documents how, despite this, the west is becoming increasingly dependent on GNSS. For example:

Despite the development in disruptions of GPS signals in aviation, the EU continues to emphasize the use of satellite-based systems in all modernization and 

digitalization in aviation in the years to come. (EC IR 1048/2018)

Norway, especially Norwegian aviation in the far north, is particularly dependent upon GNSS. Despite its findings, the report offers surprisingly little in terms of 

proposed action other than continued monitoring and diplomacy.

In fact, it declares that diplomacy with Russia is the solution.

Russia repeatedly jammed GPS in northern Norway for years, including during NATO's 2018 Trident Juncture exercise. In February 2019 Norwegian officials 

held a diplomatic meeting with the Russian military to protest and discuss the matter. The jamming then stopped. This led the report to say:

Since this meeting and until the finalization of this report on 19 December 2019, no GPS disruptions have been registered in Norwegian airspace over 

Finnmark county. If, contrary to expectation, similar problems should occur in the future, this experience shows that we have both military and diplomatic 

communication channels available that permit such problems to be addressed.

Unfortunately, shortly after the report was completed, GPS in northern Norway was being jammed again.

(Jan. 2021) Allan Klo 19 April 2020:

Powerless against GPS interference:

Once again, jamming of GPS signals has created challenges for civil aviation in eastern Finnmark. The Norwegian authorities have repeatedly addressed 

the problems of the alleged culprits – Russia – without helping.

Despite this jamming, Norway's group of State Secretaries approved the report as it was on the 6th of May 2020.

Political Context
The Norwegian government is in a politically tight spot on this. As a staunch member of the European Space Agency, Norway's leaders have 

devoted tens of millions of dollars to the Galileo GNSS project.

And in 2015, to show loyalty to the Galileo effort, they shut down the nation's Loran system. This despite warnings from internal security experts 

about GNSS vulnerability, increasing jamming and spoofing, and the desirability of maintaining sovereign, exceptionally difficult-to- disrupt PNT.

Norwegian officials also ignored observations that Russia was keeping its Loran system to use alongside satellite systems, and pleas from 

the UK to keep some of the Norwegian stations on line to enable its new precision e-Loran network.

Perhaps the actions of Norway's politicians were to be expected. After all, the United States had shut down its Loran system in 2010 to show 

loyalty to GPS. - Don't you hate it when the U.S. sets a bad example that gets others in trouble?

Yet Norway has some advantages over the U.S. in this regard.

Norway is even more dependent on GPS/GNSS than America. And Norway has a neighbor that regularly reminds them of GNSS vulnerability, and that 

they can take the signals away with the flip of the switch. And, by the way, even if Norway were interested in doing the same thing to Russia, 

it wouldn't have nearly the same effect because of the Russian Loran system.

We hope these things will eventually stir Norwegian leaders from their lethargy and set them on the path to establishing a terrestrial PNT system 

of their own.

Perhaps it will be an eLoran system like the one South Korea is building. South Korea's system will cooperate and work with neighboring Russian Loran 

to provide users greater coverage and resilience. The Korean system will also be able to operate on its own and protect the nation during those times when 

Russia and other neighbors are not in a good mood:


(Jan. 2021) Greece and France ink $3 billion contract for Rafale fighter jets:

The Greek and French defense ministers in Athens today witnessed the signature of the contract to buy 18 Rafale fighter aircraft after Greek parliamentarians 

approved the €2.5 billion ($3.04 billion) deal earlier this month.

Nikos Panagiotopoulos and his French counterpart, Florence Parly, looked on whilst Theodoros Lagios, the director general of armaments and investments at 

the Greek Ministry of Defense, and Eric Trappier, chairman and CEO of Dassault Aviation, the aircraft manufacturer, signed the contract for 12 second-hand aircraft, 

which will be taken out of the French Air Force inventory, and six new ones.

The contract includes the aircraft’s weapons. A second contract was signed for the logistical support of the aircraft.
Speaking after the signing ceremony, Parly remarked how pleased she was that Greece had made a “resolutely European choice” by opting for the French-made 

aircraft, thus becoming Dassault’s first European export customer.

(Jan. 2021) Our team delivered the first F/A-18 Super Hornet from our Service Life Modification line in San Antonio to the US Navy: 

This marks our second SLM line upgrading and extending the life of Super Hornets to ensure readiness for the U.S. Navy.

(Jan. 2021) FAA Files Reveal a Surprising Threat to Airline Safety: the U.S. Military's GPS Tests - IEEE Spectrum:

Blog Editor's (Dana A. Goward) Note: Perhaps the title of this article should have been "GPS Jamming Set to Crash Passenger Aircraft." 

One thing I learned in Aviation Safety Officer school is that aircraft accidents are not random. If you are paying attention, you can almost always see the indications 

and warnings well in advance. A host of minor problems, then some close calls. More close calls (within aviation, called "near misses"), and then finally, an aircraft is lost 

and people die. 

The problem is that human beings often have difficulty acting to prevent bad things from happening. And for those who try to head off accidents, it is usually difficult to persuade others that the time, effort, and expense is necessary.

Until after a bunch of people are dead. Then it is often a bit easier. But not always.

We knew natural gas leaks were dangerous. But nothing was done to give it an odor until the New London, Texas school exploded. 295 children had to die before we 

took action.

We knew passengers in automobiles were dying because they were not restrained in crashes. Tens of thousands had to die before we had seat belts and their

mandatory use. 

We knew hardened cockpit doors would help prevent aircraft hijackings. 2,977 people had to die on 9/11 in a direct attack on the nation before better doors 

were installed.

We know GPS signals are vulnerable and need to be integrated with stronger terrestrial signals. How many will have to die before we do that? 

(Jan. 2021) FAA Files Reveal a Surprising Threat to Airline Safety: the U.S. Military's GPS Tests:

Military tests that jam and spoof GPS signals are an accident waiting to happen
By Mark Harris 

Early one morning last May, a commercial airliner was approaching El Paso International Airport, in West Texas, when a warning popped up in the cockpit: 

“GPS Position Lost.” The pilot contacted the airline’s operations center and received a report that the U.S. Army’s White Sands Missile Range, in South 

Central New Mexico, was disrupting the GPS signal. “We knew then that it was not an aircraft GPS fault,” the pilot wrote later.

The pilot missed an approach on one runway due to high winds, then came around to try again. “We were forced to Runway 04 with a predawn landing with 

no access to [an instrument landing] with vertical guidance,” the pilot wrote. “Runway 04…has a high CFIT threat due to the climbing terrain in the local area.”

CFIT stands for “controlled flight into terrain,” and it is exactly as serious as it sounds.


(Jan. 2021) Rheinmetall and MBDA win contract for Naval Laser Weapons System - Naval News:


(Jan. 2021) After more than five years of hard work by 131 authors from 18 countries, the new book set Position, Navigation, and Timing 

Technologies in the 21st Century (PNT21) is finally ready to meet readers. Here's what you can expect to see in the book.:


(Jan. 2021) Use of autonomous vehicles in mining and farming touted at CES 2021 - GPS World:
At this year’s virtual CES 2021 trade show, Caterpillar Inc. and John Deere showcased autonomous machines that are being used worldwide in farming and mining projects. 

Check out the innovations both companies brought to the table.


University revises PNT backgrounder In response to concerns - GPS World:
January 26, 2021 - By Dana Goward

George Mason University has revised a briefing paper on positioning, navigation and timing (PNT) in response to concerns about its accuracy.

The university’s National Security Institute “NSI Backgrounder — Beyond GPS: The Frontier of Positioning, Navigation, and Timing Services” was first issued on Dec. 2. Some staff 

on Capitol Hill and members of industry soon had concerns about several of its assertions.


Responding to letters from industry in the above active link, National Security Institute (NSI) Executive Director and Professor Jamil Jaffer said he determined that three of the issues raised, while not fatal to 

the document, warranted clarification.

eLoran callout: The first was a statement in the backgrounder that the National Timing Resilience and Security Act (NTRSA) “specifies 13 technical requirements for a GPS backup, 

which essentially define the eLoran system.”

This was a concern to some on the hill as Congress is generally reluctant to specify solutions. Legislators prefer to specify outcomes and then defer to the executive branch on how to 

make them happen.

Members of industry pointed out that government systems like WWVB and the low-frequency portion of DARPA’s STOIC program: 

as well as commercial systems like NextNav and Locata, could meet or be adapted to meet the existing NTRSA requirement.

The revised backgrounder says the NTRSA “specifies 13 mainly technical requirements for a GPS back-up, which align closely with the capabilities of the eLoran system. Other systems 

may meet the Act’s requirements to varying degrees.”

Multiple technologies. The revised backgrounder also corrects a statement that the NTRSA requires the Department of Transportation to establish an eLoran system. It now says 

“a system that complies with the Act, and DOT may pursue multiple technologies in implementing the Act.”

Department officials had previously said they were taking a system-of-systems approach and expected to employ multiple technologies. Subsequently, a DOT report was released that 

documents the need for several diverse systems. It lists transmissions using low frequency: (eLoran, STOIC), ultra high frequency: (NextNav, Locata) and L-band: from space: (GPS, Satelles). 

It also says the terrestrial transmitters should be interconnected by fiber.

Public-private partnership: A third correction was made in the document to reflect how the Congressional Budget Office regarded the possibility of using a public-private partnership 

in previously proposed legislation.

Members of industry also expressed concern that one of the authors of the document serves on the advisory board for Satelles Inc. and that this was not disclosed in the paper. 
https://www.satellesinc.com/national-security-institute-policy-paper-calls-for-pnt-diversity/  The backgrounder appeared on the Satelles website the same day it was published.

The university concluded that such disclosure was not necessary as the paper said the author “provides advisory services to industry, including in the PNT area.” At the author’s request, 

though, his profile on NSI’s webpage will be updated to show his relationship with Satelles..

(Jan. 2021) Memorandum on Space Policy Directive 7 | The White House:
It looks like data and signal authentication is going to be made available for civil GPS users. This is basically what Chimera is all about on NTS-3.

From Memorandum on Space Policy Directive 7 (https://lnkd.in/eza-AGA)

"Secretary of Defense and the Secretary of Homeland Security, jointly develop and validate requirements and a funding strategy to implement data and signal authentication 

of civil GPS and wide area augmentations for homeland security and public safety purposes consistent with the Federal Radionavigation Plan or its successor plan."

(Jan. 2021) What to do when GPS is compromised:


(Jan. 2021) James Litton, GPS and precision ag pioneer, dies:

By Dana Goward

January 26, 2021

James D. Litton, GPS pioneer and founder of NavCom Technology Inc., died over the weekend at his home in California with his family at his side. He was 89 years old.

Litton was an early contributor to the development of GPS user equipment. He also played a pivotal role in the GPS-driven transformation of global agriculture that has greatly benefited humanity.

No alt text provided for this image
Litton was the director of engineering at Magnavox Research Labs when researchers were working on using CDMA for range measurements, a precursor to the GPS system. He also worked on the original proposal for GPS Phase I.

Later, as general manager of Magnavox’s Marine and Survey Systems Division, he helped develop new and advanced commercial navigation and survey receivers for both the Navy’s TRANSIT system and the Air Force’s GPS.

His team developed the first microprocessor-based commercial satellite navigation receivers and the first commercial GPS survey software. This led to Magnavox eventually having more than a 90 percent share of the survey receiver market.

The firm eventually held more than two dozen patents for improvements in GPS technology.

In 1992, Litton left Magnavox to start a consulting business. Two years later, with Ron Hatch, K.T. Woo and Jalal Alisobhani, he founded NavCom Technology Inc. With Litton as CEO, NavCom became a significant player in the GPS marketplace

Among its achievements was development — under contract — of a single-frequency WAAS-capable GPS aircraft navigation receiver.

NavCom also began a relationship with Deere & Company, supporting more efficient and productive agriculture. This relationship was so successful that Deere purchased NavCom in 1999. Litton continued to lead the company and serve as part of 

Deere’s senior management team for eight more years.

In recognition of his many achievements to the field, Jim Litton was presented the Institute of Navigation’s Hays Award in 2006.

Among his many contributions, his impact on global agriculture might well have been his greatest, according to Brad Parkinson, the original chief architect for GPS.

“His work transformed agriculture into a data-driven, technological industry that was incredibly more efficient,” Parkinson said. “The cost savings and increases in productivity have impacted billions around the world.”

With challenges related to the COVID-19 pandemic, Litton’s family are still considering arrangements for a memorial service. Information will be posted on the 

RNT Foundation website when it becomes available.

Jim's family has created a memorial fund at Doctors Without Borders for those wishing to make a donation in honor of his life and many good works. Click Here.


(Jan. 2021) AutoX, an Alibaba Group backed startup announced it had rolled out fully driverless robo-taxis on public roads in Shenzhen.

(Jan. 2021) Passwordless: The Future of Authentication:
Eliminate reliance on passwords. Download the free white paper to discover the five-step path to passwordless authentication.

(Jan. 2021) Loh’s Method: A Different Way to Solve Quadratic Equations:


In the latest episode of Visual Studio Toolbox, #ASPNET PM Sayed Hashimi shows us how to create and optimize .NET Core project templates. 

Learn more: https://msft.it/6045plHlx 

From the skies to the stars:
From propellers to propulsion, #RaytheonTech is engineering the advanced aerospace and defense technology that connects humanity to the skies and the stars. 

Learn how: https://lnkd.in/durmTMU 

(Jan. 2021) What is space debris and why is it a potential problem? Join us on 10th February 2021: “Space Debris Day”, at 1:00PM for a live Zoom 

webinar to learn about the science and politics involved in solving this astroenvironmental issue, and why it is important 

for us to better manage what we leave out in space. https://lnkd.in/gtNgfBF 
Why the risk of space collisions is skyrocketing now
See https://youtu.be/ZKKIAsQ-cww 

The OpFires countdown has begun. We're (i.e., RTX) partnering with DARPA to demonstrate the capability of a hypersonic boost glide missile that blazes through 

air defenses to engage targets at medium ranges. Read more: http://lmt.co/2XyFECe 

DARPA’s Operational Fires (OpFires) program awards a new phase of the intermediate-range hypersonic ground-launch weapons program to @LockheedMartin. 

It involves full-scale missile fabrication, assembly, and flight testing. https://lnkd.in/gPga3-P 

(Jan. 2021) Mitochondrial Changes Key to Health Problems in Space:
Living in space isn't easy. There are notable impacts on the biology of living things in the harsh environment of space. A team of scientists has now identified a possible 

underlying driver of these impacts: the powerhouse of the cell, called mitochondria, experiences changes in activity during spaceflight. Recently published in the journal 

Cell, these results used data collected over decades of experimental research on the International Space Station, including samples from 59 astronauts. Studies such 

as these are critical to understanding the effects of low gravity, radiation, confined spaces, and more as NASA sends astronauts deep into space for extended missions 

to the Moon, Mars, and beyond.

'LEO is an orbital junkyard'​ NASA - The Tragedy of the Commons & Losing Access to Space:

"LEO is an orbital space junk yard. There are millions of pieces of space junk flying in LEO. Most orbital debris comprises human-generated objects, such as pieces of space craft, 

tiny flecks of paint from a spacecraft, parts of rockets, satellites that are no longer working, or explosions of objects in orbit flying around in space at high speeds.

Most “space junk” is moving very fast and can reach speeds of 18,000 miles per hour, almost seven times faster than a bullet. Due to the rate of speed and volume of 

debris in LEO, current and future space-based services, explorations, and operations pose a safety risk to people and property in space and on Earth." - NASA Headquarters Library

Some estimates have over 100,000,000 objects in Low Earth Orbit (LEO) large enough and moving fast enough to damage satellites and other objects. 

Such collisions create more debris, which then creates more opportunities for collisions... You get the idea.

It is called the Kessler Syndrome and was featured in the film "Gravity" with Sandra Bullock and George Clooney. In the film, a Kessler event takes out the 

International Space Station. Spoiler alert, Clooney eventually dies and Bullock barely makes it back to Earth (but her hair stays miraculously intact).

Some percieve a slower but developing Kessler Event happening even now.

Debris was first blamed for damage to a satellite in 1981 (even more so from an F-15 in the late 1980's). Reports have continued since. These have included multiple instances of damage 

to the International Space Station, space shuttles, as well as satellites. We were unable to find an authoritative compilation of these events (Dear Readers, please send if you know of one), 

but it is a sure bet they are getting more, rather than less, frequent.

Space, especially LEO space, is suffering from The Tragedy of the Commons. Much like the world's oceans, cyberspace, and fresh air, many use and degrade it for their own profit, but few (if any) 

take care of and preserve it. Short term greed and a disregard for the common good - perhaps two sides of the same coin - override the long term interests of all.

Here are some short videos on the problem that may be of interest. The most pessimistic envisions humanity trapped on Earth by a LEO layer of debris too thick to even risk flying through.

Eyes on the Sky - University of Texas - A UT space video that does not feature Todd Humphreys, for some reason.

Space Debris - A journey to Earth - by the European Space Agency (ESA). ESA regularly holds conferences on this subject.

The End of Space - by Kurzgesagt a German educational animation studio.

Note: The risk to GPS/GNSS satellites at MEO is much less because there is, probably, much less debris. The only known case of MEO pollution was in 1963 when the U.S. Air Force 

at the behest of MIT Lincoln Laboratory, deployed 480 copper needles for Project West Ford, an attempt to create an artificial ionosphere to bounce radio waves off of for communications 

in case of a terrestrial or atmospheric nuclear event. NASA believes most of the needles have de-orbited by now.

All of this is not to say there aren't efforts to restore and preserve LEO. ESA plans to have a space debris collector launched in 2025. And there are multilateral international agreements 

about the need for future satellites to automatically deorbit at the end of their useful lives. This is essential - tens of thousands of new satellites are planned for LEO in the next couple of years.

Yet Russia and China continue to practice destroying satellites in space. And most of the existing debris, including the millions of lethal bits too small to be tracked, aren't going away anytime soon.

One wonders if efforts to make the problem better will ever be able to get ahead of natural and human effects that steadily make it worse.

Perhaps, one of the things we should do is ensure every service from space is also provided independently from the ground. That way, regardless of a Kessler Event, Carrington-like solar flare, 

or some other mishap to one or more space-based services, we won't be caught unprepared.

It is possible to see the future sometimes. You just have to be brave enough to not avert your eyes.

The above editorial authored by Dana A. Goward (and tampered with here and there by Tom Kerr)


(please see Dana A. Goward's original on Linkedin since many topics have active links supplied there that Dana A. Goward did not convey here)

First Fix: National timing architecture needed now:
December 14, 2020 - By Dana Goward

The Empire State Building sits atop a massive and solid foundation that hardly anyone ever sees. Above ground it has 2.8 million square feet of offices and hundreds of businesses. It houses 15,000 workers. Yet it would all come crashing down if the underlying and unseen foundation weren’t incredibly strong and dependable.

Timing is the unseen foundation of every networked technology, digital broadcast, financial transaction, electrical grid management and of most navigation systems, just to name a few applications. Yet, as GPS World readers know, signals from our dominant source of timing — GPS — are very faint and easily disrupted.

Short term, localized disruptions happen all the time, and many systems have adapted. A delivery driver using a jammer to hide from his boss is unlikely to disrupt a cell base station as he passes by, for example.

But more serious threats are out there. More and more hobbyists are finding ways to spoof receivers. Every few decades the sun flares strongly enough to fry satellites or charge the ionosphere. And because there are so few alternatives, GPS and other GNSS have become huge, tempting targets for adversary nations, terrorists, and sophisticated hackers.

Instead of Manhattan bedrock, our timing foundation is sometimes more like shifting sands.

Systems engineering tells us that, if something is essential, there ought to be two, three or more independent ways of receiving it. Most aircraft, for example, have two or three systems powering the flight controls — because controlled flight is important!

The white paper “A Resilient National Timing Architecture” outlines how the United States can leverage existing infrastructure and provide all citizens two, and many of them three, independent paths to Coordinated Universal Time (UTC).

It proposes a national timing back- bone of mature technologies with very different failure modes — GNSS, eLoran and fiber. This combination will provide rock-solid timing at the 500 ns or better level of accuracy relative to UTC everywhere across the nation, and at 100 ns or better in major metro areas. Users accessing two or more systems would be nearly bulletproof to attempted timing service disruptions.

The National Timing Resilience and Security Act of 2018 mandated a terrestrial system to back up GPS timing. Our white paper provides a path forward.

Complying with the law while benefiting current and future technologies should be sufficient motivation. If it isn’t, we must also realize that not acting on this will continue to place us behind other nations such as the United Kingdom, South Korea, Russia and China — all of whom are actively reinforcing their national timing systems.

The task will not be a simple one. Yet America was able to overcome the expense and difficulties of building GPS, at the time the world’s most refined and complex technology, and put it in space. By comparison, establishing a resilient national timing architecture using existing technology in our homeland would be child’s play.

Timing is essential. It is infrastructure for our infrastructure. If our national timing is weak, so is everything that is built upon it.

We will profit from ensuring our timing is as strong, resilient, and easily accessed as possible.

And we will suffer if it is neglected.
Relevant Comment on the above:
Jeffrey DeCoux, Chairman - Autonomy Institute - leading Intelligent, and Autonomous Infrastructure & Systems. Path to Commerce for Industry 4.0 and Autonomous Systems
We have billions of dollars being allocated to invest in the nation's digital infrastructure that supports 5G/ITS/Edge/APNT/Grid. Resilient APNT and electricity are coming.

GPS III SV04 receives operational acceptance, 1 more needed for M-code:

The fourth GPS III satellite, space vehicle (SV) 04, received U.S. Space Force’s Operational Acceptance approval. Read more about this milestone. 


(Jan. 2021) High-performance gyroscope for automotive, aeronautic and industrial applications:
CEA-Leti scientists, together with researchers at Politecnico di Milano, have developed the world’s first high-performance gyroscope for operating in severe environments, such as industrial and aeronautic equipment and automobiles.

According to the team, this breakthrough proves it is possible to detect minute rotational movement even among system vibrations.

(Feb. 2021) Trimble introduces next-generation 3D paving control platform - GPS World:
Trimble Inc. released the Trimble Roadworks 3D Paving Control Platform, a next-generation platform for 3D asphalt paving control systems. Check out the platform's 

(Feb. 2021) What if every satellite suddenly disappeared? - TED ED by Moriba Jah, 2 Feb 2021:
Blog Editor's (Dana A. Goward) Note: A great five minute video summary of all the bad things that happen when we don't have satellites. A lot of talk about GPS, as you can imagine, and
the need for terrestrial backups for all our space systems.

Of course, in addition to the two disaster scenarios described, GPS signals could also fail due to human error (think the 2016 mishap), cyber attack, and electronic 

Dr. Moriba Jah has a distinguished background in the space sciences and is currently an Asst. Professor at the University of Texas, Austin.

(Feb. 2021) The DoT’s “Complementary PNT and GPS Backup Technologies Demonstration Report” released this January has some excellent data on the relative performances of various 
systems in timing and positioning. Figures 130 and 131 of the report rank the systems on “performance sensitive” and “cost sensitive” bases respectively and has 
received a lot of attention. While I don’t disagree with the general assessments, there is considerable hazard in applying them blindly to select a national strategy.

The Gold Standard will be a "system of systems", not a particular system!

Firstly, there were several technologies NOT demonstrated, most notably 4G and 5G NR, both of which have significant (and demonstrated) timing and positioning capabilities
independent of GNSS. A second major hazard lies in deployed availability. Until and unless a technology is fully deployed over the coverage area, you will have holes 
in coverage
! The market will play a major role in deciding what will actually be available. A third consideration is domain applicability. The report partially addresses 
this in having diverse test environments ---indoor/outdoor; stationary/moving; etc. but it does not make an assessment as to whether or not the technology is applicable for a
given class of user. Fiber optic to the cell phone may NOT be as cool as it sounds.

Finally, there is the question of resiliency. NONE of the technologies was tested in an adversarial environment, e.g. jamming, cyber-attack, etc. A truly resilient 
system is a "system of systems" and the measure of its resilience is performance under attack and that is mostly a function of how well the systems are integrated.

In closing, this is an excellent report well worth reading that provides some good guidance on several technologies that could help in establishing resilient 
. Some ( e.g., Satelles / LEO Iridium) are available now for a subscription price. Others (e.g., NexNav/928 MHz Beacons) perform extremely well but 
will require significant infrastructure investment as contrasted with (UrsaNav / eLoran) which provides lesser positioning capabilities but can be deployed fairly 
. Ultimately, the choices will be made by the market!

(Feb. 2021) Detect and Avoid (DAA) Requirements Explained:
New today: "Detect and Avoid Requirements Explained According to Airspace and ACAS Classifications." Understand how your mission will determine whether your flights will operate under UTM or ATC, require #RemoteID or #ADSB, and what a certifiable #DAA system will look like.


The above prompted a comment from
James Farrell (Owner at Vergil):

Again, avoidance can NEVER succeed in dense traffic without accounting for fundamentals: 
1) instantaneous position history won't tell what's ahead,
2) transponder distance is good; cross-range is CRUDE,
3) cross-range is improved by sightline rotation,
4) that happens ONLY at dangerously CLOSE range,
4) that forces last-moment desperation climb/dive,
5) knowledge of dynamics will be increasingly essential! 

For more on the above topic, also see: https://youtu.be/84De8EM8S0U 

(Feb. 2021) Calls Grow to Find Back Up Systems for GPS - National Defense:
Blog Editor's Note - There are lots of reasons to worry about GPS vulnerability and our over-reliance on it.

Disruptions can lead to accidents (like the near crash of a passenger plane in 2019), a halt to farming operations and digital broadcasts, and severe impacts to 
telecommunications. Just to name a few.

Perhaps our biggest concern should be more existential. A major solar event or other mishap could halt GPS services for days, or even permanently. What then?

It could make the COVID-19 pandemic look like a mere warm-up act.
Calls Grow to Find Back Up Systems for GPS:
By Nick Adde

Five years ago, the Iranian navy seized and temporarily held the crew of two U.S. Navy gunboats that had entered Iranian waters. Though the 10 sailors were 
eventually released, the photos of them kneeling on the deck of an Iranian vessel with their hands behind their heads was a national embarrassment at the least, 
and a potential trigger for a more serious confrontation at worst.

Then in 2019, President Donald Trump came close to calling for an airstrike against Iran in retaliation for shooting down a Navy RQ-4 Global Hawk drone  
over the Strait of Hormuz.

Though much about both incidents remains classified, at least one expert believes that they occurred because Iran was able to interfere with the Navy crafts’ GPS
causing them to move off their planned course and into hostile territory.

The incidents point to the vulnerability of global navigation satellite systems, and those operated by the U.S. in particular, said Dana A. Goward, president of the 
Alexandria, Virginia-based Resilient Navigation and Timing Foundation, a nonprofit organization dedicated to promoting resiliency in such systems.

The earlier incident was supposed to be “an easy trip down the coast of Saudi Arabia, from one port to another,” said Goward, a retired Coast Guard captain who  
served as director of the service’s Marine Transportation System.

“Somehow they ended up way to the left, where the Iranian navy just happened to be waiting for them,” he said.

Likewise, the Global Hawk was flying near the Iranian coast but still in international airspace.

“All of a sudden it’s taking a right-hand turn toward Iran, and getting shot down while it was in their territorial airspace,” Goward explained.


(Feb. 2021) Can aviation continue to rely on satellite navigation? - EUROCONTROL:
Blog Editor's (Dana A. Goward) Note: With a passenger aircraft almost crashing into a mountain, drones big enough to kill someone crashing in back yards, and 

aircraft enroute nearly departing controlled flight, it is no wonder ICAO told its members addressing GNSS disruption is an urgent priority.

PNT Community members should find this event interesting:
This online event is part of our round of Stakeholder Forum discussions, where we tackle some of the hottest topics in European aviation with a wide range of key 

players, within and outside our industry.

Can aviation continue to rely on satellite navigation?

While the answer remains a clear “yes” in most parts of the world, it has also become a clear “no” in some areas where operations have been affected, especially on 

routes between Europe and the Middle East and Asia.

This webinar will explore:

the operational impact of radio frequency interference and how we can continue to ensure safe and efficient operations;
what measures should be taken to limit the proliferation of widespread interference to satellite navigation;
how we can ensure interference-free operations for all users of satellite navigation, including civil aviation, military and other users;
how the combination of space-based and terrestrial systems should evolve in order to deliver resilient infrastructure support to aviation at acceptable costs while 

preserving the benefits of satellite navigation.
During the 90-minute webinar, a multi-disciplinary panel will assess these challenges from the operational, regulatory, civil-military and technical perspectives.



(Feb. 2021) Skunk Works Is About to Test a Secret New Aircraft Called 'Speed Racer':

Lockheed’s Speed Racer will begin ground testing imminently. Ground testing typically involves watching and testing for reliability, checking for unusual vibrations, and 

carrying notional payloads while the aircraft is static or moving under its own power. The next step is actual flight testing.


(Feb. 2021) Airpower Was Indispensable to Defeating ISIS:

What happened during the air campaign against ISIS? What did airpower contribute to the group's defeat? And what lessons should the U.S. Air Force and joint force 

take from this campaign? This new report explores.

Research Brief related to the above mentioned report:


(Feb. 2021) Skyborg UAV aims to join frontline US fighter aircraft - GPS World:

It’s only a few weeks into the new year, yet there’s plenty happening in the UAV world. This month’s question: What’s a Skyborg? The U.S. Air Force awarded contracts 

to Kratos, Boeing and General Atomics to prove their approaches to the UAV program. 


(Mar. 2021) Federal policy aimed at GPS interference, critical infrastructure:

March 7, 2021 - By Dana Goward

In its closing days, the Trump administration issued several new policy documents affecting positioning, navigation and timing (PNT) issues.

Some have questioned the long-term impact of these, given the significant policy differences between the previous and current administrations. Yet policies in relatively non-controversial areas such as PNT are 

generally developed by career personnel who tend to remain in place from administration to administration. While they must adhere to the philosophical tenets of extant elected officials, these 

policies tend to endure longer than others.

Even if this weren’t the case, considering the wealth of other issues the new administration is grappling with, these new policies could remain in force for some time

even if the new regime ultimately decides to change them.

Several themes run through many of the documents. These include:

Space-based PNT is vulnerable and must be protected.
America needs to monitor for GNSS disruption.
More sources of PNT than just GPS are needed.
National Space Policy

The first of these late-term documents to be published was the National Space Policy issued on Dec. 9, 2020. Highlights and possible impacts for the PNT community include:

A goal to “Promote and incentivize private industry” could have implications for low-Earth orbit (LEO) PNT services.
A goal to “Increase the assurance of national critical functions” could include GPS/PNT resilience.
A pledge to “Safeguard space components of critical infrastructure” undoubtedly includes GPS. The section also has ominous statements about U.S. responses to purposeful interference and tasks the Defense and Homeland Security secretaries with having those responses ready.
Another pledge to “Maintain and Enhance Space-based Positioning, Navigation and Timing (PNT) Systems” is followed by eight explanatory paragraphs, many of which repeat previous policy. One new item is a promise to invest in detection and mitigation of harmful interference. A mention is also made of the need for multiple and diverse PNT sources, and responsible use of PNT, echoing the February 2020 Executive Order on the subject. Both of the latter two mentions were in the context of critical infrastructure and mission essential functions versus the security of the nation and economy as a whole.
Report to Congress: GPS Backup Tech Demo

Congress mandated a GPS backup technology demonstration in 2017, and $10 million was subsequently provided for that purpose. Various internal government delays resulted in the project not getting underway until March 2019. It concluded about a year later.

On Jan. 14, the Department of Transportation (DOT) posted its 457-page “Complementary PNT and GPS Backup Technologies Demonstration Report” to Congress on its website.

While some people have been critical, it is important to remember the report documents 11 vendor demonstrations, not engineering tests. Technologies were demonstrated in different locations and under differing conditions.

There is no silver bullet for meeting the nation’s needs. It must be a system of systems.

Also, the amount of effort and equipment in the demonstrations depended in some cases upon infrastructure available and the amount of money the government and vendors were able to spend. This meant that at least one technology was “demonstrated” mostly by explaining the concept, and other vendors were able to only partially demonstrate their technologies.

All of that said, the report offers valuable information about how America should make its national PNT much more resilient and reliable. First, it reinforces DOT’s message that there is no silver bullet for meeting the nation’s needs. It must be a system of systems. Second, the report goes further and says what that system of system should look like: “Those technologies are LF and UHF terrestrial and L-band satellite broadcasts for PNT functions with supporting fiber-optic time services to transmitters/control segments.”

From a policy perspective, this is a huge step forward. It resolves previous ambiguity and positions the nation to establish a resilient PNT architecture, one that will do more than be a “GPS backup.” It will be an architecture that will better support current applications and better enable emerging ones like autonomy, 5G and “NextG.”

National Research and Development Plan for Positioning, Navigation, and Timing Resilience:

Published one hour and fourteen minutes before the end of the administration on inauguration day, this plan was mandated as part of the February 2020 Executive Order on responsible use of PNT

By taking a comprehensive look at how we can do better, it provides an interesting outline of the challenges associated with America’s current over-reliance on GPS. While not a policy or directive document, 

it does suggest two or three departments and agencies that might be tasked with addressing each challenge.

It also addresses the need for interference detection and monitoring, and diverse sources of PNT.

U.S. Space-Based PNT Policy (Space Policy Directive 7)

This directive was published five days before the end of the administration and replaced the previous policy, 2004’s NSPD-39.

While the old policy calls for performance monitoring of GPS signals, the new one also has investment in interference detection and monitoring as a goal.

Perhaps the most significant change in the new policy was the absence of the words “backup capability” and the lack of a mandate for DOT to lead its establishment. Yet the policy hammers home multiple times the need for more than GPS as a source of PNT. And it doesn’t abandon the idea of government involvement in making that happen.

In addition to reinforcing Executive Order 13905 on responsible use of PNT, the directive defined a new (for presidential policies) term. “Alternative PNT Service” was described as “a PNT service that has the capability to operate completely independent of, or in conjunction with, other PNT services.” The directive goes on to say that “Multiple, varied PNT services used in combination may provide enhanced security, resilience, assurance, accuracy, availability and integrity. An alternative PNT service allows a user to transition from the primary source of PNT signals in the event of a disruption or manipulation.”

And while the policy does not say the government will establish or support an alternative PNT service, it comes pretty close. One of its goals is “Invest in… as appropriate, alternative sources of PNT for critical infrastructure, key resources, and mission-essential functions.”

It goes on to task the departments of Defense, Homeland Security and Transportation with making that happen.

So “backup” is out, “alternative PNT” is in. We agree words are important and are happy to have the new words. Let’s hope the new administration will match the new words with action (as appropriate).

(Mar. 2021) GPS Jammers Essential Tools for UK Car Theft Enterprise:
Blog Editor's Note By Dana Goward: We previously reported on the Mexican government's finding that 85% of truck thefts were aided by GPS jamming devices. While we have not
found similar national statistics reported in other parts of the world, this case is a reminder that the technology is widely available and in use.

Why wouldn't thieves use it all the time everywhere? It is likely that this is in fact happening, but many governments either aren't looking, or aren't publicizing what they find. 

Check out the story below that includes the use of "industrial strength" jammers.
Thanks to RNTF corporate member Chronos for alerting us to this story.


(Mar. 2021) Will We Be Ready if GPS Goes Down? - Wall Street Journal OpEd:
Blog Editor's Note: Ms. Diana Furchtgott-Roth served as the Deputy Assistant Secretary of Transportation. She is an adjunct professor of economics 

at George Washington University, and an RNTF member.

We applaud her commentary in the Wall Street Journal today. We especially like her sum up at the end of the piece:

"Americans depend on GPS too much for the federal government to wait for it to fail. A reliable backup is needed as soon as possible."

Will We Be Ready if GPS Goes Down?:
The Transportation Department has ideas for a backup, but it needs money from Congress.

By Diana Furchtgott-Roth

March 19, 2021 2:05 pm ET

GPS is vital to Americans, but hacking it has never been easier. Protecting the civilian Global Positioning System, an invisible utility the federal government pays 

for, falls to Transportation Secretary Pete Buttigieg NOW

He would do well to use the results of the Transportation Department’s January 2021 report on technologies that can back up GPS and keep the country moving in 

a pinch.

Three separate laws, most recently the Frank LoBiondo Coast Guard Authorization Act of 2018, assign the Transportation Department the task of providing a 

backup to GPS. The LoBiondo Act required the secretary to put in place a backup system by the end of 2020, but no funds were appropriated, so the department couldn’t proceed.

Although Congress hasn’t followed through with the money, the DOT’s new report lays out a road map.


(Mar. 2021) "Dangerous & Costly to Airlines"​ - EUROCONTROL on GNSS Interference:
Deliberate interference with GNSS by the world's militaries interferes with safe air traffic management, poses risks to aircraft, and imposes extra costs 
for fuel and transit time, according to a recent EUROCONTROL stakeholder forum.

2,000% increase in GNSS RFI incidents in 2018 as measured by voluntary incident reporting, with a sustained high rate since;
38.5% of European en-route traffic operates through regions intermittently but regularly affected by RFI;
5% of traffic in these regions could, given current levels, need special assistance.
Five presentations discussed various aspects of the problem, including that the region of heaviest regular interference was also smack across the highly 
traveled route between Europe and south Asia.

A variety of solution and mitigation efforts were suggested. These included a more deliberate monitoring systems to warn aircraft and investigation of an 
alternate wide area navigation system not vulnerable to such easy interference. Both of these echoed earlier recommendations of the International Air Transport 

Another suggestion was that belligerents limit their GPS/ GNSS jammer power to 10W versus the 100W that seems to be the current standard. The assertion is 
that doing so would be equally effective against adversaries while spilling over much less into commercial air traffic operations.
That's an idea. Though given the barrel bombs and nerve gas we have seen used in the region, we are not sure it is a suggestion that will resonate with many 
on the ground.

You can view the entire workshop and access all the presentations here: https://www.eurocontrol.int/event/eurocontrol-stakeholder-forum-gnss#register

(Mar. 2021) DSI to host 2021 Assured PNT Summit in April - GPS World:
February 12, 2021 - By Allison Kral

The Defense Strategies Institute’s (DSI) Assured Positioning, Navigation & Timing (PNT) Summit will take place April 14-15 at the Mary M. Gates Learning Center 
in Alexandria, Virginia.

No alt text provided for this image
According to DSI, the event will bring together members of the military services, Department of Defense (DoD), federal government, industry and academia in a 
“town hall” style forum to discuss how important GPS and space-based PNT systems are to the overall resilience of the warfighter, as well as critical 
infrastructure across the United States and abroad

The 2021 Assured PNT Summit also will offer senior-level insight into how the U.S. military has been a leader in integrating PNT into its everyday operations 
and how such capabilities have become vital to the military’s ability to shape the global arena, deter aggression, and fight and win wars.

Confirmed speakers for this year’s event include William Nelson, SES, director, APNT CFT, Army Futures Command; Brig. Gen. Heather L. Pringle, USAF, commander, 
Air Force Research Laboratory; Anthony C. Smith, SES, director, C3I, DoD CIO; Richard De Fatta, SES, director, U.S. Army Space & Missile Defense Center of Excellence
Cordell “Del” DeLaPena, SES, program executive officer for Space Production Space & Missile Systems Center, USAF; Harold W. Martin III, SES, director, National 
Coordination Office for Space-Based Positioning, Navigation and Timing; and Col. Jason Joose, USA, chief of staff/APNT signature effort lead, Army Futures Command.

A number of topics will be covered at the 2021 Assured PNT Summit, including:

Leading current DoD initiatives toward integrating new PNT capabilities to help the Warfighter remain resilient in a dynamic threat environment;
Synchronizing PNT, navigation warfare and space capability development efforts across the Army to help reduce key capability gaps;
Delivering resilient, affordable and sustainable space capabilities such as modernized GPS to enhance warfighter superiority;
Providing alternate PNT for potential GPS-denied environments; Accelerating the implementation of cutting-edge Air Force research projects such as NTS-3

GPS Satellite 
to provide the most value to the warfighter; Developing critical PNT-related products to enable a Soldier’s PNT capabilities in all warfighting domains;
Overseeing the collection of GPS-related information from multiple federal agencies in an effort to improve and maintain space-based PNT capabilities;
Advancing efforts to provide GPS protection for all naval air platforms; and
Detailing the Department of Homeland Security plan to test the vulnerabilities of critical infrastructure systems, networks and assets if PNT services were to be 
disrupted or manipulated.


(Mar. 2021) What Trump Administration Got Wrong About Protecting GPS Users and America:
MARCH 22, 2021 01:00 PM ET

The Global Positioning System has become the world’s most widely used tech utility.
In February of last year, President Donald Trump reversed long-standing administration policy when he issued Executive Order (13905, “Strengthening National Resilience Through Responsible 

Use of Positioning, Navigation, and Timing (PNT) Services.”

The Global Positioning System has become the world’s most widely used tech utility. America’s over-dependence on it for everything from synchronizing cellphone 

networks to managing power grids has caused government officials to call it “… a single point of failure” for the country.

While Trump’s order rightly warned of the dangers in over-relying on GPS, it also shifted away from years of executive branch policy. Rather than focusing on 

reinforcing GPS and protecting users with an alternative PNT source or sources, the order told users to protect themselves by accessing commercial services it hoped 

would be developed to meet their needs.

GPS signals underlie virtually every technology but are weak, easily blocked and imitated. And many studies have found a reasonable chance the system will be damaged 

or destroyed by solar activity within the next 50 years. These vulnerabilities pose a near-existential threat to the nation’s economy and security.

The Trump order’s warning to users—and many of its other provisions—were necessary but they were far from sufficient.

This is because the order ignored fundamental economic and security realities.

A Free Utility:

America established GPS as its gift to the world in the hope that it would be widely adopted and used. Making the signal free and its specs public were wildly successful. 

So much so that as early as 1999 a special commission told President Bill Clinton that America was likely becoming too dependent on the system.

GPS rapidly became a utility, much like a municipal water system, that serves all citizens in a multitude of ways.

Recognizing GPS’ limitations, a number of companies over the last decade have tried to develop business models providing backups and alternatives for GPS. While some 

have found niche markets with specialized users, just as Evian, Perrier and others have created niche markets for specialized water, NO alternate PNT provider has been able to 

establish a broadly adopted, wide area service. They just can’t compete with the free government service that is GPS.

The order’s hope of the market providing alternatives—and that millions will be willing to pay a fee to subscribe—is a futile one. Just as few Americans see the need to 

purchase a regular alternate supply of household water, few see the need to buy PNT services to supplement and backup GPS. Besides, if something goes wrong with the water or 

with GPS, it’s the utility provider’s fault, not theirs. The government will make sure the problem gets fixed (hopefully).

A National Security Imperative

The impacts of a prolonged GPS outage or the system’s loss will make the COVID-19 pandemic look like a warmup act.

Our national government must prevent this as part of its core duty to provide for the common defense and promote the general welfare.

The Trump-era policy promulgated by the order focuses only on critical infrastructure and large companies that do business with the government. 

And it outlines a difficult and unlikely path to protect them.

It largely ignores first responders, local, state and federal agencies, the Post Office, drone operators, medium and small businesses – in short, about 95% 

of current GPS users who help to make the nation function. Not protecting such a large portion of America from an outage will cripple law enforcement and other first responders

and greatly diminish our ability to support any sustained military operations.

And since adversary nations like Russia, China and Iran have terrestrial backup systems, America will not only be crippled, but we will be weakened far more than those who wish us ill.

In fact, some observers have opined America’s lack of a terrestrial backup system for GPS has already damaged our national security by providing both terrorists and enemies an 

exceptionally attractive target. It has certainly put America at tactical and strategic disadvantages in many situations already.

The Goal: Making the Nation Safer:

Having alternative systems will make GPS satellites and signals less attractive targets and therefore safer from malicious interference. They will also make the nation safer by 

removing a single point of failure vulnerable to solar activity, malicious threats, and accidents.

But to do that, as many GPS users as possible must also adopt and use one or more alternate systems.

Anything that inhibits adoption, like limiting it to critical infrastructure, availability only in urban areas, access fees, and the like, reduces protection of the nation.

Even if the complicated Trump plan to coerce large companies into creating systems to protect themselves worked, it would still provide far less than America needs.

America needs what our adversaries already have: terrestrial PNT systems that are easily accessed and available to all. Systems that will work in concert with GPS 

when it is available and serve in its place when it is not.


(Mar. 2021) Q: How can a GNSS satellite oscillator anomalies, even at micro-scale, be detected?:


(Mar. 2021) Keeping track of spacecraft as Earth’s water alters its spin:

Mass is constantly being redistributed around our planet, as Earth’s atmosphere, oceans and other bodies of water on and under the surface melt, shift and stir. This 

mass redistribution alters Earth’s center of gravity, which in turn speeds up and slows down the planet's spin – and so the length of the day – as well as changing 

the orientation of its 'spin axis'. These changes to Earth’s spin and orientation occur over relatively short timescales of days and weeks, and threaten communication 

between ground stations and missions in orbit and across the Solar System.

(Mar. 2021) FAA and "Last Gen"​ Navigation Mentality? - Note to the Reason Foundation:

We always find something of interest in Bob Poole's "Aviation Policy News" from the Reason Foundation.

This month it is a note he received from a colleague about the FAA and navigation. Bob published in his "Quotable Quotes" section. 

By way of background, the 2001 Volpe report mentioned was the result of a three year, presidentially mandated effort to examine if the FAA's plan to move 
aviation to navigate using only space-based assets (GPS) and do away with terrestrial beacons (VOR/DMEs) was still a good idea. Clearly being able to do 
away with a large network of terrestrial systems would have saved the FAA a lot of money. But the answer was a resounding "no". 

The report also observed that all kinds of transportation, other infrastructure, and systems in the US were becoming far too dependent upon vulnerable GPS 
. It recommended the nation investigate establishing an alternate system for when GPS, for whatever reason, was not available. 

The report was published the 29th of August, 2001, less than two weeks before 9/11. Understandably, it took the White House a while to get around to acting 
on it. But in December 2004 President Bush issued NSPD-39 which mandated the Department of Transportation lead a federal effort and establish 
a backup capability for GPS

Folks are still trying to make that happen. Doing so will make GPS a less tempting target for our enemies, and provide another way of getting vital 
positioning, navigation, and timing (PNT) services against the inevitability of a prolonged GPS disruption.

By Robert Poole

March 22, 2021

Quotable Quotes:
Despite the upcoming 20th anniversary of the Volpe GPS Vulnerability Study, FAA continues to maintain a GNSS-centric PNT mentality. While their 2016 
Performance-Based Navigation (PBN) Strategy was to retain resilient ground-based alternatives, the vast majority of Distance Measuring Equipment (DME), 
VHF Omni-directional Ranges (VORs), and Tactical Navigation (TACAN) operating in the NAS (National Airspace System) were designed in the ‘70s and installed 
in the ‘80s. Although the concept of “GPS-sole means” does not officially exist, FAA has NOT yet taken significant steps to recapitalize these 
30-40-year-old systems, although efforts to expand procedures reliant on GNSS services continue unabated. By comparison, FAA installed navaids at over 850 
sites in the 1980s and added over 100 additional locations in the 1990s. It is interesting that their current DME-VOR-TACAN (DVT) plan spans 42 years—over 
twice the normal life cycle of these equipments—and does NOT address the hundreds of aging Instrument Landing Systems (ILS) or Approach Lighting Systems 
(ALS). It is also interesting that FAA’s proposed DVT strategy is to issue Indefinite Delivery/Indefinite Quantity (ID/IQ) contracts, with TACAN antenna 
replacement being the first step. This will only serve to proliferate and expand the logistics challenges of maintaining numerous configurations by an 
aging and retiring workforce, preclude economic ordering quantities, and take decades to replace thousands of aging navaids. As reports of GNSS interference
with aviation continue to mount worldwide, it would seem prudent for FAA to prioritize the replacement of these resilient systems to ensure, as the FAA 
mission states, ‘the safest, most-efficient aviation system in the world,’ and set an example for ANSPs worldwide.”

Aviation Sector Professional, email to Robert Poole, March 15, 2021

LINK: https://reason.org/aviation-policy-news/few-u-s-airports-being-leased-climate-change-problem-grows-and-more/ 

(Mar. 2021) Industry members, non-profit urge Congress to fund GPS alternatives - GPS World:
RNT Foundation decided to sign this letter with members of industry, some of which are our members, some are not, because it does not promote an individual technology 
or company. Rather it reinforces the work and findings of the Department of Transportation.

In separate letters to members of the House of Representatives and the Senate, seven companies and a non-profit URGED Congress to support alternative positioning, 
navigation and timing systems (PNT) with the “necessary funds and other appropriate policy tools.”

Signing the letter were NextNav, UrsaNav, Satelles, Hellen Systems, OPNT, Orolia, Microchip, and the non-profit Resilient Navigation and Timing Foundation (RNTF).

The letters focus on and endorse the system-of-systems approach outlined in the Department of Transportation’s (DOT) recent report to Congress on the results of 
its GPS Backup Technology Demonstration. The report found an adequate and robust American PNT system should include space-based L-band signals, low-frequency (LF
and ultra-high-frequency (UHS) signals, and fiber connections between the terrestrial LF and UHF transmitters.

“Our country depends on GPS for critical infrastructure, and there is an urgent need for resiliency being built into our critical infrastructure. Before the report 
came out, some of us had different ideas of how the U.S. should go forward,” said Ganesh Pattabiraman, CEO of NextNav. “But the DOT report provided the data to make 
it very clear that it is a combination of technologies that need to come together to truly enable nationwide backup to GPS, and it was good to see we could get 
industry alignment on the findings.”

The letters describe many of the threats to GPS, both natural and malicious; its vulnerabilities; and the dire consequences of disruptions. They go on to state that 
robust, more reliable PNT is needed for emerging and future systems like E911, 5G, resilient electrical grids, drones and other automated systems.

Monty Johnson, CEO of OPNT, a provider of time-over-fiber services, praised the findings of the DOT report. “The key to resilience and reliability in a system-of-systems 
is including technologies that deliver the same information using starkly different means. It is hard to imagine a combination of technologies that are more diverse than 
fiber, satellites, LF and UHF.”

According to Pattabiraman, the signers of the letter agree that the DOT report made clear that there are mature technologies available today that can address the GPS 
backup issue. DOT and Congress now have the data to act to enable a much-needed resilient infrastructure for the country.

Dana A. Goward, president of the non-profit RNT Foundation, agreed. He also observed that deciding on the technologies and congressional funding were important, but only 
first steps. “The goal of this effort is not to just implement systems,” he said. “it’s to make America safer. Establishing the services quickly and efficiently will be key, 
as will ensuring they are widely adopted.”

“Protecting the nation from the consequences of a space-based PNT disruption will require that these systems be accessed and used by a wide variety of users from first 
responders and delivery services, to all forms of critical infrastructure,” Goward said. “This means the government will need to eliminate as many barriers to adoption as 
possible. One or more of these alternatives has to be available to every American. And a basic level of service has to be free, just like the GPS utility it is reinforcing. 
Fortunately, we estimate this can be done relatively inexpensively. It will be only a small fraction of the $1.7B we spent on GPS last year.”

that there are mature technologies available today that can address the GPS backup issue. DOT and Congress now have the data to act to enable a 
much-needed resilient infrastructure for the country.

The alternative to making this relatively modest investment, according to Goward, is unacceptable.

“There are lots of threats to GPS,” he said. “Take the sun for example. The most recent study I saw estimates a 70% chance solar activity will damage the GPS constellation 
in the next 30 years and a 20% chance it will destroy a big part of it. And the sun is just one of the threats we face. We can’t keep playing this kind of Russian Roulette 
with the fate of our nation. Especially when other countries like Russia and China have already taken steps to protect themselves with terrestrial systems.

A copy of the letter sent to Senators can be found here, and the one to members of the House of Representatives here:

(Mar. 2021) NIST Team Compares 3 Top Atomic Clocks With Record Accuracy Over Both Fiber and Air:

In a significant advance toward the future redefinition of the international unit of time, the second, a research team led by the National Institute of 
Standards and Technology (NIST) has compared three of the world’s leading atomic clocks with record accuracy over both air and optical fiber links. 
Described in the March 25 issue of Nature , the NIST-led work is the first to compare three clocks based on different atoms, and the first to link the most 
advanced atomic clocks in different locations over the air. These atomic clock comparisons place the scientific community one step closer to meeting the 
guidelines for redefinition of the second.
Thomas H. Kerr III comment: "These important comparisons make technologists better able to confirm the utility of these various time sources to support the 
system-of-systems approach to resilient PNT (beyond mere reliance on just GPS/GNSS) by augmenting its accuracy."

(Mar. 2021) GPS Allies Say Timing Supplement Within Reach - Communications Daily:


(Apr. 2021) Terrestrial navigation system ready for use in S. Korea to cope with jamming and electric warfare - Aju Business Daily:
Notice the "advantage" South Korea has of a belligerent, not-at-all-subtle enemy. Our adversaries only jam GPS in areas outside the United States (as far as 
we know) so we are not nearly as concerned. Hence we are far more vulnerable and at risk than South Korea. We are at risk from Russia, China, sophisticated 
terrorists, human error, solar activity...the list goes on.

If only we had better enemies!

Lim Chang-won Reporter(cwlim34@ajunews.com) | Posted : April 1, 2021, 10:17 | Updated : April 1, 2021, 10:17:

SEOUL -- To cope with unexpected interference such as North Korea's electric warfare, South Korea will launch an uninterrupted positioning navigation service 
based on radio waves from ground transmitters instead of satellites, starting with a pilot project in June for coastguard vessels and state patrol boats 
operating in volatile border areas off their west coast.

South Korea began developing a terrestrial navigation system that can provide Positioning navigation timing (PNT) information reliably by utilizing transmission 
towers on the ground in 2016 after North Korea discharged strong electric waves for systematic cross-border electronic warfare. The electric wave attack caused
no visible damage, but Seoul condemned it as a serious provocation.

PNT information, which is essential for industry and daily life, relies on the U.S. Global Positioning System (GPS). With multiple disruption tools, North
Korea has occasionally jammed GPS communications in South Korea. Seoul regards GPS disruptions as a new form of North Korea's low-level, asymmetric

In a statement published on 31 March 2021, the Seoul government announced the commercialization of an enhanced long-range navigation (eLoran) system that
provides precise visual information and calculates location by measuring the time reached by radio waves from three or more transmitters.

A pilot service will be launched on 1 June 2021, with South Korean Coast Guard vessels and patrol boats operating in maritime border areas to receive eLoran 
receivers. The service will be expanded to fishing boats and merchant ships. For a nationwide service, South Korea will establish a cooperative system with 
broadcasting, information and communication sectors to provide precise standard-time information and expand it to other industries to prevent disruptions in 
national infrastructure even when GPS is suspended.

READ MORE: https://www.ajudaily.com/view/20210401091701262 

(Apr. 2021) Next Steps in GNSS Receiver Security Validated with OSNMA Testing - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design:


(Apr. 2021) “The Mounted PNT [Positioning, Navigation and Timing] program and the APNT CFT
are continuously evaluating all the PNT technologies available to enable assured PNT to Army forces anywhere in the world.” said Lt. Col. Alexander “Raz” Rasmussen. 

“A part of this effort is the recently established PNT Modernization project office. PNT Modernization’s mission is to evaluate and test PNT technologies available
across industry, academia, and government labs. Based on applicability, mission need, and maturity, PNT technologies will be accelerated for integration into MAPS
[Mounted Assured PNT System]. We must continue to provide ‘fight tonight’ capability to Soldiers worldwide while accelerating technologies that maintain threat overmatch in the future.” 

More MAPS info here: https://lnkd.in/d2jXP7e 


(Apr. 2021) Lockheed scores $1.1B contract to build US Army’s guided rocket on heels of extended-range test:


(Apr. 2021)
Blog Editor's Note: Great article by our friend Logan Scott. While the DOT report on their GPS Backup Tech Demo does have a lot of information, we have to 
agree it is not the be all and end all on the question of "GPS backups" as some would like. 

Logan observes:

"While I don’t disagree with the general assessments, there is considerable hazard in applying them blindly to select a national strategy."

One challenge he notes is that not all candidate technologies were demonstrated. He cites PNT via 4G and 5G as one example. Also, systems like Australia's 
and WWV were not included.

We agree, by the way, that 5G, especially has potential, though it still needs a solid timing backbone to be resilient and independent of GNSS
As for WWVB, it certainly has potential and is in operation. Yet, WWVB operates at 60KHz, not that far from eLoran at 100KHz. All the engineering and 
many of the PNT standards have been done for eLoran and it is in use elsewhere in the world. Not so for WWVB. He makes a number of other cogent points 
especially about resilience. We encourage you to follow the link below and read his article.

We have to agree with Logan that the biggest draw back to the DOT report is that folks are going to read too much into what was, not engineering trials and 
evals, but a set of vendor demos
. As such they were limited by being performed in different locations and under different conditions. Some of which were 
the result of a lack of funds to perform a full demo of the technology.

The biggest plus to the project and report was it's finding the correct path forward for the nation is a system-of-systems approach with technologies that 
have starkly different failure modes.

Now we just need the government to stop admiring the problem and follow through on its decades-old promise to act.

State of Play: Resilience Is Not Just About Parts!
March 19, 2021 

By Logan Scott

LINK TO ARTICLE DISCUSSED ABOVE: https://insidegnss.com/state-of-play-resilience-is-not-just-about-parts/ 

(Apr. 2021) The Rising Threat to the Integrity of Maritime Navigation Data - The Maritime Executive:
Blog Editor's Note: A good update article by George Shaw of the General Lighthouse Authority of UK and Ireland. This is the kind of issue that tends to fall 
into the background for users. Regular updates like this help keep it in the forefront of people's minds making mishaps less likely.

We note that the US Coast Guard has identified this as a significant maritime cyber concern, and the International Maritime Organization has dubbed it a urgent
safety of navigation issue.

Of course, if mariners had another wireless source of PNT that was difficult to disrupt to work with and reinforce GNSS, this would be MUCH less of a problem
and danger.

The Rising Threat to the Integrity of Maritime Navigation Data:
By George Shaw

Loss of satellite signal is a well-known operational risk, but few mariners are aware of the threat of GNSS providing a false time, position or direction even 
when still available
. When these position errors exceed a safe margin of error, they can cause ships to derive and transmit dangerously misleading Information
GNSS is not designed with inherent real-time integrity, which refers to the users’ ability to trust the data and receive timely warnings if it is unreliable.


(Apr. 2021) The $1.5 billion Space Fence can track tiny objects in low Earth orbit as small as a marble:


(Apr. 2021) It’s Time To Declare Space Systems As Critical Infrastructure - Politico:

Blog Editor's Note: This article proposes an idea that has been raised periodically, either designating GPS as critical infrastructure or, as in this case, space systems generally.

The overall goal is to provide greater visibility and focus on the importance and criticality of space systems. Presumably this would lead to greater efforts to ensure they are 

properly protected and secure.

Believe it or not, a big challenge to designating GPS as critical infrastructure has been that GPS is a government system.

The Department of Homeland Security (DHS) is responsible for critical infrastructure protection. It has designated 16 critical infrastructure sectors to protect. Some 

examples are the transportation sector, chemical sector, and the energy sector. The way DHS tries to protect infrastructure is by gathering commercial entities from 

each sector in various forums to discuss issues, develop best practices, gain understanding, consider possible government actions, etc. 

Not a model that could be applied to a government owned satellite system like GPS.

It might be one that could be applied to commercial space. If so, the next question would be whether the appropriate government lead would be DHS, NASA because 

they have the technical expertise, Commerce as suggested by the authors, or some other entity. Perhaps It could be a non-governmental entity. Maybe a beefed up version 

of the Space Information Sharing and Analysis Center.

It’s time to declare space systems as critical infrastructure
Such a move "would galvanize the policy and stakeholder attention and resources needed to secure these systems," argue two government space experts.

04/02/2021 06:45 AM EDT

Edward Swallow is the senior vice president for civil systems at The Aerospace Corporation, a nonprofit which operates a federally funded research and 

development center for the U.S. space enterprise. Samuel Visner is a technical fellow and former director of the National Cybersecurity FFRDC at MITRE

They are also founding members of the Space Information Sharing and Analysis Center Board of Directors.

In the United States, our economy, national security and everyday lifestyle rely heavily upon thousands of space systems in orbit.

For instance, the Global Positioning System is vital for shipping and transportation, including ground, air traffic and marine navigation — anywhere in the 

world. Communication and information processing, including the world’s developing 5G networks, rely heavily on space-based infrastructure. Space-based 

systems are also critical for national security missions that protect our homeland and enable operations overseas. We have long counted on satellites for command and control 

of our armed forces, missile guidance, early warning and intelligence.

READ MORE: https://www.politico.com/news/2021/04/02/its-time-to-declare-space-systems-as-critical-infrastructure-478848

(Apr. 2021) Secure World Foundation Says Russia is Testing New LEO, GEO Anti-Satellite Technologies - Via Satellite:
The Secure World Foundation released a report suggesting that Russia is testing new Anti-Satellite (ASAT) and Direct Ascent Anti-Satellite (DA-ASAT) technologies 
that could threaten spacecraft in Low-Earth Orbit (LEO), and eventually, Geostationary Orbit (GEO).

In the April 2021 report, “Global Counterspace Capabilities: An Open Source Assessment,” co-authors Brian Weeden and Victoria Samson wrote that Russia is 
recapitalizing ASAT capabilities they had during the Cold War and testing Rendezvous and Proximity Operations (RPO) technologies in both LEO and GEO.

Some of those efforts have links to a Cold War-era LEO co-orbital ASAT program,”
Weeden and Samson wrote. “Additional evidence suggests Russia may have started a new co-orbital ASAT program called Burevestnik, potentially supported by a 
surveillance and tracking program called Nivelir. … While Russia is actively testing what appears to be a new DA-ASAT capability in their Nudol system, it is 
not yet operational and does not appear to have the capability to threaten targets beyond LEO.”

The report acknowledges the possibility that these technologies could also be used for non-aggressive surveillance of foreign satellites and notes that most
of Russia’s on-orbit RPO activities seem to fit that scenario so far. “However, Russia has deployed two ‘sub-satellites’ at high-velocity, which suggests at 
least some of their LEO RPO activities are of a weapons nature,” the report said

In April of last year, CNBC and other news outlets reported that U.S. Space Force generals believed that Russia successfully tested a missile capable of 
destroying a LEO satellite. Military officials called the test “unusual and disturbing.”

The Secure World Foundation report also studied development of militarized space capabilities in China and the United States. The report noted that China has
conducted multiple tests of RPO technologies in both LEO and GEO, which could lead to co-orbital ASAT capabilities. “However, as of yet, the public evidence 
indicates [China] has not conducted an actual destructive co-orbital intercept of a target, and there is no public proof that these RPO technologies are 
definitively being developed for counterspace use as opposed to intelligence gathering or other purposes,” said Weeden and Samson.

In regard to the United States’ anti-satellite technologies, Secure World Foundation said that the U.S. military, like China, has conducted multiple RPO 
in both LEO and GEO that could lead to a co-orbital ASAT capability, but that there is no evidence of an operational system.

Interestingly, the report notes that the United States has conducted significant research and development on the use of ground-based high energy lasers for 
potential counterspace purposes
. “We assess that there are no technological roadblocks to the U.S. operationalizing [lasers] for counterspace applications. 
With its SLR [Satellite Laser Ranging] sites and defense research facilities, the United States possesses low power laser systems with the capability to 
dazzle, and possibly blind, EO imaging satellites.

(Apr. 2021) An hour of your time. The United States must implement the foundations for artificial intelligence across the whole of government before 2025. We've not a moment to lose.

DoD Joint Artificial Intelligence Center:
The Vice Chairman of the National Security Commision on #AI Robert Work and JAIC Director LtGen Michael Groen addressed the media yesterday to discuss #artificialintelligence in the 

United States Department of Defense. Watch it here: #nationalsecurity
Powerful statements by Vice Chairman Work and JAIC Director Groen

We stand ready to support the 'Digital Corps'. Our recent delivery of the AI-powered application to the Undersecretary of Defense serves as a proof of both our capability and commitment in this area. 

Summit2Sea Consulting Erica Thomas Megan Foster, MBA Bryan Eckle Laurian (Schwallie) Eckle Eric Dorsey
Independent Linkedin Reader's comment: "Well done DoD Joint Artificial Intelligence Center"
Independent Linkedin Reader's comment: "3-star General Michael Groen reminds me of 4-star General James N. Mattis had the latter been cyber-focused." 
Independent Linkedin Reader's comment: Couldn’t agree more. The larger challenge was well stated by Thomas Friedman in the New York Times next.

China Doesn’t Respect Us Anymore — for Good Reason:
Sometimes a comedian cuts through foreign policy issues better than any diplomat. Bill Maher did that the other week with an epic rant on U.S.-China relations, nailing the most troubling contrast between the two countries: China can still get big things done. America, not so much.

For many of our political leaders, governing has become sports, entertainment or just mindless tribal warfare. No wonder China’s leaders see us as a nation in imperial decline, living off the leftover fumes of American “exceptionalism.” I wish I could say they were all wrong.

“New Rule: You’re not going to win the battle for the 21st century if you are a ‘silly people.’ And Americans are a silly people,” said Maher. “That’s the classic phrase from ‘Lawrence of Arabia’ — when Lawrence tells his Bedouin allies that as long as they stay a bunch of squabbling tribes, they will remain ‘a silly people.’ …

“We all know China does bad stuff. They break promises about Hong Kong autonomy; they put Uyghurs in camps and punish dissent. And we don’t want to be that. But it’s got to be something between authoritarian government that tells everyone what to do and a representative government that can’t do anything at all.”

Maher added: “On a national level, we’ve been having Infrastructure Week every week since 2009, but we never do anything. Half the country is having a never-ending ‘woke’ competition. … The other half believes we have to stop the lizard people, because they’re eating babies. … China sees a problem and they fix it. They build a dam. We debate what to rename it.”

Yes, China has huge problems. Its leaders are not 10 feet tall, but they are focused on real metrics of success. “China’s leaders are fierce but fragile,” argues James McGregor, the chairman of the consultancy APCO Worldwide, Greater China. “Precisely because they were not elected, they wake up every day scared of their own people, and that makes them very focused on performance” — particularly around jobs, housing and clean air.

By contrast, many U.S. politicians these days are elected from safe, gerrymandered districts and seek to stay in power by just “performing” for their base with populist theatrics.

Whenever I point this out, critics on the far right or far left ridiculously respond, “Oh, so you love China.” Actually, I am not interested in China. I care about America. My goal is to frighten us out of our complacency by getting more Americans to understand
that China can be really evil AND really focused on educating its people and building its infrastructure and adopting best practices in business and science and promoting government bureaucrats on merit — all at the same time. Condemning China for the former will have zero impact if we’re not its equal in all of the latter.

At last week’s Alaska meeting between America’s and China’s top diplomats, Chinese officials made it quite clear that they no longer fear our criticism, because they don’t respect us as they once did, and they don’t think the rest of the world does, either. Or as Yang Jiechi, China’s top foreign affairs policymaker, baldly told his U.S. counterparts: “The United States does not have the qualification to speak to China from a position of strength.”

Europe Plunders Paris for Talent, and P.S.G. Pays the Price

Surprised? What did you think, that the Chinese didn’t notice that our last president inspired his followers to ransack our Capitol, that a majority of his party did not recognize the results of our democratic election, that a member of our Congress believes that Jewish-run space lasers cause forest fires, that left-wing anarchists were allowed to take over a section of downtown Portland, creating havoc for months, that during the pandemic the U.S. printed money to help its consumers keep spending — much of it on Chinese-made goods — while China printed money to invest in even more infrastructure, and that gun violence in America is out control?

My message to China is: Be careful. Some of your diplomats sound awfully arrogant. As the proverb says: “Pride goeth before destruction, and a haughty spirit before a fall.” America still excels in a lot of areas.

But my message to my fellow Americans is: We now have to return to and double down on what was our formula for success.

And that is: educating our work force up to and beyond whatever technology demands; building the world’s best infrastructure of ports, roads and telecommunications; attracting the world’s most energetic and high-I.Q. immigrants to enrich our universities and start new businesses; legislating the best regulations to incentivize risk-taking while curbing recklessness; and steadily increasing government-funded research to push out the boundaries of science so our entrepreneurs can turn the most promising new ideas into start-ups.

On this front there is some hope, noted McGregor: “Congress has begun sorting through the hundreds of China bills introduced in the last Congress to forge bipartisan legislation to invest in science and technology, R&D and U.S. leadership in the same technologies that China has declared as the next frontiers.” And President Biden is talking about spending trillions!

Nothing could be more important. Because good ideas — respect for human rights, democracy, an independent judiciary, free markets, protection for minorities — don’t just win in the world because they are good ideas. They diffuse and are embraced because others see them producing justice, power, wealth, opportunity and stability in countries that practice them.

American ideals infused every global institution in the 20th century because we were powerful, and we were powerful because more often than not we implemented our ideals.

But, if we as a country continue to act as we have of late — “dumb as we want to be” — then our power will be diminished and with it the power of our ideals. We will have steadily less influence on China and on the world at large no matter how loudly we chant “U.S.A., U.S.A., U.S.A.” So, let’s make sure we win the Olympics that count.

The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.

Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram.

Thomas L. Friedman is the foreign affairs Op-Ed columnist. He joined the paper in 1981, and has won three Pulitzer Prizes. He is the author of seven books, including “From Beirut to Jerusalem,” which won the National Book Award.

(Apr. 2021) Secure World Foundation Says Russia is Testing New LEO, GEO Anti-Satellite Technologies - Via Satellite:
Blog Editor's Note: This article talks about Russia's activities at LEO and GEO.

Of course, even though GNSS are at MEO, this should still be a concern for the PNT community for several reasons.

Some nations have some PNT at GEO and/or LEO, and others are considering it, either with dedicated constellations, or as a part of other systems, such as OneWeb. China reportedly has PNT capability in all three orbit regimes, for example.
Also, you have to pass through MEO to get from LEO to GEO. Clearly, Russia could easily cause mischief in MEO, if they wanted to. They probably are avoiding MEO so as to not interfere with GNSS, including their own GLONASS, and because the US has said that any interference with GPS in space will be considered an attack on the nation itself.

And, as we have noted before, countering GNSS with electronic warfare with assets like Russia's reported space-based nuclear powered jammer, will be easier and more effective than attacking one or two of the satellites. So they already have what they need. And no need to test it.
Secure World Foundation Says Russia is Testing New LEO, GEO Anti-Satellite Technologies
By Jeffrey Hill | April 6, 2021

The Secure World Foundation released a report suggesting that Russia is testing new Anti-Satellite (ASAT) and Direct Ascent Anti-Satellite (DA-ASAT) technologies that could threaten spacecraft in Low-Earth Orbit (LEO), and eventually, Geostationary Orbit (GEO).

In the April 2021 report, “Global Counterspace Capabilities: An Open Source Assessment,” co-authors Brian Weeden and Victoria Samson wrote that Russia is recapitalizing ASAT capabilities they had during the Cold War and testing Rendezvous and Proximity Operations (RPO) technologies in both LEO and GEO.
“…Some of those efforts have links to a Cold War-era LEO co-orbital ASAT program,” Weeden and Samson wrote. “Additional evidence suggests Russia may have started a new co-orbital ASAT program called Burevestnik, potentially supported by a surveillance and tracking program called Nivelir. … While Russia is actively testing what appears to be a new DA-ASAT capability in their Nudol system, it is not yet operational and does not appear to have the capability to threaten targets beyond LEO.”

READ MORE: https://www.satellitetoday.com/government-military/2021/04/06/secure-world-foundation-says-russia-is-testing-new-leo-geo-anti-satellite-technologies/  
Independent Comment #1 from Linkedin Reader: A powered jammer from space will have next to no impact, on a LF (30 to 300 kHz) and MF (300 to 3000 kHz) ground based PNT technology. As atmospheric attenuation is becomes very high below 5 MHz in frequency, making powered jammers more of a local issue. With these low band terrestrial systems, this highlights the need for both a GNSS and terrestrial systems to operate side by side.
Independent Comment #2 from Linkedin Reader: which is why land based microPNT is so important.
Independent Comment #3 from Linkedin Reader: They actually don't have to develop very much from scratch, as everything is already handed over via various "helpers".
"In 1996, the Pentagon pushed for the development of an airborne laser weapon system. The result was a modified Boeing 747 with tracking lasers and a chemical oxygen iodine laser (COIL). The Airborne Laser’s first flight was over Kansas in July 18, 2002 and, after a series of flight tests, the COIL laser was test-fired in September 2008.

According to the Arms Control Association, the major issue with the airborne laser was that it wasn’t powerful enough, had limited range, and made the 747 vulnerable to anti-aircraft missiles. 

The airborne laser’s shortcomings led Defense Secretary Robert Gates to cancel the program in 2010."
Inependent Comment #4 from Linkedin Reader: My only question is why it’s taken so long for all major powers to develop a hard-kill option for Satellites.
Independent Comment #5 from Linkedin Reader: I would say because the "target" gets more valuable the more the vulnerable technology is integrated into critical systems. This is why people believe the multiple PNT systems will minimize the incentive to disrupt any particular one of them. "Sole source GPS" after decommissioning or obsoleting ground systems is an obvious high value target.
Independent Comment #6 from Linkedin Reader: John H. Johnson Sr. Agreed. Makes sense. The bigger the satellite constellation for the positioning system, the harder the targeting problem for a “hard-kill” solution in its space-based segment. It’s resilience is the challenge so the exploitable weakness may lie elsewhere in the systems architecture or in its EM domain.

(May 2021) More on Moore's Law:


(May 2021) ‘Take the bullseye off GPS before it’s too late!’ — PNT leaders at GWU webinar - GPS World

May 7, 2021 - By Dana Goward

A May 5 webinar about the GPS Backup Technology Demonstration by the U.S. Department of Transportation (DOT) provided valuable insights about the project and
intended way forward for PNT efforts in the department.

It also evolved into a policy discussion with former government leaders saying establishing alternative positioning, navigation, and timing (PNT) systems 
would make GPS safer by “taking the bullseye off,” and that “the time is now, before it is too late.”

The webinar, entitled “What Technologies Can Secure GPS?”, was hosted by the Space Policy Institute at George Washington University (GWU). A bipartisan 
constellation of civil PNT stars gathered to participate in the event.

Featured in the webinar were:

introductory remarks by Robert Hampshire, chief scientist for the U.S. Department of Transportation (DOT). He has also been nominated to be DOT’s assistant 
secretary for research and technology.
a presentation by Karen Van Dyke, director, Positioning, Navigation and Timing for DOT, and Andrew Hansen of DOT’s Volpe Transportation Systems Center.
discussion of the issues by Diana Furchtgott-Roth, adjunct professor at GWU and a DOT deputy assistant secretary during the Trump administration, and Greg 
Winfree, director of the Texas Transportation Institute at Texas A&M University and DOT assistant secretary during the Obama administration, both of whom 
led civil PNT issues for the federal government during their time in office.
Scott Pace, director of GWU’s Space Policy Institute, serving as moderator; he was executive secretary of the Space Council during the Trump administration.
Hampshire opened the event with an address that touched on Biden administration themes of “building back better,” modernizing infrastructure, reducing 
transportation deaths, making transportation more efficient, and preserving America’s technological leadership. All of these were linked to the need to 
improve PNT resiliency and reliability.

Backup tech demo did not close any doors
Van Dyke and Hansen then gave a presentation on the results of the department’s technology demonstration project.

Van Dyke pointed out that, while “GPS backup” may be a popular term, we need complementary capabilities that come into play not just when GPS is unavailable 
but work alongside it and provide additional capability and resilience all the time.

She also mentioned that the department is well aware there are more candidate technologies than those selected for the demonstration. Companies offering 
other ways of providing PNT will not be excluded from future consideration and efforts just because they were not part of the demonstration project.

Also, while the government collected the data during the demonstrations, she acknowledged that the effort was designed to “showcase the technologies in their 
best light.” Further study, stress testing, and evaluation will be needed for any system or technology that might be of interest to the government.

Key elements in the demos
Hansen discussed the particulars of how the technology demonstrations were conducted and some of the results. While the department evaluated 14 measures of 
effectiveness during the project
, Hansen said that two were key — accuracy and coverage per unit of infrastructure.

All the technologies demonstrating timing showed accuracy that would be useful across a wide range of applications, he said. Positioning accuracy, though, 
varied from a “ones of meters to around 300 meters” depending on the technology.

Hansen said that coverage per unit of infrastructure varied exceptionally between the technologies. These included satellite systems that provide global 
coverage with a fixed infrastructure, and radio frequency systems with widely different coverage areas per transmitter.

He also observed that the technology demonstration project was not the end of the department’s technical inquiries. In fact, some of its results—such as 
eLoran performance in an underground scenario—were unexpected and are being further examined.

Transportation has some of the most stringent PNT requirements for accuracy, integrity, availability, and reliability, he said. And not all safety-critical 
transportation requirements may be met by market-based business models. Commercial systems lack the open standards and specifications that have made GPS so 
useful and widely adopted. Hansen said that the department will be working on these issues going forward, as well as performance monitoring for alternative 

A recurring theme throughout the webinar from all participants was that there is no single solution, no silver bullet, to achieve sufficient national PNT 
resilience. A systems-of-systems approach was needed. In Hansen’s words “a plurality of complementary systems” is required to ensure PNT reliability and 
safety, as well as efficient transportation.

Take the bullseye off GPS! — An urgent national security issue
While agreeing with the systems-of-systems approach, Greg Winfree pointed out that a first step still needs to be taken. He said that the nation has known 
about the need for alternate PNT since a 2001 report by DOT’s Volpe Center. Twenty years later, still no long overdue first step has been taken.

Just establishing the first alternative and complementary system, Winfree said, will make GPS and the United States much safer. “We need to take the bullseye
off of GPS,” he said. GPS is so critically important to this country that it is a very attractive target for those who would do us harm. Having even one just 
alternative in place would make it much less of a target.

Diana Furchtgott-Roth pointed out that China, Russia, Iran and others have terrestrial systems that complement space-based PNT. About establishing 
alternatives, she said “The time is now, before it’s too late.”

Provisions in the United States National Space Policy provide that “[a]ny purposeful interference with or an attack upon the space systems of the United 
States or its allies that directly affects national rights will be met with a deliberate response at a time, place, manner, and domain of our choosing.”

Scott Pace also commented that an having an alternative to GPS will contribute to national security and improve global stability. It will “lower the 
pressure on us to escalate and respond” should GPS satellites be damaged, or services disrupted
, he said.

Next steps
One of the questions posed at the end of the session was about actions and expected accomplishments in alternate PNT at DOT in the next 18 months. When could 
the first alternative system be expected?

The DOT technology demonstration report recommended that the department work next to develop standards and requirements for alternative systems. Current 
government employees were appropriately reluctant to say much more.

Calling upon her recent experience in government, however, Diana Furchtgott-Roth that said she believed that the department needed time to stress test 
technologies, develop standards and finalize requirements. Since many capable technologies were mature, some already in operation, she thought the first 
capability could be up and running within a year after that.

The only missing element according to Furchtgott-Roth is funding, and the focus needs to be on motivating Congress to provide it. The stage is set, she said, 
with all parties agreeing on the importance of resilient PNT.

She observed that it is very difficult to get the two parties in Congress to agree, and to pass legislation. Yet this has happened three times in support of
establishing GPS alternatives
. And PNT is such a critical capability that the entire executive branch even came together to protect it last year opposing 
the FCC’s decision in the Ligado Networks application.

She also related that, when she was in office, she requested $15M for the current fiscal year to do needed stress testing and standards development, but the
funding did not appear in the budget.

One reason could have been questions she was asked about whether it is the government’s job to pay for an alternative to GPS, she said.

As a conservative economist, her answer was and is a resounding “Yes.” The national need is beyond the business model of one company or private entity. That 
is something also suggested in DOT’s report on the tech demo.

Also, “enormous value and vast efficiencies” come from one entity funding such a utility, she said. “Just as the government funds national defense, it should 
also provide a complement to GPS.”

George Washington University’s Space Policy Institute reports a recording of the webinar will be posted on YouTube within the next week.


(May 2021) Just how resilient are satellites?:


(May 2021) Emergency Landing - Russia Still Jamming Hard in Ukraine:
Blog Editor's Note: This report from the Organization for Security and Cooperation in Europe is no surprise. We have reported on this before and Russia is 
still Russia. They have bragged their jamming capability extends for hundreds of kilometers, so per the report, hard to say where it is coming from.

Always good to be reminded, though, that threats are still out there and result in real world consequences. 

In this case, it was an emergency landing of a UAV trying to monitor compliance (or detect non-compliance) with a peace agreement. As we have shown in other 
posts, the jamming in this area also impacts commercial airliners, ships and others.

The UN aviation and maritime organizations have both called GPS/GNSS jamming an urgent, safety of life issue.

No alt text provided for this image
Note that, even if the jamming also interferes with Russia's GLONASS satellite system, their forces still have access to terrestrial Chayka (Loran-C) for 
navigation and timing in that region.

Thanks to RNTF International Advisory Committee member Guy Buesnel for calling this report to our attention.

(May 2021) OSCE SMM Spot Report 13/2021: Emergency landing of long-range unmanned aerial vehicle due to dual GPS signal interference:

Format News and Press Release

Source OSCE

Posted 6 May 2021

On 6 May, the SMM was conducting an announced SMM long-range unmanned aerial vehicle (UAV) flight. The UAV had taken off from its base in government-
controlled Stepanivka
(54km north of Donetsk) at 12:30 and had immediately experienced dual GPS signal interference, assessed as caused by jamming, which 
then had occurred at intervals during the flight. At 16:01, while flying over areas near Kolosky (non-government-controlled, 46km south-east of Donetsk), 
the UAV had again experienced dual GPS signal interference, assessed as caused by jamming, which continued uninterrupted for the remainder of the flight.

Between 18:35 and 19:05, due to the risk of a loss of spatial control, the SMM had attempted three landings of the UAV at its base in its Emergency Control 
Mode, the first two of which had failed due to continuing dual GPS signal interference. On its third attempt, while dual GPS signal interference persisted, 
the aircraft completed an emergency landing in a field about 600m north of its designated landing spot. The SMM retrieved the UAV and an initial assessment 
did not reveal visible damage.

The Mission again highlights that since 21 March 2021 the SMM’s long-range UAVs have been experiencing increased levels of GPS signal interference on take-
off and landing
, affecting both of their GPS receivers, in areas near their base in Stepanivka (See SMM Spot Reports of 7 April 2021, 9 April 2021 and 24 
April 2021). The Mission notes that, in each case, the source of GPS signal interference could have originated from anywhere within the radius of tens of 
kilometres from the UAVs’ positions.

The SMM yet again notes that OSCE Permanent Council Decision No. 1117 specifies that the SMM shall have safe and secure access throughout Ukraine. 
Unrestricted and unconditional access to all areas is essential to ensure effective monitoring and reporting of the security situation, the ceasefire, 
the withdrawal of weapons, demining, as well as disengagement. The mandate also tasks the Mission to report on any restrictions of its freedom of movement 
or other impediments to fulfilment of its mandate.

These incidents hinder the Mission’s ability to conduct effective monitoring and reporting of the security situation in line with its mandate. Long-range 
UAVs are an essential part of SMM operations, especially at night and in areas where the Mission’s monitoring and freedom of movement are restricted. While 
the SMM cannot identify the precise source of jamming, it has observed the presence of jamming equipment on both sides of the contact line.

VIEW ORIGINAL REPORT: https://reliefweb.int/report/ukraine/osce-smm-spot-report-132021-emergency-landing-long-range-unmanned-aerial-vehicle-due 

(May 2021) Satellite-navigation systems such as GPS are at risk of jamming, Alternatives are needed - The Economist:
Blog Editor's Note: This is a good general interest article to which we contributed. It is behind a paywall, so many of our readers may choose not to access
the entire piece. 

Most significant is that a highly regarded journal is addressing the issue. A sure sign of the growth of widespread concern, and, hopefully, movement in many 
quarters to mitigate risks.

Published on May 7, 2021
Dana A. Goward
President, Resilient Navigation & Timing Foundation; Proprietor, Maritime Governance, LLC 

Blog Editor's Note: This is a good general interest article to which we contributed. It is behind a paywall, so many of our readers may choose not to access 
the entire piece. 

Most significant is that a highly regarded journal is addressing the issue. A sure sign of the growth of widespread concern, and, hopefully, movement in many
quarters to mitigate risks

5 May 2021

Back-ups for GPS
Satellite-navigation systems such as GPS are at risk of jamming Alternatives are needed

The phrase “critical infrastructure” conjures up solidly earthbound images: road and rail networks, water and sewage pipes, electricity grids, the internet,
and so on. Such stuff is so wound into the warp and weft of life that it is simultaneously both essential and taken for granted. One piece of infrastructure 
which has become critical over recent decades, though, is anything but earthbound. This is the various constellations of satellites, the most familiar of 
which is probably America’s Global Positioning System (gps), that orbit about 20,000km above Earth, broadcasting to the world precisely where they are and 
exactly what time it is.

The original purpose of the GPS and its European (Galileo), Russian (Glonass) and Chinese (BeiDou) counterparts was to enable suitably programmed receivers 
on or near the ground to calculate their whereabouts to within a few centimetres, by comparing signals from several satellites. In this role they have become 
ubiquitous, running everything from the navigation systems of planes, ships and automobiles, both military and civilian, to guiding the application of water
and fertiliser in precision agriculture. But global-navigation satellite systems (GNSS), to give their collective name, now do much more than that. By acting 
as clocks that broadcast the time accurate to within a few dozen nanoseconds, they are crucial to jobs ranging from coordinating electricity grids and 
mobile-phone networks to time-stamping financial transactions and regulating the flow of information in and out of data centres.

READ MORE (paywall ahead): https://www.economist.com/science-and-technology/2021/05/06/satellite-navigation-systems-such-as-gps-are-at-risk-of-jamming  

(May 2021) In Fixing GPS, Timing is Everything - EE Times:

By George Leopold 04.26.2021

Global Navigation Satellite Systems, particularly the vulnerable U.S. Global Positioning System, represent a single point of failure that can be rendered 
inoperable by unintentional or intentional inference. That reality, along with over-dependence on the nearly five-decade-old satellite constellation, has 
forged a western consensus to accelerate development of terrestrial GPS backups and other mitigation strategies built around complementary position, 
navigation and timing technologies.

Known in the industry as PNT, several federal agencies are working on demonstration projects aimed at testing and developing a terrestrial backup system 
should GPS be knocked out by jamming, spoofing or interference aimed at the satellite constellation’s inherently weak signal.

READ MORE: https://www.eetimes.com/in-fixing-gps-timing-is-everything/# 

(May 2021) Clear and Present Economic Danger - GW Prime:
Blog Editor's Note: An excellent article on Geospatial World Prime by RNTF Member Diana Furchtgott-Roth. 

Diana is an economist who also led civil PNT issues for the US government, so she is uniquely qualified to examine this aspect of these issues.

Clear and Present Economic Danger:
Americans depend on GPS. While military dangers are obvious, outages would also cause incalculable damages to the economy.
By Diana Furchtgott-Roth

Former Deputy Assistant Secretary for Research and Technology | Department of Transportation; and Adjunct Professor | George Washington University

Vadimir Putin’s Russia brags that his country’s new Pole-21 radio-electronic systems, soon to be installed in Siberia and the Ural Mountains, can spoof 
America’s Global Positioning System (GPS), which provides positioning, navigation, and timing services through a system of satellites, and is vital to 
Americans. Hacking it has never been easier.

Originally invented for the military, GPS was extended to civilian use by President Ronald Reagan in 1983 after the Russians downed a Korean Air Boeing 747 
that had accidentally strayed into Soviet airspace, killing all 269 people on board, including Representative Larry McDonald, a Georgia Democrat.

GPS is increasingly open to hacking, as sophisticated technology has become cheaper and more widely available. In 2019, Iran spoofed the navigation system 
of British tanker Stena Impero in the Strait of Hormuz. The ship’s crew thought they were in international waters when they were actually in Iranian 
territory. The ship and its crew were held for 10 weeks by Iran.

READ MORE: https://www.gwprime.geospatialworld.net/special-feature/clear-and-present-economic-danger/ 

(May 2021) GPS Source Receives Order for 1,000th MAPS GEN I Assured Positioning, Navigation and Timing System:

COLORADO SPRINGS, Colo. – GPS Source, a subsidiary of General Dynamics Mission Systems and the only provider of a currently fielded Assured Positioning, 
Navigation and Timing (APNT) solution available to the U.S. Army, announced today it has received an order for the 1,000th Mounted APNT System (MAPS), 
Generation I (MAPS GEN I).

MAPS GEN I is a mobile modular system that monitors GPS signals for validity and sends the validated data to military devices, even when GPS signals are 
degraded or denied. This system has been in rapid development, production, and fielding since the recognition of the critical need to protect GPS signals 
against peer and near-peer adversary electronic warfare attacks
. It is the only mounted assured PNT solution allowing warfighters to conduct mobile 
operations in a GPS-contested environment.

Read more: https://gdmissionsystems.com/articles/2021/05/11/news-release-gps-source-receives-u-s-army-order-for-1000th-maps-gen-1-apnt-system 

(May 2021) Tech that guides you to the perfect parking spot, every time:

45% reduction in parking search time? Find out how cities around the world are reducing vehicle minutes traveled in this great article by Gordon Feller 
in Engineering360 #smartcity #smartparking #cleveryourcity


Russia Tests Anti-Satellite Weapon, US Military Says:
By Rachel Jewett | July 24, 2020
U.S. Space Command reports it has evidence that Russia recently conducted an anti-satellite weapons test.

In a Thursday announcement, Space Command said Russia released a new object into orbit from Cosmos 2543 in proximity to another Russian satellite. This is 
similar to on-orbit activity conducted by Russia in 2017, and it is inconsistent with the system’s purpose as an inspector satellite

In February of this year, Space Command raised concerns about this same satellite system when a Russian satellite maneuvered near a U.S. government satellite.
Then in April, military officials said that Russia tested a Direct-Ascent Anti-Satellite (DA-ASAT) missile capable of destroying satellites in Low-Earth 
Orbit (LEO). “This is further evidence of Russia’s continuing efforts to develop and test space-based systems, and consistent with the Kremlin’s published 
military doctrine to employ weapons that hold U.S. and allied space assets at risk
,” said Gen. John W. “Jay” Raymond, commander of U.S. Space Command and U.S.
Space Force Chief of Space Operations

The Department of State, called the behavior “hypocritical and concerning.” 

This event highlights Russia’s hypocritical advocacy of outer space arms control, with which Moscow aims to restrict the capabilities of the United States 
while clearly having no intention of halting its own counterspace program — both ground-based anti-satellite capabilities and what would appear to be actual
in-orbit anti-satellite weaponry,” said U.S. Assistant Secretary of State Dr. Christopher Ford.

(May 2021) Future-proof high-filtering antennas from Antcom build interference robustness and reject out-of-band signals:


(May 2021) If I Were King of the Forest: Resilient PNT for Critical Applications:


(May 2021) Adjacent Band Interference More than just a Ligado Problem - Spirent:
Blog Editor's Note: An interesting post by Guy Buesnel, a member of RNT Foundation's International Advisory Committee. We have not often seen this issue 

raised and appreciate his stimulating the discussion.

"While Ligado is the focus of the current controversy, it’s just one example of a problem that’s likely to grow as the world becomes more dependent on radio-based 

services. The radio frequency (RF) spectrum is a finite resource, and fitting in new wireless services is increasingly difficult, with spectrum sharing between services 

becoming commonplace.

As the spectrum gets more crowded, GNSS developers and users will likely have to contend with more sources of potential ABI. That will require appropriate 
countermeasures to be built into receiver designs, such as improved filtering of unwanted signals and improved shielding against signals transmitted at low 

Full disclosure, Guy is employed by Spirent which is an RNTF supporter, and Spirent offers products and services to address interference with GPS/GNSS 

Ligado Controversy Highlights Risk of Adjacent Band Interference to GPS Receivers
By:Guy Buesnel

May 11, 2021

Ligado’s 5G network is under fire again for potential interference with GPS. Users of GNSS should assess the threats posed by adjacent band interference and 
mitigate any risks.

The ongoing political conflict over US-based Ligado’s proposed 5G network has spilled over into the media, with former deputy assistant transportation 
secretary Diana Furchtgott-Roth highlighting the risks it poses to GPS
in a fiery opinion column for the Washington Post.

Ligado’s signals will be 2 billion times as powerful as GPS signals,” she wrote on April 14th. “Just as an outdoor rock concert would drown out birdsong, 
the proposed Ligado 5G transmitters would overwhelm GPS signals.”


(May 2021) Dubins Path:


(May 2021) Resilient PNT for Critical Applications - by Logan Scott:
Logan Scott

10 articles Following

There has been much discussion of the need for resilient PNT over the past few years as dependencies have grown and an evolving threat matrix has become 
more active. As a nation, we need a measured and cost-effective response commensurate with the level of threats and the possible consequences.

What is resilience?

Do we even know what resilience is? Mostly it looks like extra cost when you don’t need it. Then, when it is needed and you don’t have it, it looks like 
failure ---sort of like the Texas power grid back in February. Resilience has costs and budgets are bounded. My working definition for resilience is that 
it is about building sufficiently secure and reliable systems out of insecure and unreliable components operating in an indeterminant environment.

How do you measure resilience? You try to break it and then decide whether the protection is adequate for the domain of use. Any system will break under 
sufficient stress.
Determining what is sufficient is a hard question but it is a key question. Resilience could end up being quantified using a series of 
tests like UL standards for safes. You expose the safe to a skilled safecracker and see how long it takes them to break in. Interestingly, the highest 
security rating, TXTL-60, only guarantees protection for 60 minutes.

The need for standards and mandates.

READ MORE: 10 articles Follow:

There has been much discussion of the need for resilient PNT over the past few years as dependencies have grown and an evolving threat matrix has become
more active. As a nation, we need a measured and cost-effective response commensurate with the level of threats and the possible consequences.

What is resilience?

Do we even know what resilience is? Mostly it looks like extra cost when you don’t need it. Then, when it is needed and you don’t have it, it looks like 
failure ---sort of like the Texas power grid back in February. Resilience has costs and budgets are bounded. My working definition for resilience is that 
it is about building sufficiently secure and reliable systems out of insecure and unreliable components operating in an indeterminant environment.

How do you measure resilience? You try to break it and then decide whether the protection is adequate for the domain of use. Any system will break under 
sufficient stress. Determining what is sufficient is a hard question but it is a key question. Resilience could end up being quantified using a series of 
tests like UL standards for safes. You expose the safe to a skilled safecracker and see how long it takes them to break in. Interestingly, the highest 
security rating, TXTL-60, only guarantees protection for 60 minutes.

The need for standards and mandates.

A core question we have not addressed at a national policy level is how to incentivize resilience. When seat belts were invented, they were made available 
as an option by Ford and others. It was not a popular option. Less than 2% of buyers elected to get them. Then, through a series of federal mandates, they 
became required equipment and later, we saw requirements to use them. The point being that safety standards are needed, they have costs, and, if they are 
left optional, they may not be implemented or used.

I like that DHS is addressing resiliency as a risk management question but leaving the implementation of protections entirely up to the user community 
strikes me as unworkable. Our user communities are rarely aware of the potential risks, much less how to address them. Even when they are aware of the 
risks, industry is often more driven by cost considerations under nominal conditions, and they fail to prepare. I’ll pick on the Texas power grid in 
February again, but I could also have picked on “just in time” manufacturing systems vulnerable to supply chain disruptions, or the Suez Canal. By 
establishing standards and exposure-based testing procedures, vendors and buyers in critical infrastructure domains can avoid the more egregious outcomes 
in a cost-effective manner.

The need for Modular Open Systems Approaches (MOSA)

In prior discussions I have noted that building a resilient architecture is not just about having the right parts; they must be integrated correctly (and 
tested). MOSA is about effectively leveraging the capabilities of diverse system components and maintaining currency as new innovations and technologies 
become available. MOSA is a platform, it is an operating system, it is an enabler. It is not a point solution.

A cell phone’s positioning process is a great example of MOSA. Android phones come in diverse flavors and have a rapid innovation cycle based on a rich and 
constantly evolving ecosystem of parts. Yet, they all manage to integrate sensors together to establish position with good accuracy both indoors and 
outdoors. That said, cellphones performed abysmally when exposed to inadvertent spoofing at the ION GNSS+ conference in 2017.

In many ways, integrity and resilience are highly intertwined problems and so, there are opportunities within MOSA constructs to approach the problem of 
safely integrating less than 100% trusted, 100% reliable components. Experience with cybersecurity shows the need for a rapid update and response cycle—MOSA 
will help.

The need for authentication

Authentication is about knowing where your data comes from, knowing where your software comes from, and establishing a chain of evidence to establish 
provenance. In the MOSA paradigm, if subsystems can report problems due to spoofing, jamming, cyberattack, hardware failure, software corruption etc. 
AND, there are performance and security monitors in place to aggregate information and watch for discrepancies, a more effective and resilient response 
can be mounted. OS-NMA and Chimera can help by providing unambiguous discrepancy reports. Depending on the operating domain, it may even be possible to 
report problems to higher authorities so as to establish patterns and causes. For instance, jamming might be rapidly geolocated using crowdsourcing methods 
ala. J911 but such an approach is viable only if you can establish trust in your sources.

The need for trustable multi-GNSS

In the quest for resilience and augmentations, I am not convinced that we as a nation have fully explored how to safely integrate foreign navigation 
systems into critical applications. Access to more signals and more systems offers considerable resilience potential. Instead, the FCC has unilaterally 
restricted their use under part 25 rules with limited justification. Perversely, this has led to some US companies flying their satellites under foreign 
flags so as to gain legal access to FCC proscribed navigation signals. These same restrictions limit the performance of precision positioning systems, 
receiver autonomous integrity algorithms, positive train control systems, and, spoofing detection processes.

One of the things I found fascinating about the Galileo failure in July 2019 was that the satellites all continued to produce good ranging signals. If you 
could provide your own ephemeris, say from JPL, NASA, NSWC, and/or other sources, you still got great performance. Treating foreign navigation satellites 
as “signals of opportunity” and using curated and signed US generated ephemeris strikes me as a useful augmentation. Much less trust is placed in the 
foreign state, yet you get a lot of augmentation benefit for minimal cost. Additionally, you limit the impact of a global system’s outage. If Galileo had 
been the only game in town, its one-week outage would have been catastrophic. As it was, its absence was noted but had almost no effect on GNSS dependent 

The need for an honest evaluation of Ligado’s impact on

GNSS really is different from communications. The FCC, by setting a standard where the mechanism of harm is to place GNSS receivers in deep and uncontrolled
saturation, ignores the possibility of normally harmless signals mixing and causing harm. None of the testing to date has explored this issue and so, our 
national policy might be the RF equivalent of "mixing alcohol and fentanyl and hoping for the best". Furthermore, the FCC showed almost no cognizance of the 
importance of GNSS based remote sensing in monitoring climate change. The RF smog that Ligado’s signals will create restrict our ability to develop a clearer picture 

of what is happening. The FCC’s decision needs to be revisited using sound engineering as a basis.

Augmentations and the role of markets

One of the most insidious things about GNSS is its price to the user: FREE. That, combined with its worldwide coverage and superb accuracy in both time and 
positioning creates significant barriers to entry for new offerings. In the commercial arena, a new entry that provides only the same services as GNSS, 
maybe a little better, seems doomed. A successful entrant will need to have a value-added proposition with features that cannot be met using GNSS.

Communications facilities, indoor operation, proof of integrity and location, and uninterruptable service would all be on my short list. In large measure, 
these capabilities can be provided by combining GNSS with other sensors and systems especially if we use the full constellation of 125 navigation satellites
on orbit and healthy now. That said, I do expect new entrants.

5G NR and 802.11 both have strong potential to meet the requirements of my short list, especially as they move towards higher frequencies. Yes, the ranges 
there will be short, but densities will be high. Both technologies have strong and active initiatives within their standards setting process oriented 
towards providing accurate, high integrity positioning. Also, because they are extant systems, there is less pressure to offer ubiquitous service at 
inception, a daunting challenge for a brand new entrant.

I expect LEO satellite systems will also have a role. Because they have high angular rates across the sky, you can get nearly instant on cm level 
positioning. Operating at higher frequencies, eg. X, Ku or even V-band, they can simultaneously provide strong communications capabilities when outdoors 
and so, might play very well in the autonomous vehicle markets. Yes, the antenna issues are challenging, but they ride a wave of actual deployments.

The role of government

So, what is the proper role for government? Well first, stably fund, maintain, and operate GPS. It is critical infrastructure, not easily supplanted. 
Providing secure ephemeris and integrity data to support safe use of multi GNSS should be funded. Of course, removing FCC roadblocks to its use is also 
essential. PPP data services should be considered as part of the package to promote rapid adoption of “safe ephemeris”.

Beyond that, government’s role should be one of dare I say it, leadership. Defining what we want for resilience and what standards of performance are 
needed in critical applications is only part of the solution. We also need to take action to ensure these standards are met by introducing clear 
requirements and ensuring necessary infrastructure is available. Developing an integrated infrastructure plan that uses GEO, MEO, LEO and terrestrial 
components to our best advantage is a necessary step. Government needs to influence approaches not only as a provider of public infrastructure but as 
a customer for private infrastructure. Resilience is best achieved as a cooperative undertaking with industry but absent leadership, nothing is going 
to happen. Until it does.

Important Comment by Grant Taylor:
The role for government is by most important part of any new PNT technology rollout, as any service will need to be public accessible, like what GPS is. 
This is where I am running into dead ends with my ground based PNT system, as open access and a standard business model simply do not go together. The 
only way to provide alternatives to GPS, would be through public private partnerships, where private enterprises could support new technology and have 
setup / operating costs reimbursed by the government. This may work here in Canada, but would be a major issue to overcome within the US, where government 
and private enterprises working together are viewed as a bad thing. (Just look at healthcare systems as an example.)
EU Draft Adjacent Band Interference Specification is Available (ETSI EN 303 413 V1.1.0):

(May 2021) New Liquid Coating Could Make Stealth Aircraft Invisible and Hypersonic - The Debrief:
"In an attempt to improve on current materials, which notoriously have several drawbacks, a team from the North Carolina State University has developed a 
new ceramic-based coating that not only offers dramatic improvements in radar invisibility but will likely result in a whole host of improvements to the 
aircraft’s overall performance."


(May 2021) What are Global Navigation Satellite Systems (#GNSS) and how do they support position, navigation and timing (#PNT) applications: 

across the world?

Learn how GNSS were developed and how they enable the work we do around the world >> https://hxgn.biz/3hBRs1E 


(May 2021) Don't Just Bail Out Uncle Sam, Help Ordinary Americans Too - Real Clear Markets (Ligado issue):

Blog Editor's Note: Another great piece by RNT Foundation member, Diana Furchtgott-Roth. She makes the point that in its decision to approve Ligado's 
application, the FCC required the company to reimburse the U.S. government for any harm done to its equipment and systems. But what about the rest of us? 

Right on, Diana!
Don't Just Bail Out Uncle Sam, Help Ordinary Americans Too
By Diana Furchtgott-Roth

The cyberattack on the Colonial Pipeline has increased awareness of the fragility of infrastructure. It should also serve as a reminder to policymakers of 
a very real threat to the Global Positioning System, and of an ill-advised decision that protects government users from having to foot the bill when their 
GPS receivers are affected--while ignoring ordinary Americans and industries.

The risk comes from an April 2020 Federal Communications Commission order granting an application from Ligado Networks to operate a terrestrial network 
using spectrum next to the bands reserved for GPS. And while the FCC’s order acknowledged the risk by requiring Ligado to pay for damages to federal 
devices, it does not require the company to compensate individuals and companies, such as pipelines, helicopter terrain awareness warning systems, car 
navigation systems, and power plants -- costs that could run into the tens of billions of dollars.

READ MORE: https://www.realclearmarkets.com/articles/2021/05/20/dont_just_bail_out_uncle_sam_help_ordinary_americans_too_777973.html 

(May 2021) MDA Holds Briefing on FY22 Defense Budget:

Navy Vice Adm. Jon A. Hill, director, Missile Defense Agency, and Michelle C. Atkinson, director for operations briefs the news media on President Joe 
Biden’s fiscal 2022 defense budget, May 28, 2021.


Focused on MDA: https://www.defense.gov/Watch/Video/videoid/799271/dvpcc/false/#DVIDSVideoPlayer581 
(June 2021) Special issue of ACM: History of MatLab: 


(May 2021) Startling GAO Report on DOD Navigation - Webinar June 15th:

The General Accountability Office (GAO) released a somewhat scathing report about Department of Defense navigation programs this month.

Among their findings and inferences were:

Navigation requirements for projects and systems are often overstated with managers just defaulting to GPS accuracy requirements
Resilience is not a requirement for navigation systems in many cases
Alternate (non-GPS) navigation systems are not a priority for the department, and are actively opposed in some instances
There is a lack of coordination across the department on alternate PNT systemsThe Institute of Navigation and the RNT Foundation will hose a webinar on the 

15th of June featuring two of the report's authors. 

Attendance is open to the public and free, but advance registration is required.

REGISTER HERE: https://www.ion.org/publications/webinars.cfm 

(May 2021) Northrop Grumman to supply navigation payloads for DARPA’s Blackjack satellites - Space News:



 (May 2021) Weighing the Costs of GPS Disruption and Developing Backup Capabilities:

GPS signals are susceptible to both unintentional and intentional disruption, leaving critical infrastructure vulnerable. But how do the costs of a 
potential GPS backup compare to the threats that such a backup would mitigate?



(June 2021) New GAJT Protects Against RF Interference and Jamming in Marine Environments - Defense Advancement:

The new GAJT-410MS from Hexagon | NovAtel is the latest in GPS Anti-Jam Technology (GAJT) that will provide interference mitigation and jammer 
direction-finding for advanced situational awareness in marine environments.

The GAJT-410MS provides dynamic protection on both GPS L1 and L2 bands, as well as Galileo E1, QZSS L1 and L2 and SBAS L1 to combat intentional 
and unintentional interference. 

For more information:

(June 2021) $17M proposed for DOT resilient PNT initiatives - GPS World:
$17M proposed for DOT resilient PNT initiatives
June 4, 2021 - By Dana Goward

Office and Management and Budget (OMB) seeks to extend Trump policies and repeal timing law counter to its own study and industry input
The Biden administration’s budget proposal delivered to Congress last week includes $17 million for the small Department of Transportation (DOT) office 
responsible for leading civil positioning, navigation and timing (PNT) efforts for the nation. This is a marked increase over the $2 million allocated in 
2020 and estimated $5 million being spent this fiscal year.

At the same time, it seeks to repeal the National Timing Resilience and Security Act of 2018 that mandated DOT establish a terrestrial timing backup for GPS
This, despite the findings of a recently published RAND study completed for the Department of Homeland Security (DHS), and other input from a 
telecommunications industry group.

Proposed Spending
The administration’s budget proposes $17 million for the DOT Office of Research and Technology to be split among three areas of effort.

Monitoring and detection. The first is a $3.5 million “(GNSS) performance monitoring and interference detection” project. This is a one-time request that is
expected to be followed by a request for $1 million in yearly funding to maintain and operate the capability.

While these may not seem like sufficient funds to many, DOT is tasked with working with other departments and agencies, and to leverage existing 
capabilities. The National Geospatial-Intelligence Agency (NGA) is specifically named as an important partner with DOT in this effort. NGA already has 
responsibility for issuing worldwide navigation warnings for U.S. interests.
It also has access to a wide variety of information that could be used for 
the project.

Signal authentication. Another $3.5 million is proposed for Executive Order (EO) 13905 Implementation and GPS Signal Authentication. The EO was issued in 
February 2020. It seeks to leverage market forces and education to create additional sources of PNT and encourage users to access them. This approach has 
been criticized by many as unworkable without extensive regulation and mandates for users, while still not addressing the majority of American companies 
and users.

$1.5 million of this $3.5 million will go to further implement the EO through development of a “PNT threat space model” and otherwise support inter-
department PNT profile and research and development efforts.

$2 million would be allocated for a one-time investment in GPS signal authentication to “result in the development and validation of requirements for 
data and signal authentication capability for civil GPS,”
reads the proposal. DOT has regularly requested much greater sums to establish civil signal 
monitoring, leading many to believe the requirements are already well known. One industry observer suggested this could be “a study in lieu of action.”

GPS Backup. $10 million would be spent for “GPS Backup/Complementary PNT Technologies Research,” essentially follow-on studies to the DOT GPS  
Backup Technologies Demonstration. “These efforts will further develop PNT modeling, simulation, and testing tools, as well as standards and  
performance monitoring tools needed to evaluate integration of diverse positioning, navigation, and/or timing technologies into end-user applications.
This work will also support development of cyber-secure receivers,” reads the proposal.

Proposed Repeal of Timing Law
More surprising to many than the significant increase in proposed funding is inclusion of a proposal to repeal the National Timing Resilience and Security 
Act of 2018 (NTRSA).

One congressional staff member expressed shock at seeing that provision. “The act was the epitome of thoughtful, bipartisan congressional effort,” the 
staff member said. “It was co-sponsored in the Senate by Markey and Cruz, for crying out loud. You can’t get more bipartisan than that. To have this dumped 
on us without any notice or consultation is amazing. It is not something I would expect from this White House. I am not sure how serious a proposal it is.”

Some observers on the hill and elsewhere have opined that, rather than the repeal proposal being a well-vetted administration policy, it is an effort by 
OMB staff held over from the previous administration to carry forward and preserve President Turmp’s Executive Order 13905 and other PNT policies.
Rather than focusing on establishing a GPS backup capability; they, instead, urged PNT users to find and pay for alternatives on their own.

Harsh Tone, False Assertions
Compounding the surprise is the exceptionally harsh tone in the proposal, and assertions that many claim are outright false.

Among the problems with the language seen by observers is its assertion that NTRSA seeks to establish a single backup for GPS services.

“It’s unclear to me where such an assertion is supported in the record,” said Greg Winfree, former Assistant Secretary at DOT in the Obama administration
NTRSA requires the department to incorporate findings from the GPS back-up demonstration program. That project found a variety of systems are 
needed to protect America,” he said. “NTRSA does require establishment of at least one system, which is incredibly important. Without at least one
alternative in place, GPS is one of highest priority targets for our enemies. We have to get the bullseye off of GPS. NTRSA does that.”

This point on national security was reinforced by Scott Pace, head of the Space Policy Institute at George Washington University (GWU). Pace was executive 
director for the Space Council in the Trump administration
. At a recent GWU webinar on the topic, he commented that having an alternative to GPS will 
contribute to national security and improve global stability
. It will “lower the pressure on us to escalate and respond” should GPS satellites be damaged
or services disrupted, he said.

China, Russia, and other nations have terrestrial PNT alternatives to GNSS already in operation. This imbalance creates strategic and tactical problems
for the United States, according to many analysts.

The proposed budget also describes NTRSA’s goal of providing at least one backup as “inefficient, anti-competitive and potentially harmful to the existing 
market for back-up/complementary PNT services.”

“Exactly the opposite is true,” according to Diana Furchtgott-Roth, GWU economics professor. Until January of this year, she led civil PNT issues within 
the Trump administration as a Deputy Assistant Secretary for Research and Technology at DOT
. “DOT’s Complementary PNT and GPS Backup 
Technologies Demonstration Report, published in January, specifically stated that a variety of technologies are needed to complement GPS. What is the most
cost-efficient in an urban area is not necessarily the most cost-efficient in a rural or maritime area.”

PNT is a utility used by every American. Having affordable complementary service available to people in rural and urban areas is the height of efficiency. 
It is unquestionably in the interests of national and economic security. In fact, access to at least one alternative should be free so to encourage 
adoption and best protect the nation,” she said.

GPS is now a free service provided by the government, and the government is responsible for making sure that it is reliable. GPS outages would cause
harm across a broad range of economic activities, including emergency services, general aviation, pipelines, and the electricity grid,” according to 

Not-So-New and Contradictory Research:
The proposal to repeal NTRSA cites “recent federal analyses” as part of its justification. One of these is likely a report done for the Department of 
Homeland Security (DHS) by the RAND Corporation. Touted in a press release last month as “new research” and labeled “Published 2021,” the work was actually 
completed in 2019
. DHS representatives have said the delay in publication was needed for review and approval.

Yet the report was the basis for a DHS report to Congress submitted in April 2020. This has caused some to opine that its publication was timed to 
reinforce OMB’s effort to repeal NTRSA.
“You don’t submit reports to Congress based on un-reviewed, un-approved material,” said a retired DHS official. 
"The timing of its release is clearly deliberate.”

The study, “Analyzing a More Resilient National Positioning, Navigation, and Timing Capability,” takes a cost-benefit approach to the issue. One of its 
high-level findings is that government investment in a duplicate, GPS-like backup capability is not warranted.

At the same time, it found that government investment in a national timing network, such as the one mandated by the NTRSA, is likely warranted. Saying 
that a complete backup for all GPS services in all parts of the country is not cost-beneficial, the study says there are some “…federal initiatives that 
do appear to be cost effective or close to cost effective.” These include “Timing-only backup through fiber/FirstNet, eLoran, or STL [Satelles].”

According to the retired DHS official, this directly contradicts OMB’s assertion that NTRSA should be repealed.Either they didn’t read the whole thing, 
or they counted on most people not reading farther than the top-level recommendations,”
he said. “And those top recommendations were clearly selected to 
match OMB’s desired outcome.

Telecommunications Industry Cites Need for NTRSA Provisions:
The May 2021 “Report to the President on Communications Resiliency” also runs counter to claims made in the budget proposal. In it, the president’s 
National Security Telecommunications Advisory Committee (coordinated by DHS) cites the need for GPS alternatives in telecommunications and urges
President Biden to fund them. It specifically mentions the need for a national timing architecture, and cites the provisions of NTRSA several times as a step 
in the right direction.

The industry group Alliance for Telecommunications Solutions also sent letters in May to congressional leaders urging funding for GPS alternatives.

Continuing the Discussion:
Congress has become increasingly dissatisfied with executive branch actions on resilient PNT over the last decade.

The most recent evidence of this is an extensive and highly critical report of the Department of Defense’s approach to PNT resilience released May 10 by 
the Government Accountability Office (GAO)
. Among its recommendations was to not rely on GPS as a primary PNT source but look to more resilient technologies.

While President Trump’s 2020 Executive Order did not make precisely the same recommendation to civil users, it did focus on “responsible use” of PNT
and transitioning to using additional, non-GPS dependent sources.

The question still under discussion is how far the government should go to support such a transition.

Seasoned observers regularly comment that Congress has the “power of the purse” and every president’s budget is “dead on arrival” regardless of which
 party controls the White House.

It seems clear that resilient PNT will be a topic of lively debate between the Congress and the White House, as well as internally on the hill, for the 
foreseeable future.

(June 2021) "The Russia Trap"​ - Single Points of Failure & GPS:
Blog Editor's Note: We were interested to find the discussion of the importance of resilience and PNT in George Beebe's book "The Russia Trap." 

Beebe talks about "War by Other Means" and how simmering tensions can cause seemingly innocuous interactions to spiral out of control. Hence the 
"trap" potentially leading to an otherwise unthinkable nuclear war.

One of the key strategies to avoid this, he says, is the ability for America to "absorb shocks," by which he means "resilience." The ability to 
resist disruption as much as possible, and when not possible to minimize the disruption...

He starts his chapter "Absorbing Shocks" by pointing out that we have shock absorbers on our cars because we know that, despite the best efforts 
of highway departments, there are always going to be bumps in the road. Shock absorbers aren't there to "correct these defects, but to make them 
less damaging to vehicles and less painful to drivers and passengers."

Beebe discusses several areas in which America is significantly under-resilient. His discussion of technological resilience is pertinent to on-going 
discussions in the PNT world.

How Our Shadow War with Russia Could Spiral into Nuclear Catastrophe

Part of designing resilience into the system involves identifying critical "single points of failure" features and building backups that can 
compensate for their damage or loss. As processes that were once performed by humans have increasingly grown more automated, we have realized
stunning efficiencies...

These systems are not only vulnerable to cyber-interference from Russia and a range of other state-sponsored and individual cyber-actors but also 
to extreme weather events...

The American Global Positioning System (GPS) is but one example of a system upon which numerous critical military and commercial functions depend, 
but which is highly vulnerable to disruption and at present is not adequately backed up by emergency alternative systems. Plans have recently been
put in place to provide such a backup, but they have been moving slowly. Most experts agree that the "eLORAN" system (Enhanced Long-Range Aids to 
Navigation), developed by the US Coast Guard, can provide an effective non-GPS-dependent timing and navigation system that can sustain critical
national communications and other GPS-related functions in the event of a sustained outage...

But discussions about the need for a backup system have been underway for nearly twenty years, and even now the new legislation makes implementation 
"subject to the availability of appropriations." The pace of progress has lagged vastly behind the urgency of the problem.

Blog Editor's additional note: eLoran has been identified by multiple government studies and twice been recommended by the US National Space-based 
Positioning, Navigation, and Timing Advisory Board.
It was also one of several technologies in the Department of Transportation GPS Backup Technology 
Demonstration. The resulting report said multiple systems were needed to adequately "backup" GPS. Also that, based on the demonstrations, L-band signals 
from space, Low Frequency, and UHF signals were needed, and that the terrestrial transmitters should be connected by fiber. eLoran is one of several Low 
Frequency systems that could be employed.

(June 2021) This, from an excellent deep dive by RAND on the resilience of US Positioning, Navigation, and Timing capabilities: https://buff.ly/3uXFdzt 
See this gentle rebuttle by Dana A. Gowerd:
Hi Brian,

The high level conclusions are, I think, misleading for policy makers. The study actually says that backing up GPS timing is likely worthwhile, as is backing up positioning 

in limited areas..

The study was completed in 2019 to support a Trump administration report to Congress (sent in April 2020) opposing a law and other congressional efforts to get them 

to establish a timing backup for GPS

Likely why the "backing up GPS not worth it" was highlighted and "backing up timing everywhere and positioning in some areas" was NOT.

Not sure why DHS and OMB want to keep America vulnerable/weak relative to China, Russia, & Iran in our ability to withstand disruptions to GNSS signals.

The "cost-benefit" approach also ignored strategic issues like our overall resilience and the need to "take the bullseye off of GPS" as one of the most attractive targets 

for our adversaries.

See https://www.gpsworld.com/17m-proposed-for-dot-resilient-pnt-initiatives/  

(June 2021) Air Force Gen. John W. Raymond: Chinese lasers, jammers threaten GPS satellites - The Washington Times:
Blog Editor's Note: We have talked a lot in recent posts about the PNT gap between the U.S.A. and our adversaries China, Russia, and Iran. It is a gap that,
as Beebe says in "The Russia Trap" (could also be titled "the China Trap") creates conditions that could easily spiral us into nuclear war. 

Think that claim is a bit "out there"? A single bullet started WWI. - But, we are so much smarter now... NOT! - Read the book before you decide. And consider
the comments we have reported from former Obama and Trump administration officials along the same lines.

US policy is that if anyone messes with our critical space assets the nation will mount "...a deliberate response at a time, place, manner, and domain of its

Concerns expressed by Beebe and others are that, if when GPS is interfered with the US has no fallback capability, such a response will necessarily be 
harsher, more provocative, and more likely to lead to an escalating conflict.

While serving officials are unlikely to comment in such a way, they do regularly comment on threats and vulnerabilities. We need to understand these reports 
in the larger context of great power competition.

The below report is yet another four star trying to signal civilian leadership that we "really have a problem here."
Air Force Gen. John W. Raymond: Chinese lasers, jammers threaten GPS satellites
By Bill Gertz - The Washington Times - Monday, May 10, 2021

China’s space weapons include missiles and killer satellites, but Beijing’s most worrying arms are lasers and electronic jammers capable of destroying or 
disrupting Global Positioning System navigation satellites used by the U.S. military
, the general in charge of space says.

READ MORE: https://www.washingtontimes.com/news/2021/may/10/air-force-gen-john-w-raymond-chinese-lasers-jammer/  

(June 2021) GMV awarded contract for Galileo HAS data generator - GPS World:
GMV has been awarded a contract for the implementation of the Galileo High Accuracy data generator (HADG):

(June 2021) Robust, credible and layered missile defense is the foundation of deterrence:


(June 2021) Let the Coast Guard Operate eLoran - US Naval Institute Proceedings:

Blog Editor's Note: Up front caveat - the editor has deep Coast Guard experience and more that a passing familiarity with eLoran. In fact, he probably 
still is on the "bad list" of a major telecommunications company because he was not able to arrange a two month delay of the 2010 shutdown of Loran-C in 
the U.S. The company had been using it as a timing reference.

That said, eLoran has been regularly recommended as a complement to GPS by government studies and the national PNT advisory board. And Loran is in 
operation elsewhere in the world. So, if it was part of the suite of solutions the US adopted, it would provide opportunities for constructive engagement with others.
And we know at least one senior Capitol Hill staff member who thinks that having the Coast Guard resume this duty is the way to go.

A good article. We particularly like the sidebar "The Dangerous Radio-Navigation Capability Gap." This is a point that seems to have been missed by many 
policy makers, though it is being discussed more recently. See our recent post on "The Russia Trap" and the comments of officials from the Obama and Trump 
administrations in this article.

Let the Coast Guard Operate eLORAN
The United States must address its GPS capability gap, and the Coast Guard’s expertise makes it the right service to lead the way.
By Ensign David W. Zenkel, U.S. Coast Guard
June 2021Proceedings


(June 2021) Cybersecurity Experts Push President Biden To Protect GPS Satellites And The Connected Car - Forbes:

Blog Editor's Note: Great article with some interesting background. And more widely applicable. Just remove "connected car" from the title and substitute, 
well... just about anything, and it should still work. "President Biden, we urge you to protect GPS satellites and the... electrical grid... the network... 
delivery services..." - you name it.

In truth, though, a lot of the easiest fill-in-the-blanks are transportation related. That's why DOT has long had the rose pinned on them for civil PNT

And yes, as is reported in this article, PNT is infrastructure! Critical infrastructure! - Can someone in government say that out loud, please?

May 18, 2021,07:10am EDT|

Cybersecurity Experts Push President Biden To Protect GPS Satellites And The Connected Car

Steve Tengler, Senior Contributor on Transportation

Sometimes when you exclaim the sky is unprotected, they mentally label you as Chicken Little and ignore your alarms. Or sometimes they might believe your 
warnings yet quietly follow the group inertia that’s the cornerstone of groupthink..

Such is the tale of Lisa Donnan, an internationally recognized expert in cybersecurity and operating partner at Option3 Ventures, and Julian Gresser, the 
former advisor to the U.S. State Department and World Bank and co-founder of The Balance Group. They have vigorously waved the Caution Flag regarding an 
insecure, trusted, non-critical infrastructure (satellites) communicating to a trusting non-critical infrastructure (vehicles) that could disrupt a vast 
network of highways, bridges and tunnels that are recognized as critical infrastructure. 

READ MORE: https://www-forbes-com.cdn.ampproject.org/c/s/www.forbes.com/sites/stevetengler/2021/05/18/cybersecurity-experts-push-president-biden-to-protect-gps-satellites-and-the-connected-car/amp/

(June 2021) New Algorithm Helps Autonomous Vehicles Find Themselves, Summer or Winter:

A new Science Robotics paper https://lnkd.in/g8mV8dP  on Learning based Visual Terrain-Relative Navigation was published today. Tony Fragoso, Connor Lee, 
Austin McCoy. Funded by Boeing, National Science Foundation (NSF), and Caltech.


(June 2021) U.S. government prepares to issue landmark report on UFOs:

The U.S. government, once openly dismissive of UFO sightings that for decades sparked the popular imagination, is poised to issue an expansive account of what it 

calls "unidentified aerial phenomena" based heavily on observations by American military pilots.

----------------------------------------------------------------------------------------------A Criticism:
James Kiessling, 1st degree connection
Systems architect and analyst

Gads - observations by pilots - that's lovely - an unimpeachable source since their ego's cannot admit that training to fly does not make you an excellent 
observer or expert at artifacts that onboard sensors can create. Having actually analyzed some of the source data - I expect that with time, at least 70% 
of the cases - certainly over 85% where recorded data is available can be explained. I am far more interested in the story from: 


(June 2021) Extremely accurate time is increasingly critical. This place is in charge of it. - National Geographic:

Blog Editor's Note: Interesting article about the UK's capabilities. Also timely since we just did a webinar last week, in partnership 
with Hoptroff, on timing in the UK with Leon Lobo of the National Physical Laboratory. Look for the recording of the webinar to be posted soon.

In the U.S. our timekeepers are the National Institutes of Standards in Boulder, CO, and the U.S. Naval Observatory in Washington, DC.

And at the risk of repeating the message too many times we will remind everyone that, not only is timing important, it also has to get 
to folks so they can use it. Establishment of a national timing system to backup GPS has bee the subject of recommendations in the U.S. 
for years, including:

The National Security Telecommunications Advisory Committee (NSTAC), a government board of major telecom CEOs and executives, recommended 
to President Biden in May that he fund a National Timing Architecture.

The US National Space-based PNT Advisory Board recommended a terrestrial timing backup for GPS
The Alliance for Telecommunications Industry Solutions (ATIS) wrote to senior members of Congress urging them to invest in a national 
timing system. PNT Foundation
published a white paper in October 2020 entitled "A Resilient National Timing Architecture"
A recently released report for DHS by RAND found that federal investment in a timing system is likely worthwhile.
The UK is moving forward, China, Russia, Iran, and South Korea are already there. Where is the US?

If you've ever been mystified by the term 'atomic clock,' or wondered what quartz has to do with time, this is the lab with the answers:
By Dominic Bliss

Teddington, on the southwestern edge of London, is home to three of the most precise clocks on the planet. They are accurate to one billionth 
of a second per year.
So accurate, in fact, that for them to lose or gain just one second, they would need to keep ticking for the next 14 billion 
years; until the end of the universe.
Bear that in mind when you’re next changing the batteries in your wristwatch.

These clocks, housed inside the UK’s National Metrology Institute – the centre responsible for developing an maintaining measurement standards and 
itself located at the National Physical Laboratory – are known as optical atomic clocks, and they’re more accurate even than the previous generation 
of cesium atomic clocks. Of course they bear no resemblance whatsoever to any timepiece you might wear on your wrist or set atop your mantelpiece. 
There are no hands or clock faces or spinning wheels or any of that mundane horology.



(June 2021) Quantum random number generator sets benchmark for size, performance:
As pervasive as they are in everyday uses, like encryption and security, randomly generated digital numbers are seldom truly random. So far, 
only bulky, relatively slow quantum random number generators (QRNGs) can achieve levels of randomness on par with the basic laws of quantum 
physics, but researchers are looking to make these devices faster and more portable. In Applied Physics Letters, by AIP Publishing, scientists 
from China present the fastest real-time QRNG to date to make the devices quicker and more portable.

(July 2021) Navy ditches futuristic railgun, eyes hypersonic missiles:
After $500mm spent, US Navy has pulled the plug (for now) on the railgun which fires projectiles at up to 
seven times the speed of sound using electricity.

Its new focus is a hypervelocity projectile that can be fired from ship's existing missile systems.


(July 2021) Many technologies can help GNSS, but few can replace it - GPS World:
Blog Editor's Note: "Yeah, verily" to the author's point that anyone who talks about replacing GNSS is blowing smoke (and probably selling something).

Unfortunately when we talk about ADDITIONAL or ALTERNATE sources of PNT, folks often wrongly think "replacement," or "duplication," or "redundant." 
(Of course, you say redundant to engineers and their eyes light up in adoration. You say the same thing to budgeteers and their cost cutting knives 
come out.

When we talk about the need for sources in addition to GPS/GNSS we aren't saying that PNT baby is ugly and should be done away with. We are saying it 
is precious and deserving of our utmost care and protection.

That's why, in the words of Texas Transportation Institute Director Greg Winfree, we need to "get the bullseye off GPS." One of thousands of reasons why 
America needs to have additional, widely adopted, PNT sources. 

Our adversaries have long realized that relying entirely on space for such essential services is tantamount to putting your neck on the chopping block 
and waiting for the axe to fall.
It is time we do as well.

Whoa, whoa, whoa, isn't that a bit over dramatic? Where do you get off with such statements? - "Neck on the chopping block," "waiting for the axe to fall"
- indeed!

OK, sure. We could probably use more discussion about repairing the condo building's foundation before we actually do something.

Let's talk more about pipeline and other cyber-security, ensuring electricity in Texas during the winter, fixing the levees in New Orleans, hardening 
cockpit doors against hijackers, the health impacts of tobacco, installing seatbelts in cars. - What's the worst that could happen?

BTW- Welcome back to Matteo Luccio, the new Editor-in-Chief at GPS World. Matteo began his career in the industry in 2000 as Managing Editor at GPS 
before moving on to other opportunities. He has recently returned to this new role!

Many technologies can help GNSS, but few can replace it:
Matteo Luccio
Alternative. Complementary. Backup. Co-primary. These are some of the terms used to refer to sources of positioning, navigation and timing (PNT) data 

other than GNSS satellites.

The four current GNSS constellations — supplemented by two regional ones and by public and private augmentation systems — have firmly established 
themselves as the primary source of PNT data by virtue of their accuracy, reliability, global coverage and ubiquitous use. Yet, this widespread 
dependency on them — especially on GPS — coupled with their well-known vulnerabilities to jamming, spoofing, other RF interference, multipath, 
solar flares and space debris
(see page 10) — make the development of alternative sources of PNT data imperative. In fact, the U.S. Congress has 
repeatedly mandated it.

Typically, when talking about alternative PNT, we are referring to sources of PNT data that either were not originally developed for navigation purposes 
such as television broadcast towers used as “beacons of opportunity” — or that use a higher broadcast power or a different frequency band than 

GNSS. They include legacy systems and new versions of legacy systems, such as eLoran.

READ MORE: https://www-gpsworld-com.cdn.ampproject.org/c/s/www.gpsworld.com/many-technologies-can-help-gnss-but-few-can-replace-it/amp/  

(July 2021) U.S. Navy Ship Spoofed to Crimea:

Last week a UK Royal Navy destroyer and Dutch Royal Navy ship safely moored in Odessa, Ukraine, were spoofed to appear to be at locations off-shore of a 

Russian naval base on Crimea.

This week, it was a US Navy ship moored in the same port that was spoofed.

These are interesting cases in several ways.

First, how was it done?

No other vessels seem to have been impacted. So this is much different from the wide-area spoofing the Russians have long conducted in the area.
It could have been highly targeted GPS spoofing that only impacted the three ships. But the three ships were in port alongside a pier. Did they 
even have their GPS and AIS activated?

It could be that GPS spoofing had nothing to do with it and just AIS signals were imitated and detected by satellites.
It's possible that the AIS equipment aboard the three ships was programmed by the ships' crews to transmit the false information.

Second, who did it?
The Russians are clearly capable of doing this. They have regularly spoofed large numbers of vessels in the Black Sea over the last five years. 
This was a bit different as only one or two vessels were impacted, but it is not that big of an additional challenge
The NATO (UK, Dutch, US) crews could have done it. They certainly had access to the equipment and the ability to do it.

Could have been a third party? Perhaps a bit more of a challenge than for the other folks, but not a particularly a heavy lift for a reasonably competent 
RF hacker.

Third, why was it done?

If it was the Russians, likely yet another demonstration of their impressive electronic warfare capability and to show dominance over the West
If it was the NATO ship crews, perhaps it was a way of nettling the Russians without the trouble of having to actually sail by. Or trying to confuse 
them with a feint.
The UK ship, HMS Defender, actually sailed something close to the spoofed route several days later and was harassed by Russian 


 - Will be interesting to see if the US Navy ship does the same.
If it was a third party, perhaps it was just to cause confusion, hate, and discontent. In the 1997 James Bond film "Tomorrow Never Dies" the super-villian 
spoofs a Royal Navy ship into Chinese waters to provoke an armed conflict. See clip on our YouTube channel here.
Interesting to see life imitating art 24 years later!

(July 2021) Alternate navigation using satellite signals of opportunity - Roke:

Blog Editor's Note: We remember about 10 years ago when smart GNSS folks said this likely possible but not practical and wouldn't result in anything 
worth using.
A number also said spoofing was theoretically possible but would never be a practical threat. It is interesting to see how many things have 
changed since then. 

GPS is a good example of how, with enough time and effort, possible can often become practical. Some trace GPS back to a couple guys at JHU APL 
listening to the doppler on Sputnik in 1957 and calculating its trajectory and positions. Getting location information from a satellite was possible, 
but not practical. It took 36 years (1993) until the first GPS constellation was operational. (Comment by Tom Kerr: NAVSAT/Transit was done much 

earlier for U.S. submarines.)

This idea is also currently being investigated by others including Army Futures Command and the UT Radionav Lab. Perhaps its time has come. 

Another thing to remember is that a system doesn't have to perform as well as GPS to be useful. GPS often provides way more than users need. 
GPS might give you 27 inches accuracy, for example, but how many of us could make do with 100 feet or even 100 yards? Especially if we are 
just looking for a fall back for when GPS is not available or trustworthy for whatever reason?

We also note that the UK is especially interested in this problem. At least at the political level, much of the justification for investing 
in OneWeb was to offset being excluded from Galileo after Brexit.

It will be interesting to see how well these kinds of efforts do, and how well they need to do, to be successful and adopted for use.

Alternate navigation using satellite signals of opportunity


We are heavily reliant on Global Navigation Satellite Systems (GNSS) for navigation, positioning and timing services, both for critical infrastructure 
and military operations as well as in normal life. However, GNSS signals are weak, making then vulnerable to both deliberate and accidental 
interference and deception (spoofing). An alternate means of navigation is required to take over when GNSS is completely denied and to validate 
it when it is not.


Stronger satellite signals at similar frequencies can be used to supplement and take over from GNSS signals, creating signals of opportunity to 
support positioning and timing. They are designed to communicate with small terminals such as satellite phones or modems, so can be processed to 
a similar size as a traditional GNSS receiver. Unlike terrestrial signals of opportunity like TV transmitters or mobile basestations, satellite 
signals have the advantages of providing global coverage and are not vulnerable to local power disruptions or outages. Roke was funded by the 
Defence Science and Technology Laboratory (Dstl) to investigate this approach, and we constructed a prototype antenna array capable of receiving 
satellite signals from a range of different sources in L and S bands. This enabled measurement of direction, Doppler, and propagation time for 
each satellite. We then conducted a number of 4x4 trials to confirm the conclusions from the outcome.


This research shows that that is possible to exploit the transmissions from the existing Iridium, Globalstar, and Orbcomm constellations to achieve 
navigation and timing for a moving platform. This is currently realized using an antenna array but could be achieved from a single antenna for more 
space constrained platforms. Future work would seek to further improve positioning accuracy by exploiting more satellite signals and to mature the 
concept to higher Technology Readiness Levels (TRL), in collaboration with government, military users, and industrial partners.

READ MORE & Watch Video: https://roke.co.uk/innovations/alternate-navigation-using-satellite-signals-of-opportunity

(July 2021) GPS at risk: Those signals are more vulnerable than you realize:
That has people worried about how to protect them and what we're doing for backup.

https://www.cnet.com/news/gps-at-risk-those-signals-are-more-vulnerable-than-you-realize/     (This link has accompanying images when it was streamed on 10 July 2021)

The Cessna Citation Excel was approaching the Sun Valley, Idaho, airport when something seemed off about its flight path. Like a lot of planes, 
it was tuned to GPS for guidance. Usually, that's a good thing. On this day in August 2018, however, a problem arose. The GPS signals near the 
airport were unreliable, and smoke in the area made for poor visibility. The midsize business jet was off-course and flying too low in the 
mountainous terrain.

The likely cause for the wonky GPS readings? Military activity that caused jamming of the signals, according to an account from NASA's Aviation 
Safety Reporting System
, which collates information provided by pilots, air traffic controllers and other aviation professionals. Fortunately, 
radar on the ground provided a more accurate reading, and controllers got the plane to its destination safely.

Robert Rodriguez/CNET
It wasn't an isolated event, according to reporting by IEEE Spectrum and others.

GPS is all too susceptible to jamming and its trickster cousin, spoofing. The signals used by aircraft, ships, farm tractors and your smartphone 
originate from satellites 12,000 miles (19,300 kilometers) out in space. By the time they reach Earth, they're vanishingly weak and easily overwhelmed
A satellite launched in June to the GPS constellation represents a tiny step in making the service more secure. But satellites themselves face dangers.

All those threats have lots of people worried. Just about everything, you see, relies on GPS.

The highly precise signals from the Global Positioning System have worked their way into nearly every fabric of modern life, from recording bank 
transactions to synchronizing electrical grids to helping you find the nearest Starbucks
. Businesses and individuals can use the system's PNT -- 
positioning, navigation and timing -- capabilities for next to nothing. In the US, GPS has about $1 billion a day in economic impact, according to 
the National Institute of Standards and Technology
. It's also vital to the operations of the US military.

There's so much riding on GPS that a 2018 federal law sought to address one of the biggest underlying issues: the absence of a dedicated backup

Any substantive damage or disruption to the system would be bad news.

"My hope is we can get ahead of the bang and at least get ... some resilience put in the systems [that depend on GPS] before the bad thing happens," 
says Dana Goward, president of the Resilient Navigation and Timing Foundation, a Washington, DC-based nonprofit.

A backup would have a lot to prove.

"It's actually hard to create this giant, one-size-fits-all replacement for GPS," says Richard Mason, a senior engineer at Rand Corp. and lead author 
of a report on national PNT capability commissioned by the Department of Homeland Security in 2019 and released to the public in May of this year.
report is skeptical about how much government intervention is needed, despite GPS' vulnerabilities

On the plus side, says Mason, "there are lots of little partial backups."
For instance: Your phone could lose GPS, Mason says, and it would still give you some sense of where you are based on cellular signals (what's known as 
assisted GPS), though not as precisely.
Aircraft have alternative navigation systems. Financial firms can get timing services from other sources.

So what's the big deal then? It's that we're addicted to GPS on a grand scale.

Those signals from space have become "the de facto national reference," the National Security Telecommunications Advisory Committee said in a report to 
President Joe Biden in May. "Such wide adoption means their vulnerabilities pose a near-existential threat."

The group recommended the government develop a strategy for a "National Timing Architecture" and appropriating sufficient funds to create it.

The threats facing GPS:

There's precedent for the US government to fund something like GPS because it built GPS in the first place, primarily as a military technology, starting 
in the 1970s. By the 1990s, satellite navigation was starting to become a noticeable part of civilian life.

Right now, Washington spends about $1.8 billion a year to keep GPS up and running. The US Space Force manages the satellites and the ground stations that 
track them. (It took over the responsibility from the Air Force after it was spun out into a separate branch 
in December 2019.
) The Transportation Department is the lead civilian agency for PNT efforts.

The GPS constellation consists of 31 satellites located in medium Earth orbit. Those satellites carry atomic clocks, and onboard radios send precise 
timing signals from them to receivers on the ground, including the GPS chip in your phone. GPS signals reach more than 4 billion military and civilian 
users worldwide, according to the Space Force.

Those timing signals get translated into location data when a receiver syncs up signals from multiple satellites. The way the satellites are spread out 
around the globe, you should always be within sight of at least four.

GPS was the first of what's known as a global navigation satellite system, or GNSS. But it isn't the only one: China's Beidou, Russia's Glonass and the 
EU's Galileo all serve similar purposes.
In 2018, the FCC authorized Galileo signals for reception in the US, which means they could serve as a GPS 
backup, at least to a degree. But GPS itself is the only system under US control. 

All satellites are vulnerable to threats out in orbit over which we have little control. For example, space debris could damage individual satellites
or severe solar storms might short circuit the operations of hundreds or more

They're also vulnerable to anti-satellite weapons and cyber intrusions by potential adversaries who know how much our economy and our military depend 
on satellites. The more satellites you knock out or confuse, the worse off we are.

Gen. John Raymond, head of the US Space Force, told the House Appropriations Committee defense subcommittee in May that we need to be worried. 

"Both China and Russia are developing capabilities to deny our access to space," Raymond said. "There's an active threat in the domain."

But the more immediate dangers are more down to Earth: jamming (broadcasting a signal that's stronger than the weak one coming from space) and spoofing 
(broadcasting a signal that looks like GPS and feeding false information).
It's cheap and easy to get away with. The Russians have jammed or spoofed GPS 
signals in Scandinavia, Ukraine and Syria. North Korea has targeted them in South Korea. And then there are those flight disruptions in the US,
which may, 
ironically, have resulted from the US military's efforts to figure out how to deal with that problem.

"The threat that we're most concerned about with GPS is jamming," Raymond said.

The law seeking a GPS backup

A few years back, the National Timing Resilience and Security Act directed the transportation secretary to establish a land-based timing system that could 
serve as a backup for GPS within two years. That deadline came and went in late 2020, but in January of this year the Transportation Department reported 
to Congress on the "roadmap to implementation" it's been following toward that goal. 

A companion DOT report detailed a variety of technologies that could provide "complementary service in the event of GPS disruptions." Some commercially 
available technologies, it said, could go part way toward mimicking GPS' timing services. But the agency said none would be able to serve as a universal 
backup for the positioning and navigation capabilities.

Of the 11 technologies evaluated by the Transportation Department, one hit the mark in all the use cases: a metropolitan beacon system made by Sunnyvale, 
California-based NextNav. The beacons -- transmitters that send out the radio signals -- are set up on land, rather than in space, and are clustered in 
urban areas (hence "metropolitan").

For NextNav, the real-world application is its up-and-coming TerraPoint service, which gives a glimpse of how GPS-like capabilities are possible from 
something that isn't GPS.

TerraPoint beacons, set up on cell towers and building rooftops, are about the size of a dorm room refrigerator, sporting an omnidirectional antenna and 
a 110-volt power supply, and they're spaced about eight to 10 kilometers apart (versus that 12,000-mile range for GPS).
That makes for a much more robust 
signal. CEO Ganesh Pattabiraman estimates they're "about 100,000 times stronger than GPS."

The commercial service that NextNav is working toward would be independent of GPS but function just like it, providing full position, navigation and 
timing data, according to Pattabiraman. Each of its transmitters has an atomic clock and sends a precise, low-frequency timing signal to receivers 
equipped with chips from companies such as Broadcom and GCT Semiconductor that support GPS, Galileo, Glonass and other GNSS.
The service is designed 
to operate with mass market devices like mobile phones, cars and drones as the network gets built out.

"It looks just like another GPS signal," Pattabiraman said. To the receiver, "it's just another constellation, except it happens to be land-based."

TerraPoint is deployed at scale only in the San Francisco Bay Area, where eVTOL companies like Joby Aviation are doing tests with it for urban 
navigation, takeoff and landing operations.
It has a more limited presence in a number of other areas, too. NASA, for instance, has deployed a 
TerraPoint network at Langley, Virginia, for urban drone operations. NextNav expects that an acquisition announced in June, and done with a public 
offering in mind, will give it funding to expand.

Key to getting any GPS alternative into widespread use is to make it as easy to use as, well, GPS. Alternatives like the now defunct Loran radio 
navigation system required separate and bulky receivers, and the US government put an end to it a decade ago.
Some companies are working on services 
using what's known as enhanced Loran, aka eLoran, but it has yet to become more than a niche application in the US. 

"The good thing about NextNav, and things like NextNav," said Rand's Mason, "is that [eventually] it would just be in every smartphone, and so you're 
using it whether you know it or not."

That isn't to say a GPS backup has to be earthbound. Companies like Satelles, which also participated in the Transportation Department demonstrations, 
use the Iridium constellation of low Earth orbit satellites at an altitude of just 480 miles (780 km). It's already providing timing and location 
services, deployed as a backup for GPS for customers including financial networks and energy utilities. 

A startup called Xona Space Systems is designing its own low-orbit PNT system. In May, the Defense Advanced Research Projects Agency, or DARPA, awarded 
Northrop Grumman a contract to demonstrate how low-orbit satellites would perform providing PNT signals. Researchers are looking into whether SpaceX's 
Starlink satellites, built to beam broadband from orbit to Earth, could be pressed into service as a PNT resource.

Some of those options are still just on paper. But even those that are in operation don't have the scale of the long-established GPS.

Meanwhile, GPS itself is getting a boost. The GPS satellite that went up in June is the fifth in a new series known as GPS III, which is designed to be up 
to three times more accurate and have up to eight times the anti-jamming capability. For the military specifically, it's helping enable the encrypted 
M-Code signal that's tough on jamming and spoofing.

Eight times a weak signal, however, still isn't a signal that's much of a match for powerful jammers and spoofers operating nearby.

The role of government: 

What makes GPS so attractive for so many applications is that it already exists. It's essentially universal. It's cheap and easy to use. That also makes 
it hard to muster enthusiasm for spending time and money to come up with something that does what it does, as widely as it does.

Plus, those partial backups add up to … something.

The big question is how much the US government needs or wants to lean into building a sizable backup for GPS.

Rand recommends restraint, though it acknowledges there are some potential federal initiatives that could be cost-effective, including a timing-only 
backup or law enforcement efforts focused on GPS jamming.

"There's not a compelling case for government to do a lot more than it's doing or [to do] a big new backup system," Mason said. "There's also the 
question of, 'Is anybody going to use it?'"

That isn't good enough for Goward, of the Resilient Navigation and Timing Foundation. He sees China as having thoroughly outpaced the US in 
establishing a sophisticated, comprehensive approach to PNT that includes three types of satellites at different altitudes, plus eLoran and PNT 
capabilities in the telecom system for independence from space.

He wants lawmakers to take action soon. 

One thing Congress will have to consider: the budget proposed in late May for fiscal 2022, which starts in October, includes a line calling for the 
repeal of the National Timing Resilience and Security Act -- a tacit acknowledgement that we aren't likely to see that GPS backup mandated by the law 
anytime soon. (It also includes $10 million for research into backup and complementary systems.)

Goward estimates the US might be able to spend just $50 million to $75 million a year for a timing system that everybody in the country could access. 
He calls it "budget dust" compared with what we're already spending on GPS.

"The next step," he says, "is for Congress to decide what it wants to do."

In the meantime, the jamming goes on, and pilots like those in that Cessna outside Sun Valley will need to cast a wary eye on what their GPS device is 
telling them.

GPS rules everything. A new satellite launch keeps a big upgrade rolling:
It's a lot more than just driving directions. Managed by the US Space Force, GPS factors into a huge amount of the high-tech world we live in.

On June 17, about 10 minutes after noon local time, a SpaceX Falcon 9 rocket rose into the heavens from Cape Canaveral, Florida, carrying a boxy, 
5,000-pound, antenna-studded GPS satellite toward its destination 12,500 miles away, up in what's known as medium Earth orbit. From that distant 
vantage point, it'll soon beam signals that'll help you find your way to your cousin's new house out in the suburbs or a vacation destination two 
states away.

If you stop at an ATM along the way to grab some cash, those signals will also help the bank know your withdrawal happened after your direct deposit 
paycheck refreshed your finances. They'll be a factor, too, in whether your cellphone call to your cousin, or the rental agent, goes through without 
garbling or fading.

Those signals may well be coming from a GPS III satellite, the newest members of a constellation of satellites that have become a constant and 
intimate presence in our daily lives. With GPS III, we're getting not just new boxes in the sky, but a series of upgrades that'll help make the 
system better for all of us here on Earth. And we'll need it.

The Global Positioning System has become vital to nearly all sectors of the country's critical infrastructure, with much of its work happening 
behind the scenes, and likely to a much greater extent than you realize. GPS tells us where we are and helps us get where we're going, but a core 
aspect of the technology is when — the timing of, well, more or less a zillion things. It plays a critical role in financial transactions and 
stock trades, forecasting the weather, monitoring earthquakes and keeping the power grid humming.

"It's so much more than just driving directions," says Tonya Ladwig, acting vice president of space navigation systems at Lockheed Martin, which 
built that satellite.

According to a June 2019 study commissioned by the National Institute of Standards and Technology, GPS has about $1 billion a day in economic impact 
in the US. Its reach is, simply, mind-blowing.

"Gauging the overall value of GPS is nearly impossible," writes Greg Milner in Pinpoint, a 2016 book about how the space-based system came to be and 
the effect it's having on the world. "It has become difficult to untangle the worth of GPS from the worth of everything."

That's a lot to put on the shoulders of not much more than a couple dozen satellites and what turns out to be a wisp of signal by the time it reaches 
your phone or an airplane coming in for a safe landing. Which is why experts and lawmakers have long fretted over GPS' susceptibility to jamming and 
spoofing and the possibility that this invaluable resource could become a single point of massive failure.

I think most people don't realize how much they depend on GPS day in and day out. It would be a bad day if we didn't have GPS.
Maj. Gen. DeAnna Burt
GPS is the premier service among just a handful of global navigation satellite systems, or GNSS, which include the European Union's Galileo, Russia's 
Glonass and China's BeiDou. It's in the midst of a long-running modernization intended to deliver better signals to folks on the ground and to make the
satellites more robust in space. That's good news not just for Uber drivers, pilots, bankers, geologists, farmers doing precision agriculture, and users 
of drones and self-driving cars
, but also for the sector that got the whole GPS ball rolling in the first place: the US military.

And the military isn't just a heavy-duty GPS user. It also runs the service, for all of us around the world.

How GPS works: Atomic clocks in space:

What makes GPS an always-on resource -- every bit as much a reliable utility as the electricity and water in your house -- is the coverage the satellites 

There are 31 satellites in the GPS constellation, and 24 are considered the minimum for the core constellation to work as it's supposed to. Those two 
dozen are spread out in six orbital planes, so you should always be within view of at least four at any given moment. The remaining seven are essentially 
spares, to be rotated in as necessary. Though they're continuously beaming signals down to Earth that you'll pick up in your phone, fitness tracker or 
boating sat-nav device, they don't know where you are. They just broadcast, like a radio station in space.

"The GPS satellites are actually just highly precise atomic clocks, hooked to a radio transmitting a time signal," says Dana Goward, president of the 
Resilient Navigation and Timing Foundation, a Washington, DC-based nonprofit.

On the ground, your GPS receiver -- which is what your iPhone or Galaxy phone is, thanks to a GPS chip -- picks up the signals from four or more satellites. 

By measuring slight differences in the signals' time of arrival, all the way down to nanoseconds, it can calculate where you are and whether you're in motion.

"[Location] is a byproduct of how the system works," says Scott Burgett, director of GNSS and software engineering at Garmin, which makes devices including 
fitness trackers and smartwatches. "All the satellites transmit signals, and they're synchronized pretty accurately, but in order to actually get your 
position information, you have to solve for time."

The timing data gets translated into highly precise three-dimensional location information -- latitude, longitude and altitude -- as well as speed and 
direction. That's where Google Maps, Apple Maps and other geographic information systems come into play. It's how we get to the part where you have a 
street address and you say, "I'll put that in my GPS," and Waze lets you know to take Exit 27, go 3.5 miles and turn left into the parking lot of the 
beer and burger joint you've heard good things about.

Or it just gets used as a time stamp, pure and simple. Think financial transactions, for instance.

"The timing aspect of this is probably more widely used than the where-are-you aspect," Goward says.

How Space Force fits in:

The US Space Force operates and maintains the GPS constellation. Each satellite -- picture a PODS storage container, metallic rather than white, with 
solar arrays sticking out like a pair of wings -- makes two transits around the planet every day. 

Even as precisely programmed as those orbits are, the satellites still need their flight paths tended to around the clock. 

"Those GPS vehicles are only as accurate as the data we provide them," says 1st Lt. Andrew Johnson, a crew commander in the 2nd Space Operations 
Squadron, or 2 SOPS. "We get where the satellite thinks it is, we know where the satellite is, and we'll basically bake that into a nice little 
message, we'll send it up to the vehicle, and the vehicle goes, 'OK I'm actually here,' and that change in information fine tunes the signal."

Two members of the 2nd Space Operations Squadron designate the first GPS III satellite as healthy and active for users on Jan. 13, 2020. To make room for 
it, 2 SOPS pushed a GPS IIA satellite to a higher, less congested, "disposal orbit." Designed for 7.5 years of service, the older satellite had been 
operational for 26 years.

Johnson and 2 SOPS (pronounced "two sops") keep tabs on the GPS satellites from Schriever Air Force Base, located just east of Colorado Springs, Colorado. 
There are also 16 tracking stations scattered around the globe.

It's no accident that the US Space Force, spun off a year and a half ago from the Air Force Space Command and carrying on its GPS mission, is wrangling a 
service that's vital to devices used by millions of civilians and businesses worldwide. The origins of GPS stretch back to secret work by the Department 
of Defense in the 1970s, in a quest for precision targeting. As Milner recounts it, GPS chief architect Brad Parkinson summed up that goal in the phrase 
"Drop five bombs in the same hole."

In 1983, after a Korean Air Lines passenger jet strayed into Soviet airspace and got shot down, killing 269 people, President Ronald Reagan declassified 
GPS to give civilian aircraft access to the navigation signals. Almost a decade later, GPS famously earned its stripes as a military resource during 
Operation Desert Storm, when it helped guide US and allied forces across desert expanses to a swift victory over Iraq during the Gulf War.

Space has become a junkyard, and it's getting worse
How SpaceX Starlink broadband will envelop Earth and transform the sky
Orbits explained: It's hard to get into space -- but great once you're there
Space Force still has military users top of mind as it carries out its GPS mission. 

"For us, it's to deliver sustained, reliable GPS capabilities to America's warfighters," says Maj. Gen. DeAnna Burt, director of operations and 
communications at Space Force headquarters in Peterson Air Force Base, Colorado. Space Force also works closely with civilian and commercial partners 
to keep things running smoothly, she tells me. "We're always looking to improve not only our military capabilities but our civilian capabilities as well."

Though the funding to keep things running goes through the Pentagon -- the Space Force GPS program has a 2021 fiscal year budget of nearly $1.8 billion -- 
there's civilian oversight as well. The Defense Department and the Transportation Department co-chair the US government's National Executive Committee for 
Space-Based Positioning, Navigation and Timing, which coordinates GPS-related matters across federal agencies and includes representatives from Boeing, 
Garmin, Google, Ohio State and Stanford.

Note the keywords in that committee name: positioning, navigation and timing, or PNT. Where you are, where you're going, and when the signals hit a receiver. 
It's a term that's inescapable when you're talking with folks who live and breathe GPS.

What we're getting with GPS III:

Like any technology of a certain vintage -- the Air Force Space Command declared full operational capability for GPS in April 1995 -- the system needs to 
be regularly updated, and what that means right now is GPS III.

Here's what GPS III promises: The signals will be up to three times more accurate, and they'll have up to eight times the anti-jamming capability, though 
you and I probably won't see dramatic changes anytime soon. The satellites are projected to have a 15-year lifespan, double that of those from the early 
part of the previous generation, though the older ones have tended to stay in business longer than expected. A modular design means it's easier to make 
timely changes on the assembly line or to send software uploads to the satellites on orbit.

There's also a new civilian frequency, called L1C. Besides helping with signal strength, it's compatible with Galileo, the EU's counterpart to GPS

In November 2018, the FCC authorized Galileo signals to be received in the US, which made it that much more likely you'll have multiple satellites in view 
-- in the double figures even, when technically you only need four to get a good, accurate location

The addition of the L1C signal with GPS III will likely make matters even better. 

"If you have more satellites," says Garmin's Burgett, "you can have more direct line-of-sight signals available to you, and you can get a better fix.

The military, meanwhile, is getting, among other things, the encrypted M Code that's key to the enhanced anti-jamming and anti-spoofing capabilities, as 
well as spot beam capability for focused signals in combat areas. The satellite that launched June 17 is the 24th satellite equipped with M Code, which 
will make the feature fully operational. "What that M Code does is ... it'll allow you to receive the encrypted signal much faster," says Burt, the Space 
Force general.

A little bit down the road, the addition of a laser retro-reflector array will allow the positioning of satellites to be refined via ground-based laser.

The first of the GPS III generation of satellites, all built by Lockheed Martin at its Littleton, Colorado, facility, lifted off in late 2018 and became 
operational in January 2020. The second, third and fourth also became operational as that year rolled along. The latest satellite, dubbed SV05

was the first GPS III satellite to be launched in 2021; it became operational last week, and the Space Force expects it to become available to all 

global users in September. 

Lockheed Martin has a contract to deliver a total of 10 GPS III satellites, at a reported average cost of $529 million apiece, but the company says the 
last two of them will come in at around $200 million each. When that's done, it'll move ahead with a batch called GPS III F, an additional 22 satellites 
to continue replacing older models, through the coming decade. 

"It takes a long time to replenish the GPS constellation," Burgett says. "It takes years."

GPS' weak spots:
It might seem like GPS is pretty much always there when you need it, but it's more vulnerable than you may realize. If you live in a city with tall 
buildings, you've probably fumed waiting for an Uber driver to get to where you're standing -- it could be that buildings are blocking the satellite 
signals in what's known as the urban canyon effect.

That's a line-of-sight issue, and it can often be resolved by moving, if you can, to a spot with a better view of the heavens. The US government says 
that GPS-enabled smartphones are typically accurate to within a 16-foot (5-meter) radius under the open sky.

Then there's interference -- other, stronger signals making too much radio "noise" nearby. Experts routinely refer to the GPS signals as weak by the 
time they get from outer space to phones and other gear on Earth, and that relative lack of strength can be a serious problem.

"Because it's such a weak signal, it's very, very easy to block, to jam," Goward says. "Virtually any noise within that frequency is going to keep you 
from hearing the GPS signal."

Space Force's Burt likens it to a nearby sound system at full blast: "If you were at the dinner table and there was a 500-watt stereo playing at full 
volume in the kitchen, would you be able to hear the conversation going on around you? You might pick up pieces, parts of it, but not pick up all of it."

The US military has to worry about hostile forces jamming or spoofing GPS signals to hide troop movements or to keep friendly forces from getting where 
they're supposed to go, or weapons from hitting their targets.

Outside of war zones, some countries use GPS interference to mask the whereabouts of VIPs, while criminals use it to pull off shipping heists. The 
nonprofit Skytruth, which uses satellite images and data to track polluters and poachers, in 2019 reported on GPS manipulation at oil terminals in 
China likely intended to hide activities that run afoul of export controls.

The Pentagon and other government agencies, meanwhile, are aghast at the Federal Communications Commission's approval in April 2020 of a controversial 
plan by a company called Ligado to create a nationwide 5G network.
The frequencies Ligado would be using are very close to those employed for GPS

Ligado says it's sorted out any interference issues, but Defense Department CIO Dana Deasy said in a Senate hearing in May 2020 that 

"there are too many unknowns and the risks are too great."

The vulnerabilities of the satellite signals are something the GPS community has been thinking about for a long time, along with the need for some sort 
of backup. The idea is to provide a ground-based service -- such as what's known as eLoran -- that might not be as good but that would suffice when 
somebody's jamming or spoofing or if the satellites aren't available. 

There have been a number of false starts down that road over the years. A new push came at the end of 2018 with the National Timing Resilience and 
Security Act, which directed the Secretary of Transportation to establish a terrestrial timing system that could serve as a backup for GPS within 
two years. We're past that mark now, with nothing much to show for it. The Transportation Department did issue a report to Congress in January of 
this year showing how various "complementary PNT and GPS backup technologies" performed in demonstrations.

A more limited proposal came in February 2020 when President Donald Trump signed an executive order on PNT, which at least got the NIST in October to 
draft guidance on developing a timing system free of GPS.

In the years ahead, there will be more Space Force rocket launches carrying the latest GPS III satellites from Lockheed Martin. Modernization of the 
constellation will continue apace, new applications will appear, and as much as we're hooked on GPS services now, we're likely to only get more dependent.

Satellite timing is everywhere on Earth and in everything.

"I think most people don't realize how much they depend on GPS day in and day out," Space Force's Burt says. "It would be a bad day if we didn't have GPS."

Originally published Nov. 23, 2020. 

(July 2021) Ensuring Continuous PNT Services:

All sectors of the economy are adversely impacted by GPS/GNSS vulnerability. However, the impact is different in each sector. RF interference could have 

tremendous impact across different sectors, including offshore oil and gas, agriculture, automotive, construction, mining, or even within the consumer market. How do 
we protect GNSS against vulnerabilities and minimize the risks?

Read this opinion piece by Michael Ritter, President, Hexagon AB here: https://buff.ly/3hVQhZo  


(July 2021) Spoofing GPS in Indonesia to Make Things Work Better - Vice:


Blog Editor's Note: "Adversarial Interoperability (AKA Competitive Compatibility/comcom), the practice of modifying an existing technology against 
the wishes (or without permission) of its maker."

We were certainly familiar with the practice, but learned the name of the phenomenon while researching this piece.

In this instance, corporate overlords require that the driver closest to the call gets to respond. But that just causes massive traffic james of 
drivers wanting to be near popular pickup spots. Something that is not in anyone's best interest.

People jam and spoof GPS for lots of reasons. Most not so good. Sometimes to not let the rules keep them from doing the right thing.

Tech by Vice

Delivery Drivers Are Using Grey Market Apps to Make Their Jobs Suck Less
In Indonesia, unofficial apps let delivery drivers filter orders and spoof their GPS location to beat the algorithms at their own game.


By Rida Qadri

The McDonald’s on Jalan Salemba Raya, Jakarta’s crowded main thoroughfare, is a magnet for food delivery orders. On any given day, a dozen or 
so app-based delivery drivers—locally called ojol—wait in the parking lot. Inch by inch, they try to move as close as they can to the center 
of the lot, desperate to have the matching algorithms recognize their proximity and assign them an order.

But even more drivers are there virtually, using GPS-spoofing apps to position themselves right in the center of the McDonald's lot while they 
physically wait under nearby shelters. Using these unofficial apps, known as tuyul, drivers can set their GPS pins at the optimal location they 
would like orders from, without having to physically drive there.

In Jakarta, these kinds of unauthorized apps are a common tool-of-the-trade among app drivers working for Gojek, a $10 billion delivery and 
transport "super app" that is the Indonesian equivalent of Postmates, Apple Pay, Venmo, and Uber. Though Indonesia is by far its biggest market, 
Gojek operates in more than 200 cities in Indonesia, Singapore, Vietnam, and Thailand.

READ MORE: https://www.cnbc.com/2021/01/27/gojek-wants-to-expand-further-outside-indonesia-this-year-co-ceo-says.html

(July 2021) Does Anybody Really Know What Time It Is? - Does Anybody Really Care... About Time?:
Yes, there are folks who know what time it is.

And, yes, there are lots of folks who care!

In fact, just about everyone cares, though most most folks don't realize it.

Precise time underpins virtually every technology from navigation systems, networks, cell phones, and digital broadcast, to financial transactions 
and control systems for electrical grids.

So, whether they know it or not, pretty much everyone cares - a lot!

The folks who really know what time it is are NIST and USNO (even though they usually disagree by a handful of nanoseconds. Wonder why this isn't 
pico or femtoseconds?)

Most of us use USNO time because USNO feeds GPS. And, regardless of whether you are on a computer or cell phone, if you trace the time source back 
far enough, you are likely to end up at a GPS signal.

This makes GPS, in the words of one DHS official, a "single point of failure."

We should have other ways besides GPS to ensure folks can access precise time. As part of its tech infrastructure, for example, China has instituted 
multiple ways, both wireless and wired, for its citizens and applications to access precise time.

Our white paper "A Resilient National Timing Architecture" discusses how the US we can use policy and technology to provide multiple, resilient paths 
to precise time for all its citizens for about $50M to $75M a year.

The telecommunications industry agrees the US needs this. In May, a group of telecom CEOs and senior execs told President Biden he should work with 
industry and fund a national timing architecture. A telecom industry standards group told Congress the same thing a day later.

And Congress agrees the country needs this. The National Timing Resilience and Security Act of 2018 was signed by President Trump and requires a 
terrestrial timing system to work with and backup GPS be established by December of last year. Sadly, the last administration failed to request or 
identify funding and nothing has been done yet.

This year the new administration has requested funding to study the issue (again). Let's hope Congress is more action oriented and provides funding 
for a solution.

Because we really do need to know what time it is. And we really do care... about time.

 (July 2021) US Space Force issues ICD revisions for GPS - GPS World:

The U.S. Space Force Space and Missile Systems Center (SMC) has issued official, signed Interface Specification (IS) and Interface Control Document 
(ICD) revisions for GPS. Read more at the link below.


(July 2021) Trio of HawkEye 360 formation-flying microsatellites launched for RF geolocation - GPS World:

HawkEye 360 Inc. successfully launched its Cluster 3 radio frequency geolocation microsatellites built by Space Flight Laboratory (SFL). They join 
in orbit the HawkEye 360 Cluster 2 and Cluster 1 Pathfinder satellites. Read more at the link below. (Artist’s rendering: Hawkeye 360)


HawkEye 360 Inc. announced the successful launch of its Cluster 3 radio frequency geolocation microsatellites built by Space Flight Laboratory (SFL). 
Carried aboard the June 30 SpaceX Transporter 2 mission, the Cluster 3 formation-flying microsatellites quickly established communication with the 
company’s satellite operations center. They join in orbit the HawkEye 360 Cluster 2 and Cluster 1 Pathfinder satellites.

The HawkEye 360 Constellation detects and geolocates RF signals for maritime situational awareness, emergency response, national security and spectrum 
analysis applications. Cluster 3 significantly expands HawkEye 360’s capacity, and is part of its second generation of advanced RF-sensing satellites.

“With the addition of our second-gen satellites, we’ll offer more frequent, timely and actionable data and insights to our government, commercial and 
humanitarian partners,” said CEO John Serafini.

“The increased revisit frequency and capacity Cluster 3 brings to our constellation are essential to detecting, characterizing, and understanding the 
continuously changing RF activity important to our clients,” said Alex Fox, Executive Vice President for Sales and Marketing.

Seven more clusters are fully funded and scheduled for launch in 2021 and 2022 to achieve collection revisits as frequent as every 20 minutes, Fox said. 
“Each cluster will offer new innovations to address a rapidly growing set of requirements needed by our defense, security and commerce clients. We plan 
on expanding the constellation past the initial 10 clusters to achieve near-persistent monitoring of global RF activity, which will drive even more 
value and ensure our continued dominance in the industry.”

HawkEye 360 delivers a layer of intelligence to help understand human activity on Earth. The constellation detects, characterizes and precisely 
geolocates these RF signals from a broad range of emitters, including VHF marine radios, UHF push-to-talk radios, maritime and land-based radar 
, L-band satellite devices and emergency beacons.

By processing and analyzing these RF data, the company delivers actionable insights for national, tactical and homeland security operations, 
maritime domain awareness, environmental protection and new applications in the commercial sector, the company said.

The HawkEye 360 launch brings to 20 the total number of SFL satellites placed into orbit in less than a year. The Cluster 3 satellites were built 
on SFL’s 30-kg Defiant microsatellite bus.

HawkEye 360 selected SFL due to the importance of formation flying by multiple satellites for successful RF geolocation. SFL is the acknowledged leader 
in developing and implementing high-performance attitude control systems that make it possible for relatively low-cost nanosatellites and microsatellites 
to fly in stable formations while in orbit.

The previous HawkEye 360 satellite clusters built by SFL were the Pathfinder launched in 2018 and Cluster 2 in January. Each Cluster is comprised of 
three satellites.

Other launches of SFL-built satellites in the past year include missions developed for the Norwegian Space Agency (NOSA) in Norway, the Dubai-based 
Mohammed Bin Rashid Space Centre (MBRSC) in the United Arab Emirates, GHGSat Inc. of Canada, Space-SI of Slovenia, and a Canada-based tele-
communications company.

(July 2021) GNSS as an Instrument of National Power - GLONASS Case Study:

Blog Editor's Note: This article is about GLONASS but could be easily about GPS, Bei Dou, or even Galileo. Certainly they are instruments of soft power 
(economic, political, etc,), And they have the potential for espionage and other national applications.

Several particularly interesting bits in this piece. 

First, the question from the Czech government as to whether the GLONASS ground station the Russians asked to place in their country would be passive or 
emitting. Long time, still no answer from the Russians. Hence no Czech ground station. Probably a good idea.

Second, the idea that GLONASS ground stations and satellites could likely also serve as intelligence gathering assets, or more.

Third, that Russia may want wide adoption of GLONASS so as to insulate the system from deliberate jamming, spoofing, cyberattack, and so on:

"There’s also a safety-in-numbers approach to Russia’s sales pitch. The more countries dependent on GLONASS, the less likelihood there is for any one 
of them to try to hack it. “It is very tricky to want to mess with the U.S. GPS system,” Porras told Newlines, “in large part because you don’t know 
how widespread the implications can be.” Russia, he said, wants in on that deterrent capability."

Interesting idea. It seems to us, though, that, if GLONASS were to be widely adopted, it would become a more attractive target for most, rather than 
less. Perhaps some participating nation-states might be less likely to hack it, but then they probably would not have been big threats to begin with. 
Adversary nations, terrorists, and rouge hackers, on the other hand, would be more interested in hacking it if the impacts were going to be more widely 

Perhaps Russia is not quite so concerned because it has a terrestrial Chayka/Loran system that operates in parallel with GLONASS/GNSS. Very adept at 
electronic warfare themselves, perhaps they have already ensured their critical infrastructure, systems, and applications use both GNSS and Chayka.

Finally, the comment at the end of the article that Russia "...is focused on advancing its own national interest at the expense of other nations.”

Without being too cynical, we expect that, upon closer examination, EVERY nation is always seeking to advance its own national interest. Those nations 
with a short time horizon, perhaps those driven by an individual who only cares about what can be done during their time in power, tend to take 
advantage of other nations. Those with a longer time horizon see the value of respecting others and cultivating good long relationships. Some are 
better than others, but no nation has been able to do this consistently.
GLONASS, Moscow’s answer to GPS, is set to launch an upgraded satellite network later this year, which it hopes to sell to the U.S. and Europe. Buyer 

Holger Roonemaa, Holger Roonemaa is an investigative journalist based in Tallinn, Estonia

Michael Weiss, Michael Weiss is a senior editor at Newlines

July 12, 2021

Russia is preparing to introduce a new generation of its GLONASS satellite navigation system, with expanded global infrastructure. Several Western 
intelligence agencies say the program is also being used to conduct high-level espionage.

A joint investigation by Newlines, Delfi.ee in Estonia, and Respekt magazine in the Czech Republic reveals that GLONASS contains two new mechanisms 
for conducting espionage, including on nuclear weapons systems.

READ MORE: https://newlinesmag.com/reportage/western-intelligence-fears-new-russian-sat-nav-espionage-capabilities/ 

(July 2021) Parrot's new ANAFI Ai UAV drone is 4G connected - GPS World:

Drone-maker Parrot has released a new drone for professionals. The ANAFI Ai UAV uses 4G as its main data link between the drone and the operator
so that users will no longer experience transmission limitations. Read more at the link below.

Drone-maker Parrot has released a new drone for professionals. The ANAFI Ai UAV uses 4G as its main data link between the drone and the operator, 
so that users will no longer experience transmission limitations.

The 4G also enables precise control at any distance. For beyond-visual-line-of-sight (BVLOS) flights, it stays connected even behind obstacles.

For the first time, ANAFI Ai embeds a secure element in the drone and in its Skycontroller 4. The 4G link between the drone and the user’s phone 
is encrypted. The secure element protects both the integrity of the software and the privacy of data transferred.

Parrot’s piloting application is open source. Parrot offers developers a software development kit (SDK) to create custom code for the drone to 
execute during flight. The SDK gives access to all flight sensors, including obstacle-avoidance sensors, occupancy grid and internet access.

ANAFI Ai’s obstacle-avoidance system detects obstacles in all directions, using stereo cameras to sense objects and automatically avoid them.

ANAFI Ai incorporates a 48MP main camera and a powerfully stabilized 4K 60-fps/HDR 10 camera to capture finely detailed aerial images and smooth 
video footage.

ANAFI Ai will be available in the second half of 2021 through Parrot Drone Enterprise Partners and Enterprise Drone Reseller Network.

(July 2021) Nanosatellites Could Play Pivotal Role in Defense Against Enemy Missiles:

"These satellites will test key technologies that mitigate risk for systems, such as the Hypersonic and Ballistic Tracking Space Sensor," Walt Chai, 
MDA director for space sensors, said. "The CNCE Block 1 mission will demonstrate the viability of advanced communications technologies using reduced 
size, weight and power in support of missile defense communications architectures."

(July 2021) US Air Force plane navigates by tiny changes in Earth's magnetic field:

It's exciting to see magnetic navigation being utilized and tested more and more. While offering more challenges to overcome initially, MagNav is far 
more difficult to jam than traditional GPS systems and therefore offers a more robust and trustworthy navigation system with the increased data coming 
from test flights such as these.

"A simple compass needle aligns with the strong magnetic field produced by Earth’s liquid-iron core, but a more sensitive magnetometer can also pick 
up fainter magnetic fields embedded in rocks that make up Earth’s crust. These fields have a pattern as complex and distinctive as topography. By 
measuring the strength and direction of the crustal field and how it changes during a flight, you can work out where you are in the magnetic landscape."


(July 2021) China’s Beidou system makes great strides in adoption: white paper - Global Times:

Blog Editor's Note: We thought we would offer this article as a follow-on to yesterday's post about GNSS as an instrument of national power. China is 
particularly good at using Bei Dou for soft power.

Also note how they have used Bei Dou as to stimulate economic growth domestically, and to ensure their sovereign independence from non-Chinese system.

We are not sure folks in the US have really learned the lesson of how GPS stimulated so much growth and generated so much economic benefit.

If they had, perhaps the US would be more eager to, like China, build upon that success and develop other national PNT, both terrestrial and at LEO.

Caveat: Global Times is an arm of China's state media. As such, everything should be taken with a grain of salt. Nevertheless, the article provides 
good insight into China's government's thinking.

China’s Beidou system makes great strides in adoption: white paper:

By Global Times Published: May 18, 2021 08:28 PM

China's self-developed BeiDou Navigation Satellite System (BDS) has been widely adopted in a wide range of areas, including transport, public security, 
agriculture and other activities related to people's daily life, according to an industry report on Tuesday.

Underscoring the widespread adoption, the number of devices such as smartphones that have BDS navigation functions has reached 1 billion at the end of 
2020, showed the white paper released by the GNSS and LBS Association of China.

Sales of chips and modules that are compatible with the BDS exceeded 150 million sets as of 2020, with quarterly shipments of more than over 10 million 
. Meanwhile, total shipments of Beidou-powered high-precision chipsets, modules and boards surpassed 1 million last year, with main application 
scenarios including connected cars, drones and agricultural machinery.

The BDS also played a major role in China's fight against the COVID-19 outbreak, surveying and drawing plans based on BeiDou's high-precision technology 
greatly reduced the time needed to build healthcare facilities in Central China's Hubei Province and Northwest China's Shaanxi Province, among other regions.

Globally, BDS has been providing services to more than 100 million users, with solutions like precision agriculture, vehicle and ship monitoring, and smart 
ports having been successfully applied in ASEAN, South Asia, Eastern Europe and other regions, according to the white paper.

International mainstream chip manufacturers also widely support the BDS, while most smartphone series of Chinese brands including Huawei, Vivo, OPPO and 
Xiaomi are Beidou-compatible, it said.

Behind the impressive numbers lay China's constant vitality in technological innovation. In 2020, 28-nanometer SoC chips, which enable mobile devices to 
receive signals from Beidou-3, were widely used in the Internet of Things and the consumer electronics sectors.

A more advanced 22-nm chip that supports dual-frequency positioning and will further increase the accuracy of the system has entered mass production.

The white paper pointed out that in order to realize self-reliance in key sectors and deal with challenges brought about by the industry's development, 
more work should be done to actively support the standardized development of the BDS and promote comprehensive, large-scale application of the technology.

In China, the satellite navigation and location services industry is becoming mature, with all links on the industry chain expanding in 2020.

READ MORE: https://www.globaltimes.cn/page/202105/1223806.shtml 

(July 2021) You’ve got space mail!:

This week, find out how we’re teaming up with the European Space Agency to address global climate change.

Read this story & more: https://conta.cc/2UVl3K4 

(July 2021) GPSPatron seeks to protect critical infrastructure - GPS World:

GPSPatron is offering products and services to protect equipment, particularly GNSS-dependent critical infrastructure. Its GP-Probe TGE2 is designed 
to protect time servers against threats including spoofing, jamming, ionospheric scintillation and system errors. Read more at the link below.


(July 2021) The growing problem of jamming and spoofing of GPS satellite navigation signals just keeps getting worse - M&AE:
Blog Editor's Note: Our initial response to this article was "Duh!" Aside from stating the obvious, it is a short piece that, initially, doesn't 
seem to add much to the community discussion.

But it does point out that the problem "keeps getting worse." And why wouldn't it? 

Equipment to interfere with GPS/GNSS continues to become less expensive, easier to use, and more capable.

And, as we regularly show in this space, people continue to find new reasons to interfere with the signals. Everything from great power competition 
between navys to delivery drivers subverting the dumb decisions of their cluesless bosses.

Also, there is little movement to make GPS/GNSS signals more difficult to disrupt. Sure, the US military has M code and Galileo is instituting PRS 
, but these are marginal improvements at best, are costly, and are not available to 99% of users who aren't in government.

Sad that China is so far ahead of the West on this. They have established PNT capability in LEO, MEO, and GEO, expanded eLoran to cover the whole 
, are using 5G telecom for PNT, and are aggressively working on inexpensive clocks and IMUs

While not as advanced as China, Russia, South Korea, Iran, Saudi Arabia and others are still way ahead of the West.

What's it gonna take for the US and Europe to wake up?

Oh, by the way, there is one more bit this very short article adds to the discussion - the subhead "There's precedent for the US government to fund 
something like
GPS because it built GPS in the first place..." 

An interesting point for those in government who want to shirk responsibility for protecting the public.

John Keller, chief editor

Military & Aerospace Electronics

July 20th, 2021

The growing problem of jamming and spoofing of GPS satellite navigation signals just keeps getting worse:
There's precedent for the US government to fund something like GPS because it built GPS in the first place, primarily as a military technology.
WASHINGTON – The Cessna Citation Excel business jet was approaching the Sun Valley, Idaho, airport when something seemed off about its flight path. 
Like a lot of planes, it was tuned to GPS for guidance. Usually, that's a good thing. On this day in August 2018, however, a problem arose. The GPS 
signals near the airport were unreliable, and smoke in the area made for poor visibility.
The midsize business jet was off-course and flying too low 
in the mountainous terrain. CNET reports. Continue reading original article

The Military & Aerospace Electronics take:

20 July 2021 -- The likely cause for the wonky GPS readings? Military activity that caused jamming of the signals, according to an account from NASA's 
Aviation Safety Reporting System, which collates information provided by pilots, air traffic controllers and other aviation professionals. Fortunately, 
radar on the ground provided a more accurate reading, and controllers got the plane to its destination safely.

It wasn't an isolated event. GPS is all too susceptible to jamming and its trickster cousin, spoofing.

READ MORE: https://www.militaryaerospace.com/rf-analog/article/14207023/gps-signals-jamming 

(July 2021) UrsaNav trials eLoran as vital GNSS backup using ADVA’s grandmaster clock solution - Business Wire:
Blog Editor's Note: Another example of timing and navigation interests joining forces.

Full disclosure - UrsaNav and Oscilloquartz, an ADVA brand, are both corporate members of the RNT Foundation.
UrsaNav trials eLoran as vital GNSS backup using ADVA’s grandmaster clock solution

July 27, 2021 03:00 AM Eastern Daylight Time

NORTH BILLERICA, Mass.--(BUSINESS WIRE)--ADVA (FSE: ADV) today announced that UrsaNav and ADVA have conducted an enhanced 
long-range navigation (eLoran) field trial using UrsaNav’s eLoran receiver and ADVA’s Oscilloquartz grandmaster clock technology. 
The successful demo shows that eLoran offers a robust and reliable backup for GPS and other GNSS and could be used to provide an 
assured position, navigation, and timing (PNT) service. The trial follows US federal executive order 13905 aimed at strengthening 
national resilience through PNT services, including protecting critical infrastructure such as electrical power grid and communication 
networks from rising cyber threats. By harnessing ADVA’s flexible OSA 5420 Series, designed with assured PNT (aPNT) technology, UrsaNav 
has shown that eLoran can provide a new layer of protection and significantly boost timing resilience and security.

READ MORE: https://www.businesswire.com/news/home/20210727005101/en/UrsaNav-trials-eLoran-as-vital-GNSS-backup-using-ADVA%E2%80%99s-grandmaster-clock-solution  

(August 2021) Combating Foreign Disinformation on Social Media Study Overview and Conclusions:

by Raphael S. Cohen, Nathan Beauchamp-Mustafaga, Joe Cheravitch, Alyssa Demus, Scott W. Harold, Jeffrey W. Hornung, Jenny Jun, Michael Schwille, Elina Treyger, Nathan Vest

Related Topics:
Cyber Warfare,
Information Operations,
The Internet,
Psychological Warfare,
Social Media Analysis

How are state adversaries using disinformation on social media to advance their interests? What does the Joint Force—and the U.S. Air Force (USAF) 
in particular—need to be prepared to do in response? Drawing on a host of different primary and secondary sources and more than 150 original 
interviews from across the U.S. government, the joint force, industry, civil society, and subject-matter experts from nine countries around the 
world, researchers examined how China, Russia, and North Korea have used disinformation on social media and what the United States and its allies 
and partners are doing in response.
The authors found that disinformation campaigns on social media may be more nuanced than they are commonly 
portrayed. Still, much of the response to disinformation remains ad hoc and uncoordinated. Disinformation campaigns on social media will likely 
increase over the coming decade, but it remains unclear who has the competitive edge in this race; disinformation techniques and countermeasures 
are evolving at the same time.
This overview of a multi-volume series presents recommendations to better prepare for this new age of communications 

Key Findings
Disinformation campaigns on social media might be more nuanced than commonly portrayed
Russia and Iran have used this tactic abroad more than China and North Korea have.
State-led disinformation campaigns on social media are a relatively recent phenomenon.
The campaigns can intimidate, divide, and discredit, but there is limited evidence that they can change strongly held beliefs.
Smaller, locally popular social media platforms could be at higher risk of disinformation than larger, mainstream ones.
Disinformation campaigns on social media have clearly notched operational successes, but their strategic impact is less certain.
Disinformation campaigns on social media will likely increase over the coming decade.
Much of the response to disinformation remains ad hoc and uncoordinated
The U.S. government's lead for countering disinformation, the Department of State's Global Engagement Center, lacks the necessary 
political and institutional clout to direct a coordinated effort.
The joint force's efforts to man, train, and equip forces for counter-disinformation remain ad hoc and service-dependent.
Allies and partners have tried other countermeasures, mostly with ambiguous effects.
Industry—particularly after the 2016 election interference—has made an active effort to counter disinformation, but companies' 
responses are shaped by their business models.
Civil society groups play an important, often overlooked role.
Although disinformation campaigns on social media will likely increase over the coming decade, it remains unclear who has the 
competitive edge in this race because disinformation techniques and countermeasures are evolving at the same time

The USAF, in general, and Air Force Special Operations Command, in particular, should expand their information operations capabilities 
and responsibilities.
The joint force should know the information environment and look beyond U.S. platforms. It should also train for disinformation, focus 
on key demographics, minimize widespread bans on smart phone and social media use, increase transparency, enforce message discipline, 
and conduct a Department of Defense–wide review of the information operations force.
The U.S. government should publish a counter-disinformation strategy, leverage civil society groups and industry without outsourcing th
e counter-disinformation fight, avoid bans on social networks, balance counter-disinformation efforts with a commitment to freedom of 
speech, and carefully weigh risks while focusing offensive influence efforts on truthful information.

(August 2021) Upgrades to NASA’s Space Communications Infrastructure Pave the Way to Higher Data Rates:

The ability to transmit and receive data is crucial in space exploration. Spacecraft need robust networking capabilities to send data – 
including large files like photos and videos - captured by onboard instruments to Earth as well as simultaneously receiving commands 
from control centers. NASA has made significant strides to improve the agency’s space communications capabilities while simultaneously 
maintaining ongoing operations and service to a large number of missions.


(August 2021) What happens to British ships when satellites don't work? - BBC News:

Blog Editor's Note: This article has a number of interesting observations even though it conflates and confuses satnav and satcomms.

The comments by the former head of the British Navy (First Sea Lord), who was also the nation's first minister for cybersecurity, are 
particularly worth noting. Some examples:

"I thought I'd ask the government, I thought they'd have processes, but it became very clear from their answers that they don't understand 
what the problem is."
"If you don't have a fallback for a system, you can bet your bottom dollar that someone will exploit that," 
"GPS can very easily be messed up. We know the Russians are practicing this."
Also interesting that the government spokesperson said mariners should be proficient in celestial navigation as a backup. Celestial nav i
s OK if you are at sea, not in danger of hitting anything, and want to have a rough idea of where you are amongst the great waters. Not so 
much otherwise. There are other backup methods for close in. But if we really can't trust electronic nav, that ripples through the entire 
staffing, training, equippage and cost equation and has major impacts on the safety and effectiveness of both naval and merchant operations.

The government rep just shrugging the problem off and saying "celestial" like it is a magic bullet just reinforces the First Sea Lord's comment 
that they don't understand the problem.

We do note in all fairness that, as mentioned in Parliament, the UK government has a national PNT Strategy under development. No information is 
available, though, on when it will be published.

Also, our experience in the U.S. government is that strategies are often published as a way to give the impression of action without having to 
actually do anything. We have been informed by some who have reason to know that this is not the case in the UK, or at least won't be the case 
for the PNT strategy.

Let's hope.

What happens to British ships when satellites don't work?:
By Richard Morris

Political reporter, BBC News

28 July 2021

The Royal Navy and Britain's merchant fleet, along with most others around the world, rely on satellites for navigation - but what happens if 
they don't work?
It's a question that troubles the former First Sea Lord, Lord West of Spithead, who has spent months trying to find out if the UK has a back-up plan.

"My concern is that those people who are not friends with us are looking at ways to knock out satellite communications," he says.

"I thought I'd ask the government, I thought they'd have processes, but it became very clear from their answers that they don't understand what 
the problem is.

"There's no proper system for achieving communication if satellites collapse."

The Labour peer, who was the UK's first cyber-security minister under Prime Minister Gordon Brown, is convinced the government needs to act to 
protect the British fleet.

"If you don't have a fallback for a system, you can bet your bottom dollar that someone will exploit that," he says.

"The best fallback is probably old VHF [radio] systems. GPS can very easily be messed up. We know the Russians are practicing this."

READ MORE: https://www.bbc.com/news/uk-politics-57440787  

(August 2021) 17 Statistical Hypothesis Tests in Python (Cheat Sheet) - Machine Learning Mastery:

Last Updated on November 28, 2019

Quick-reference guide to the 17 statistical hypothesis tests that you need in
applied machine learning, with sample code in Python.
Although there are hundreds of statistical hypothesis tests that you could use, there is only a small subset that you may need to use in a machine 
learning project.

(August 2021) 1National PNT Infrastructure; Getting the U.S. on the Path to Resilience - ION Newsletter:

Blog Editor's Note: An excellent summary of where America has been with PNT resilience and policy and where it needs to go.

Interesting to note that the false rationale "GPS is expensive so we need to economize and have fewer other PNT sources" seems to have persisted 
from the 1980's until today. It doesn't help that the way the Department of Defense describes GPS III makes it sound like it will solve all the 
nation's problems.

As the good book says, "The sins of the father shall be visited upon the children to the third and fourth generation." Not a threat so much as a 
description of the way society works.

We really enjoy the news, commentary, interviews, and navigation history in the quarterly ION Newsletters. If you are not already an ION member, 
we heartily recommend it. Visit https://www.ion.org/ 

Getting the U.S. on the Path to Resilience
Doug Taggart, President, Overlook Systems Technologies, Inc.

There is a dichotomy between our national space-based positioning, navigation and timing (PNT) policies and the decades-old recognition that 
overreliance on the Global Positioning System (GPS) as the single source for PNT leaves U.S. critical infrastructure vulnerable.

The May 2021 Colonial Pipeline computer hack serves as an all too recent example of how vulnerable Americans are to single-source supply chains. 
The hack, attributed to a group known as DarkSide, shut down 5,500 miles of pipeline, interrupting the flow of gasoline across the United States’ 
Southeast and MidAtlantic regions.

The ramifications of an intentional disruption of GPS have been theorized about and analyzed ad nauseum. Even if only one specific sector of our 
critical infrastructure was the primary target of a space-based PNT interruption, there would most certainly be collateral damage beyond the 
intended target.

We must find a way to get out of this unending refusal to address the reality of overreliance. Though national spacebased PNT policy, dating back 
to the Bush era, has highlighted the need for a backup to GPS, nothing has been done to date.

The 1984 Federal Radionavigation Plan’s (FRP) Executive Summary contained a passage that clearly conveyed the challenge of meeting the needs of 
all PNT users.
“The goal [of the FRP] is to select a suitable mix of these common civil/military systems which can meet diverse user requirements 
for accuracy, reliability, coverage, operational utility, and cost; provide adequate capability for future growth; and minimize duplication of 
services. The process of selecting a system mix is a complex task, since user requirements vary widely and change with time.”

READ MORE: https://rntfnd.org/wp-content/uploads/ION-Summer21-Doug-Taggart.pdf

(August 2021) The Biden Administration and Civil PNT – So Far, So Good. Sorta. - ION Newsletter:
Blog Editor's Note: The author is President of the RNT Foundation.

This article was written a month or so ago when the newsletter was in preparation. Since then the infrastructure bill has been formulated in the Senate 
without any mention, so far, of needed essential infrastructure in the form of a complement and backup for GPS.

Also in the news since that time have been a lot of reports about Chinese and Russian anti-satellite technology, and what it means for GPS. And these 
reports are coming from government sources like General Raymond, the Space Force Commander.

Stay tuned...
The Biden Administration and Civil PNT – So Far, So Good. Sorta.
By Dana Goward, President of the Resilient Navigation & Timing Foundation

The Biden administration has proposed $17 million in funding for resilient civil positioning, navigation and timing (PNT) efforts at the Department o
Transportation (DOT) for fiscal year 2022. While this might not be much compared to DOT’s overall PNT responsibilities, it is a marked increase over the 
estimated $5 million being expended this year and the $2 million spent last fiscal year

Who Decides?

While presidents have long acknowledged the importance of civil use of the Global Positioning System (GPS) and PNT, their administrations, regardless of 
party, have struggled to match that with funding. This is likely because, while the DOT is the lead for civil PNT issues, GPS is seen as a Department of 
Defense (DOD) responsibility. Requests to fund GPS and PNT needs through DOT are difficult to explain to harried bureaucrats and congressional staff.

Also, for the most part, civil PNT issues have been relatively low profile, not rising to the attention of the chief executive. Aside from President 
making GPS available for civil use and President Clinton doing away with selective availability, civil PNT issues generally have been the 
province of career civil servants.

This has given career staff closest to the White House an outsized role. Until recently, they had not shown much visible interest in civil PNT issues
Often, they have been actively hostile.

As one example, despite President Bush’s 2004 mandate for a backup capability for GPS, staff at the Office of Management and Budget (OMB) were able to 
block the announced solution in the first days of the Obama administration. This despite four years of government wide research, negotiation, and broad 
agreement on the way forward.

Again, in 2015, after the Obama administration wrote Congress saying it would build a terrestrial backup for GPS, OMB staff made sure nothing ever 

This seems to also have been true in the Trump administration. In 2018 President Trump signed legislation that included the National Timing Resilience 
and Security Act (NTRSA). The Act required at least one terrestrial timing backup for GPS be established by December 2020. Yet no action was taken to 
comply. Having failed to meet, or even work toward, the Act’s deadline, in February 2020 the administration instead issued Executive Order 13905 focusing 
on encouraging civil GPS users to protect themselves.

In its last days, the administration did publish a new national space-based PNT policy that addressed a number of civil PNT issues. It called for, among 
other things, additional research, and interference monitoring and detection. Also, for the government to “…identify and implement, as appropriate, 
alternative sources of PNT for critical infrastructure, key resources, and mission-essential functions.”

Senior Leaders Engaging

The long-standing status of civil PNT as a third- or fourth-tier issue may be changing with the Biden administration.

Political appointees seem very much aware of PNT’s importance, the impact of the Federal Communications Commission’s (FCC) decision in favor of Ligado 
Networks, extensive jamming and spoofing around the world, and the fact that—unlike China, Russian, Iran and othersthe United States has no widely 
implemented fallbacks or alternatives to space-based PNT.
They are also aware that the NTRSA remains unexecuted and there is political peril in America 
not being prepared for yet another nationwide problem. These have all been reflected in reported comments by Department of Transportation Secretary Pete 
Buttigieg, DOT Deputy Secretary Polly Trottenberg, and other senior members of the administration.

Bringing even more awareness of PNT issues to the Biden administration is Caitlin Durkovich, senior director for resilience and response at the National 
Security Council. She previously served in the Obama administration as assistant secretary for infrastructure protection at the Department of Homeland 
Security. In that role she became very much aware of the importance of PNT, once describing GPS as a “single point of failure.”

Increased Funding Proposed

This increased awareness and appreciation at senior levels already has influenced the budget process — a clear indicator, as then-Senator Biden said, of 
what people really care about.

The $17 million requested for resilient PNT issues in the administration’s proposal for fiscal year 2022 is grouped in three areas. While it is questionable 
whether this amount will be sufficient for the listed efforts, it is at least a start.

A sum of $3.5 million is requested for “GNSS Performance Monitoring and Interference Detection Capability.” This one is really two related projects.

The first is civil GPS signal monitoring. Convincing folks within the administration and/or Congress of the need for this has been a multiyear challenge 
for DOT
. It is good to see the Biden administration agreeing with the need right off the bat.

The second is for establishing an interference monitoring and detection capability that could also geolocate disruption sources. This has been discussed
as a “should do” in policy documents since 2004. The Federal Communications Commission’s decision on Ligado Networks may have been the final impetus for 
action as it is mentioned as part of the budget justification.

Another $3.5 million is requested for “Executive Order 13905 Implementation and GPS Signal Authentication.” This is another two-parter. The first is 
vulnerability assessments and studies
. The second will look at validating and authenticating civil GPS signals.

The lion’s share of the request, $10 million, is for “GPS Backup/Complementary PNT Technologies Research.” This is to execute the recommendations from 
the DOT GPS Backup Technology Demonstration. It will fund efforts to develop alternate PNT safety-critical standards for transportation, performance 
monitoring capabilities
, and a vulnerability and performance testing framework.

A Strange Twist/ Insult to Congress?

One facet of the budget request that has baffled members of Congress and their staffs, as well as outside observers, is a proposal in the budget 
submission to repeal the NTRSA.

One congressional staff member who, like all the others who shared their perspectives for this story, spoke on background due to ongoing budget 
negotiations, said, “We are stunned. This is the exact opposite of what we have been hearing from senior leaders in DOT and expecting in the budget.” 
Another was shocked when no one from the administration consulted with concerned members of Congress before sending the proposal forward. “I can think 
of very few instances when an administration has surprised and embarrassed members like this. Not even a phone call or email to explain or give us a 
heads-up. It’s a real insult.

Speculation as to how this happened and what it means abounds.

“Numerous senior administration officials seem to agree with doing something to execute the Timing Act,” said one retired official. “The lack of 
coordination with Congress tells me that this likely was slipped in by someone at OMB thinking it would be under the political radar.”

As to motivation, some say that it is a continuation of decades-old opposition within OMB to doing anything to protect civil users. The philosophy 
being the government should not be in the civil PNT business. Others say that it is more of a process concern than opposition to establishing a timing 
capability. “OMB has long opposed PPPs [public private partnerships],” said a Capitol Hill staffer familiar with the issue. “They see NTRSA as facilitating 
a PPP, and they hate that.”

Still Talking

With a pandemic to battle, an economy to restore, the climate to rescue, and a volatile international situation to work on, it is likely that senior folks 
in the Biden administration have not had much time in the last six months to think a lot about civil PNT. And realistically, compared to so many other 
things, civil PNT is going along OK, for now.

And while the landscape and players may be confusing, Americans concerned about civil PNT issues might be encouraged, nonetheless. If the old Hollywood 
maxim, “It doesn’t matter what they say, as long as they are talking about you,” holds true, things are looking up. Despite everything, the level of 
conversation in Washington
about civil PNT has never been higher. 

RNTF will be hosting GAO Report sessions at ION’s JNC and ION GNSS+.

On May 10, 2021, the Government Accountability Office (GAO) released its report “Defense Navigation Capabilities: DOD is Developing Positioning, Navigation, 
and Timing Technologies to Complement GPS.” Among the report’s recommendations were that the Department of Defense consider using resilient technologies 
as the cornerstone of its PNT efforts going forward, instead of its current plan to build its plans around GPS.

The full report is available for download at: https://www.gao.gov/assets/gao21-320sp.pdf 

The Resilient Navigation and Timing Foundation hosted a webinar, facilitated by ION, on the report that can be viewed for free at: 

The Resilient Navigation and Timing Foundation will be hosting informational sessions at ION’s JNC and ION GNSS+ conferences with the report’s 
authors and invite interested parties to attend.

GET PDF OF ARTICLE HERE: https://rntfnd.org/wp-content/uploads/ION-Summer21-GOWARD.pdf   

(August 2021) Canada, Denmark, Finland, Iceland, Norway, Russia, Sweden, and the U.S. have long cooperated in the Arctic region

—even when their respective interests have clashed on other matters.

But conditions in the Arctic are evolving. This new report examines:


(August 2021) Infrastructure Bill Neglects GPS Threats - Forbes:

Blog Editor's Note: An excellent article by RNTF member Diana Furchtgott-Roth. Diana is a professor at GWU and previously served as Deputy Assistant Secretary 

for Research and Technology at the U.S. Department of Transportation.

Diana is right on target. But we need to remember that, just because this bill does not specifically mention DOT and a complementary and backup system for GPS, 

that doesn't mean all is lost.

There are sufficient laws on the books already to justify an appropriation to DOT for a complementary and backup system for GPS. These include:

-Organic DOT responsibilities outlined in Title 10 and Title 50 provisions regarding civil GPS and PNT
-The National Timing Resilience and Security Act of 20218
-Provisions included in the current infrastructure bill regarding support for broadband (PNT is a critical enabler) 
-Provisions in the current bill related to Intelligent Transportation Systems
We aren't attorneys or expert congressional staff. So if we can think of the above items there are likely more ways in which such funding can be supported 

by existing law and/or through the current infrastructure bill.

Question is whether anyone in Congress thinks it is important enough, and has enough pull to do so. Let's hope. 

And, of course, there is the regular appropriations process for fiscal 2022. That will still be in the works for the next month or so.

And let's all keep up the input to our legislators telling them how important this is. Maybe by forwarding Diana's excellent article!

Thanks for the great work, Diana!

Infrastructure Bill Neglects GPS Threats:

by Diana Furchtgott-Roth

Contributor on Transportation

I write on transportation and tech topics shaping tomorrow’s news.

The $1 trillion bipartisan infrastructure bill that was voted out of the Senate on August 10 has no funding for strengthening the Global Positioning System 

(GPS) to make sure that Americans can navigate without getting spoofed. The House should correct the Senate’s omission.

With $50 billion over the next decade allocated in the bill for cyber-attacks and climate change, it makes sense to designate $1 billion of this amount to the 

Transportation Department to reinforce GPS.

In the last two decades, GPS has become essential foundational technology for many industries. Without accurate GPS, daily life would become almost 

unrecognizable. Imagine not having cell phone service, or the ambulance to your house being delayed while the driver consulted a road map and hunted for house 


Malicious interference with GPS, an invisible utility paid for by the federal government, is increasingly common. GPS satellites could be damaged by electromagnetic 

storms or hostile military action.

Today, GPS outages and gaps are real, not hypothetical. Naval ships operating in the Persian Gulf have been lured into Iranian waters and seized through GPS 


READ MORE: https://www.forbes.com/sites/dianafurchtgott-roth/2021/08/10/infrastructure-bill-neglects-gps-threats/?sh=55db58eb23ad

(August 2021) Startups Map Out Strategies To Augment Or Backup GPS - SpaceNews:

Blog Editor's Note: Interesting article on some space-based services with the potential to augment or offer an alternative to GPS/ GNSS. 

As we have said before, space-based systems offer things you can't get from terrestrial and need to be part of a coherent and resilient PNT architecture. 
It is hard to imagine, though, how space-based alone could be sufficient. 

The outlet is "SpaceNews," so it is perhaps understandable they would chose not to mention the many companies that offer terrestrial augments and 

At the same time, establishing terrestrial systems will "take the bullseye off of space" making it a safer environment for all.

With terrestrial anti-satellite lasers, nuclear powered EW satellites lofted by Russia, and all manner of Chinese and Russian ASAT vehicles going into 
orbit, we would think space folks would be very interested in things that can de-escalate the environment. Even if those things were on the ground.

All that said, it is good to see the market ready to provide these kinds of services. A big unanswered question, though - who is going to pay, and why?

Full disclosure, Xona Space Systems is a corporate supporter of the RNT Foundation
Startups map out strategies to augment or backup GPS
by Debra Werner — August 4, 2021

Companies investing billions of dollars in autonomous cars, delivery drones and urban air taxis are counting on precise and reliable location data being 
available when they need it.

GPS-level accuracy of 4.9 meters for a smartphone operating under clear skies won’t be good enough. Before autonomous cars can speed down highways, they 
will need to know their location within around 10 centimeters with roughly one error every billion miles.

“When you start doing the math, you realize almost every car in your fleet has to have sub-10-centimeter accuracy for its entire lifetime,” said Patrick 
Shannon, CEO and co-founder of TrustPoint, a startup based in Silicon Valley and Northern Virginia developing a new global navigation satellite system 

READ MORE: https://spacenews.com/startup-pnt-services/ 

(August 2021) US Defense Department looking for GNSS disruption detection and analysis - GPS World:

US Defense Department looking for GNSS disruption detection and analysis
August 13, 2021 - By Dana Goward

Est. reading time: 1:30

The U.S. Department of Defense wants help making sense of commercially and publicly available information that could be used to detect GNSS disruptors
especially over large areas.

Obtaining the ability to detect and geolocate GNSS disruptions has been cited as an unmet need in a number of U.S. national policies and plans dealing 
with positioning, navigation and timing.

The recently posted solicitation calls the project “HARMONIOUS ROOK Situational Awareness for Intentional Disruption of Global Navigation Satellite 
System (GNSS) Users.”
The solicitation says:

“The Department of Defense (DoD) seeks commercial solutions leveraging machine-driven analytics and datasets derived from publicly/commercially available 
information (PAI/CAI) to provide a situational awareness capability for intentional global navigation satellite system (GNSS) disruptions. This 
solicitation is particularly focused on persistent, large-area coverage of falsified GNSS emitters that result in localized spoofing phenomenology.”

Studies and analyses by non-profit organizations and commercial entities have demonstrated the ability of non-governmental organizations to do this kind 
of work and produce remarkable results. In 2017, our Resilient Navigation and Timing Foundation detected and reported on widespread GPS spoofing in the 
Black Sea.

Another non-profit, C4ADS, built upon our work and produced a detailed 2019 report on GPS spoofing in Russia and Syria. In 2019 and 2020, the 
environmentally oriented non-profit SkyTruth reported on circle spoofing in China and around the globe. In July, SkyTruth revealed warship activities 
being misreported in Automatic Identification System databases.

This acquisition is being led by the Defense Innovation Unit, or DIU. The unit was specifically created to accelerate the adoption of commercial technology 
and services by the defense and national security establishments. While letting a traditional DoD contract for a prototype can often take up to 18 months
DIU aims to award contracts within 60 to 90 days of identifying the problem.

To do this, DIU uses the government’s “commercial solutions opening” process, which is designed to be simple and quick.

Companies who provide analytic services and those who have unique data sets are both encouraged to apply. The deadline is August 23.

Dana A. Goward is president of the Resilient Navigation and Timing Foundation

READ IN GPS WORLD: https://www.gpsworld.com/us-defense-department-looking-for-gnss-disruption-detection-and-analysis/  

(August 2021) Hackers Use Morse Code To Bypass Security:


(August 2021) What is complementary/alternative PNT? - GPS World:

Blog Editor's Note: This is a long piece so we won't add much to it with a long commentary. Only to say that since our inception, we have endorsed the 
architecture/ system of systems approach, as envisioned in the US govt's still-in-use 2008 National PNT Architecture.

Full disclosure: Spirent, Orolia, and UrsaNav are RNT Foundation corporate supporters.

PNT powers unmanned vehicles for transportation, ag (agriculture) and more.

August 16, 2021 - By Matteo Luccio

What is complementary / alternative positioning, navigation, and timing (PNT)? In this month’s cover story, five of our marketing partners share their 
perspective on this question and explain how their products address it.

The four global navigation satellite systems (GNSS), two regional navigation satellite systems and public and private augmentation services continue to 
provide exceptional levels of accuracy and reliability for positioning, navigation and timing (PNT). Yet their well-known vulnerabilities also continue 
to fuel the need for alternative/complementary sources of PNT data, especially for new and rapidly expanding user segments such as autonomous vehicles.

What constitutes a complementary service to GNSS for PNT and what constitutes a true alternative is partly a matter of definition and opinion. In a 
January report, the U.S. Department of Transportation stated.

…suitable and mature technologies are available to owners and operators of critical infrastructure to access complementary PNT services as a backup 
to GPS. To achieve the parallel objective of resilience, as described in Executive Order (EO) 13905, that path should involve a plurality of diverse 
PNT technologies. Promoting critical infrastructure owner/operator use of those technologies that show strong performance, operational diversity, 
operational readiness, and cost-effectiveness is worthwhile. Based on this demonstration, those technologies are LF and UHF terrestrial and L-band 
satellite broadcasts for PNT functions with supporting fiber optic time services to transmitters/control segments. (Andrew Hansen et al., Complementary 
PNT and GPS Backup Technologies Demonstration Report
, prepared for the Office of the Assistant Secretary for Research and Technology, Department o
Transportation, January 2021, p. 195.

For this year’s Q&A on complementary / alternative PNT, I asked five companies in the GNSS/PNT space to tell us how they define the issue, what solutions 
they prioritize, what markets they target, and which of their products specifically address the need to make PNT more resilient.

The participants are:

-Roger Hart, Director of Engineering, Spirent Federal Systems
-David Sohn, Solution Architect, Orolia
-Matthieu Noko, Product Manager, SBG Systems
-Jacob Amacker, Product Engineer, OxTS
-Charles Schue, Founder & CEO, UrsaNav
How do you define alternative PNT?

READ MORE: https://www.gpsworld.com/pnt-powers-unmanned-vehicles-for-transportation-ag-and-more-gps-world/ 

(August 2021) This collision avoidance tool could cut the risk of in-orbit crashes:


The technology is designed to address one of the most pressing issues facing spacecraft operators in low-Earth orbit.(LEO).

The U.S. Department of Defense tracks more than 27,000 pieces of space junk in low-Earth orbit. NASA:

By Denise Chow
A new collision avoidance platform that helps space companies keep tabs on their satellites and surroundings could cut the risk of crashes in 
orbit that generate harmful space junk.

Slingshot Aerospace, a startup based in Austin, Texas, and El Segundo, California, announced Thursday the launch of the communications platform 
that will allow satellite operators to assess the location of spacecraft in their fleet and coordinate any maneuvers that may be necessary to dodge 
objects nearby.

The technology is designed to address one of the most pressing issues facing spacecraft operators in low-Earth orbit, as the area around the planet 
has become increasingly crowded with satellite systems for telecommunications, GPS, and other functions.

The platform, called Slingshot Beacon, aims to reduce the risk of collisions in low-Earth orbit, said Melanie Stricklan, co-founder and CEO of Slingshot 
Aerospace. The company's pilot program includes the United Kingdom-based communications company OneWeb, the data and analytics firm Spire Global, 

and several other operators, accounting for 53 percent of satellite constellations in low-Earth orbit, she added.

Collision avoidance will be an essential component of the growing private space industry, particularly as an estimated 115,000 satellites are expected 
to be in operation in low-Earth orbit by 2030. This is in addition to more than 27,000 pieces of space junk — ranging from defunct satellites to spent 
rocket parts to wayward bits of debris — that are already tracked by the U.S. Department of Defense.

Several different agencies, including NASA and the Defense Department, track orbital debris but Slingshot Aerospace is hoping to make it easier for 
companies to communicate about collision risks and avoid potentially catastrophic situations in orbit.

"We've created a new Wild West and it didn't have to be this way," Stricklan said. "We have to keep these orbits sustainable because the entire world is 
dependent on space.

Slingshot Beacon is designed to help companies resolve issues in orbit, notify other satellite operators of planned maneuvers and mitigate future risks. 
Stricklan said she hopes the tool will invite greater collaboration among companies and among various nations.

"This allows us to reduce uncertainty and communicate across borders, across companies and across silos that exist today," she said.

The mounting space junk problem was highlighted recently, after an object crashed into the International Space Station and damaged the orbiting lab’s 
robotic arm.
The incident, found during a routine inspection May 12, demonstrated the growing threat posed by orbital debris and the need for greater 
situational awareness in orbit.

(August 2021) New FPGA's to be made in U.S. (for critical applications):


Intel recently announced a new technology that enables customers to significantly reduce the size, weight, power and cost of systems used in radar, 
electronic defense, high-end commercial test equipment and 5G/6G communications markets. Delivering the highest analog converter sample rates in the 
industry, this transformative technology integrates FPGAs and high-performance analog-to-digital converters (ADC) and digital-to-analog converters (DAC), 
a revolutionary step toward providing a single component to improve performance, reduce power consumption and shrink the physical size of circuitry. 

With this announcement, Intel extends technology scaling from digital semiconductors into the realm of digital plus analog applications. In 5G and 6G 
applications, the bandwidth attained with such high sample rates will directly correlate to high communication bandwidth to enable transporting the 
massive amount of data the world is now moving wirelessly. 


(August 2021) NASA Tests Machine to Power the Future of Aviation Propulsion:

(August 2021)  It takes GRIT to protect your position:

Available on all NovAtel OEM7 products, GNSS Resilience and Integrity Technology (GRIT) enables situational awareness and interference mitigation tools 
to protect your position, navigation and timing against global navigation satellite system (GNSS) interference.

Detailed situational awareness is the first step to building resiliency and integrity of a user’s position. GRIT includes NovAtel’s successful Interference 
Toolkit (ITK) and spoofing detection to identify when your GNSS signal is under threat. Once a user’s environment is characterized, GRIT enables 
interference mitigation through anti-jam technology and digital filters. Users can characterize jamming signals and develop their own interference location 

Read more here: https://lnkd.in/gUnYm2m 

(August 2021) China’s Anti-Satellite Weapons Could Conquer Taiwan—Or Start a War - The National Interest:

Blog Editor's Note: Great article showing, again, how China plays the long game. Contrast their 30 and 40 year efforts with what seems to 
be a two-year planning window in the U. S. based on elections to the House of Representatives. Or maybe it is a four-year window based on 
presidential terms.

And don't forget that China's emotional commitment is to neutralizing the U. S. in space because of the "unforgettable humiliation."

So... space is important. It is a battleground. The U.S. has more in space than anyone else. We DEPEND on space more than anyone else.

Raise hands, please, if you don't understand why our space assets are gigantic, high priority targets for our adversaries.

China’s Anti-Satellite Weapons Could Conquer Taiwan—Or Start a War:
Should the United States fail to intervene, the consequences would be disastrous for both Washington and its allies in East Asia, and potentially 
the credibility of U.S. defense commitments around the globe.

by Brian G. Chow Brandon Kelley

On July 1, 2021—the one-hundredth birthday of the Chinese Communist Party—President Xi Jinping declared that China will “advance peaceful national 
reunification” with Taiwan. It would be easy to dismiss such statements as mere political rhetoric: certainly, Taiwan would never willingly accede 
to Chinese demands to rejoin the fold. But China’s rapidly advancing anti-satellite (ASAT) capabilities could open up another avenue: deterring 
United States intervention on Taiwan’s behalf in order to coerce reunification without firing a shot.

If current trends hold, then China’s Strategic Support Force will be capable by the late 2020s of holding key U.S. space assets at risk. Chinese 
military doctrine, statements by senior officials, and past behavior all suggest that China may well believe threatening such assets to be an 
effective means of deterring U.S. intervention. If so, then the United States would face a type of “Sophie’s Choice”: decline to intervene, 
potentially leading allies to follow suit and Taiwan to succumb without a fight, thereby enabling Xi to achieve his goal of “peacefully” snuffing 
out Taiwanese independence; or start a war that would, at best, be long and bloody and might well even cross the nuclear threshold.

READ MORE: https://nationalinterest.org/feature/china%E2%80%99s-anti-satellite-weapons-could-conquer-taiwan%E2%80%94or-start-war-192135 

(August 2021) Microchip offers new chip-scale atomic clock for defense - GPS World:

Microchip Technology Inc. is offering the new SA65 chip-scale atomic clock (CSAC), providing precise timing accuracy and stability in extreme environments.

(August 2021) Joint All-Domain Command and Control: Background and Issues for Congress:


https://crsreports.congress.gov/product/pdf/R/R46725/2  (or maybe click here)

(August 2021) U.S. military doubles down on GPS despite vulnerabilities - SpaceNews:

Blog Editor's Note: This article is a interesting follow-on to GAO's report on "DoD Navigation Capabilities." The article is worth reading for additional 
information it brings to light.

The author also refers to a RAND report we have discussed before that found "The military’s huge dependence on PNT data makes GPS an attractive target for 
adversaries." - Yup!

One of the big findings of the GAO report was the point highlighted in the title of this article. Also disturbing was the GAO's finding that within DOD, 
Alternate PNT efforts don't have senior leader support, and senior leaders are not in the mood for a large investment in a new navigation infrastructure. 
Pretty clear that this issue is in the not-yet-important category for them.

Perhaps this effort could be helped along if DOD thought about purchasing PNT services from a commercial provider. This could likely be much less expensive 
and up and running much sooner than would be the case with a government major system acquisition.

Individual leaders who understand and care can make such a difference. Without the vision and passion of Dr. Brad Parkinson and his patron Dr. Malcom 
Currie, DOD's Deputy Director of Research and Engineering, GPS would never seen the light of day. None of the services wanted it. To quote the Navy "we 
already know where we are!"

RNTF hosted another discussion with staff from GAO about "DOD Navigation Capabilities." At the ION Joint Navigation Conference last night. Here is a video 
of a similar on-line discussion we hosted with ION in June. If you are wondering what in the world DOD is thinking about wrt PNT, viewing the video and 
reading the report will provide a lot of answers. Though some of them are disturbing.

Bottom line (or maybe top line) - senior DOD leaders need to start caring about the PNT infrastructure that underpins so much of their technology. Else 
everything they have now and might build will increasingly be just a house of cards.

U.S. military doubles down on GPS despite vulnerabilities:
by Sandra Erwin — August 9, 2021

Space weapons meant to target U.S. satellites are a growing concern for the U.S. military. Especially worrisome are electronic jamming devices designed 
to interfere with GPS signals.

That threat is “real today and concerning,” the chief of space operations of the U.S. Space Force Gen. John Raymond told the House Appropriations 
Committee’s defense subcommittee during a hearing in May.

Raymond pointed at China and Russia as the primary actors pursuing technologies aimed at “robust jamming of GPS and communications satellites.”

READ MORE: https://spacenews.com/u-s-military-doubles-down-on-gps-despite-vulnerabilities/ 

(August 2021) Today at The Institute of Navigation's #JNC2021 conference:

 Hexagon's Autonomy & Positioning division's president and CEO Michael Ritter presents on spoofing detection in our OEM7 receivers.

Spoofing has been a well-known threat in military applications, with operations coming under threat more frequently in recent years. For appropriate and 

effective mitigation to be taken, spoofing detection must be reliable and correct.

Don't miss our presentation today at 14:10 ET at #JNC in Ballroom B.

Learn more >> https://hxgn.biz/3DcEbFk 

(August 2021)  https://www.nationaldefensemagazine.org/articles/2021/8/26/navy-marines-gearing-up-for-space-warfare 

(August 2021) GOOD QUOTES: 

James Kiessling: "AN/SPY-1 or AN/SPY-6 is pretty much irrelevant to SSA. Its a rare satellite pass / orientation that provides a suitable target 

to support a current calibration assessment."

John McGlynn: "High-gain, phased-array-antennas, Wiley-Coyote-ACME Signal Processing is all cool but there's only so much power that you can put into a 
transmit beam from a SHIP...it eventually comes down to Joules per dwell time and you just don't have enough when 1/R4 dominates."

(August 2021) https://devblogs.microsoft.com/visualstudio/revamped-project-properties-ui/ 

(August 2021) U.S. Navy and Marines gearing up for space warfare: https://www.nationaldefensemagazine.org/articles/2021/8/26/navy-marines-gearing-up-for-space-warfare 

(August 2021) U.S. military doubles down on GPS despite vulnerabilities - SpaceNews:

Blog Editor's Note: This article is a interesting follow-on to GAO's report on "DoD Navigation Capabilities." The article is worth reading for additional 
information it brings to light.

The author also refers to a RAND report we have discussed before that found "The military’s huge dependence on PNT data makes GPS an attractive target for 
" - Yup!

One of the big findings of the GAO report was the point highlighted in the title of this article. Also disturbing was the GAO's finding that within DOD
Alternate PNT efforts don't have senior leader support, and senior leaders are not in the mood for a large investment in a new navigation infrastructure. 
Pretty clear that this issue is in the not-yet-important category for them.

Perhaps this effort could be helped along if DOD thought about purchasing PNT services from a commercial provider. This could likely be much less expensive 
and up and running much sooner than would be the case with a government major system acquisition.

Individual leaders who understand and care can make such a difference. Without the vision and passion of Dr. Brad Parkinson and his patron Dr. Malcom 
, DOD's Deputy Director of Research and Engineering, GPS would never seen the light of day. None of the services wanted it. To quote the Navy "we 
already know where we are!"

RNTF hosted another discussion with staff from GAO about "DOD Navigation Capabilities."At the ION Joint Navigation Conference last night. Here is a video 
of a similar on-line discussion we hosted with ION in June. If you are wondering what in the world DOD is thinking about wrt PNT, viewing the video and 
reading the report will provide a lot of answers. Though some of them are disturbing.

Bottom line (or maybe top line) - senior DOD leaders need to start caring about the PNT infrastructure that underpins so much of their technology. Else 
everything they have now and might build will increasingly be just a house of cards.

U.S. military doubles down on GPS despite vulnerabilities
by Sandra Erwin — August 9, 2021

Space weapons meant to target U.S. satellites are a growing concern for the U.S. military. Especially worrisome are electronic jamming devices designed 
to interfere with GPS signals.

That threat is “real today and concerning,” the chief of space operations of the U.S. Space Force Gen. John Raymond told the House Appropriations 
Committee’s defense subcommittee during a hearing in May.

Raymond pointed at China and Russia as the primary actors pursuing technologies aimed at “robust jamming of GPS and communications satellites.”

READ MORE: https://spacenews.com/u-s-military-doubles-down-on-gps-despite-vulnerabilities/ 

(September 2021) With SV08, 3 GPS III satellites ready for launch:


(September 2021) National Academies Proposes Team to Study FCC Ligado Decision - GPS World:

National Academies Proposes Team to Study FCC Ligado Decision
September 2, 2021 - By Dana Goward

The National Academies has announced its proposed team to examine the analysis and decision-making process by the Federal Communications Commission (FCC
in the matter of Ligado Networks. Individuals and organizations wishing to comment on the appropriateness of any of the members of that team or on any other 
aspect of this study have until September 19.

The April 2020 decision by the FCC has generated significant controversy and opposition within the public and Congress. This resulted in, among other things, 
seven separate petitions for reconsideration being filed, all of which are still pending, and several provisions in the National Defense Authorization Act 
for 2021. One of those provisions requires the Department of Defense to sponsor a study of the technical assumptions and analyses that went into the 

FCC’s decision to allow Ligado Networks to operate.

According to the post on the National Academies website, the study will consider:

“(1) Which of the two prevailing proposed approaches to evaluating harmful interference concerns — one based on a signal-to-noise interference protection 
criterion and the other based on a device-by-device measurement of the GPS position error — most effectively mitigates risks of harmful interference with 
GPS services and DOD operations and activities.

(2) The potential for harmful interference from the proposed Ligado network to mobile satellite services including GPS and other commercial or DOD services 
including the potential to affect Department of Defense (DOD) operations, and activities.

(3) The feasibility, practicality, and effectiveness of the mitigation measures proposed in the FCC order with respect to DOD devices, operations, and 

This announcement is the first significant public step for the effort, which is expected to take approximately 12 to 18 months. Sources say that there will 
likely be public and classified versions of the report. The classified version is likely to take significantly longer to compile.

The proposed study team members are:

Chair: J. Michael McQuade


Jennifer Lacroix Alvarez
Kristine M. Larson
John L. Manferdelli
Preston F. Marshall
Y. Jade Morton
Richard Reaser, Jr.
Jeffrey H. Reed
Nambirajan Seshadri

(September 2021) James Kiessling's positive endorsement:
Sound recommendations - I normally see certain political leaning 'think tanks' as stealth marketing but this OpEd is clearly about making more effective 
uses of multiple billion dollar assets and gaining capabilities far sooner. My complete technical endorsement - Well done Heritage!.

(September 2021) Two years since the Tesla GPS hack:

Blog Editor's Note: An interesting reminder of a hallmark event within the PNT community. We are sure it had a significant impact on the folks at Tesla
and probably significant but probably lesser impact at other car companies. 

We would have hoped that all GNSS users would take the lesson to heart and in the last two years taken significant steps to upgrade all their receivers 
and antennas to make them more resilient to spoofing. Probably didn't happen.

Toward the end of the article Roi mentions the inclusion of cybersecurity provisions in the U.N. regulations. Great acknowledgement of the impact of 
Regulus's work and the impact it has had.

Just the U.N. saying manufacturers have to demonstrate their vehicles are cybersecure, though, is a long way from making that a reality. That will have 
to be interpreted and enforced by national governments - each with their own definitions of what that means and structures for requirements and enforcement. 

Well done again to Regulus making an important step in this long journey.

Full disclosure - Regulus is a corporate member of the RNT Foundation.
Two years since the Tesla GPS hack
August 30, 2021 - By Roi Mit

In June 2019, Regulus Cyber’s experts successfully spoofed the GPS-based navigation system of a Tesla Model 3 vehicle. This experiment provided an 
important warning for all companies using GNSS location and timing: these technologies, on which they depend, are highly vulnerable to spoofing attacks. 
In the two years since the experiment, companies and governments have continued to research the potential harm that can be caused by spoofing attacks and 
are learning more about how to defend themselves from them.

The Tesla experiment was groundbreaking because it was the first time that a level 2.5 autonomous vehicle was exposed to a sophisticated GPS spoofing 
attack and its behavior recorded.

We chose Tesla’s Model 3 because it had the most sophisticated advanced driver assistance system (ADAS) at the time, called Navigate on Autopilot 
(abbreviated NOA or Autopilot), which uses GPS to make several driving decisions. However, this experiment exposed several cybersecurity issues 
potentially affecting all vehicles relying on GPS as part of their sensor fusion for autonomous decision making.

READ MORE: https://www.gpsworld.com/two-years-since-the-tesla-gps-hack/?utm_source=Defense+PNT+%2B+Geointelligence&utm_medium=Newsletter&utm_campaign=NCMCD210902002&oly_enc_id=9675F1206356D9T 

(September 2021) House Armed Services Committee Interested in New, Non-GPS PNT Constellation:
The House version of the National Defense Authorization Act for 2022, which begins on the first of October, requires the Secretary of the Air Force to 
provide a briefing to the Armed Services Committee about establishment of a new PNT constellation.

Specifically mentioned is the Air Force's Navigation Technology Satellite 3 (NTS-3) program. Cited in the language are the fact that is features a 
"...steerable, high-power phased array antenna coupled with a digital signal generator that can be reprogrammed on orbit, enabling operators to quickly 
deploy newly developed, advanced signals as they encounter electronic threats."

Also noted is that "NTS-3 will be working on PNT enhancements such as experimental antennas, flexible and secure signals, increased automation, and use 
of commercial assets."

The briefing is also to include "... a detailed funding, development, procurement, and launch plan.." and talk about how satellites can be rapidly deployed 
to meet emerging electronic warfare threats.

We find the mention of commercial assets and rapid deployment to be particularly interesting. Unfortunately, the briefing will undoubtedly be classified. 
But we would love to be a fly on the wall.

LINK TO NDAA PROVISION: https://armedservices.house.gov/_cache/files/6/8/6851607b-a0bf-4f59-8073-69400fd673fc/EF79C94AAFA1C0E2D673B2B64EDE0830.bills-117hr4350ih-strsubcommitteemarkup.pdf#page=26 

“Investment in a 21st-century Intelligent & Autonomous Infrastructure is among the highest priorities for stimulating economic expansion, national security, 
and job growth.”
Autonomy Institute https://youtu.be/9-w0G7sD8NQ  

(September 2021) Attack on GPS the Next 9-11? - Video Report KPIX News, San Francisco:
This four minute piece from the CBS affiliate in San Francisco poses an interesting question. 

There are certainly plenty of individuals, groups, and governments out there who might like to bring the U.S. to its knees.

For example, in 1996 China suffered what their military calls "The Unforgettable Humiliation" when they lost two of their missiles in flight because, 
they say, the U.S. interfered with GPS signals.

China then labored for 24 years to build Bei Dou and make themselves independent of U.S. satnav. They also made themselves independent of space for PNT 
with services from eLoran, a combination of fiber and 5G, and other systems

So now that they don't need GPS or space for PNT, maybe it's time for some payback for the humiliation with an attack on GPS. It might be seen by many 
in China as fitting. And maybe it could be done in a way that can't be traced back to them.

Or maybe China holds GPS hostage and trades it for something they want, like Taiwan, or the South China Sea.

With America so vulnerable, the future holds a wealth of possibilities for our adversaries.

Our thanks to Molly McCrea at KPIX. She has reported on GPS vulnerability before and also produced this story.

KPIX Original Report: Next 911 Could Be A Cyberattack On Vulnerable GPS Systems Program: 
KPIX 5 News EveningCategories: News, Technology & Computing, Local News, KPIXTV, Top Story, Google

As the nation marks the 20th anniversary of the 911 terror attack on U.S. soil, Juliette Goodrich tells of another growing security threat leaving us 
vulnerable to catastrophe.
CLICK IMAGE OR HERE FOR VIDEO: https://sanfrancisco.cbslocal.com/video/5991674-kpix-original-report-next-911-could-be-a-cyberattack-on-vulnerable-gps-systems/ 

Bathymetric surveys dip into Dead Sea - GPS World:

(September 2021) Strengthening PNT to Avert Economic Setbacks - GW Prime:

Blog Editor's Note: A good overview article.

One note, though. The $1.3B loss per day shown for the U.S. should we be without GPS comes from an RTI study done for the National Institute of 
Standards and Technology.
That seems like a big loss that we should act to prevent (and we should).

But U.S. GPD is about $63B/day. So that means the RTI study says that if we lose GPS, our economy will only suffer by 2%.

Does that amount seem way low to you? It does to us.

Strengthening PNT to Avert Economic Setbacks
Resilient PNT is neither a particular technology nor a service; it is actually a combination of many things, depending on the scale and scope of 

applications and systems.
By Ananya Narain

Director | GW Consulting

The world we live in today is critically dependent on Positioning, Navigation and Timing (PNT) services provided by the Global Navigation Satellite System (GNSS). 

Of course, the Global Positioning System (GPS), developed by the US, is the most widely used technology. Apart from commercial operations, we heavily rely on PNT 

services for national security and critical infrastructure applications. From squadron coordinates for military missions, precise location data for search and rescue 

operations, scientific pursuits for environmental and disaster monitoring to increasing efficiency and productivity in areas like construction, oil and gas, and mining, 

everything runs on PNT. Perhaps that is why the value of these services is growing by the day. However, the heightened reliance on these services can lead to 

socio-economic losses as these systems are prone to disruptions, interruptions, and manipulations.

READ MORE: https://www.gwprime.geospatialworld.net/technology-and-innovation/strengthening-pnt-to-avert-economic-setbacks/ 

(September 2021) DARPA awards Lockheed Martin $25 million contract modification for integration of Blackjack satellites - SpaceNews:

LockheedMartin is the satellite integrator for Blackjack, a project to demonstrate the capabilities of small satellites in low Earth orbit for #military 
communications, missile warning and navigation.


(September 2021) Sensors to be used in NASA space applications are characterized in:

General principles applicable in the space application domain are covered in State of the Art of Small Spacecraft Technology:

(September 2021) Time to Build. Intelligent, autonomous, and electrified infrastructure is the equivalent of the atomic energy race of the 1940s:

National sovereignty and global productivity will go to the nation that deploys the Intelligent Infrastructure supporting Industry 4.0. Unleashing the largest productivity boom in world history. Autonomy Institute

(September 2021) Could a GPS 9/11 Happen? - Location Business News:
By Kevin Dennehy
September 15, 2021

More industry experts are calling for backups to the Global Positioning System as the 20th anniversary of the 9/11 terror attacks recently passed. This 
week, in an interview with a San Francisco television station, both former U.S. Secretary of Defense Leon Panetta, industry expert Dana Goward and others 
said a major disaster could be on the horizon if GPS is not protected!

Goward, who is president of the Resilient Navigation & Timing Foundation, doesn’t think the U.S. government is doing enough to protect GPS’ signal and 
“Absolutely not. Twenty years ago, a government report issued just before 9-11 that called for a series of measures to protect GPS frequencies, 
toughen receivers, and provide alternate sources of timing and location information,”
he said. “These have never been seriously acted upon.”

In fact, Goward believes that the situation today is worse than it was in September 2001. “Over the last two decades, the FCC has significantly reduced 
its enforcement staff and its ability to detect and deter disruptions,”
he said. “The FCC decision in the Ligado Networks case has, according to the 
executive branch, authorized substantial interference with GPS signals for many users. And in 2010 when the Loran navigation and timing system was 
shutdown, instead of being upgraded as promised, we lost the only widely and publicly available alternative system.”

READ MORE: https://locationbusinessnews.com/could-a-gps-9-11-happen 

(September 2021) Engineering various sources of loss provides new features for perfect light absorption:

Natural and manmade physical structures all lose energy, and scientists work hard to eliminate that loss or compensate for it. Optical and photonic 
devices lose energy through light scattering, radiation, or material absorption. In some situations, however, intentionally yet carefully designing 
loss in open optical devices and systems can lead to unconventional physical phenomena which inspires novel methods for optical control and engineering.


(September 2021) Galileo, OneWeb and the UK’s sovereignty way forward - GPS World:
September 15, 2021 - By Dana Goward

A discussion with Admiral Lord West

Admiral Lord Alan West of Spithead has served the United Kingdom as First Sea Lord and led the government’s efforts for counter terrorism and cybersecurity. 
He has been a member of the House of Lords since 2007 and has stayed engaged with defence and maritime issues. RNT Foundation President Dana A. Goward 
spoke with him in early September about the UK’s way forward for GPS-like services.

DG: The UK government has been talking for years about the nation’s vulnerability to disruption of space-based signals such as those from GPS and Galileo
What is being done about it?

LW: Unfortunately, the government is not being as transparent as we might like on this. I do know from comments made in the House of Lords that there is 
a group developing a strategy. Also, that the Cabinet Office — our equivalent of the National Security Council in the United States — is deciding who is 
to be in charge and how things will be run.

I have heard the strategy group will propose a mix of technologies such as has been discussed in the United States. The idea of having several different 
systems, I am sure, is so that something interfering with one won’t disrupt them all.

This is all supposed to published in November. But I am concerned that government distractions with COVID, Afghanistan, and other issues will delay that.

DG: What about the OneWeb project? That doesn’t seem to be waiting for a November announcement. And there is talk it may provide GPS-like timing and 
navigation services.

LW: OneWeb is moving forward, but at present it is only about 5G and making it available more quickly and broadly. There may be a OneWeb Phase 2 that 
includes modified or additional satellites to provide positioning, navigation, and timing (PNT), but that is to be decided.

Admiral Sir Alan West, then First Sea Lord, is pictured with the official chart of anchorages for the International Fleet Review. (Photo: DP Kilfeather’s 
book Trafalgar 200 Through the Lens, Queen Elizabeth II 80th Birthday Edition, CC BY-SA 2.5)

DG: How about the UK rejoining Galileo?

LW: Actually, that makes a lot of sense from a practical point of view for both the UK and Europe. Unfortunately, there were a lot of hurt feelings on 
the continent with Brexit, some EU leaders seemed to be in punishment mode, and expulsion from Galileo was part of the fallout. I think that in due course 
as tempers cool, we will fully re-engage with the European Space Agency.

DG: So, no UK project for a GPS equivalent?

LW: The government allocated £90 million to that, which enabled a thorough look at the idea but was woefully inadequate to even start a project. Doing a 
British version of GPS or Galileo would be hugely expensive and doesn’t make sense. There are better, cheaper ways of getting what we need.

DG: And what does the UK need? What is the goal?

LW: We need several things.

First, we need a global capability that is ours, or that we are closely partnered in, to support the UK’s worldwide military and economic interests.

We also need to have something in place so that, even if space is denied to us — and that is getting to be more and more of a threat each day — we can 
keep our industries, critical infrastructure and economy going at home.

And third, we need a resilient PNT capability as a foundation for current applications, and to build on for such things as autonomy, intelligent 
, and the like.

DG: So how do you get there?

LW: For the global bit, the OneWeb, and perhaps an even closer partnership with the United States on GPS.

At home, we definitely need a sovereign capability for when space is denied by solar weather or our adversaries. Also to be a check on space signals 
because our adversaries and criminals are spoofing them more and more.

I have always thought eLoran was a good choice. The UK pioneered its development and had the world’s first operational system in 2015. It is really 
hard to interfere with the signal
, and there are other features that could be added to it that would make it even more robust.

There was a very interesting report called MarRINav ( https://marrinav.com/marrinav-reports/ )
put out last year about what UK maritime needs to ensure it can navigate regardless of whether 
the satellites are working or not. They came up with a reasonably inexpensive combination of systems anchored by eLoran.

By the way, it is interesting that the MarRINav study was funded by the European Space Agency. They seem to understand that satellites are not the be 
all and end all for PNT services.

DG: That all seems pretty straightforward and the right thing to do. What’s standing in the way?

LW: Well, so few people understand the problem. The population as a whole is almost completely unaware. At some level government understands all 13 
of our critical infrastructure sectors could be impacted, but the people senior enough to drive action have dozens of other issues to deal with that 
probably seem more urgent.

DG: I wonder what it will take to make it seem urgent enough.

LW: Let’s hope the wakeup call is something short of a national disaster.

(September 2021) UK’s Future Force To Lean Heavily Into Robotics, AI & Hybrid Power:

The British Army is leaning heavily into robotics, ai and hybrid-power technology as part of a new acquisition process dubbed Mercury, according to a 
British Army leader involved in future procurement planning.

The Army is grappling with how to acquire technologies that it believes it will need in the future, how to spiral in those technologies across its 
equipment programs and how to cultivate skills in its soldiers to use capabilities as they come online.

"Driving innovation to achieve its goals, the Army must better identify technologies that will likely change the way the service operates and fights", 
Col. Christopher Coton, the service’s assistant head for concepts, said at the DSEI defense exhibition in London on Sept. 15, 2021.

(September 2021) Space Systems Command declares three GPS III space vehicles 'Available for Launch' - GPS World:


(September 2021) Air Force begins construction of simulation and wargaming facility for space and lasers:



(September 2021) Raytheon buys another fast-growing Colorado space company - Denver Business Journal:


(September 2021) GPS Lessons from Before 9/11 Still Endanger the U.S. - Nextgov:.
By Dana A. Goward,

President, Resilient Navigation and Timing Foundation

SEPTEMBER 16, 2021 02:16 PM ET

“Public policy must ensure, primarily, that safety is maintained even in the event of loss of GPS,” officials wrote in the 2001 Volpe Report.
Secretary of Transportation Norman Mineta hefted the report in his hand. Three years in the making, it described America’s over-reliance on the Global 
Positioning System and what should be done about it.

This was important. He wanted to read and understand it better before it was made available to the public. So, although the report was dated Aug. 29, 2001, 
it wasn’t released until Sept. 10.

The next day the world changed. And the report’s calls for immediate and specific actions across government to protect GPS and its users were put on the 
back burner.

The 2001 Volpe Study’s Warning About GPS 

“Critical infrastructure” first emerged as a federal term of art in 1996 when President Bill Clinton established a commission to figure out what it was 
and how to protect it. As part of its findings the commission noted transportation’s increasing reliance on GPS, especially in aviation, and recommended 
a closer look.

The result was a 113-page document by DOT’s John A. Volpe National Transportation Systems Center published in 2001.

Considering today’s lack of protection for frequencies, vulnerable receivers and the absence of widely available alternatives to GPS, one might be tempted 
to think these problems were neither known nor envisioned 20 years ago.

A quick glance at the Volpe report shows just the opposite.

Its assessment of system vulnerabilities, threats and potential severe consequences could have been written today.

Problems with accidental interference and deliberate jamming were well-known and documented. Spoofing and “hazardously misleading information” were listed 
as likely to be a problem. And while a direct attack on the GPS Operational Control Segment and/or satellites was seen as less likely, total system loss 
for one reason or another was contemplated.

Almost all the report’s recommendations also apply today nearly as much as they did 20 years ago.

It’s very first recommendation began: “Public policy must ensure, primarily, that safety is maintained even in the event of loss of GPS.”

The report went on to discuss the need for things like risk assessment, protecting frequencies through regulation and interference detection, improving 
signals, toughening receivers, and the need for backup systems.

About the last it said: “Backups for positioning and precision timing are necessary for all GPS applications involving the potential for life-threatening 
situations or major economic or environmental impacts.”

Through the Lens of 9/11

After the attacks of 9/11, the government’s response to the Volpe report was understandably delayed.

When it did come in 2004, officials viewed the report as much through a lens of national security as much as the original focus of fostering transportation 
safety and protecting the economy.

This was reflected in December 2004’s National Security President Directive- (NSPD) 39 which assigned a wide variety of GPS-related duties to various 
federal departments and agencies. These included:

Good spectrum management to protect GPS frequencies.
Detection, location, attribution of interference, along enforcement actions to deter future events.
Development of a GPS alternative by the Defense Department to be used for national security, and
Acquisition of GPS backup capabilities to support “…critical transportation, homeland security, and other critical civil and commercial infrastructure …” 

by the Transportation Department.
With the unclassified portion at only 13 pages and signed by the president, NSPD- 39 was, for a government document, a concise set of orders to protect 
the nation.

It came at a time when the pain of an attack on the homeland was still palpable. And when the twin humiliations of failed intelligence, and failure to 
take simple anti-hijacking precautions like hardening cockpit doors were still keenly felt.

One would have expected prompt and decisive action to put the president’s orders into effect.

20 Years of Inaction and Regression

Yet 20 years after the first comprehensive official warnings about GPS vulnerability, America has still failed to act.

In fact, rather than moving forward, in some areas we have regressed.

Instead of being careful to protect GPS frequencies, the Federal Communications Commission (FCC) has licensed operations that many say will interfere
with GPS signals.

And rather than improving its ability to detect violations and act against jammers and spoofers, the FCC has reduced staff and equipment.

GPS alternative projects within the Department of Defense are still in the science- project stage. The Government Accountability Office reports those 
efforts don’t have the support of senior leadership and often die often or "die on the vine".

And despite nearly a dozen studies, a law requiring establishment of a national alternative for GPS timing, and public promises by two administrations 
to create a backup system, nothing has been done. Worse, a national alternative system used by some telecom and other industries was terminated 
in 2010 against the recommendation of nearly every engineer and technologist in government.

Structured to Fail

The reasons for inaction and backward movement on these issues over the decades are many and varied.

Responsibility for positioning, navigation, and timing (PNT), issues is divided between a variety of departments. Authority to make real changes was 
reserved for officials at the Executive Office of the President who typically have neither the expertise nor time to deal with such issues.

GPS services have been generally reliable with no major incident to highlight vulnerabilities. In the absence of a media- worthy event, busy bureaucrats 
and political leaders have not had to focus on the threat.

And when it comes to alternatives, advocacy within government and by defense contractors for GPS-related programs has been vigorous. As is the case with 
any major project, efforts that might seem to compete with it or reduce its priority have faced major uphill challenges.

So, rather than being propelled forward as critical to our nation’s well-being, these issues have languished and America’s capabilities have atrophied.

Dangers Increasing

All while China, Russia, Iran, and others have added satellite PNT capability and/or upgraded terrestrial systems that can work with GPS and stand in for 
it when it is not available.

They have gained huge tactical and strategic advantages over America by using the last two decades to actually do the things we have only talked about.

Some analysts have opined that GPS is the highest priority target for those who would do America harm, from lone wolf hackers to hostile nations.

And many think it is time to “get the bullseye off GPS” with complementary and backup systems and restore America’s place in the world as PNT leader.

Failing to do so will leave the cockpit doors open to nearly everyone, and the nation vulnerable to another devastating attack.

Dana A. Goward is president of the Resilient Navigation and Timing Foundation.

READ AT NEXTGOV: https://www.nextgov.com/ideas/2021/09/gps-lessons-911-still-endanger-us/185400/ 

(September 2021) How should we secure PNT resilience? - GPS World Editorial Advisory Board:

Blog Editor's Note: There is a lot to unpack in the three short responses to the question posted to the panel. 

Our response to their answers is "all of the above." We absolutely need A holistic approach that includes interference detection and mitigation, 
widespread use of more robust receivers, and multiple complementary alternatives.

Budgeteers often look for a single, quick, and inexpensive fix to a given. Good luck with that.

There is no quick fix for a thirty year addiction to a single source of wireless precise time and location. Take the patient abruptly off the drug an 
he suffers severely or dies. Rather, you have to make the drug less harmful, the patient stronger, and provide alternative medicines in case the primary 
one is not available or doesn't provide all the patient needs.

PNT is one of those really important national services that requires continual leadership and management. We have failed as a nation to do this and are 
in in great danger as a result.

EAB Q&A: How should we secure PNT resilience?:
September 13, 2021 - By Tracy Cozzens

Two decades ago, the Volpe National Transportation System Center released its landmark report on the vulnerability of GPS. Have this study and its many 
successors helped move us to the necessary levels of PNT resilience? Have we done enough? What is left to be done?

READ MORE AT GPS WORLD: https://www.gpsworld.com/eab-qa-how-should-we-secure-pnt-resilience/ 

(September 2021) Johns Hopkins APL Scientists Contribute Award-Winning Breakthrough to AI-Driven Climate Initiative:


(September 2021) U.S. generals planning for a space war they see as all but inevitable - SpaceNews:

Blog Editor's Note: If you really need electricity and there is a chance the electrical grid might go down, you get a generator... If there is a 
chance your ship will be torpedoed, you make sure you have a lifeboat... If you might not have PNT from space...

There is no space system that is as important to the well being of the United States as the Global Positioning System (GPS).

If military commanders and politicians are looking at GPS as just another weapons system, we are in deep trouble.
U.S. generals planning for a space war they see as all but inevitable
by Sandra Erwin — September 17, 2021

A ship in the Pacific Ocean carrying a high-power laser takes aim at a U.S. spy satellite, blinding its sensors and denying the United States critical 
eyes in the sky.

This is one scenario that military officials and civilian leaders fear could lead to escalation and wider conflict as rival nations like China and Russia 
step up development and deployments of anti-satellite weapons.

If a satellite came under attack, depending on the circumstances, “the appropriate measures can be taken,” said Lt. Gen. John Shaw, deputy commander of 
U.S. Space Command.

READ MORE: https://spacenews.com/u-s-generals-planning-for-a-space-war-they-see-as-all-but-inevitable/

(September 2021) How quickly do algorithms improve?:

Algorithms are sort of like a parent to a computer. They tell the computer how to make sense of information so they can, in turn, make something useful 
out of it. The more efficient the algorithm, the less work the computer has to do. For all of the technological progress in computing hardware, and the 
much debated lifespan of "Moore’s Law", computer performance is only one side of the picture. Behind the scenes a second trend is happening: Algorithms 
are being improved, so in turn less computing power is needed. While algorithmic efficiency may have less of a spotlight, you’d definitely notice if 
your trusty search engine suddenly became one-tenth as fast, or if moving through big datasets felt like wading through sludge.
How quickly do algorithms improve?
MIT scientists show how fast algorithms are improving across a broad range of examples, demonstrating their critical importance in advancing computing.


(September 2021) The Mars helicopter: What’s it up to now?:

Having established that it can fly in the Martian atmosphere and having achieved all its own test objectives, its role is now scouting out routes for its big brother,

Perseverance rover.


(September 2021) GPS Disruption Warning - U.S. Maritime Administration:

Blog Editor's Note: This is the most recent warning issued for GPS disruption by the U.S. Maritime Administration (MARAD). For most of the last four or 
five years, MARAD has had a similar warning active and on the books.

The advisory points out that this is a worldwide problem, but is especially a concern in the eastern Mediterranean. We recommend perusing the 
Coast Guard website, where all the reports are listed. Most are in the Eastern Med, but we think you will be surprised by the wide and interesting distribution of 

Note that while this is a warning about GPS disruption, other GNSS are likely impacted also. Most of the world's jammers don't discriminate between systems 
and interfere with most satnavs.
2021-010-Various-GPS Interference

This revised advisory cancels U.S. Maritime Advisory 2021-004

1. Reference: None.

2. Issue: Instances of significant GPS interference have been reported worldwide in the maritime domain. This interference is resulting in lost or 
inaccurate GPS signals affecting bridge navigation, GPS-based timing, and communications equipment (include satellite communications equipment).
Over the last six months, areas from which multiple instances have been reported include the eastern and central Mediterranean Sea and in the vicinity of 
the Suez Canal. The U.S. Coast Guard Navigation Center (NAVCEN) web page, https://go.usa.gov/xMZ2q , contains a chronological list of recently reported 
GPS problems.

3. Guidance: Exercise caution when underway and prior to getting underway. The NAVCEN and NATO Shipping Center websites contain information regarding 
effective navigation practices for vessels experiencing GPS disruption. The information reaffirms safe navigation practices when experiencing 
GPS disruptions, provides useful details on reporting disruptions, and is intended to generate further discussion within the maritime community about 
other disruption mitigation practices and procedures. This guidance also recommends reporting such incidents in real time; noting critical information 
such as the location (latitude/longitude), date, time, and duration of the outage/disruption; and providing photographs or screen shots of equipment failures 
failures experienced to facilitate analysis. 
The NAVCEN information is available at: 

4. Contact Information: Maritime GPS disruptions or anomalies should be reported immediately to the NAVCEN at 
or via phone at 703-313-5900, 24-hours a day. NAVCEN will further disseminate reported instances of GPS interference in this region to the NATO Shipping 

5. Cancellation: This message will automatically expire on March 14, 2022.

For more information about U.S. Maritime Alerts and Advisories, including subscription details, please visit https://go.usa.gov/xMZTS

LINK TO THE ADVISORY ON THE MARAD SITE: https://www.maritime.dot.gov/msci/2021-010-various-gps-interference 

(September 2021) Air Force’s top civilian hints at changes to hypersonic weapons programs:


(September 2021) Op-Ed: Australia's First Nuclear Sub Project Comes With Big Risks:


(September 2021) A New Understanding of Galaxy Evolution with NASA’s Roman Space Telescope:

When NASA’s Nancy Grace Roman Space Telescope launches in the mid-2020s, it will revolutionize astronomy by providing a panoramic field of view
at least 100 times greater than Hubble's at similar image sharpness, or resolution. The Roman Space Telescope will survey the sky up to thousands of 
times faster than can be done with Hubble.
This combination of wide field, high resolution, and an efficient survey approach promises new understandings 
in many areas, particularly in how galaxies form and evolve over cosmic time. How did the largest structures in the universe assemble? How did our 
Milky Way galaxy come to be in its current form? These are among the questions that Roman will help answer. Galaxies are conglomerations of stars, gas, 
dust, and dark matter. The largest can span hundreds of thousands of light-years. Many gather together in clusters containing hundreds of galaxies, 
while others are relatively isolated

(September 2021) Xona Space Systems fully funds GPS-alternative demo mission - SpaceNews:

Blog Editor's Note: A big announcement from Xona Space Systems yesterday. - Full disclosure, Xona is an RNTF corporate member

This is likely good timing for Xona. Government interest in LEO PNT seems to be growing.

DARPA has a LEO PNT project underway with Northrup Grumman (NG). Last week NG announced it had received a contract award from DARPA
for Phase 2 of the project. With an in-space demo funded, Xona may have leapfrogged that effort. 

Army Futures Command, working with our friend Todd Humphries at the Univ. of Texas Radionavigation Laboratory, has been investigating LEO PNT by 
leveraging commercial satcom constellations.

Congress has also expressed interest in LEO PNT. The House Armed Services Committee has suggested it could be had from, or by partnering with, 
commercial providers. See our commentary and a link to the HASC document here (below).

Clearly the idea of LEO PNT is "of the moment." It is something we heartily support as part of a robust and resilient PNT architecture. See our 
free downloadable graphic here: https://rntfnd.org/wp-content/uploads/RNT-ecosystem_3.29-v4.pdf 

Xona Space Systems fully funds GPS-alternative demo mission
by Jason Rainbow — September 22, 2021

TAMPA, Fla. — Californian startup Xona Space Systems has raised $8 million to fully fund an orbital demonstration next year of its navigation payload, 
which aims to provide an alternative to GPS and other global navigation satellite systems.

Early-stage investor MaC Venture Capital and Seraphim Space Investment Trust, a fund that was recently listed on the London Stock Exchange, led the 
funding round.

Xona CEO Brian Manning said it brings the venture’s total funding to $10 million, including $1 million from a pre-seed round and another $1 million 
secured in grants.

READ MORE: https://spacenews.com/xona-space-systems-fully-funds-gps-alternative-demo-mission/ 

Next-Gen Satellite Navigation: Our Investment in Xona Space Systems:
Jim Adler

22 Sep 2021 

The space sector is booming. With space tourism stoking public interest to new highs, space solutions are riding a record wave of investment, building 
on the $7.6 billion invested in 2020.

The former rocket engineer in me delights at the growing enthusiasm for space, while my current investor self poses the typical nagging questions of 
product viability, operational scalability, as well as path to revenue and earnings.

Fortunately, even in crowded markets, there are early-stage startups that offer the complete package — a compelling vision, disruptive tech, a feasible 
business model, an experienced team, and a solid path to product-market fit. That’s why I’m truly excited to announce our investment in Xona Space Systems
who’s building the next generation of satellite navigation systems.

READ MORE: https://medium.com/toyota-ventures/next-gen-satellite-navigation-our-investment-in-xona-space-systems-bdff7c02f659 

(September 2021) NASA and Italy to send first GNSS receiver to the Moon - GPS World:

The innovative GPS and Galileo receiver, provided by Qascom, will experiment with satellite-based positioning on the lunar surface.

(September 2021) Rolls-Royce’s all-electric aircraft completes first flight:


(September 2021) Here are the cheap counter-drone solutions DoD tested in the Arizona desert:

Here are the cheap counter-drone solutions DoD tested in the Arizona desert:  https://trib.al/toPNVUC 

(Apr. 2021) Would Russia Invade Ukraine and China Invade Taiwan Simultaneously? - 19FortyFive:

"To avoid even the possibility of stumbling into such a horrific dilemma, the United States needs to urgently reform how it engages with the rest of the world. The reality 

is that the U.S. military genuinely is the strongest in the world right now (though both Russia and China have made significant strides in modernizing their forces) and 

can deter any nation – China and Russia included – from launching an unprovoked attack against our country. But we must concurrently recognize that our military is 

not invincible, capable of imposing our will on all nations of the world, simultaneously."


(Apr. 2021) New Tactical ISR Satellites Provide Global, Persistent Support for Warfighters:

The LM 400-based tactical ISR satellites will play a key role in Joint All-Domain Command and Control (JADC2) by allowing tactical warfighters to better employ 

space-based capabilities. #LockheedMartin is also developing and building 10 #space vehicles over the next two years for the Space Development Agency’s 

Transport Layer Tranche 0, cited as the backbone of JADC2, enabling even more connectivity between ISR and #warfighters.


(Apr. 2021) DARPA chooses three firms to design nuclear-powered space vehicle:

Defense Advanced Research Projects Agency (DARPA) has picked three companies to design a nuclear thermal propulsion system that will operate above  

low Earth orbit in 2025, the U.S. agency announced April 12.

General Atomics, BLUE ORIGIN and Lockheed Martin received contract awards and will be the prime contractors for the first phase of the Demonstration 

Rocket for Agile Cislunar Operations, or DRACO, program.

DARPA believes nuclear-powered propulsion could enable rapid maneuver in space — a capability that is difficult to achieve with current electric and chemical 

propulsion systems.

(Apr. 2021) Assured PNT Summit - Opening Remarks:
Defense Strategies Institute Assured PNT Summit

Moderator: Dana A. Goward

Opening Comments, 14 April 2021:

Good morning! So good to see everyone and be here on behalf of the RNT Foundation. We are a scientific and educational charity. As such, we endorse no products 
or services but are pleased to be cooperating with DSI on this effort and appreciate the program’s commercial sponsors. Thanks to all!

This event is closed to the media and there will be no recordings. All comments are not for attribution, the “Chatham House Rules.” We are looking for a free
and open exchange of ideas from everyone.

One exception that I will make is that you are free, and encouraged, to quote and attribute anything I say. All we do at the RNT Foundation is open source and 
publicly releasable as part of our educational efforts.

Assured PNT:

Air Force U-2 pilots purchase Garmin watches and navigate using Glonass and BeiDou to conduct their surveillance missions because the GPS jamming is so bad.
Thousands of ships, well offshore in the Black Sea, incorrectly report that they are moored in the middle of inland Russian airports.
Hundreds of ships and fitness users in China and Iran report they are far from their true location and traveling in counterclockwise circles.
Civil drones lose GPS signals and crash into houses.
A commercial airliner nearly impacts a mountain because of GPS interference.
NATO Exercises in Norway and elsewhere are jammed by transmitters in the Russian homeland.
Criminals routinely use jamming and spoofing to steal cargo and evade police.
And our sun is always lurking in the background with the threat of a major event that could keep GPS signals from getting through for days, or even
Carrington event that will immediately destroy half the satellites, then others as they come into view.

Assured PNT – everybody wants it, nobody has it. At least NOT in the U.S.!

In 2016, Iran announced they had created a terrestrial navigation and timing system that makes them independent from space.
Saudi Arabia has a similar system.
South Korea has gone one step further by modernizing their terrestrial system and integrating it in a system-of-systems approach with GNSS and 

maritime R-mode 

Russia and the Commonwealth of Independent States republished their radio-navigation plan last year saying they are retaining and upgrading their 

Chayka system so as to not be dependent upon space-based navigation and timing.
There is also an indication that Russia may have an expeditionary 

version of this system for its forces to take into battle.
China has the most resilient Assured PNT structure and plan, though. At 2019’s Stanford PNT symposium, they announced their plan for “comprehensive” 

PNT. One involving satellites at GEO, MEO, and LEO, expanding their Loran system to cover the entire country, upgrading it to eLoran, developing WiFi and 

5G-based timing and navigation, and expanding research on interials(?) and clocks. Everything we have seen since then leads us to believe that they are 

executing this plan. China seems to believe in and be dedicated to the idea of Assured PNT.
While we talk a lot about assured PNT in the United States and the West, we have done little. And so, we have lost the global PNT conflict in all three 

phases of war: tactical, operational, and strategic!

Our tactical disadvantages are made clear every day, especially in the middle east and other conflict and operating areas. Just last week, for example, 
Russia or its proxies restarted jamming operations in eastern Ukraine as a part of the Russian troop buildup on the border. As a result, the Organization 
for Security Cooperation in Europe has been unable to use its long-range UAVs to monitor compliance with the Minsk Protocols.

The U.S. and the west have been hampered at the operational level of war as well. Our adversaries have (already) shaped the battle spaces around the 

world with jamming and spoofing forcing us to accommodate to the conditions they have created. We should be shaping it to our advantage and 

making them adapt.

And we are certainly at a strategic disadvantage when our adversaries can directly or through a proxy strike a devastating blow to our homeland by 

interfering with GPS, while a similar action on our part would have much less (of an adverse) effect on them.

We are dangerously behind where we need to be. This (situation) has not been lost on Congress, which has mandated improvements in Assured PNT for 

both military and civil applications, although, despite deadlines, those improvements have yet to come about.

I hope that today and tomorrow we will find out about how America is going to catch-up and, perhaps, even regain the lead in the undeclared global PNT war.

We have a very impressive list of topics and speakers for you today and tomorrow. This is a unique opportunity for you to interact with them, so we want to 
encourage a free & open exchange under our "Chatham House rules". Please ask questions, engage the speakers and take advantage of this opportunity.

As you listen to their presentations, you might want to think about how they are addressing the holistic approach to assured PNT that my colleagues and I at
the National PNT Advisory Board have adoptedProtect, Toughen (robustify), and Augment.

Protect the satellites and signals, Toughen users and their equipment, and Augment GPS/GNSS signals with alternative PNT sources.

(Apr. 2021) What Technologies Can Secure GPS? - Webinar w/Civil PNT Leaders fm 3 Administrations:
Blog Editor's Note: This WILL be interesting. Hosted and moderated by Scott Pace (GWU Space Policy Institute, Exec Dir of Space Council in the last administration), 

it will feature Greg Winfree, Diana Furchtgott-Roth, and Dr. Robert Hampshire.

Greg & Diana (both RNT Foundation members!) were the leads at DoT Research and Technology in the Obama and Trump administrations, and therefore the 

leaders for civil PNT policy in the federal government. Dr. Hampshire is filling that role in the Biden administration.

This is a free event but you do have to register in advance.

From the event page on Eventbrite:

What Technologies Can Secure GPS?
Join us for a discussion of the Department of Transportation's Complementary PNT and GPS Backup Technologies Demonstration Report.

About this Event
Three separate laws have required the U.S. Department of Transportation (DOT) to back up and complement the Global Positioning System, subject to congressional 

appropriations. To provide a roadmap, in January 2021, the Department released its Complementary PNT and GPS Backup Technologies Demonstration 


During this webinar, Acting Assistant Secretary Robert Hampshire will offer introductory remarks and DOT's Karen Van Dyke and Andrew Hansen will follow up 

with a presentation of the report. George Washington University Adjunct Professor Diana Furchtgott-Roth and the Texas Transportation Institute's Greg 

Winfree will provide comments.

A public Q&A will follow the discussion. The program will open with remarks from Scott Pace, director of the Space Policy Institute, who will also moderate 

the discussion.

Date And Time
5 May 2021

2:00 PM - 3:30 PM ET
REGISTER HERE: https://www.eventbrite.com/e/what-technologies-can-secure-gps-tickets-150834212189  

(Mar. 2021) Big New Interceptor Deal Part Of Biden Missile Defense Push:

The Biden administration is pushing ahead with multiple missile defense initiatives in its first 100 days, a sign the Pentagon will make new investments in 
the capability to meet developing Chinese, North Korean and Russian capabilities.


(Apr. 2021) Next-gen intercontinental ballistic missile interceptor estimated to cost nearly $18 billion:

The Pentagon’s Next-Generation Interceptor that is being competitively developed to replace the current ground-based interceptors within the United States’ 
homeland intercontinental ballistic missile defense system is estimated to cost nearly $18 billion across the life of the program.

An independent cost estimate from the Defense Department’s Cost Assessment and Program Evaluation (CAPE) office — first reported by Bloomberg and since 
obtained by Defense News — has determined the total cost to develop the NGI will come to roughly $13 billion while procurement as well as operation and 
sustainment will come to a little over $2 billion each.

The Pentagon announced in August 2019 its intention to build a new NGI after the Redesigned Kill Vehicle (RKV) program — that would upgrade the Ground-Based 
Interceptors (GBI) with the ability to go after more complex threats more reliably — was abruptly killed. 

#pentagon #defense #defence #defenseindustry #defenceindustry 

(Apr. 2021) OneWeb PNT Possibilities:
Blog Editor's (Dana A. Goward) Note: Some buzz last week on this due to public comments made by the OneWeb CEO, Neil Masterson:

There are several ways OneWeb could be used for . Future satellites could be modified for the purpose, future payloads could carry purpose-built satellites, and 

PNT could be inferred from the thousands of communications satellites forecast in the constellation. All are possibilities. All have costs and technical challenges.

Or, there could be no PNT functionality at all.

Here are a couple of reports pertaining to Masterson's comments:
OneWeb may demonstrate a navigation payload later this year, CEO Neil Masterson said today at the Satellite 2021 LEO Digital Forum. OneWeb could offer a 

"real alternative" to Galileo with its second-generation satellites, which are scheduled to enter service in 2024, but may provide "good enough" precision navigation 

and timing (PNT) before that. The U.K. is seeking alternatives to Galileo's secure navigation signal since it is no longer part of the European Union. After 

initially considering building its own PNT constellation, the U.K. announced plans last year to consider commercial alternatives including one proposed by OneWeb

Since PNT has become a cornerstone of economic and military activity, governments around the world are looking for ways to augment or reinforce PNT services. The 

U.S. government identified "suitable, mature and commercially available technologies to backup or complement the timing services provided by GPS," in a 

Transportation Department report released in January 2021. Due to varied PNT use cases, however, no single PNT system can take the place of GPS. Instead,

 the report recommends adoption of "a diverse universe of positioning and navigation technologies."

(Apr. 2021) Russia ramps up GPS jamming along with troops at Ukraine border - GPS World:

April 21, 2021 - By Dana A. Goward

Two recent reports from the Organization for Security and Co-operation in Europe (OSCE) have described a recent increase in GPS jamming, presumably by Russian 

or pro-Russian forces in Ukraine. This comes as Russia has increased its troop numbers and activity along its border with Ukraine.

OSCE is charged with a Special Monitoring Mission (SMM) in Ukraine which observes and reports on how well both sides are adhering to the Minsk Protocol agreement. 

The agreement was signed in September 2014 by participants in the conflict in an effort to end open hostilities.

One of the ways the OSCE mission monitors activity and compliance in the region is with long range UAVs. As early as November 2014, the organization reported 

UAV operations being thwarted by interference with GPS signals.

Two recent OSCE spot reports have highlighted a resurgence in jamming.

An 7 April 2021 report described interference that prevented a UAV takeoff the previous day. While the organization’s UAVs had been experiencing increased

interference since March 2021, this was the first time since October 2014 that it had thwarted a mission before takeoff.

The report also documented an increasing level of jamming activity.

“Over the last two months, 62.5 percent of SMM long-range UAV flights encountered GPS signal interference and on 75 percent of the affected flights it occurred 

more than once.”

A second report on 9 April 2021 outlined continuing problems that caused missions to be aborted. It emphasized that this was a violation of the agreement 

signed by all parties and greatly hampered OSCE’s mission.

Any GPS signal interference hinders the Mission’s ability to conduct effective monitoring and reporting of the security situation in line with its mandate. 

Long-range UAVs are an essential part of SMM operations, especially at night and in areas where the Mission’s monitoring and freedom of movement are restricted.”

GPS jamming and spoofing are important parts of Russia’s arsenal to counter any technological advantage the west may have over their forces. A 2015 

Sputnik article bragged their electronic warfare kept U.S. cruise missiles from hitting their targets at the start of the 2003 invasion of Iraq. Also, that this advanced 

capability “renders aircraft carriers useless.”

Interference with GPS signals is a regular feature of Russian military and internal security operations.

Upon more than one occasion, Russia has jammed GPS signals near NATO exercises and regularly jams broad areas in the Middle East from a base in Syria

Its spoofing of GPS signals in Moscow and the Black Sea to cause receivers to report that they are at airports kilometers away from their true location 

has been well documented.

The United States has formally expressed concerns about the recent increase in the number of Russian troops and their activity at the Ukrainian border. It has been 

reported that two U.S. Navy ships are on their way to the Black Sea to help monitor the situation.

Dana A. Goward is president of the Resilient Navigation and Timing Foundation.

(Apr. 2021) https://machinelearningmastery.com/gradient-in-machine-learning/ 

(Apr. 2021) The Need for Resilient PNT Has Never Been Greater - EE Times:
Blog Editor's Note: A very good summary article by Guy Buesnel, a long time RNT Foundation supporter and member of our International Advisory Committee.

For more information on the system-of-systems approach he describes in the article, we recommend the very thorough MarRINav report sponsored by the 

European Space Agency and led by our friends at NLA International.

The Need for Resilient PNT Has Never Been Greater
By Guy Buesnel, Spirent Communications 04.22.2021 

Real-world instances of Global Navigation Satellite System jamming and spoofing have been steadily increasing in recent years. Those incidents include 
hundreds of commercial ships being spoofed in the Black Sea and repeated GNSS jamming affecting commercial aviation in Norway.

Air traffic manager Eurocontrol recently disclosed more than 3,500 instances of GPS jamming were reported by pilots during 2019 alone.

Elsewhere, the U.S. Federal Communications Commission has conditionally approved an application by satellite communications provider Ligado Networks to 
deploy a low-power terrestrial nationwide network in the L-Band to support 5G and Internet of Things services. The decision means that GNSS systems and 
devices must be capable of resisting adjacent-band radio frequency interference at extremely high-power levels while still providing extremely accurate 
and precise data to users.

Over-dependence on GPS and other navigation aids along with growing vulnerabilities including jamming, spoofing and other forms of interference highlight 
the need for terrestrial backups to current GNSS systems. We take a hard look at the scope of the problem and possible remedies in our upcoming GPS Special 

READ MORE: https://www.eetimes.com/the-need-for-resilient-pnt-has-never-been-greater/# 

(Apr. 2021) The Intelligence Community's Deadly Bias Toward Classified Sources:

by Cortney Weinbaum

April 12, 2021

For years, government officials, commissions, and think tanks have warned that the U.S. intelligence community has blinded itself to enormous sources of 
intelligence, simply because the information is publicly available.
In other words, the intelligence community would prefer to rely on billion-dollar 
classified satellites and intelligence-collection programs rather than to gather unclassified information on the internet for free.

Examples are rife. Russia conducted a strategic misinformation campaign to influence the results of elections in multiple countries, including the UK, 
Ukraine (PDF), France, and, eventually, the United States (PDF), and they did it on social media in view of everyone
, except the intelligence officers who 
only look at classified sources. Despite the signals that were available, U.S. elected officials (PDF) described not being adequately warned.…

The remainder of this commentary is available at defenseone.com. 

(Mar. 2021) Space Debris Threatens GNSS:
Blog Editor's Note: The greatest threat from space debris is unquestionably at LEO. Many in the PNT community have considered GPS, Galileo, and other GNSS at 
MEO relatively safe from debris. It seems "that ain't necessarily so". 

Papers on debris at MEO are difficult to come by. We did find one from an ESA conference that found collisions at LEO were responsible for much of the debris 
at MEO

The recently developed Aerospace Debris Environment Projection Tool was used to project the future debris environment in medium Earth orbit (MEO) over the 
next 200 years. The entire Earth orbital population was modeled to account for the possibility of cross-coupling between the MEO population and the low Earth 
orbit (LEO) and geosynchronous populations via objects on highly eccentric orbits that transit through MEO
. It was found that a large fraction of the MEO debris 
originated from collisions in LEO involving satellites and rocket bodies that transit through LEO and MEO

Another paper pointed out that too much debris at LEO could make it difficult to transit the zone safely and put satellites in MEO and GEO in jeaprody

The incident reported below is likely not the first time a GNSS satellite has been threatened by space debris. It does serve as an alert, though, reminding 
us to not be complacent about any potential threat to these systems that are so essential to so many technologies and services.

Galileo satellite performs collision avoidance maneuver:
March 25, 2021 - By Tracy Cozzens

In a first for Galileo, a satellite performed a collision-avoidance maneuver to avoid space debris.

Under the management of the European GNSS Agency (GSA), the maneuver for satellite GSAT0219 was performed 6 March 2021 following a collision risk alert received 
from EU Space Surveillance and Tracking (EUSST).


(Mar. 2021) Aviation Groups Petition Govt over Deliberate GPS Jamming:

Blog Editor's Note: Aviation is somewhat unique among modes of transportation as it has an alternate PNT system for when GPS is not available. It is a network 
of short range terrestrial beacons of VORs, DMEs, and TACANs (TACAN is military only). See graphic courtesy of Mitch Narins, Strategic Synergies, LLC.
As one example, we reported three years ago about concerns formally expressed by the Radio Technical Commission, Aviation.

Recently an IEEE article revealed the FAA has a wealth of data showing that such disruptions are exceptionally common.

The letters below make it fairly clear the government has failed to adequately address these concerns.

There are undoubtedly several reasons for these on-going problems. 

One is that, apparently, the FAA and DOD have not been willing to engage with the community on this issue.

Another is that, on the aircraft side, the FAA authorizes many small aircraft to operate without formal electronic navigation capability. They ostensibly 
find their way by visual references (looking at the ground for landmarks, following roads, etc). However, most do have a non-certified "situational awareness" 
GPS receiver, not really authorized by the FAA for navigation, but undoubtedly used as such. When GPS is deliberately jammed these aircraft are put at even 
greater risk than others.

Also, many better equipped aircraft that do have VOR and DME capability, do not have navigation systems that integrate the information from these beacons to
allow point-to-point navigation (a capability call "area navigation," or RNAV). So when GPS is not available, these aircraft must fly longer and less 
efficient routes between beacon waypoints. 

These on-going challenges in aviation provide lessons for future alternate PNT systems. Not only must the alternate system provide sufficient coverage and 
availability, it must also be widely adopted by users and integrated into their systems for it to be effective. Government has a number of tools available 
to make this happen. When it fails to use all those tools, the alternate system is much less effective in protecting the public, and on-going problems 
We should also note that despite the FAA touting the VOR/DME/TACAN system as its alternative to GPS, the agency has failed to recapitalize the network, along 
with Instrument Landing Systems (ILS) at airports.

Much of the equipment in use is well beyond its service life. And we are told that, while the FAA has some minimal VOR and DME replacement equipment on hand, 
it failed to budget for installation. So a lot of the new equipment tends to sit in government warehouses collecting dust. 

And while new, more effective and efficient ILS equipment is available, it has not been acquired. We are told that this poses a safety problem for landing 
aircraft, and foregoes an approximate 20% increase in airport efficiency that has been realized by other nations.

All told, quite a few reasons the aviation community is unhappy with the FAA's approach to navigation.
NBAA, AOPA Call Upon Agencies to Mitigate Impact of Intentional GPS Interference.
Contact: Dan Hubbard, 202-783-9360, dhubbard@nbaa.org

Washington, DC, March 5, 2021 – The National Business Aviation Association (NBAA) and the Aircraft Owners and Pilots Association (AOPA), in a letter to the 
Federal Aviation Administration (FAA) and Department of Defense (DOD), expressed concern about restrictions to airspace and airports caused by the intentional 
jamming of GPS
and are seeking mitigations on the operational impact of these interference events.

In a letter to the FAA and DOD, the organizations recognized the importance of DOD’s mission and the agency’s need to simulate the loss of GPS as part of its 
effort to defend and maintain the global navigation system. However, as NBAA and AOPA noted, the National Airspace System (NAS) has become increasingly reliant 
on GPS as the primary source of navigation and aircraft system functionality, while reducing reliance on ground-based navigational infrastructure.

“Despite reduced operations in the NAS over the past year, general aviation continues to show increased activity and volume, exceeding commercial airline 
operations,” the letter states. “In recent months, operators have continued to report operational impacts and reduced access to airspace and airports 
resulting from intentional GPS jamming events.”

Read NBAA’s and AOPA’s full letter to the FAA and DOD. (pdf)

The associations’ letter also noted the aviation community had NOT received a response from the FAA or DOD to a 2018 RTCA report on the operational impacts 
of intentional GPS interference, which included more than two dozen detailed recommendations to limit the operational impact of these events on civilian air 

During the RTCA deliberations, the FAA and DOD acknowledged that the frequency and impact of these intentional jamming events grew significantly over the 
preceding decade and would continue to escalate, the trade groups added.

“The growing reliance on GPS in the National Airspace System, combined with the increasing frequency of intentional GPS jamming events, makes it imperative 
that the FAA and the DOD have mitigations in place to ensure the safety and reliability of the NAS during these events,” said Heidi Williams, NBAA director,
air traffic services and infrastructure. “We look forward to working with the agencies to employ the RTCA report’s recommendations and ensure our national 
security and the safety and efficiency of the NAS.” “It is vital that pilots have continuity and access to optimal navigational and safety tools, of which 
GPS is vital,” said Jim Coon, AOPA senior vice president of government affairs and advocacy. “We strongly support our warfighters, but we believe DOD and 
FAA should review their GPS testing processes so that our nation’s airspace continues to be as safe as possible.”


(Mar. 2021) Protect your PNT with GPS Ant-Jam Technology from Hexagon | NovAtel:

GNSS technology establishes your Position, Navigation, and Time (PNT) in the environment -- but we have to protect it.

Defend your PNT in challenging environments through Hexagon | NovAtel anti-jam antennas, interference mitigation and GNSS+INS combined systems.

Read more about how to protect the integrity of your APNT solution >> https://hxgn.biz/3u8HCY3 

(Mar. 2021) This morning the Prime Minister of Australia Scott Morrison officially unveiled our Australian Space Discovery Centre to the public!:

The Prime Minister was joined by the Premier of South Australia, Steven Marshall, Australian Space Agency Head, Enrico Palermo, Australian Space Agency 
Advisory Board Chair, Dr. Megan Clark
, and Australia’s Chief Scientist, Cathy Foley.

The Australian Space Discovery centre is based at Lot Fourteen in Adelaide, South Australia and officially opens in May (2021)!

Find out more and pre-book your experience here: https://bit.ly/3r7zZjZ 

(Mar. 2021) Our BookEnd column in March's MWJournal features "Introduction to LabVIEW FPGA for RF, Radar, and Electronic Warfare Applications." 

Topics include best practices for multi-FPGA solutions and guidance for high throughput, low latency FPGA-based RF systems.


(Mar. 2021) Next 10 years of EGNOS to focus on drones:


Air Force Wants Lasers on Fighter Jets by 2025:

Lockheed Martin is working toward outfitting a directed energy system on fighter jets by the middle of the decade. To build and manufacture the systems, 

we are investing more than $20 million into our Orlando-based optical components center.


How The Once Elusive Dream Of Laser Weapons Suddenly Became A Reality:

A good piece below on how industrial applications have helped make military lasers a reality for small scale applications (and why Star Wars is still a pipe dream):


Laser Weapons On The Battlefield Of Tomorrow: Separating Fact From Fiction:


FLIR Systems Acquires Altavian, Inc.:

FLIR Systems Acquires Altavian, Inc. https://bit.ly/2VsKtvS  


Raytheon Technologies to Buy Smallsat Maker Blue Canyon; Roy Azevedo Quoted:


Cheap GPS jammers a major threat to drones - ZD Net:
The article mentions interference with a display involving hundreds of drones. There have been other incidents, of course, in China and elsewhere. One example is the UK accident we reported on that could have resulted in a fatality, according to the government's investigation report.

We agree with the below article that GPS/GNSS receivers should include better hardware and software to make them more resilient to jamming and spoofing.

That's only part of the solution, though. A holistic approach is needed if GPS/GNSS is to be managed property. We agree with the "Protect, Toughen, and Augment" scheme advocated by the National Space-based Positioning, Navigation, and Timing Advisory Board.

Jammers that can be bought for as little as $50 threaten commercial drones, but there are options.
With rotors whirring and airframes hurling through the air, drones can be very dangerous when flights don't go as planned. There's been much teeth gnashing over the FAA's measured approach to commercial drone policy adoption, but the fact is there are real dangers, including from bad actors using inexpensive GPS jammers.

GPS signal jamming technology is evolving, decreasing in size and cost. Today, jammers can be bought online for as low as $50. Long a threat to military assets, jamming is now a commercial concern as commercial drone deliveries become a reality, and attacks are becoming pervasive globally. This threat now affects commercial, law enforcement, and defense drones on critical missions.


Drone Warfare:


China expanding Loran as GNSS backup - GPS World:



Directions 2021: BDS marches to new era of global services - GPS World:
Earlier this year, BDS-3, the global version of the BeiDou Navigation Satellite System (BDS), was formally commissioned, marking the completion of its three-step development process. Read about the system's services and accomplishments.


South Korea discusses decision to combine GPS and eLoran - Geospatial World:


What is mobile mapping?


Learn about how #GNSS antennas and receivers are combined with Inertial Navigation Systems to provide highly accurate data on the positioning, velocity and attitude of moving objects, and how engineers use these devices to document landscapes and more >> https://hxgn.biz/2Vkj7aM 

Next Generation Interceptor: Never Fail Defense Against Evolving Threats:

The Next Generation Interceptor program is focused on strengthening first-line defenses against advanced emerging missile threats.

This challenge is not one to be taken lightly – and we're throwing the weight of the Lockheed Martin enterprise behind our proposed solution. We're developing a cutting-edge offering based on our expertise from other strategic defense systems, like Terminal High Altitude Area Defense and hypersonic strike systems. And we're counting on more than our proven systems – we're also focused on designing for the future. We're leveraging the best technologies and smart tools for this mission, relying heavily on digital engineering, DevSecOps and other tech like AI and machine learning.

Learn more about the need for NGI, and how we plan to deliver for our warfighters: https://www.lockheedmartin.com/en-us/capabilities/space/space-missile-defense.html 


Acquisition of AGI Extends the Digital Thread Throughout the Mission | Ansys Blog


Raytheon awarded $235.6M for production of Silent Knight Radar:


China's Version of GPS is Better, Says US Satellite Receiver Company:

Re: fake news about Beidou: the nominal number of MEO satellites is the same (24) for both GPS and Beidou. The GEO and IGSO satellites of the Beidou constellation are useful only above China.
I am not surprised that Galileo and Beidou may have a somehow better performance than GPS, but, quoting Bernard of Chartres, we should not forget that: "We are dwarfs standing on the shoulders of giants".


Many thanks to Black Dot GNSS and Simon Banville for digging a little deeper into the data behind our "RTK From the Sky" white paper.

We'll be participating in a webinar this month and sharing further technical details behind instantaneous cm-level #PPP corrections, stay tuned!

#GNSS #Webinar 


Science: Death by "Spaghettification": Scientists Record Last Moments of Star Devoured by a Black Hole:

The phenomenon, known as a tidal disruption event, is the closest flare of its kind yet recorded, occurring just 215 million light-years from Earth.


The phenomenon, known as a tidal disruption event, is the closest flare of its kind yet recorded, occurring just 215 million light-years from Earth. It is caused when a star passes too close to a black hole and the extreme gravitational pull from the black hole shreds the star into thin streams of material – a process called ‘spaghettification’. During this process some of the material falls into the black hole, releasing a bright flare of energy which astronomers can detect.


Search and Rescue beacons developed at Goddard have helped locate more than 46,000 people through Cospas-Sarsat, an international cooperative system for search and rescue.

Now Maryland-based Concentric Real Time LLC has licensed a 2nd generation of this technology to be used by individuals who carry personal locator beacons in case of emergency. The 2nd generation technology allows for higher-resolution signaling that produces highly accurate location results. Learn more about NASA technology available for licensing at: https://lnkd.in/eUDZCWY 

Learn more about the new licensed technology at: https://lnkd.in/eJ9WQMK 

Aerospace Corporation:

Massive THANK YOU to the firefighting crews who saved the historic Mt. Wilson Observatory when it was threatened by the #BobcatFire. Our MAFIOT Project is among the major space observation programs being housed at the site.

Read: https://lnkd.in/gMtXhsH 

“We are grateful to the firefighters who put their lives on the line to battle the fire around the facility,” said Dave Cardoza, the Principal Director of Aerospace's Electronics and Photonics Laboratory. “The fact that the structures are still standing is a testament to the dedication that they put into their jobs. This will allow us to continue our important work on the mountain.”

Collins Aerospace wins contract to improve anti-jamming for warfighters:

The United States Army awarded Collins Aerospace a Phase III contract to build the second generation of its Mounted Assured Position Navigation and Timing System (MAPS). Learn more about the MAPS program.


The future of the U.S. Coast Guard is in outer space:

The #USCG and outer space? CAPT Michael Sinclair at Brookings explores the possibilities of leveraging advances in space technology to facilitate the execution of the Coast Guard’s 11 statutory missions here on earth.


APN-086 Datum Transformations & Plate Tectonics Compensation:

For information on the above, please click this link here

Timing is Everything: To Protect Geospatial and the World, We Need Bullet-proof Time:


Planes continue to fly into a GPS dark hole over the Mediterranean, puzzling experts - Fortune:


GSA releases 3rd GNSS User Technology Report - GPS World:

The European GNSS Agency (GSA) released its latest GNSS User Technology Report, providing a comprehensive analysis of GNSS trends and developments. Get an overview of the report:


NASA Science: 

Particles smaller than an atom hurtle through the universe nearly at the speed of light, blasted into space from something, somewhere, in the cosmos. A scientific collaboration of the Pierre Auger Observatory, including researchers from the University of Delaware, has measured the most powerful of these particles — ultra-high-energy cosmic rays — with unprecedented precision. In doing so, they have found a “kink” in the energy spectrum that is shining more light on the possible origins of these subatomic space travelers. The team’s findings are based on the analysis of 215,030 cosmic ray events with energies above 2.5 quintillion electron volts (eV), recorded over the past decade by the Pierre Auger Observatory in Argentina. It is the largest observatory in the world for studying cosmic rays.


AI Facts Every Dev Should Know: Artificial intelligence is older than you, probably!:


Timekeeping Theory Combines Quantum Clocks and Einstein’s Relativity:


Allie K. Miller at Amazon:
Forbes AI Innovator of the Year | Artificial Intelligence at Amazon | LinkedIn Top Voice 2019 | 750K+ followers

This home can fold and unfold in 10 minutes. Anyone else love researching the future of construction, real estate, and urban development?
Source: Mashable (Please search Google for this)

WTO: EU can impose tariffs on $4 billion of U.S. goods:


Featured Innovator: Kaitlin Moore:

Meet Kaitlin Moore, an atomic physicist in the field of #quantum science and #engineering at our Applied Sciences division. There, she and the team she’s part of are spearheading advancements in the potentially world-changing realm of #quantumsensing and #quantumcommunications.
Read more about our latest featured innovator: https://bit.ly/2HPxv7R 

On October 5th, the Real-Time Working Group of the International GNSS Service (IGS) will release the first version of the new IGS-SSR standard! It will be accessible at: https://lnkd.in/dY3EVry.

The IGS SSR format is an open standard for dissemination of real-time products to support the IGS Real-Time Service and the wider community. The messages support multi-GNSS and include corrections for orbits, clocks, DCB's, phase-biases and ionospheric delays. Extensions to also cover satellite attitude, phase center offsets and variations and group delay variations are planned in the near future. The goal is to create a self-contained and scalable standard for a wide range of real-time applications.
International GNSS Service.

On 9 December 2020, this new (incoming) website will be moved from its temporary home on igscb.org to our main website, IGS.org. The content in the current (outgoing) IGS.org website will be archived.

Also on 9 December 2020, ALL FTP access to ftp://ftp.igs.org  will be permanently terminated and replaced with a secured https://files.igs.org/ . Data, content, and directory hierarchy will remain unchanged.

Precise time for all: Paper calls for resilient national timing - GPS World:



GNSS simulator companies help pilots find their way:

Find out how GNSS is playing a role in enhancing safety and training when using flight simulators


How many Global Navigation Satellite System do you know? Only GPS? GPS and GLONASS?:

Check the right answer in the book "An Introduction to GNSS..." from NovAtel Inc.


P.S.: Don't forget to pay attention to two regional systems!

GPS/GNSS industry recollections and predictions from the GPS World Editorial Advisory Board - GPS World:

Members of the GPS World Editorial Advisory Board share their memories and thoughts about the GPS industry over the past 30 years. Find out what they had to say.


Timing is Everything: To Protect Geospatial and the World, We Need Bullet-proof Time:


The shape of water: bathymetry in action - GPS World:

Population growth in coastal areas and sea level rise due to climate change are driving the need for bathymetric data for planning and emergency management. Learn more about bathymetry and how the data is used. 


MGUE Increment 2 contracts awarded to Rockwell Collins, L3 and Raytheon - GPS World:

The U.S. Space Force’s Space and Missile Systems Center awarded the Military Global Positioning System User Equipment (MGUE) Increment 2 Miniature Serial Interface with Next-Generation ASIC to Rockwell Collins, L3 Technologies and Raytheon Technologies. Get more details.


Space Force planning a ‘disruptive’ acquisitions command - SpaceNews:

Gen. John Raymond said the Space Systems Command will include a mix of legacy and nontraditional procurement offices.


US Navy plans to raise new fleet in Indo Pacific, says top US official:

I’ve been advocating for this since 2001: First Fleet. It’s back, and it’s Area of Operation (AO) will be SE Asia and the Indian Ocean. Wizard. #usn #usnavy #1stFleet #scs #India #Singapore #Australia #IO #indopacific 


Boeing subsidiary ready to launch satellite de-orbiting experiment:


SpaceX's Falcon 9 rocket with the U.S.-European Sentinel-6 Michael Freilich satellite rolled out for launch this afternoon! This #SeeingTheSeas mission is set for liftoff tomorrow at 12:17 p.m. EST (5:17 p.m. UTC):

Join the virtual NASA Social and watch with us: https://lnkd.in/gqDb3CM 

Russia Says U.S. Missile Defense Test Proves It Lied About Global Missile Shield:


(May 2021) U.S. Army’s Terrestrial Layer Prototype Readies for Delivery:

Getting capability to soldiers on the battlefield faster is our mission. We’re working with the U.S. #Army to rapidly develop the Terrestrial Layer System, 
which will help soldiers better address signals found in the immediate electromagnetic environment.

Resilient PNT critical to maritime advancement:

The International Maritime Organization has issued a resolution for maritime cyber-risk management effective in January 2021. 


(May 2021) Space debris endangers GPS - GPS World:

By Ken Eppens, Founder and CEO, OrbitGuardians.com

19% of tracked space objects threaten GPS and other GNSS satellites. While there are much fewer objects in MEO than in LEO, the risk in the former is 
arguably greater because GPS is so critical to almost all of our technology.

The Risk:
GNSS satellites, especially GPS satellites, are critical to the well-being and smooth functioning of economies and national security. This is especially 
true in Europe and the United States, which do not have complementary terrestrial systems able to provide vital positioning, navigation and timing (PNT
services when signals from space are not available.

While the probability of debris damage to GNSS in medium Earth orbit (MEO) is much less than for satellites in low Earth orbit (LEO), the consequences
of such an event would be much, much higher. The loss of one satellite would be a concern; that of multiple satellites, a major problem. The unthinkable chaos,
national security damage, and severe economic impacts to the $21 trillion U.S. GDP make the risk unacceptable.

For those who think we need not worry about the low probability of collisions at MEO, the Galileo collision avoidance maneuver in March 2021 should 
be a wakeup call. The problem is here. We need to act now.

READ MORE: https://www.gpsworld.com/space-debris-endangers-gps/  

(May 2021) New Automotive GNSS/INS Positioning Family for ADAS and Autonomy:

Hexagon|NovAtel has new PIM222A automotive GNSS for advanced driver assistance systems & autonomy. Precise positioning, velocity, attitude. #autonomy  
#ADAS #driverlesscars #autonomouscars https://bit.ly/3hNFzGf 


(May 2021) Telecom groups press president, Congress for GPS alternatives - GPS World:
May 25, 2021 - By Dana Goward

America urgently needs alternatives to GPS and the government must fund efforts to make that happen. So say separate documents sent to President Biden and 
senior members of Congress earlier this month.

On May 6, the government’s National Security Telecommunications Advisory Committee (NSTAC) issued its “Report to the President on Communications Resiliency.” 
The next day the industry group Alliance for Telecommunications Industry Solutions (ATIS) sent letters to Congress. Both organizations identify the need for
alternatives to GPS to support telecommunications and other critical infrastructure. Both also urge government funding for the effort.

NSTAC is a federal advisory committee composed of 18 members from the telecommunications industry. Most are CEOs and very senior leaders in companies
such as AT&T, Microsoft, and Iridium.

This month’s NSTAC report highlights the critical role that PNT, especially timing, plays in telecommunications. It notes that widespread use of GPS makes 
the system vulnerable to a host of threats. To address this, the group recommends the administration consider an approach “similar to that reflected in the 
Resilient Navigation and Timing Foundation’s paper entitled “A Resilient National Timing Architecture.” Further, to enhance the ability of commercial 
entities to afford leveraging this architecture, the Administration should appropriate sufficient funds to lay the foundation for creating this timing 
architecture, with the Federal Government being the first customer for what will ultimately become a resilient, interconnected network for PNT delivery.”

Federal funding is necessary, according to the board, because free GPS services eliminate market demand for alternatives.

ATIS sent letters to leaders in the House and Senate citing an “urgent need” for funding deployment and adoption of GPS alternatives for use in critical 
infrastructures, including telecommunications.

ATIS develops standards and other technical deliverables for information and communications technology (ICT) and services companies on a broad range of 
issues, including 5G and the Internet of Things (IoT).

Network and system synchronization is key for telecommunications. At present this is done almost exclusively using signals from GPS. ATIS had previously 
documented in reports and letters to Congress the vulnerability of GPS signals and the need for complementary and alternative systems to use when GPS is
not available.

The letters outline the criticality of precision timing to critical infrastructure, industries, first responders, and U.S. government entities. They cite 
applications such as E9-1-1 and Assisted GPS used to find wireless handsets, as well as critical infrastructure networks, as some of the applications at 

ATIS also endorsed the findings of a recent Department of Transportation (DOT) report to Congress. That report documented that there exist “suitable, 
mature and commercially available technologies” able to provide alternatives to GPS.

Also mentioned was the appropriateness of government funding. “The role of government in protecting its citizens suggests an imperative to safeguard the 
capabilities of critical infrastructure industries by facilitating resilient PNT.”

Some in previous administrations had questioned whether it was necessary and appropriate for the government to fund GPS alternatives. According to NSTAC and
ATIS, the answer is “yes” to both.

While the Biden administration has not made any official statements on the matter, reports of conversations with recent appointees seem to indicate that 
they agree with the need for government funding. There also seems to be bipartisan support for this view.

As one example, Ms. Diana Furchtgott-Roth, a conservative economist who served in the Trump administration as the leader for civil PNT issues, supports 
government funding wholeheartedly. At a recent webinar she indicated that the national need is beyond the business model of any company. “Just as the 
government funds national defense, it should also provide a complement to GPS,” she said.

The NSTAC “Report to the President on Communications Resiliency” can be found.

ATIS letters to members in the House can be found here: 


and to members in the Senate here:


(May 2021) “Investment in a 21st-century Intelligent & Autonomous Infrastructure is among the highest priorities for stimulating economic expansion

national security, and job growth. Edge computing, 5G wireless, Intelligent Transportation Systems, RESILIENT APNT, and resilient electrical grids 

will drive the largest infrastructure buildout in our nation's history.” Autonomy Institute 


Which recent GNSS/INS innovations have been most helpful in advancing bathymetry? Which upcoming ones will be?:


(May 2021) China's space ambitions target satellites, a US vulnerability - Nikkei Asia:

Blog Editor's Notes: This article hits so many of the strategic concerns around US over-reliance on GPS. And it is from a source in Japan, a country 
probably even more worried about China than the U.S., if that is possible.

The article sub-head says everything: "American military's reliance on Earth orbit creates Achilles' heel."

Yet a recent GAO report says DOD is not looking seriously at GPS alternatives and is still planning to have GPS as the centerpiece of its navigation 
strategy going forward.

And further on in the article: "Losing satellite function would leave the American military like a giant whose central nervous system has been damaged."

It also points out that, with satellites out of the picture, a conflict, such as a dispute in the straits of Taiwan, could come down to more conventional 
forces. Let's see... who has more troops, sailors, and equipment, and who can get them there the quickest...?

Follow the READ MORE link at the bottom of the post to see the whole article.
China's space ambitions target satellites, a US vulnerability:
American military's reliance on Earth orbit creates Achilles' heel
HIROYUKI AKITA, Nikkei commentator

May 26, 2021 19:45 JST

TOKYO -- When China landed a probe on Mars this month, President Xi Jinping hailed the success of the mission as well as the status of Beijing's burgeoning 
space program.

"The landing left a Chinese mark on Mars for the first time," he said, per Xinhua News Agency. "It is another landmark progress in China's space industry 

The Tianwen-1 mission resulted in China becoming only the second country to land a rover on Mars successfully, after the U.S. In 2019, China accomplished 
the first successful landing of a probe on the far side of the moon. Beijing last month launched a central unit of its space station, with plans to complete
the base in 2022.

Beyond the scientific or military interests, China's push into space is fueled fundamentally by Beijing's ambition to become a superpower and catch up with 
the U.S.

"It requires absurdly huge costs and comes with risk to send humans into space," said Kazuto Suzuki, a University of Tokyo professor and expert on security 
in space. "If the aim is purely militaristic, it would only require launching sophisticated satellites. But they build a space station, go to the moon, and 
probe Mars because they want to demonstrate China's technological advancements to its people and the international community."

READ MORE: https://asia.nikkei.com/Spotlight/Comment/China-s-space-ambitions-target-satellites-a-US-vulnerability 

Services Infusing AI into Air, Land, Sea Robots:


New algorithm could unleash the power of quantum computers:

A new algorithm that fast forwards simulations could bring greater use ability to current and near-term quantum computers, opening the way for applications to run past strict time limits that hamper many quantum calculations. “Quantum computers have a limited time to perform calculations before their useful quantum nature, which we call coherence, breaks down,” said Andrew Sornborger of the Computer, Computational, and Statistical Sciences division at Los Alamos National Laboratory, and senior author on a paper announcing the research. “With a new algorithm that we have developed and tested, we will be able to fast forward quantum simulations to solve problems that were previously out of reach.”


Schools Weren't Prepared for a Crisis Like COVID-19:

How did schools' planning *before* the pandemic affect their transitions to remote learning when COVID-19 hit? Results from our new national survey provide some insights.


Ada Lovelace Day is a worldwide celebration of the achievements that women have made in STEM industries, which stands for science, technology, engineering, and math.

The day is about increasing the profile of females in STEM. The hope is that by doing this we will help to create new role models for women all across the globe and encourage more females to take roles within STEM sectors.

WOMEN IN TECH - Global Movement Nadia Mannell Carine de Meyere Candyce Costa A IDM Lindalia Sofia Junqueira Reis Isabel Velarde, Founder, CEO Innovation Hub Consulting® Dr. Cara Antoine Claudia Mendes Silva Elina Valeeva Jenyfer Maisonneuve Joanna Carson Mandi Gunsberger, GAICD Polina Vasilenko Monika Rizovska Katerina Trajchevska Melissa Slaymaker

Tactical Airborne Laser Weapon System (TALWS):


Hexagon launches autonomy kits for agriculture with demo tractor - GPS World:

Hexagon’s Autonomy and Positioning division has launched its first autonomy positioning and sensing kits for the agriculture market. Learn more about the kits, which the company validated in its new autonomous research and development tractor.

The evolution of GPS satellites and their use today - GPS World: 

From Cold War origins of a chirping beach ball traveling through space 63 years ago, now more than 2,600 satellites enhance our terrestrial lives. Here's how satellite technology has gotten to this point. (Photo: U.S. Army/DARPA) #satellite #technology


Norway Govt Wants GPS Backup - Offering $910K To Develop for Maritime Pilots
Blog Editor's (Dana A. Goward) Notes:

Less than a million dollars (US) doesn't seem like much to develop a navigation system.

Also, there are existing systems already developed (or nearly there) that could be implemented. But they certainly cannot be had for such a small sum.

Perhaps the Norwegian government just wants to fund a study.

But why is a study needed? The problem of GNSS disruption in maritime has already been addressed by the European Space Agency (ESA), of which Norway is a member in good standing.

Last year ESA's NAVISP program sponsored a very comprehensive, year-long study of requirements and solutions for resilient maritime navigation. The 1,100 pages of reports of the MarRINav project outline process, findings, results and recommendations in great detail. True, it was written with a focus on the UK, but the methodology and results can be applied anywhere. 

We hope that this announcement isn't just a way for government leaders to give the appearance of action so it doesn't have to actually do anything. 

No alt text provided for this image

(Technical Weekly)

Most of the pilots have experienced GPS failure. Now they want to develop a safer alternative
Over the next few months, the Norwegian Coastal Administration will announce NOK 8.5 million to those who can develop a secure backup for satellite navigation.
The senses, local knowledge and radar are the most important tools the pilots use for unloading ships safely in port, but they have increasingly become dependent on satellite navigation such as GPS. These signals can be lost, either by accident or as a result of deliberate hacking.

- It can lead to dangerous situations and unwanted incidents, says Odd Sveinung Hareide, advisor and project manager in the pilot service.

The pilotage service will therefore in November announce a contract of NOK 8.55 million for someone who can develop a backup solution for satellite navigation. The new sensor technology will be able to compensate for the unreliability of satellite navigation and warn when the signals are affected. 

Basically, it should be a mobile solution that can be used by the pilotage service, but the goal is that the solution can also be used in shipping in general. 

The goal is to sign the development contract in early 2021. The finished prototype is scheduled to be ready in 2023.

READ MORE Site has a header button for version in English (but TeK Associates could not find it!)

Very Long Baseline Array (VLBA) Makes First Direct Distance Measurement to Magnetar:

Fenton Heirtzler, Organic materials chemistry and nonlinear optics:

"Very cool! Thanks for the enlightenment on magnetars (I had never heard of them). Maybe you could amend your posting to include the distance which was measured? 
Would it be reasonable to assume that there are no other heavenly bodies anywhere nearby to this? 
Can this thing be considered a massive ferromagnetic object, and is there any way to learn what its atomic composition would be?
There are other speculative questions, but I assume that at this point in time, there are no answers for them...."

RL Poole, Author, The Leedskalnin Codex: Breakthroughs in Understanding the Coral Castle - #1 Best Seller in the Physics of Gravity (Amazon Kindle):

"I read the Wikipedia reference. It says in the same place, that these magnetic fields are a hundred million times stronger than any man-made magnet."

Fenton Heirtzler:

" Is there any pop science magazine article on this...? I am afraid I wouldn't know. I think that is a question better directed at Google. I watched a science program about magnetars years ago, and found them fascinating. 

"Classical magnetism occurs when the nuclear spins of atoms are spatially aligned (I think). So is a magneton one big unidirectional nuclear spin ?" Says, who?

Magnetars are FASCINATING."

Free navigation tutorials (from China and Andover, MA): (THK: Danger)

Precise Navigation Made Simple:
ACEINNA’s inertial solutions deliver high precision in an easy-to-use open source development environment. Our fully temperature calibrated solutions deliver the performance needed to sense the real-world motion of today’s intelligent systems. (THK: Danger)


Vulnerabilities of GPS is a big concern: Dana Goward - Geospatial World:

Satellite systems have become an integral part of our businesses for precise navigation and timing services. Yet GPS/GNSS jamming, spoofing, and other forms of interference appear to be growing in frequency and severity. Recently, the Senate Armed Services Committee (SASC) asked Pentagon to provide Combatant Commander’s alternate position, navigation and timing (PNT) systems to GPS within two years.

We caught up with Dana Goward, a member of the National PNT Advisory Board, and President & Director of RNT Foundation, an independent, member-supported non-profit that works in the area building awareness about the importance and vulnerabilities of navigation and timing systems, encourages development and implementation of resilient terrestrial systems, and advocates for policies to deter spoofing and jamming. Goward is retired from the federal Senior Executive Service having served as the maritime navigation authority for the United States. He has represented the US at IMO, IALA, the UN anti-piracy working group, and other international forums. He is also a Senior Adviser to Space Command’s Purposeful Interference Response Team.

Why is there so much concern around vulnerabilities of GPS?
It’s not just about GPS; all GNSS signals are weak. They are 20,000 km above the Earth, powered by solar panels, and are transmitting all the time, after all. Just as a matter of physics, it’s very easy to block a relatively weak signal. That is what GPS jamming is. Also, because the different global navigation satellites systems want to increase their user base, they release all the information about their signals so they can be integrated into other systems. But if you know exactly what the signals look like, you know how to imitate them. This makes the signals open to spoofing as well. That is another significant challenge, because, in many ways spoofing is worse than jamming — instead of no information, spoofing can give you hazardously misleading information.

ALSO READ: Why Resilient PNT Infrastructure is Imperative to Global Economic Growth

All GNSS are relatively the same signal strength and in same general frequency band, and they are all in space. Naturally, they are subjected to same kind of vulnerabilities — severe solar activity, malicious high-power electro-magnetic pulses, local jamming, spoofing, etc. Even urban canyons and downtown cities are a challenge as the signals tend to bounce off buildings and can cause problems for receivers. Using multiple GNSS systems at the same time does protect users a bit if one of the systems suffers a cyberattack or an equipment failure. So, it does offer some measure of additional resilience. But, generally, they all have similar vulnerabilities and are subject to the same threats, so the added resilience and security is marginal.

These shared vulnerabilities have been a concern for some time. There are all kinds of incentives for individuals and organizations to interfere with GPS signals — from delivery drivers taking long breaks, to criminal organizations wanting to divert a shipment, to nations looking to counter the armed forces of another. For example, American generals have said that Syria and the Middle East have the highest intensity of electronic warfare anywhere on the face of the planet. A lot of that is GPS/GNSS jamming and spoofing.

Interestingly, a recent sampling by the European Union found 500,000 instances of transmissions on GNSS frequency that should not have been there. About 10% of them were determined to be malicious and intentional, while the others were just apparently accidental. So, there are a lot of vulnerabilities in the system, and a lot of real-world threats

From cellular networks to power grids to transport systems, GNSS is the source of accurate, synchronized time for almost everything. A 2012 Boston Consulting Group study found that the geospatial services fueled by GPS resulted in $1.4 trillion a year in savings to the US economy and another $1.6 trillion in added revenues. A London Economics study found that if GPS/GNSS went away for five days, the UK economy would suffer losses of £5.2 billion, which translates to $482 billion per year.

We are fortunate that nothing really bad has happened so far. At the RNT Foundation we encourage responsible governments to try to get ahead of things and prevent mishaps, rather than waiting for them to happen before swinging into action.

Tell us about the details of the FCC-Ligado controversy?
Ligado is really an interesting case. Ligado Networks, an American satellite communications company, claims they want to establish a low-power nationwide 5G network. And it has been allotted space in the L-band spectrum which is the same band as that of GPS and other GNSS. US government tests have shown that these transmissions will interfere with GPS reception for many users. Naturally, a lot of organizations and individuals, including the Executive branch of the government, are concerned about its possible impact on GPS and are of the opinion that we shouldn’t go ahead with this. However, the Federal Communications Commission, which is an independent agency and works on its own under a congressional mandate, is convinced that this isn’t going to be that much of a problem, approved the request, and is refusing to budge.

Ever since, the opposition to the proposal has been growing. The entire executive branch of the government, including the Department of Defense and Department of Transportation, have amplified their protest and a number of organizations including the RNT Foundation, have formerly requested that the FCC reconsider their decision. Now, there is some legislation in Congress to examine the decision. The end of that story is yet to be written.

One of my thoughts here is that the FCC is the ‘communications’ commission, not the ‘navigation’ or ‘geospatial’ commission. Radio communications are different from radio navigation in a lot of ways. In fact, they are almost opposites — in radio communications you are blasting the 1s and 0s through the surrounding noise to get the message through, while in radio navigation you look down within the background noise for the 1s and 0s. And rather than identifying the 1s and 0s as the message in communications, radio navigation precisely measures the time of the change from a 1 to a 0 so the receiver can figure out its location. There are a bunch of other differences as well.

It could well be that the radio and communications engineers at FCC didn’t have the right context to evaluate the Ligado proposal as it would affect navigation. As an example — I was on a panel with the head of Ligado who is a communications engineer. I said there were tests that found Ligado transmissions violated the government safety buffer for GPS failures. I said that, rather than using the safety buffer in its tests, Ligado had tested the GPS receivers to the point of failure. Ligado’s CEO replied that they hadn’t done that. They had just tested the receivers to where they started “giving bad information.” OK, so that’s worse. Bad information is worse than no information at all.

But it shows the difference between the way communications engineers and navigation engineers view things. In communications, a little bit of interference might not be so bad. You could probably understand the overall message. Or, if it is two-way communications, you could ask for a repeat. Not so for navigation. One of the first signs of interference with GPS/GNSS signals in many receivers is bad, potentially hazardous, information. A safety report to NASA last year detailed how a passenger aircraft nearly crashed into a mountain because of this kind of interference with its GPS receiver.


FAA gives go-ahead for Amazon drone-delivery tests - GPS World:

Amazon received Federal Aviation Administration approval to use drones to deliver packages. Find out what this could mean for package delivery times.


Collaboration aimed at GNSS solution for IoT modems - GPS World

Synopsys Inc and Nestwave are collaborating to combine Nestwave’s geolocation software with the Synopsys DesignWare ARC IoT Communications Subsystem for a complete low-power GNSS solution for integration into IoT modems. Get more details. (Image: metamorworks/iStock/Getty Images Plus/Getty Images) #GNSS  #IoT  #communications 


Impact of UK Jamming Trials - More Details
And here is the notice:

2nd September 2020 SW2020/187

Jamming trial impacting electronic situational awareness devices, UAS command systems and GNSS receivers: 8 Sep – 4 Dec, Luce Bay
Jamming activity will take place 8 September – 4 December 2020 in and around Luce Bay. The activity may affect GNSS receivers along with UAS and cockpit devices operating on 433, 868, 915, 2400, 5800 MHz operating up to 40,000FT AMSL within 55NM of 545020N 045548W (West Freugh).

During the trials impacted systems may suffer intermittent or total failure. Individual events will not exceed 2 minutes in duration with no more than 5 events per hour. Activity will take place in daytime hours between 0830 and 1600.

For further information contact spectrum@caa.co.uk 

Emergency cease jamming contact 01776 888932 or 01776 888930 

First Fix: New year, new opportunities for GNSS industry - GPS World:

As we embark on a new year, 2021 ushers in a new administration and the start of the 117th Congress. With these changes comes a litany of opportunities, as well as challenges, for the nearly four-decade-old GPS industry, says the GPS Innovation Alliance (GPSIA)'s J. David Grossman.


Aviation Policy News: Airline Bailouts and Revenue Sources for Air Traffic Control During Pandemic:


SAE International EDGE Report: Air Traffic Management:


Building a better aerial imagery program beyond UAVs:


New Photon-Counting Camera Captures 3D Images with Record Speed and Resolution:


Researchers have developed the first mega-pixel photon-counting camera based on new-generation image sensor technology that uses single-photon avalanche diodes (SPADs). The new camera can detect single photons of light at unprecedented speeds, a capability that could advance applications that require fast acquisition of 3D images such as augmented reality and LiDAR systems for autonomous vehicles.


Distributing high-precision time over optical networks in the 5G world - GPS World:
Mobile operators are investing heavily in the deployment of LTE-Advanced and 5G networks that will transform cellular communications and connectivity. Check out some challenges they face. 


No silver bullet for US PNT: Many sources needed - GPS World:

At the moment, the U.S. GPS provides the vast majority of PNT services in the U.S. and around the world. Yet, like all space-based systems, its signals are weak and very vulnerable to interference. (Image: DOT) #GPS #PNT #space


Enemy jammer takes first test flight aboard EA-18G Growler:


Securing PNT Workshop Looks at GNSS Back-up Options - Inside GNSS:






Multipath GNSS signals are a threat to timing receivers in 4G and 5G networks - Spirent Blog:




Friday 04/17/2020 Ligado / FCC Roundup - What might really happen:






FCC Chairman Moves Forward on Ligado Approval - Inside GNSS:


Attorney General William P. Barr’s Statement on FCC Chairman Pai’s Draft Order to Approve Ligado’s Application to Facilitate 5G and Internet of Things Services:


FCC Chairman Moves Forward on Ligado Approval Interfering with GPS:
The Federal Communications Commission announced April 16 that Chairman Ajit Pai is circulating a draft proposal within the Commission that would approve a plan by Ligado Networks to use frequencies neighboring those used by GPS for a 5G terrestrial service.


"On November 18th 2020, the Federal Communications Commission unanimously voted to value streaming video and entertainment above human life." - Debby Bezzina, MBA,PMP, Managing Director for CCAT.

Debby was featured on the Michigan Department of Transportation's Talking Michigan Transportation Podcast. For more of her insights on the recent FCC ruling, listen here: http://myumi.ch/bvPVY 

#SaveTheSafetySpectrum #DSRC #CV2X  

NATO’s new tool shows the impact of GPS jammers:


NATO’s new tool shows the impact of GPS jammers - C4ISRNet (More):




Now Operational, BeiDou Could Conceal Cybersecurity Threat:


Defense Secretary Fires on FCC about Ligado - What else to remember:

It is clear that Defense Secretary Esper is upset with the FCC for dismissing his concerns about national security and Ligado out of hand. The below article documents some of his frustration. This article is a pretty good opening salvo for tomorrow's hearing by the Senate Armed Services Committee.

As we go into tomorrow's hearing, though, there are a couple things to keep in mind that we have not heard about at all in the media to date,

First, the FCC giving away (no charge to Ligado other than application fees) this satellite spectrum for terrestrial use means it won't be available for space assets. We understand the L-Band is ideal for space-based PNT. So if we want any more of it (like the LEO systems Chinese are building and the US Air Force is experimenting with) our options are going to be that much more limited. Spectrum is a finite resource.

Second, we didn't need to be here. The executive branch has long said that we need to take better care of our GPS and PNT with: 1) a system to detect and identify disruption sources; 2) far wider use of receivers that reject many forms of interference; and 3) signals from a terrestrial system that would stabilize GPS signals in receivers making them very resistant to interference, and provide PNT when GPS isn't available at all.

The Pentagon made its case against Ligado. What now? - C4ISRNet:




Pai to Congress "You're Wrong"​ - FCC fires back on Ligado Decision:
Blog Editor's (Dana A. Goward) Note: The more we read materials from each side of this issue, the more the opponents seem to be talking past each other. They might as well be speaking different languages. Everyone sees themselves as doing the right thing and is puzzled by why the other side sees them as in error at best and a force for evil at the worst.

We are sure that everyone is trying to do the right thing, but there are clearly some fundamental disconnects as to how folks see the world, interpret data, from testing, etc. 

That is why we have called for an independent expert evaluation of the testing results and a cost-benefit analysis so as to better inform public policy decisions.

Chairman Pai Letter to House Armed Services Committee Chair Adam Smith
In a letter to Congressman Adam Smith, Chair of the House Armed Services Committee, last week, FCC Chairman Ajit Pai refuted claims that he and the unanimous, bipartisan vote of the Commission had erred in their decision on Ligado Networks.

Over the course of four pages he said that:

- National security and the safety of the public was a critical concern for him and the commission

- He would never do anything to compromise safety and security

- There is a fundamental misconception that the FCC has authorized "sharing" spectrum. GPS has not (sic) right to operate in the spectrum allocated to Ligado.

- Regarding consultation with the Department of Defense

"... the Department of Defense was provided with numerous opportunities over nearly a decade to provide the
Commission with any relevant evidence it wished to submit."

The commission considers all comments provided for the docket and formally sought comments six separate times over the course of nine years.

The commission provided DoD, via NTIA, a draft order to consider in October 2019.

He (Chairman Pai) personally spoke to the Secretary of Defense and other senior DoD officials on the matter

- The FCC's process and decisions are not impugned just because another agency doesn't like the outcome

- FCC's excellent career staff worked for years on technical analysis supporting the decision.

- FCC did not violate the law regarding the need to "resolve concerns." Paragraphs 129 and 130 of the order did that.

- DoD never offered a classified briefing (if they had, he would have taken it), nor did they enter into the record any testing results.

All five FCC Commissioners responded to Chairman Smith's letter. Here are copies of all the letters:

FCC’s Ligado decision broadens, deepens opposition - GPS World

Last week, 27 members of the U.S. House Agriculture Committee sent a letter to Federal Communications Commission Chairman (FCC) Ajit Pai. In it, they urged him to reconsider the FCC’s decision to allow Ligado Networks to operate a terrestrial nationwide network that the executive branch says will cause harmful interference to GPS signals for many users. This concern and opposition from a sector not traditionally engaged in GPS or positioning, navigation and timing (PNT) issues is just one example of how the FCC’s decision — rather than putting the issue to rest — has instead recruited a whole new set of actors from across multiple sectors for the opposition. Many observers don’t see this as surprising.

According to one observer, previously it was easy for many to assume the FCC would reject Ligado’s proposal. The entire executive branch had been vehemently opposed for years. So had aviation groups, the weather community, geospatial interests and some satellite communications concerns. With such opposition from so many important quarters, it was reasonable for many to assume they need not become involved. Now that the FCC has acted to the contrary, these interests have become well energized. The FCC decision also empowered opponents to educate and recruit others who don’t normally think or worry about GPS and PNT issues, folks like farmers and agricultural interests. As one insider said, “The existing opposition can now go to just about anyone in any sector and say, ‘This is going to happen and it will harm your operation. There are no ifs, ands, or buts. The FCC has decided’.”

Agriculture’s reliance on GPS
Agriculture is a good example. While not the sector that first springs to mind when most people think about GPS, farming has become dependent on augmented GPS for precisely and automatically driving machinery, minimizing fertilizer and pesticide use, and a wide variety of other productivity gains over pre-GPS operations. “GPS is critically important to the commercial agriculture, mining, forestry and rural manufacturing industries. In fact, GPS has become the single most significant technological advancement for American farm equipment in the past two decades… [A 2019 RTI study] found that during planting season, if GPS were interrupted, the economic impact to the agriculture sector could amount to losses of $15 billion due to lower crop yields. Moreover, an earlier study suggested GPS-enabled precision agriculture could save farmers an estimated 10 to 15 percent in operating costs and purchased inputs. This same study estimated the benefits of GPS to precision agriculture between $10 and $17 billion.”

Department of Transportation studies have shown that high-precision GPS receivers, such as those used in agriculture, could be impacted within 3,000 meters of a Ligado transmitters. With tens of thousands of transmitters deployed in a nationwide network, this could pose a real problem for American farming. Other sectors have also become involved in the opposition. The recently formed Keep GPS Working Coalition has members representing aviation, surface transportation, maritime, agriculture and equipment manufacturing. This formal and public coalition, though, seems to be just the tip of the opposition iceberg.

Almost 100 dissenting organizations:
According to some involved with protesting the FCC’s decision, there are nearly a hundred organizations and companies that are working in some way to have it overturned. These include multiple aviation, delivery service, agriculture, surface transportation, geospatial, weather, maritime, space and technology interests. One sign of the influence they are having is an increase in concerns being expressed by members of Congress.

There’s a growing need for positioning solutions for Advanced Driver-Assistance Systems (#ADAS) in #autonomous vehicles. #GNSS-reliant vehicles require lane-level resolution in order to navigate safely and reliably. Additional sensors are used to enhance this accuracy, but what role does GNSS play in these sensor suites?

Hexagon | NovAtel technical sales rep Kevin Doherty explains how GNSS is integrated into R&D through series production to deliver #autonomy and #positioning - assured.

Watch now >> https://hxgn.biz/2C4LGmq 

FCC Chooses a bit more 5G over aviation safety. Again!:


The #UAE has taken an exciting leap in the #spaceeconomy with its recent successful launch of the Hope spacecraft to #Mars.

By sometime in Feb of next year (2021) it will enter a Martian orbit and begin collecting, analyzing and transmitting Mars atmospheric, climate and weather data. The launch used #Japan H-IIA rockets from Japan’s Tanegashima Space Center and with contract support from Mitsubishi Heavy Industries. The UAE used a unique approach to build the spacecraft themselves deploying strong academic coordination.

Given the UAE success already from the project by both staying on its $200M budget and short timetables it is likely to serve as a new model for other nations #Space �� ambitions.


U.S. Department of Transportation announces drone Remote ID partners - GPS World:


A new, more secure GPS signal could be ready by 2020:


How Vulnerable Is G.P.S.?
An engineering professor has proved—and exploited—its vulnerabilities. by Greg Milner August 6, 2020

The proliferation of G.P.S. interference is a major reckoning for the country’s military and defense systems.

In the cool, dark hours after midnight on June 20, 2012, Todd Humphreys made the final preparations for his attack on the Global Positioning System. He stood alone in the middle of White Sands Missile Range, in southern New Mexico, sixty miles north of Juárez. All around him were the glowing gypsum dunes of the Chihuahuan Desert. In the distance, the snow-capped San Andres Mountains loomed.

On a hill about a kilometre away, his team was gathered around a flat metal box the size of a carry-on suitcase. The electronic machinery inside the box was called a spoofer—a weapon by another name. Soon, a Hornet Mini, a drone-operated helicopter popular with law-enforcement and rescue agencies, was scheduled to appear forty feet above them. Then the spoofer would be put to the test.




Technology establishes your Position, Navigation, and Time (PNT) in the environment -- but we have to protect it.

Defend your #PNT in challenging environments through Hexagon | NovAtel anti-jam antennas, interference mitigation, and GNSS+INS combined systems.

Read more about how to protect the integrity of your PNT solution >> https://hxgn.biz/2RM4zg9 


Feds outline all the ways they can get you for messing with drones:
The Advisory on the Application of Federal Laws to the Acquisition and Use of Technology to Detect and Mitigate Unmanned Aircraft Systems was jointly issued by the Justice Department, Federal Communications Commission, Department of Homeland Security, and Transportation Department. It starts out noting that Congress has only given the authority to those four departments plus the Department of Energy to do such things. No other entities, including state, local, and tribal law enforcement, are allowed - and presumably could be sanctioned if they did so.

When talking about measures that involve jamming or spoofing GPS, the advisory cites 18 U.S.C. § 1367, Interference with the Operation of a Satellite that "...generally prohibits “obstruct[ing] or hinder[ing] any satellite transmission.”

We will try to avoid any snarky comments about the FCC's decision on Ligado Networks at this point...

The National Geodetic Survey (NGS) recently announced two new items related to the modernized National Spatial Reference System. Check out the updates.



ESA project calls for terrestrial navigation systems to reduce risk


Webinar to discuss MarRINav project results:

In 2018 the first-ever European Radionavigation Plan said “It is recognized that GNSS should not be the sole source of PNT information. Alternative PNT systems, not necessarily using radio frequencies, should thus be put in place where the criticality of the application requires it.”Graphic from MarRINav report showing system of systems approach to PNT resilience and reliability. In 2019 the European Space Agency (ESA) published a permanent open call for proposals for positioning, navigation, and timing studies and systems, including those that had nothing to do with space.

One of the first fruits of this is the ESA-funded Maritime Resilience and Integrity of Navigation project, or MarRINav, recently completed by researchers in the United Kingdom. “Maritime navigation and port operations are critical for almost every nation,” said Jonathan Turner, one of the MarRINav project team. “As an island nation with a strong maritime heritage, we in the United Kingdom perhaps have an even greater appreciation of this.” Turner is co-founder of the blue economy solutions company NLA International, which led a team of eight organizations cooperating on the project. While MarRINav focused its analysis on the United Kingdom, the intent was to provide information, and an analysis framework, that could also be used by other nations.

Maritime is one of sectors most dependent upon Global Navigation Satellite Systems, according to the project reports, and one of the ones with the greatest awareness of GNSS vulnerabilities and their consequences. MarRINav concludes that integrity and resilience are two of the most important parameters for maritime navigation. Maritime is also one of the sectors most ready to integrate space and terrestrial navigation systems, according to the report’s authors. The International Maritime Organization has already introduced a performance standard for a Multi-System Receiver, or MSR, that will incorporate a wide variety of navigation signals.

Despite the distractions of Brexit over the last four years, the United Kingdom has been particularly focused on its vulnerability to GNSS outages.

Eyeing Russia, Army fields jam-resistant GPS in Europe:


U.S. Space Command blasts Russia for anti-satellite missile test - SpaceNews (Why, because they did not use an F-15 double thruster instead?):


US Air Force selects Raytheon Missiles & Defense to develop Long-Range Standoff weapon:


What we know about Iran’s counter-space weapons:


Norway says Russia jammed GPS signal during NATO drill:










Norway Powerless Against GPS Interference - NRK:



Russia’s new navigation plan reveals a fear of jamming - C4ISRNet:



In addition to jamming NATO exercises and spoofing GPS receivers to protect VIPs, Moscow also claims it added GPS jammers to over 250,000 domestic cell towers to help defeat U.S. cruise missiles should they attack.

Letter to Karen Van Dyke (DOT):  http://rntfnd.org/wp-content/uploads/Alliance_for_Telecommunications_Industry_Solutions_ATIS_Copper_Optical_Access_Synchronization_and_Transport_Committee_COAST-2.pdf 




Communication and Navigation Satellite Signal Broadcast Histories and Interruptions:
Please click menu items scattered around the top for a more detailed view.
I just ran across this overview summary:

https://www.gpsworld.com/survey-accuracy-the-future-of-precision-with-5-gnss-constellations/         My Speculation on the cause of Boeing 737 MAX 8 Failure

FCC to approve spectrum plan that Pentagon claims will harm GPS - C4ISRNet



Congressmen demand answers after Pentagon issues GPS warning - C4ISRNet:


https://rntfnd.org/wp-content/uploads/2020-04-10-DeFazio-Garamendi-Letter-to-DOT-GPS.pdf  (Chao's letter)

In response to this filed by Ligado:


Resolution scheduled here:


Multi-agency Report Opposing Ligado Request Could Be Last Element in Controversy - Inside GNSS:



Senate Armed Services, Former FCC Commissioner Slam Ligado:


It’s Time for the FCC to Terminate the ‘LightSquared’ Proceeding:


17 December 2020-Coalition supports NDAA provisions to protect GPS against Ligado - GPS World:

The Keep GPS Working Coalition issued a statement in support of the inclusion of provisions related to GPS in the National Defense Authorization Act

Check it out now: https://www.gpsworld.com/coalition-supports-ndaa-provisions-to-protect-gps-against-ligado/ 

New Executive Order regarding PNT:



Industry perspective: Next-gen PNT needs careful assessment:


Three obstacles are slowing space sensors for hypersonic threats:



Four Challenges to Hypersonics:


Pentagon's Top R&D Chief Throws Cold Water On Laser Missile Defense Aspirations:

"Turn out the lights - the Party is over" Marketing flacks can go find something else to do for a few years instead of hawking concepts from movies based on comic books. Directed Energy lost its key advocate. 



Six months of reported GPS issues:


Analysis and Overview:



Lockheed’s Skunk Works Team to Help Update Air Force Reconnaissance Aircraft Avionics:


DHS S&T Invites Critical Infrastructure Owners and Operators to GPS Spoofing Test Event - HS Today:


New GPS 'circle spoofing' moves ship locations thousands of miles - GPS World:

New research by Bjorn Bergman of the environmental non-profit SkyTruth has found ships in various parts of the world reporting locations thousands of miles away and circling at precisely 20 knots. 


COSMIC-1 mission for GPS reflectometry comes to an end - GPS World
The COSMIC-1 program ended last month, when the last of six tiny satellites were decommissioned. Find out how long the satellites were in space. 


The Department of Homeland Security (DHS), Science and Technology Directorate (S&T) announced today an opportunity for critical infrastructure owners & operators and Global Positioning System (GPS) equipment manufacturers to test their equipment against GPS spoofing. The 2020 GPS Testing for Critical Infrastructure (GET-CI) event will be held later this year and is the third in this series of test opportunities.


Modernizing SIGINT—Technology Adapts to Serve Multiple Missions and Masters:
In this month’s Journal of Electromagnetic Dominance, I have a discussion with John Haystead about the evolving relationship between Signals Intelligence and electronic support measures, and the blurring of the lines between SIGINT, communications intelligence, and electronic intelligence. Spectrum dominance is the key for our DoD customers, and BAE Systems is poised at the forefront of innovation in this discriminator. At the end of the day, situational awareness across a variety of missions in as compact, efficient and upgradeable a package as possible is the goal. To read more on this important technology, check out May’s feature article in JED.


More Jamming and Spoofing of GPS:



Click here to see some other aspects of GPS evolution.               Brad Parkinson’s 2017 wish list: https://rntfnd.org/wp-content/uploads/Three-Wishes-v11s.pdf  

Click  here to see MORE aspects of GPS evolution.        https://www.septentrio.com/en/applications/referencestations  

USDOT seeks university to help secure automated navigation:                                                    


Raytheon, to replace OCX hardware by 2022 for $378 million:


The War perpetrated by Others on GPS (Part II) and other updates:






GPS III - Misleading Sound Bites Harm Nation - National Defense:



PCCW Global and UniStrong to link GNSS tech with telecoms, airports - GPS World:
PCCW GLOBAL Limited and UniStrong APAC Pte Ltd will collaborate on developing GNSS technologies and services for the telecommunications and aviation industries. Read more on the partnership and their goals.


Second GPS III Satellite Declared Ready for Military Use:


GPS Backup Analysis Stays on Track:



If your GPS position, navigation and time are under threat from jamming, then you need to consider NovAtel® Anti-Jam antennas. These are designed to defend against sources of interference -- that's assured positioning.

Read more about  NovAtel®'s GPS Anti-Jam Technology
>> https://hxgn.biz/2zl1vEp 

A new system, called WarLoc, makes it possible to locate warfighters and first responders in GPS-denied environments. 

Read more about the system, created by Robotic Research, LLC. (Photo: Robotic Research) #GPS:


CHC Navigation introduces Apache3 marine drone - GPS World:
The 2020 Apache3 Marine Drone provides a series of new features and additional enhancements to make lake, river and coastal hydrographic surveys more productive, according to maker CHC Navigation. Learn more about the drone. (Photo: CHC Navigation) #drone  #marine  #survey:


TeK Associates follows novel INS developments and relative INS accuracies: Familiar with Electro-statically supported Gyro (ESG) such as the airborne Micro, the SSBN ESG, as well as that in the Gravity-Probe satellite), Laser Gyros, Fiber Optics Gyros, Wine glass\tuning fork gyros, Microelectromechanical systems (MEMS) Gyroscopes. Prof. Christopher Jekelis (Ohio University, Columbus, OH) published mathematical model for Cold-Atom Gyros, as well as conventional mechanical spinning rotor gyros and their analysis.

We follow evolving procedures for moving platform shipborne and  in-air alignment gyro-compassing and alternative mechanizations: Local Level, Space-Stable, Wander-Azimuth, Strapdown and associated transformations (and typical frequency of re-calculation sample rates).  Surprisingly, new insights have recently been offered that much of the technology harkens back to analog gyro behavior more than is currently necessary in this digital age of extremely high processing speeds which can now support relatively high external GPS updates within strapdown gyroscope implementations. Previous notions of coning, sculling, the dynamics of Schuler loop oscillations being activated, or 24 hour diurnal oscillations are no longer necessary in Navigation systems mechanized with MEMS throughout and with GPS or differential GPS updates on the order of seconds or minutes because the gyros no longer need to go open loop without a compensating and ameliorating external  navaid fix for anything that approaches a significant fraction of the ~hour and a half Schuler period [30].

We are familiar with typical operational constraints and weapon system accuracies of several military platforms as well: e.g., Ships Submersible Ballistic Nuclear (SSBNs) submarines (a.k.a. Boomers), Ships Submersible Nuclear (SSN) submarines (a.k.a., attack subs), which allied countrys submarines use degaussing coils and which use flash, deperm procedures,  etc. We are also familiar with the tenets, details, and history of Search and Screening: e.g., detection range, worse case detection threats, observables-in-the-military-sense, countermeasures and counter-countermeasures for various sensors, etc. See [1] to [7] for perspectives on our early experience in this area. We are also knowledgeable in the associated terminology such as that of U.S. submarine alertness levels: 1SQ, 2SQ,..., Operation Sanguine [before the name change in the 1970s to evade the scrutiny of protesters ], TACAMO, long trailing wire antenna (BCA), pig tail antenna, whip antenna, Blue-green laser, Counter Value vs. Counter Force, Mid-course star fix, firing keys (where located and who has access, and orderly sequence of events, and expected synchronizations and chain-of-command), etc.

Our SSBN submarines can launch while submerged; while those of many other countries must surface first before they can launch.

We are cognizant of the Society of Old Crows, of the Countermeasures Handbook (we possess several back issues), and Paladin Press publications over the years (that should never have been allowed to appear). CV motion models, Lamps helicopters and ships, use of  ship-borne winch and cables dropped from helicopters seeking to land onboard in rough seas (where cable is secured to winch and helicopter pulls cable taught and is reeled in slowly so that Helicopter motion automatically matches that of the deck of the ship as both pitch, roll, and yaw together (to avoid damaging the helicopter with a nasty unexpected impact with the deck of the much more massive ship capable of preserving inertia by inflicting a severe impulse force as a big crushing blow over the short period of time-BANG!) We know about historical pipe dreams that failed miserably as well as alternative more robust approaches (using older technology) that was good enough without being vulnerable to a myriad of difficulties associated with other things going wrong (one example being trying to use a laser-based reflection system to guide the helicopter to land on the deck in rough seas-obvious vulnerabilities being: fog, battle smoke, electronic failures at an extremely critical time ala Murphys law, laser orientation capability for interacting with surface ships deck-in-motion possibly falling out of sufficient calibration [as needed to retrieve the necessary reflection close to perpendicular to the moving deck for instantaneous round trip timing-so you cant solve the problem until you have already solved the problem] and needing additional INS components with their additional costs and vulnerabilities and operational procedures). Thank Michael Athans and AlphaTech for the less practical approach, described above. Example 2: What about the attempt to align several (two or more) surface ships at sea in tandem to create an effective landing strip for those super-sized carrier air craft to take-off and land for re-supply at sea. Although some of their numerous computer studies demonstrated feasibility, please just think about being in the North Atlantic with typical winter weather conditions involving very high sea states and then try to pull off this stunt. We have Raman Mehra and Scientific Systems to thank for this second one. Both examples were funded by the U.S. Navy and further reported in an open unclassified forum but my critical ear hears all and I dont soon forget these apparent technical boondoggles but do continue to wonder how they ever got pass other watchdogs. I guess it pays to be well connected. Its not my cup of tea though. I have to say what I see and what I smell. We Kerrs (curs) are well-known watchdogs too. We try to avoid stepping in it as our predecessors did! Sometimes we mark our territory as a good alpha dog. Arrrooooo! Better to lead than to follow since the scenery is much better and more interesting (as every sled dog knows).

Rodriguez, J. J., Aggarwal, J. K., “Matching Aerial Images to 3D Terrain Maps,” IEEE Trans. on Pattern Analysis and Machine Intelligence, Vol. 12, No. 12, pp. 1138-1149, Dec. 1990: Sparse terrain profile data are stored onboard and direct measurement of relative shifts between images are used to estimate position and velocity; however, an EKF is deemed superior here to use of merely a Kalman filter that uses altitude estimates in order to estimate aircraft position and velocity. 

Heeger, D. J., Jepson, A. D., “Subspace Methods for Recovering Rigid Motion I: Algorithm and Implementation,” International Journal of Computer Vision, Vol. 7, No. 2, pp. 95-117, Jan. 1992: Terrain matching methods are also used to estimate platform position and orientation via comparisons to an on-board digital elevation map. 

Soatto, S., Frezza, R., Perona, P., “Motion Estimation via Dynamic Vision,” IEEE Trans. on Automatic Control, Vol. 41, No. 3, pp. 95-117, Mar. 1996: A least squares formulation is used to recover user's 3D motion (3 translation variables and 6 rotation variables or 4 if quaternions are utilized). 

Goyurfil, P., Rotstein, H., “Partial Aircraft State Estimation from Visual Motion Using the Substate Constraint Approach,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 24, No. 5, pp. 1016-1025, Sep.-Oct. 2001: What is called an implicit EKF is used here to estimate aircraft states-aircraft velocities, angular rates, angle of attack, and angle of sideslip but not aircraft Euler angles nor inertial location. Measurements available are the image points of N featured objects, which are tracked from one frame to another. 

Craig Lawson, John F. Raquet, Michael J. Veth, “The Impact of Attitude on Image-Based Integrity,” Navigation: Journal of the Institute of Navigation, Vol. 57, No. 4, pp. 249-292, Winter 2010: Being aware of the historical importance of having good satellite geometry when seeking to utilize GPS for positioning and for timing (characterized by HDOP, VDOP, TDOP, and GDOP), they analogously extrapolate these ideas to the geometry of their airborne image collecting and refer to this as image integrity (similar to how researchers endeavor to associate sufficient Integrity to GPS measurements). Also see: Dennis Milbert, “Dilution of Precision Revisited,” Navigation: Journal of The Institute of Navigation (ION), Vol. 55, No. 1, pp. 67-81, Spring 2008.

Hoshizaki, T., Andrisani, D., Braun, A. W., Mulyana, A. K., and Bethel, J. S., Performance of Integrated Electro-Optical Navigation Systems,” Navigation: Journal of the Institute of Navigation, Vol. 51, No. 2, pp. 101-122, Summer 2004: Contains good modeling and they have a “tightly coupled system consisting of INS, GPS, and EO” all working together to simultaneously benefit both navigation and photogrammetry (estimates platform states, sensor biases, and unknown ground object coordinates using a single Kalman filter).

Kyungsuk Lee, Jason M. Kriesel, Nahum Gat, Autonomous Airborne Video-Aided Navigation,” Navigation: Journal of the Institute of Navigation, Vol. 57, No. 3, pp. 163-173, Fall 2010: ONR-funded discussion utilizes (1) “digitally stored georeferenced landmark images” (altimeter/DTED), (2) video from an onboard camera, and (3) data from an IMU. Relative position and motion are tracked by comparing simple mathematical representations of consecutive video frames. A single image frame is periodically compared to a landmark image to determine absolute position and to correct for possible drift or bias in calculating the relative motion.

Crassidis, J. L., Markley, F. L., Cheng, Y., “Survey of Nonlinear Attitude Estimation Methods,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 30, No. 1, pp. 12-28, Jan. 2007: An excellent survey on the subject of attitude estimation. It provides insights into what is important in estimation algorithms. It is a more practical and rigorous addendum to their many earlier NASA surveys, concerned with utilizing alternative EKF's or Nonlinear Luenberger Observers (as alternatives to Extended Kalman filter-based approaches). Compare to [152] below. (Thomas H. Kerr III comment: This version is more concise.)

Maji, M., Junkins, J. L., Turner, J. D., Jth Moment Extended Kalman Filtering for Estimation of Nonlinear Dynamic Systems,” AIAA Guidance, Navigation, and Control Conference and Exhibit, Honolulu, HI, Paper No. AIAA 2008-7386, pp. 1-18, 18-21 Aug. 2008: Explores two variations on JMEKF formulations that properly handle higher order moments (that lurk in the background while trying to get good estimates and covariances from EKF’s). Approximations utilized are acknowledged and properly handled (rather than ignored, as is usually the case). 

Scorse, W. T., Crassidis, A. L., Robust Longitudinal and transverse Rate Gyro Bias Estimation for Precise Pitch and Roll Attitude Estimation in Highly Dynamic Operating Environments Utilizing a Two Dimensional Accelerometer Array,” AIAA Atmospheric Flight Mechanics Conference, Paper No. AIAA 2011-6447, Portland, OR, pp. 1-28, 8-11 Aug. 2011: Using the latest in rigorous real-time estimation algorithms (neither a particle filter nor an unscented/Oxford/Sigma-Point filter) for enabling accurate pointing (precise pitch and roll) within an aircraft within a high dynamics operating environment is reported. While it does utilize rate integrating gyros, as does SYERS-2C, it also utilizes 2D accelerometer arrays and compares to an onboard gravity map to achieve its accuracy. 

Discussing Gyroscopes (the heart of an INS)

The classical mechanical  gyroscope has a relatively massive rotor suspended within a framework of light supporting rings called gimbals which have nearly frictionless bearings (as the ideal that is sought) that are used to help isolate the central spinning rotor from all outside influences (i.e., torques). At high rotation speeds of the rotor, the gyroscope exhibits extraordinary stability of its balance and maintains the orientation of the direction of the high speed rotation axis of its central rotor in where it points in 3-dimensional space. The implication or consequence of the physical law known as the conservation of angular momentum is that the angular momentum of the rotor is constant and it maintains not only its magnitude or speed of spin, but also its direction in space of the spin axis in the absence of any external torques. The classical gyroscope finds application in gyro-compasses (as an alternative to using a magnetic compass) and in more sophisticated Inertial Navigation Systems (that reveal location and orientation of vehicles on the earth; and under and over the sea, respectively, in submarines and ships; and in space in aircraft, in rockets, and in missiles). However, there are many more common examples of gyroscopic motion and its associated stability: spinning tops  and their associated almost mysterious precession behavior, the spinning wheels of bicycles and motorcycles keeping them from falling over even in a severe leaning angle, the spin of the Earth in space as it orbits the sun, even the behavior of a boomerang as it is being hurled are all examples of gyroscopic motion.

Classical Inertial Navigation Systems:


The typical mechanical spinning-rotor gyroscope found within classical Inertial Navigation Systems (INS) is constructed by suspending a relatively massive spinning rotor inside three orthogonally mounted support rings called gimbals. Mounting each of these rotors on axes with high quality bearing surfaces with low friction insures that very little resisting torque is  exerted on the inside rotor as the rotor continues to spin. Electrical torquers (not shown here) are utilized to initially spin up the inner-most rotor to its nominal speed and to maintain its angular velocity, as continuously monitored by electrical or mechanical pick-offs (also not shown here). Modern day INS gyros take many different forms based on whatever other particular inherent physical principle is being exploited, such as that for wine glass acoustic frequency vibrating gyros, for electro-statically supported spherical gyros, for electro-magnetically supported spherical gyros, for ring laser gyros (RLG), for fiber optic gyros, for atomic quantum spin gyros, for Cold Atom gyros, etc. Other important aspects are in exactly how the two or more gyros are implemented or bound together within an Inertial Navigation System (INS) such as in a Space Stable configuration, in a  Local-Level  configuration (as either Wander Azimuth, Free Inertial, or North Pointing), or in a Strap-Down configuration, and in its corresponding Navigation filter formulation, which can be implemented in three different alternative ways but with the differential feedback form being somewhat of a standard now. New insights have been recently revealed into how modern MEMS gyros may now be implemented in Strap Down configurations without the same hassles or operational constraints being present that were historically associated with handling the classical spinning rotor gyros depicted here. A Charles Stark Draper Laboratory study and report in the late 1960s had concluded that a preferred optimal configuration for redundant gyros (with a one-degree-of-freedom input axis) was being located in a certain prescribed way as placed along all the faces of a regular dodecahedron. It is indeed a pity that Draper seems to have forgotten this 40 year old conclusion of theirs as they now work with MEMS gyros for which  Draper should again appropriately invoke the very same solution (but they dont),

Gyroscopic Precession:

If a gyroscope is tipped away from its original orientation, the gimbals will try to reorient to keep the spin axis of the rotor aligned in the same original direction as conservation of momentum. If released after being tipped over in this new  orientation, the gyroscope will precess in the indicated direction depicted here due to the external torque exerted  on the gyroscope by gravity.



Euler angle representations of 3D rotations can be problematic at singularities; Direction Cosine Matrices (DCM) are 3 by 3 and include much redundancy and achieve a rotation goal in 3 space via 3 separate constituent rotations; Quarterions get the job done concisely by picking a particular direction in space as the axis of rotation and then performing merely a single rotation about that axis: four numbers suffice (but for practical reasons, there is a need to normalize within a software implementation otherwise nice theoretical structural results are jeopardized by ever present computer round-off). Please see: Bernard Friedland, Analysis of Strapdown Navigation Using Quaternions, IEEE Transactions on Aerospace and Electronic Systems, Vol. 14 , No. 5, pp. 764-768, Sept. 1978. 

While 3 by 3 matrix rotations are well known to enable rotations in 3D Euclidean space, less well known is that a 4 by 4 matrix multiply can enact both a rotation and an offset (as first deduced by people in computer graphics as a neat insight beyond what physicists and other engineers had realized). I frequently saw engineers in shock with their jaws dropped when they could work it out and prove it to themselves but had never studied it in school. My first encounter with this new aspect just mentioned was in: 
-Kerr, T. H., Comments on `Determining if Two Solid Ellipsoids Intersect’, AIAA Journal of Guidance, Control, and Dynamics, Vol. 28, No. 1, pp. 189-190, Jan.-Feb. 2005. (I found a way to simplify their earlier result) 
-Kerr, T. H., Integral Evaluation Enabling Performance Trade-offs for Two Confidence Region-Based Failure Detection, AIAA Journal of Guidance, Control, and Dynamics, Vol. 29, No. 3, pp. 757-762, May-Jun. 2006. (I summarized the above described simplification in a single line in this paper.) http://www.tekassociates.biz/tkerrcr2roc.pdf  

From James Farrell in May 2020: "Of potential interest to you: an IMU interface standard under development, with SAE International involved, requiring raw uncorrected increments from gyros and accelerometers plus coefficients for purposes of compensation. In addition to the usual well-known error sources, there is a wide variety of (less familiar) motion-sensitive degradations. A tip-of-the-iceberg is shown at https://jlfblog.com/gyro-mounting-misalignment".

New Gyroscope technology: https://www.linkedin.com/pulse/new-gyroscope-borrows-best-from-mems-optical-devices-lieberman-/?trackingId=0rPjqUMjUM0sa%2B%2BDuQWyzQ%3D%3D  


Quantum Antenna Solution Makes Resilient PNT Receivers Easier/Better:

https://www.linkedin.com/pulse/quantum-antenna-solution-makes-resilient-pnt-receivers-dana-a-goward/?trackingId=qu2IE9Qv6WCuZA5OUBZUbA%3D%3D https://phys.org/news/2020-03-scientists-quantum-sensor-entire-radio.html


University of Michigan gyroscope could reduce dependence on GPS in electronics:
Researchers powered the University of Michigan have developed a small but powerful gyroscope that could reduce the GPS-dependency of drones and autonomous cars. According to U-M’s Schlumberger Professor of Engineering, Khalil Najafi, the gyroscope -- a device used to measure and maintain navigation found in smartphones and other technologies -- is 10,000 times more accurate than a typical smartphone gyroscope but at only 10 times the cost.

Optical Gyro + MEMS Fab: A Match Made in INS Heaven?:
Gyroscope designs used in inertial navigation systems (INS) fall into three basic groups: the classic spinning-rotor mechanical gyro (still in use in specialized situations due to its superior performance capabilities); the optical-based laser gyro using either a mirrored, close-loop path or a lengthy, coiled optical fiber (capable of very high performance, but with substantial weight and size); and the MEMS device (small, light, and low power, with lesser—yet still very good—performance). Now, a team based at the California Institute of Technology (Caltech) has devised, analyzed, built, and tested a laser-based gyro that also leverages the unique capabilities of microelectromechanical-systems (MEMS) technology (but not a MEMS-gyro core) for some of its internal components.

Deep Learning for Inertial Navigation:
A short review of cutting edge deep learning-based solutions for inertial navigation.

We are cognizant of the necessary interaction between the architectures associated with various alternative approaches to multi-target tracking and Kalman filter-based target tracking algorithms in use (alternative tracking algorithms hypothesized as possible modern replacements).

Our primary strength is having an in depth awareness of all the Kalman filter estimation-based approaches used to date for handling failure\fault detection in an INS or in GPS RAIM, or in a GPS/INS hybrid. We are analytic algorithm specialists. This is our area of greatest familiarity.

Even more usefull information is availed here following the 305 references provided immediately below (click this link to automatically move pass these citations).

Historical Account of our experience therein:

[1] Kerr, T. H., “Poseidon Improvement Studies: Real-Time Failure Detection in the SINS\ESGM (U),” TASC Report TR-418-20, Reading, MA, June 1974 (Confidential) for Navy, SP-2413 (Jerome “Jerry” Katz).
[2] Kerr, T. H., “Failure Detection in the SINS\ESGM System (U),” TASC Report TR-528-3-1, Reading, MA, July 1975 (Confidential) for Navy, SP-2413 (Jerome “Jerry” Katz).
[3] Kerr, T. H., “Improving ESGM Failure Detection in the SINS\ESGM System (U),” TASC Report TR-678-3-1, Reading, MA, October 1976 (Confidential) for Navy, SP-2413 (Jerome “Jerry” Katz).
[4] Kerr, T. H., “Preliminary Quantitative Evaluation of Accuracy\Observables Trade-off in Selecting Loran\NAVSAT Fix Strategies (U),” TASC Technical Information Memorandum TIM-889-3-1, Reading, MA, December 1977 (Confidential) for Navy, SP-2413 (Jerome “Jerry” Katz).
[5] Kerr, T. H., “Improving C-3 SSBN Navaid Utilization (U),” TASC Technical Information Memorandum TIM-1390-3-1, Reading, MA, August 1979 (Secret) for Navy, SP-2413 (Jerome Jerry Katz)

[6] Kerr, T. H., “Modeling and Evaluating an Empirical INS Difference Monitoring Procedure Used to Sequence SSBN Navaid Fixes,” Proceedings of the Annual Meeting of the Institute of Navigation, U.S. Naval Academy, Annapolis, Md., 9-11 June 1981. (Selected for reprinting in Navigation: Journal of the Institute of Navigation, Vol. 28, No. 4, pp. 263-285, Winter 1981-82). 

[7] Kerr, T. H., “Impact of Navigation Accuracy in Optimized Straight-Line Surveillance\Detection of Undersea Buried Pipe Valves,” Proceedings of National Marine Meeting of the Institute of Navigation (ION), Cambridge, MA, 27-29 October 1982.

[8]  Kerr, T. H., “Stability Conditions for the RelNav Community as a Decentralized Estimator-Final Report,” Intermetrics, Inc. Report No. IR-480, Cambridge, MA, 10 August 1980, for NADC (Warminster, PA).

[9] Kerr, T. H., and Chin, L., “A Stable Decentralized Filtering Implementation for JTIDS RelNav,” Proceedings of IEEE Position, Location, and Navigation Symposium (PLANS), Atlantic City, NJ, 8-11 December 1980.   ( Kerr, T. H., and Chin, L., “A Stable Decentralized Filtering Implementation for JTIDS RelNav,” Proceedings of IEEE Position, Location, and Navigation Symposium (PLANS), Atlantic City, NJ, 8-11 December 1980.  )

[10] Kerr, T. H., and Chin, L., “The Theory and Techniques of Discrete-Time Decentralized Filters,” in Advances in the Techniques and Technology in the Application of Nonlinear Filters and Kalman Filters, edited by C. T. Leondes, NATO Advisory Group for Aerospace Research and Development, AGARDograph No. 256, Noordhoff International Publishing, Lieden, 1981.

[11] Kerr, T. H., and Rogers, R., Report on PINS Filter Design Review (of Magnavox), Intermetrics Memo, Cambridge, MA, 11 August 1983, for NOSC (San Diego, CA). (Minesweeper Navigation)

[12] Kerr, T. H., “GPS\SSN Antenna Detectability,” Intermetrics Report No. IR-MA-199, Cambridge, MA, 15 March 1983, for NADC (George Lowenstein).

[13] Kerr, T. H., “Functional and Mathematical Structural Analysis of the Passive Tracking Algorithm (PTA),” Intermetrics Report No. IR-MA-208, Cambridge, MA, 25 May 1983, for NADC. (LAMPS Sonobuoy algorithms.)

[14] Kerr, T. H., “Navy GPS\SSN Phase II User Equipment DT&E Magnavox Modification Center (Mod Center) Test Report,” 1 June 1985, for NADC Code 4022 (George Lowenstein).

[15] Kerr, T. H., “Navy GPS\SSN Phase II User Equipment DT&E Rockwell-Collins Modification Center (Mod Center) Test Report,” 1 June 1985, for NADC Code 4022 (George Lowenstein).

[16] Kerr, T. H., “Navy GPS\SSN Phase II User Equipment DT&E Rockwell-Collins Developmental Test and Evaluation (Operational Readiness) [DT&E (OR)] Test Report,” 10 June 1985, for NADC Code 4022 (George Lowenstein).

[17] Kerr, T. H., “Magnavox Military Utility Test Report,” 10 June 1985, for NADC Code 4022 (for George Lowenstein).

[18] Kerr, T. H., “Phase III GPS Integration; Volume 1: GPS U.E. Characteristics,” Intermetrics Report IR-MA-177, Cambridge, MA, January 1983, for Navair and for NOSC (Richard Akita).

[19] Kerr, T. H., Decentralized Filtering and Redundancy Management Failure Detection for Multi-Sensor Integrated Navigation Systems, Proceedings of the National Technical Meeting of the Institute of Navigation (ION), San Diego, CA, 15-17 January 1985.

[20] Kerr, T. H., “Use of GPS\INS in the Design of Airborne Multisensor Data Collection Missions (for Tuning NN-based ATR algorithms),” the Institute of Navigation Proceedings of GPS-94, Salt Lake City, UT, pp. 1173-1188, 20-23 Sept. 1994.

[21] Kerr, T. H., “Further Comments on ‘Optimal Sensor Selection Strategy for Discrete-Time Estimators’,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 31, No. 3, pp. 1159-1166, June 1995.

[22] Kerr, T. H., “Sensor Scheduling in Kalman Filters: Evaluating a Procedure for Varying Submarine Navaids,” Proceedings of 57th Annual Meeting of the Institute of Navigation, pp. 310-324, Albuquerque, NM, 9-13 June 2001.  

[23] Kerr, T. H., Sensor Scheduling in Kalman Filters: varying navaid fixes for trading-off submarine NAV accuracy vs. ASW exposure,” Proceedings of The Workshop on Estimation, Tracking, and Fusion: A Tribute to Yaakov Bar-Shalom (on the occasion of his 60th Birthday) following the Fourth ONR/GTRI Workshop on Target Tracking and Sensor Fusion, Naval Postgraduate School, Monterey, CA, pp. 104-122, 17 May 2001.

[24] Kerr, T. H., Further Critical Perspectives on Certain Aspects of GPS Development and Use,” Proceedings of 57th Annual Meeting of the Institute of Navigation, 9-13 June 2001.

(To see a high level overview slide show associated with the topics of the preceding paper, please click here to obtain the main executable file stpete.exe. In order to view the slideshow, user must first also download these auxiliary files: this associated .DLL file, then this .DLL file, then this VBX file, all to the same folder location on their local computer, where stpete.exe resides. Our Website host required temporary conversion to exclusively lower case spellings. Once this is done, merely click on stpete.exe to start the show and click on screen to move to the next screen in the sequence until the end [when it closes and stops].)

[25] Biezad, D. J., Integrated Navigation and Guidance Systems, AIAA Education Series, Reston, VA, 1999.

[26] Sofir, I., “Improved Method for Calculating Exact Geodetic Latitude and Attitude-Revisited, AIAA Journal of Guidance, Control, and Dynamics, Vol. 23, No. 2, ff. 369, 2000.

[27] Siouris, G. M., “Navigation: Inertial,” Encyclopedia of Physical Science and Technology, 2nd Edition, V. 10, pp. 595-647, Academic Press, NY, 1992.

[28] Jordan, J. F., Wood, L. J., “Navigation: Space Missions,” Encyclopedia of Physical Science and Technology, 2nd Edition, Vol. 10, pp. 649-673, Academic Press, NY, 1992.

[29] Ward, P., “Navigation: Satellites,” Encyclopedia of Physical Science and Technology, 2nd Edition, Vol. 10, pp. 675-702, Academic Press, NY, 1992.

[30] Farrell, J. L., “Strapdown at the Crossroads, Navigation, Journal of the Institute of Navigation, Vol. 51, No. 4, pp. 249-257, Winter 2004. (A good modern perspective! Correction in Vol. 52, No. 1, page iii, Spring 2005. Strong conclusions in this paper should be viewed  as being somewhat controversial.)

[31] Kerr, T. H., “Comment on `Precision Free-Inertial Navigation with Gravity Compensation by an Onboard Gradiometer’, AIAA Journal of Guidance, Control, and Dynamics, Vol. 30, No. 4, July-Aug. 2007.

[32] Felter, S. C., Wu, N. E., “A Relative Navigation System for Formation Flight,IEEE Trans. on Aerospace and Electronic Systems, Vol. 33, No. 7, pp. 958-967, July 1997.

[33] Juang, J.-C., Huang, G.-S., “Development of GPS-Based Altitude Determination Algorithms,IEEE Trans. on Aerospace and Electronic Systems, Vol. 33, No. 7, pp. 968-976, July 1997.

[34] Chatterji, G. B., Menon, P. K., Sridhar, B., “GPS/Machine Vision Navigation System for Aircraft,IEEE Trans. on Aerospace and Electronic Systems, Vol. 33, No. 7, pp. 1012-1095, July 1997.

[35] Xiong, P., “Spacial and Temporal Processing for Global Navigation Satellite Systems: GPS receiver paradigm,IEEE Trans. on Aerospace and Electronic Systems, Vol. 39, No. 7, pp. 936-948, July 2003.

[36] Madhani, P. H., “Application of Successive Interference Cancellation to GPS Pseudolite Near-Far Problem,IEEE Trans. on Aerospace and Electronic Systems, Vol. 39, No. 4, pp. 481-488, April 2003.

[37] Luo, N., “Multiple Moving Platform, GPS, Relative Positioning,IEEE Trans. on Aerospace and Electronic Systems, Vol. 39, No. 7, pp. 936-948, July 2003.

[38] Fante, R. L., “Multipath-induced bias, GPS time-of-arrival, Evaluation and Reduction,IEEE Trans. on Aerospace and Electronic Systems, Vol. 39, No. 7, pp. 911-920, July 2003.

[39] Qi, H., “GPS/INS Integration: Direct Kalman Filtering Approach,IEEE Trans. on Aerospace and Electronic Systems, Vol. 38, No. 1, pp. 687-693, Jan. 2002.

[40] Shin, D.-H., “TOA and TDOA Positioning Error,IEEE Trans. on Aerospace and Electronic Systems, Vol. 38, No. 1, pp. 307-308, Jan. 2002.

[41] Pervan, B., “Sigma Inflation for Local Area Augmentation of GPS,IEEE Trans. on Aerospace and Electronic Systems, Vol. 37, No. 10, pp. 1301-1311, Out. 2001.

[42] Praasch, M. S., “SS-Ranging Multipath Model Validation for DGPS,IEEE Trans. on Aerospace and Electronic Systems, Vol. 37, No. 1, pp. 298-304, Jan. 2001.

[43] Ray, J. K., “Carrier Multipath Mitigation, Multiantenna System,IEEE Trans. on Aerospace and Electronic Systems, Vol. 37, No. 1, pp. 183-195, Jan. 2001.

[44] Kim, K. H., Lee, J. G., Park, C. G., “Adaptive Two Stage Extended Kalman Filter for a Fault-Tolerant INS-GPS Loosely Coupled System,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 45, No. 1, pp. 125-137, Jan. 2009.

[45] Jardak, N., Samama, N., “Indoor Positioning Based on GPS-Repeators: Performance Enhancement using an Open Code Loop Architecture,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 45, No. 1, pp. 347-359, Jan. 2009.

[46] “Noncoherrent Integrations for GNSS Detection: Analysis and Comparisons,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 45, No. 1, pp. 360-375, Jan. 2009.

[47] Chiang, K.-W., Noureldin, A., El-Sheimy, N., “Constructive Neural-Networks-Based MEMS/GPS Integration Scheme,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 2, pp. 582-594, April 2008.

[48] Farrell, W. J., “Interacting Multiple Model Filter for Tactical Ballistic Missile Tracking,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 2, pp. 418-426, April 2008.

[49] Borio, D., Camoriano, L., Lo Presti, L., Fantino, M., “DTFT-Based Frequency Lock Loop for GNSS Applications,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 2, pp. 595-612, April 2008.

[50] Kaplan, L. M., “Assignment Costs for Multiple Sensor Track-to-Track Association,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 2, pp. 655-675, April 2008.

[51] Bon, N., Khenchaf, A., Garello, R., “GLRT Subspace Detection for Range and Doppler Distributed Targets,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 2, pp. 678-695, April 2008.

[52] Juang, J.-C., “Multi-Objective Approach to GNSS Code Discrimination Design,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 2, pp. 481-492, April 2008.

[53] Geren, W. P., Murphy, T., Pankaskif, T. A., “Analysis of Airborne GPS Multipath Effects using High-Fidelity EM Models,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 2, pp. 711-723, April 2008.

[54] Jan, S.-S., Gebre-Egziabher, D., Walter, T., Enge, P., “Improving GPS-Based Landing System Performance using an Empirical Barometric Altimeter Confidence Bound,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 1, pp. 127-146, Jan. 2008.

[55] Lambert, H. C., “Tracking Filter for the Mitigation of the Ionospheric Range Bias,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 1, pp. 339-348, Jan. 2008.

[56] Tudoroiu, N., Khorasani, K., “Satellite Fault Diagnosis using a Bank of Interacting Kalman Filters,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 43, No. 4, pp. 1334-1350, Oct. 2007.

[57] Musicki, D., La Scala, B., “Multi-Target Tracking in Clutter Without Measurement Assignment,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 3, pp. 877-896, July 2008.

[58] Blanch, J., Walter, T., Enge, P., “Position Error Bound Calculation for GNSS Using Measurement Residuals,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 3, pp. 977-984, July 2008.

[59] Musicki, D., “Multi-Target Tracking using Multiple Passive Bearings-Only Asynchronous Sensors,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 3, pp. 1151-1160, July 2008.  Also see: http://www.gallup.unm.edu/~smarandache/NATOASI_ATJDTSPK.pdf 

[60] Foster, C. C., Elkaim, G. H., “Extension of a Two-Step Calibration Methodology to Include Nonorthogonal Sensor Axes,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 3, pp. 1070-1078, July 2008.

[61] Borio, D., Camoriano, L., Lo Presti, L., “Impact of GPS Acquisition Strategy on Decision Probabilities,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 3, pp. 996-1011, July 2008.

[62] Lee, J., Pullen, S., Enge, P., “Sigma-Mean Monitoring for the Local Area Augmentation of GPS,IEEE Trans. on Aerospace and Electronic Systems, Vol. 42, No. 2, pp. 625-635, Apr. 2006.

[63] Bednarz, S., Misra, P., “Receiver Clock-Based Integrity Monitoring for GPS Precision Approaches,IEEE Trans. on Aerospace and Electronic Systems, Vol. 42, No. 2, pp. 636-643, Apr. 2006.

[64] Heo, M.-B., Pervan, B., “Carrier Phase Navigation Architecture for Shipboard Relative GPS,IEEE Trans. on Aerospace and Electronic Systems, Vol. 42, No. 2, pp. 670-679, Apr. 2006.

[65] Pacher, M., Porter, A., Polat, M., INS-Aiding Using Bearings-Only Measurements of an Unknown Ground Object,Navigation: Journal of the Institute of Navigation, Vol. 53, No. 1, pp. 1-20, Spring 2006.

[66] Wendel, J., Metzger, J., Moenikes, R., Maier, A., Trommer, G. F., A Performance Comparison of Tightly Coupled GPS/INS Navigation Systems Based on Extended and Sigma Point Kalman Filters,Navigation: Journal of the Institute of Navigation, Vol. 53, No. 1, pp. 21-31, Spring 2006.

[67] Farrell, J. L., Full Integrity Testing for GPS/INS,Navigation: Journal of the Institute of Navigation, Vol. 53, No. 1, pp. 33-40, Spring 2006.

[68] Hwang, P. Y., Brown, R. G., RAIM-FDE Revisited: A New Breakthrough in Availability Performance with nioRAIM (Novel Integrity-Optimized RAIM),Navigation: Journal of the Institute of Navigation, Vol. 53, No. 1, pp. 41-51, Spring 2006.

[69] Alves, D. B. M., Monico, J. F. G., Mitigating Systematic Errors for Single Frequency GPS Receivers Employing A Penalized Least Squares Methodology,Navigation: Journal of the Institute of Navigation, Vol. 53, No. 1, pp. 53-60, Spring 2006.

[70] Fante, R. L., Vaccaro, J. J., “Cancellation of Jammers and Jammer Multipath in a GPS Receiver,IEEE AES Systems Magazine, Vol. 13, No. 11, pp. 25-28, Nov. 1998.

[71] Fante, R. L., Vaccaro, J. J., “Wideband Cancellation of Interference in a GPS Receive Array,IEEE Trans. on Aerospace and Electronic Systems, Vol. 36, No. 2, pp. 549-564, April 2000.

[72] Counselman, C. C., “Array Antennas for DGPS,IEEE Systems Magazine, Vol. 13, No. 12, pp. 15-19, Dec. 1998.

[73] Rabideau, D. J., “Clutter and Jammer Multipath Cancellation in Airborne Adaptive Radar,IEEE Trans. on Aerospace and Electronic Systems, Vol. 36, No. 2, pp. 565-583, April 2000.

[74] Myers, L., Improved Radio Jamming Techniques: Electronic Guerilla Warfare, ISBN 0873645200, Paladin Press, Boulder, CO, 1989.

[75] Daher, J. K., Harris, J. M., Wheeler, M. L., “An Evaluation of the Radio Frequency Susceptibility of Commercial GPS Receivers,IEEE AES Systems Magazine, Vol. 9, No. 10, pp. 21-25, October 1994.

[76] White, N. A., “Detection of Interference/Jamming and Spoofing in DGPS-aided Inertial Systems,IEEE Trans. on Aerospace and Electronic Systems, Vol. 34, No. 5, pp. 1208-1217, Oct. 1998.

[77] White, N. A., Maybeck, P. S., DeVilbiss, S. L., “Detection of Interference/Jamming and Spoofing in a DGPS-Aided Inertial System,IEEE Trans. on Aerospace and Electronic Systems, Vol. 34, No. 4 pp. 1208-1217, Oct. 1998.

[78] Pinker, A., Smith, D., Walker, D., “Jamming the GPS Signal,Proceedings of the 55th Annual Meeting of the ION, Cambridge, MA, 28-30 June 1999.

[79] Littlepage, R. S., “The Impact of Interference on Civil GPS,Proceedings of the 55th Annual Meeting of the ION, Cambridge, MA, 28-30 June 1999. (He warned us early on! His presentation was more explicit than his paper. He was truly concerned.)

[80] Goldstein, J. S., “Multistage partially adaptive STAP CFAR detection algorithm,IEEE Trans. on Aerospace and Electronic Systems, Vol. 35, No. 2, pp. 645-669,  April 1999.

[81] Saha, R. K., “Effect of Common Process Noise on Two-Sensor Track Fusion,AIAA Journal of Guidance, Control, and Dynamics, Vol. 19, No. 4, pp. 829-835, July-August 1996.

[82] Fitzgerald, R. J., “Effects of Range-Doppler Coupling on Chirp Radar Tracking  Accuracy,IEEE Transactions on Aerospace and Electronic Systems, Vol. AES-10, No. 4, pp. 528-532, July 1974.

[83] Brennan, L. E., Reed, I. S., “Theory of Adaptive Radar,IEEE Trans. on Aerospace and Electronic Systems, Vol. 9, No., pp. 237-252, March 1973.

[84] Brennan, L. E., Mallett, J. D., Reed, I. S., “Adaptive Arrays in Airborne MTI Radar,IEEE Trans. on Antennas and Propagation, Vol. 24, No. 5, pp. 607-615, September 1978.

[85] Arregui, F. J. (ed.), Sensors Based on Nanostructured Materials, Springer Science & Business Media LLC, 2009.

[86] Righini, G. C., Tajani, A., Cutolo, A., An Introduction to Optoelectronic Sensors, World Scientific, NY, 2009.

[87] Vladimir Cherkassky and Filip Mulier, Learning from Data: Concepts, Theory, and Methods, John Wiley & Sons, Inc., NY, 1998.

[88] Gupta, S. N., “An Extension of Closed-Form Solutions of Target-Tracking Filters with Discrete Measurements,IEEE Trans. on Aerospace and Electronic Systems, Vol. 20, No. 6, pp. 839-840, Nov. 1984.

[89] Junichiro Toriwaki, Hiroyuki Yoshida, Fundamentals of Three-Dimensional Digital Processing, Springer-Verlag, London, 2009.

[90] Julien Bourgeois, Wolfgang Minker, Time-Domain Beamforming and Blind Source Separation: Speech Input in the Car Environment, Springer Science + Business Media, NY, 2009.

[91] Jekeli, C., “Navigation Error Analysis of Atom Interferometer Inertial Sensing, Navigation: Journal of the Institute of Navigation, Vol. 52, No. 1, pp. 1-14, Spring 2005.

[92] Another intriguing wrinkle is conveyed in Fernandez-Alcada, R., Navarro-Moreno, Ruiz-Molina, J. C., Oya, A., “Recursive Linear Estimation for Doubly Stochastic Poisson Processes,” Proceedings of the World Congress on Engineering (WCE), Vol. II, London, UK, pp. 2-6, 2-4 July 2007.

[93] Huddle, J.R., “Inertial Navigation System Error Model Considerations in Kalman Filter Applications,” Control and Dynamic Systems: Advances in Theory and Applications - Nonlinear and Kalman Filtering Techniques, Vol. 20, Academic Press, NY, pp. 294-340, Part 2 of 3, 1983.

[94] Lechner, W., “Application of Model Switching and Adaptive Kalman Filtering for Aided Strapdown Navigation Systems,” Control and Dynamic Systems: Advances in Theory and Applications - Nonlinear and Kalman Filtering Techniques, Vol. 20, Academic Press, NY, pp. 155-185, Part 2 of 3, 1983.

[95] Chien, T. T., “An Adaptive Technique for a Redundant-Sensor Navigation System,” Report No. T-560, C. S. Draper Laboratory, Cambridge, MA, 1972.

[96] Salazar, M. R., “State Estimation of Ballistic Trajectories with Angle-Only Measurements,” Control and Dynamic Systems: Advances in Theory and Applications - Nonlinear and Kalman Filtering Techniques, Vol. 21, Academic Press, NY, pp. 117-175, Part 3 of 3, 1984.

[97] Hsiao, C.- Y., “Computational Techniques in Angle-Only Tracking Filtering,” Control and Dynamic Systems: Advances in Theory and Applications - Nonlinear and Kalman Filtering Techniques, Vol. 29, Academic Press, NY, pp. 101-134, Part 2 of 3, 1988.

[98] Liang, D. F., “Comparisons of Nonlinear Recursive Filters for Systems with Non-negligible Nonlinearities,” Control and Dynamic Systems: Advances in Theory and Applications - Nonlinear and Kalman Filtering Techniques, Vol. 20, Academic Press, NY, pp. 341-402, Part 2 of 3, 1983.

[99] Yannis A. Phillis, “Algorithms for Systems with Multiplicative Noise,” Control and Dynamic Systems: Advances in Theory and Applications - Nonlinear and Kalman Filtering Techniques, Vol. 30, Academic Press, NY, pp. 65-83, Part 3 of 3, 1989.

[100] Yannis A. Phillis and Vassilis S. Kouikoglou, “Minimax Estimation and Control of Multiplicative Systems,” Control and Dynamic Systems: Advances in Theory and Applications - Nonlinear and Kalman Filtering Techniques, Vol. 31, Academic Press, NY, pp. 93-124, Part 1 of 3, 1989.

[101] Ahn, B.-H., Regan, R., et al, “Inertial Technology for the Future,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 20, No. 4, pp. 414-444, Jul. 1984.

[102] Jayawardhana, B., Logemann, H., and Ryan, E. P., “The Circle Criterion and Input-to-State Stability: new perspectives on a classical result,” IEEE Control System Magazine, pp. 32-67, Vol. 31, No. 4, August 2011.

[103] Yan, J., Hoag, J. B., Hindman, R. E., Bernstein, D. S.,  “Longitudinal Aircraft Dynamics and the Instantaneous Acceleration Center of Rotation: the case of the vanishing zeros,” IEEE Control System Magazine, pp. 68-92, Vol. 31, No. 4, August 2011.

[104] Bergin, J., Guerci, J. R., MIMO Radar: Theory and Practice, Artech House, Boston, 2018.

[105] Son, J. S., Thomas, G., Flores, B. C., Range-Doppler Radar Imaging and Motion Compensation, Artech House, Boston, 2001.

[106] Guerci, J. R., Space-Time Adaptive Processing for Radar, Artech House, Boston, 2003.

[107] Hudson, J. E., Adaptive Array Principles, Peter Peregrinus, Ltd., London, U. K., 1981, reprinted 1989, 1991. 

[108] Copps, E. M., “An aspect of the role of the clock in a GPS receiver,” Navigation, Journal of The (U.S.) Institute of Navigation, Vol. 31, No. 3, pp. 233-242, 1986. Also in Global Positioning System, papers published in Navigation, reprinted by The (U.S.) Institute of Navigation, Vol. III,  pp. 44-53, 1986. 

[109] Copps, E. M.,  Geier, G. J.,  Fidler, W. C. and Grundy, P. A. , “Optimal processing of GPS signals,” Proceedings of the Thirty-Sixth Annual Meeting of The (U.S.) Institute of Navigation, Monterey, CA, 23- 26 June, pp. 17-24, 1980. Also in Navigation, Journal of The (U.S.) Institute of Navigation, Vol. 27, No. 3, pp. 171-182, 1984. Also in Global Positioning System, papers published in Navigation, reprinted by The Institute of Navigation, Vol. II, pp. 13-24, 1984. (cf., [178])

[110] Kashyap, S. K., Naidu, V. P. S., Singh, J., Girija, G., Rao, J. R., “Tracking of Multiple Targets Using Interactive Multiple Model and Data Association Filter,” Journal of Aerospace Science and Technologies, Vol. 58, No. 1, pp. 66-74, 2006.

NAVIGATION via Visual Cues Using Only Imaging Sensors:
[111] Rodriguez, J. J., Aggarwal, J. K., “Matching Aerial Images to 3D Terrain Maps,” IEEE Trans. on Pattern Analysis and Machine Intelligence, Vol. 12, No. 12, pp. 1138-1149, Dec. 1990: Sparse terrain profile data are stored onboard and direct measurement of relative shifts between images are used to estimate position and velocity; however, an EKF is deemed superior here to use of merely a Kalman filter that uses altitude estimates in order to estimate aircraft position and velocity. 
[112] Heeger, D. J., Jepson, A. D., “Subspace Methods for Recovering Rigid Motion I: Algorithm and Implementation,” International Journal of Computer Vision, Vol. 7, No. 2, pp. 95-117, Jan. 1992: Terrain matching methods are also used to estimate platform position and orientation via comparisons to an on-board digital elevation map. 
[113] Soatto, S., Frezza, R., Perona, P., “Motion Estimation via Dynamic Vision,” IEEE Trans. on Automatic Control, Vol. 41, No. 3, pp. 95-117, Mar. 1996: A least squares formulation is used to recover user's 3D motion (3 translation variables and 6 rotation variables or 4 if quaternions are utilized). 
[114] Goyurfil, P., Rotstein, H., “Partial Aircraft State Estimation from Visual Motion Using the Substate Constraint Approach,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 24, No. 5, pp. 1016-1025, Sep.-Oct. 2001: What is called an implicit EKF is used here to estimate aircraft states-aircraft velocities, angular rates, angle of attack, and angle of sideslip but not aircraft Euler angles nor inertial location. Measurements available are the image points of N featured objects, which are tracked from one frame to another. 
[115] Hoshizaki, T., Andrisani, D., Braun, A. W., Mulyana, A. K., and Bethel, J. S., “Performance of Integrated Electro-Optical Navigation Systems,” Navigation: Journal of the Institute of Navigation, Vol. 51, No. 2, pp. 101-122, Summer 2004: Contains good modeling and they have a “tightly coupled system consisting of INS, GPS, and EO” all working together to simultaneously benefit both navigation and photogrammetry (estimates platform states, sensor biases, and unknown ground object coordinates using a single Kalman filter).Use of control points avoided pre-stored terrain. 
[116] Kyungsuk Lee, Jason M. Kriesel, Nahum Gat, “Autonomous Airborne Video-Aided Navigation,” Navigation: Journal of the Institute of Navigation, Vol. 57, No. 3, pp. 163-173, Fall 2010: ONR-funded discussion utilizes (1) “digitally stored georeferenced landmark images” (altimeter/DTED), (2) video from an onboard camera, and (3) data from an IMU. Relative position and motion are tracked by comparing simple mathematical representations of consecutive video frames. A single image frame is periodically compared to a landmark image to determine absolute position and to correct for possible drift or bias in calculating the relative motion. 
[117] Craig Lawson, John F. Raquet, Michael J. Veth, “The Impact of Attitude on Image-Based Integrity,” Navigation: Journal of the Institute of Navigation, Vol. 57, No. 4, pp. 249-292, Winter 2010: Being aware of the historical importance of having good satellite geometry when seeking to utilize GPS for positioning and for timing (characterized by HDOP, VDOP, TDOP, and GDOP), they analogously extrapolate these ideas to the geometry of their airborne image collecting and refer to this as image integrity (similar to how researchers endeavor to associate sufficient Integrity to GPS measurements). Known a/c attitude significantly beats unknown attitude (altitude-indexed). Also see: [159] by Dennis Milbert further below. 
Likely comparable Classified DoD Pointing Improvements: Cobra Ball/Cobra Eye & other airborne Laser developments.
Rigorous updates in airborne estimation for attitude determination:
[118] Crassidis, J. L., Markley, F. L., Cheng, Y., “Survey of Nonlinear Attitude Estimation Methods,” Journal of Guidance, Control, and Dynamics, Vol. 30, No. 1, pp. 12-28, Jan. 2007: An excellent survey on the subject of attitude estimation. It provides insights into what is important in estimation algorithms. It is a more practical and rigorous addendum to their many earlier surveys, concerned with utilizing alternative EKF's or Nonlinear Luenberger Observers (as alternatives to Extended Kalman filter-based approaches). They admonish to “stick with EKF”.
[119] Majji, M., Junkins, J. L., Turner, J. D., “Jth Moment Extended Kalman Filtering for Estimation of Nonlinear Dynamic Systems,” AIAA Guidance, Navigation, and Control Conference and Exhibit, Honolulu, HI, Paper No. AIAA 2008-7386, pp. 1-18, 18-21 Aug. 2008: Explores two variations on JMEKF formulations that properly handle higher order moments (that lurk in the background while trying to get good estimates and covariances from EKF’s). Approximations utilized are acknowledged and properly handled (rather than ignored, as is usually the case). Errors reduced by several orders of magnitude within 5 sec., but results in normalized units (for comparisons to ordinary EKF approach, which it beat by a wide margin). Down side is its larger CPU burden yet to be completely quantified.
[120] Scorse, W. T., Crassidis, A. L., “Robust Longitudinal and transverse Rate Gyro Bias Estimation for Precise Pitch and Roll Attitude Estimation in Highly Dynamic Operating Environments Utilizing a Two Dimensional Accelerometer Array,” AIAA Atmospheric Flight Mechanics Conference, Paper No. AIAA 2011-6447, Portland, OR, pp. 1-28, 8-11 Aug. 2011: Using the latest in rigorous real-time estimation algorithms (neither a particle filter nor an unscented/Oxford /Sigma-Point filter) for enabling accurate pointing (precise pitch and roll) within an aircraft within a high dynamics operating environment is reported. While it does utilize rate integrating gyros. It also utilizes 2D accelerometer arrays and compares to an onboard gravity map to achieve its accuracy. Following reasonably large offsets, got back to within 0.1 degree pointing error within 10 seconds but results much worse with turbulence present. 
[121] Jensen, Kenneth J., “Generalized Nonlinear Complementary Attitude Filter,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 34, No. 5, pp. 1588-1593 , Sept.-Oct. 2011: Achieves a big breakthrough by providing a proof of this particular EKF’s global stability as a consequence and now states that it possesses “almost” global asymptotic stability; however, the term “almost” is required terminology to keep probability theorists and purists happy with the wording of his claim. Author Jensen attains his results by utilizing appropriate stochastic Lyapunov functions (proper handling of such is due to Prof. Emeritus Harold J. Kushner, Brown Univ.). I don’t know whether Jensen was the first to achieve this new result?
[122] La Scala, B. F., Bitmead, R. R., James, M. R., “Conditions for stability of the Extended Kalman Filter and their application to the frequency tracking problem,” Math. Control, Signals Syst. (MCSS), vol. 8, No. 1, pp. 1-26, Mar. 1995: Proof of Stability for yet another EKF. Now worries about EFK divergence evaporate for this application.
[123] Reif, K., Gunther, S., Yaz, E., Unbehauen, R., “Stochastic stability of the continuous-time extended Kalman filter,” Proc. Inst. Elect. Eng., Vol. 147, p. 45, 2000: Proof of Stability for yet another EKF. Now worries about EFK divergence evaporate for this application
[124] Salcudean, S., “A globally convergent angular velocity observer for rigid body motion,” IEEE Trans. on Autom. Control, Vol. 36, No. 12, pp.1493-1497, Dec. 1991: Proof of Stability for Luenberger Observer use too (~EKF). 
Rigorous Matrix Kalman Filter (MKF) updates in airborne estimation for attitude determination (Cont.’d):

In anticipation of later success, I have explored some possibilities offered by the following novel Kalman filter variants that use matrix sensor (allowing simultaneous angle) measurements in lieu of the more familiar version of a Kalman filter involving only vector sensor (one-direction-at-a-time) measurements. 
(JTIDS RelNav used multilateration and only ordinary Kalman filters with vector sensors on each platform but had many participants in the net who automatically responded at regular short intervals!)
[125] Choukroun, D., Weiss, H., Bar-Itzhack, I. Y., Oshman, “Kalman Filtering for Matrix Estimation,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 42, No. 1, pp. 147-159, Jan. 2006: A linear Matrix Kalman filter for DCM. DCM Refinement #1 
[126] Choukroun, D., Weiss, H., Bar-Itzhack, I. Y., Oshman, “Direction Cosine Matrix Estimation from Vector Observations Using a Matrix Kalman Filter,” AIAA Guidance, Navigation, and Control Conference and Exhibit, pp. 1-11, Aug. 2003: A linear Matrix Kalman Filter for DMC using either vector or matrix measurement updates. DCM Refinement #2 . 
[127] Choukroun, D., “A Novel Quaternion Kalman Filter using GPS Measurements,” Proceedings of ION GPS, Portland, OR, pp. 1117-1128, 24-27 Sep. 2002: An alternative viewpoint: Quaternion Refinement #1.
[128] Choukroun, D., Weiss, H., Bar-Itzhack, I. Y., Oshman, “Kalman Filtering for Matrix Estimation,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 42, No. 1, pp. 147-159, Jan. 2006: Quaternion Refinement #2.
[129] Choukroun, D., Bar-Itzhack, I. Y., Oshman, “Novel Quaternion Kalman Filter,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 42, No. 1, pp. 174-190, Jan. 2006: Quaternion Refinement #3.
[130] Choukroun, D., Weiss, H., Bar-Itzhack, I. Y., Oshman, “Direction Cosine Matrix Estimation From Vector Observations Using A Matrix Kalman Filter,” Proceedings of AIAA Guidance, Navigation, and Control Conference and Exhibit, Austin, TX, pp. 1-11, 11-14 August 2003: DCM Refinement #3 
[131] Choukroun, D., “Ito Stochastic Modeling for Attitude Quarternion Filtering,”
Proceedings of Joint 48th IEEE Conference on Decision and Control and 28th Chinese Control Conference, Shanghai, P. R. China, pp. 733-738, 16-18 Dec. 2009: Quaternion Refinement #4.

In the above,  DCM = Direction Cosine Matrix; and for the Quaterion Matrices, the quaterions are to be normalized. One can convert from quaternions to DCM and vice versa. For the Matrix KF material, above, a major contributor was Daniel Choukroun, B. S. (Summa cum Laude), M.S., Ph.D. (1997, 2000, 2003), post-doc (UCLA), currently an Assistant Professor at Delft University of Technology, Netherlands.

In Thomas H. Kerr III's humble opinion, Angle Only Tracking (AOT) can also be accommodated within the above structure by updating from two (or more) different time-synchronized (via sorted time-tags) noncolocated sensors (with lever arms appropriately accounted for) simultaneously (thus used as a matrix measurement). The optimal estimator retains a linear syructure and is finite dimensional. This is the benefit of this novel approach. 
NASA updates in Spaceborne estimation for attitude determination:
[132] Cheng, Y., Landis Markley, F., Crassidis, J. L. Oshman, Y., “Averaging Quaternions,” Advances in the Astronautical Sciences series, Vol. 127, American Astronautical Society, AAS paper No. 07-213, 2007: Will eventually Summarize!
[133] Landis Markley, F., “Attitude Filtering on SO(3),” Advances in the Astronautical Sciences series, Vol. 122, American Astronautical Society, AAS paper No. 06-460, 2006: Will eventually Summarize!
[134] Cheng, Y., Crassidis, J. L., and Landis Markley, F., “Attitude Estimation for Large Field-of-View Sensors,” Advances in the Astronautical Sciences series, Vol. 122, American Astronautical Society, AAS paper No. 06-462, 2006: Will eventually Summarize!
[135] Landis Markley, F., “Attitude Estimation or Quaternion Estimation?,” Advances in the Astronautical Sciences series, Vol. 115, American Astronautical Society, AAS paper No. 03-264, 2003: Critical and thorough Analysis of 3 different EKF’s vs. Technion MKF. MKF was ultimately improved by this investigation.
[136] Reynolds, R., Landis Markley, F., Crassidis, J. L., “Asymptotically Optimal Attitude and Rate Bias Estimation with Guaranteed Convergence,” Advances in the Astronautical Sciences series, Vol. 132, American Astronautical Society, AAS paper No. 08-286, 2008: Will eventually Summarize!
Estimation Results for Bilinear Systems (to tie into the MKF results above):
[137] Halawani, T. U., Mohler, R. R., and Kolodziej, W. J., “A two-step bilinear filtering algorithm,” IEEE Transactions on Acoustics, Speech, and Signal Processing, Vol. 32, 344-352, 1984: Will eventually Summarize! 
[138] Glielmo, L., Marino, P., Setola, R., Vasca, F., “Parallel Kalman Filter Algorithm for State Estimation in Bilinear Systems,” Proceedings of the 33rd Conference on Decision and Control, Lake Buena Vista, FL, pp. 1228-1229, Dec. 1994: Will eventually Summarize!
[139] Wang, Z., Qiao, H., “Robust Filtering for Bilinear Uncertain Stochastic Discrete-Time Systems,” IEEE Trans. on Signal Processing, Vol. 50, No. 3, pp. 560-567, Mar. 2002: In general, “Robust” approaches usually have a sluggish response time.
[140]] Lopes dos Santos, P., Ramos, J. A., Frias, R., “Derivation of a Bilinear Kalman Filter with Autocorrelated Inputs,” Proceedings of the 46th Conference on Decision and Control, New Orleans, LA, pp, 6196-6202, 12-14 Dec. 2007: Structure similar to what above Technion MKF exhibits.

While linear systems are very tractable, general nonlinear systems are less so. Bilinear systems are close to being linear systems and so are somewhat more tractable, and likewise for their associated Optimal estimators.
Prof. Roger W. Brockett (Harvard-Emeritus) discusses how to handle bilinear systems in:
[141] Brockett, R. W., "Finite Dimensional Linear Systems," SIAM Classics in Applied Mathematics, 2015 (original in 1970).

We can provide 17 more examples of practical estimators for bilinear systems, as have been reported in the technical literature by others over the last 40+ years, (some involving Lie Algebras and Lie Brackets such as those provided by A. S. Willsky and J. T.-H. Lo for SO(2) and by many others later).


[143] S. Blackman and R. Popoli, Design and Analysis of Modern Tracking Systems, Artech House, Boston, MA, 1999.

[144] B. D. Tapley, M. M. Watkins, J. C. Ries, G. W. Davis, R. J. Eanes, S. R. Poole, H. J. Rim, B. E. Schutz, and C. K. Shum, “The joint gravity model 3,” Journal of Geophysical Research, Vol. 101, No. B12, pp. 28 029–28 049, Dec. 1996.

[145] N. Bergman, “Recursive Bayesian estimation: Navigation and tracking applications,” Ph.D. dissertation, Linkoping University, SE-581 83 Linkoping, Sweden, April 1999.

[146] N. Bergman, Sequential Monte Carlo Methods in Practice, New York: Springer, New York, 2001 (Chapter: Posterior Cramér-Rao Bounds for Sequential Estimation, pp. 321–338).

[147] Vytas B. Gylys, Kalman Filters and Nonlinear Filters, Texas Instruments Inc.

[148] Wasim Huleihel, Joseph Tabrikian, and Reuven Shavit, “Optimal Adaptive Waveform Design for Cognitive MIMO Radar,”
IEEE Transactions on Signal Processing, Vol., 61, No. 20, pp. 5075-, Oct. 2013. [Assumes fixed, known target range and Doppler information and only in the conclusion do they sketch how it may, perhaps, be successfully extended to a more realistic situation where the target is actually moving with respect to the radar. Did anyone actually follow-up to see whether it actually resolves as they speculated? No wonder Dr. Eli Brookner is “up in arms” about MIMO practitioners either doing what can already be done conventionally or about overstepping or overstating what MIMO can actually do! Perhaps benefits of MIMO in communications applications are better justified.]

[149] M. Morf, J.R. Dobbins, B. Friedlander, T. Kailath, “Square-root algorithms for parallel processing in optimal estimation,” Automatica, Vol. 15, No. 3, pp. 299-306, 1979.

[150] H. H. Afshari, S. A. Gadsden, S. Habbi, “Gaussian Filters for parameter and state estimation: a general review of the theory and recent trends,” Signal Processing, Vol. 135, pp. 218-238, 2017.

[151] http://www.gallup.unm.edu/~smarandache/NATOASI_ATJDTSPK.pdf 

[152] F. Landis Markley, John L. Crassidis, Yang Cheng, “Nonlinear Attitude Filtering Methods,” American Institute of Aeronautics and Astronautics, pp. 1-32,  2007. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20050212421.pdf    Landis.Markley@nasa.gov   AIAA Fellow
I. Introduction (from the above [152], and copied verbatim, as follows next)
The extended Kalman (EKF) is the workhorse of real-time spacecraft attitude estimation. Since the group SO(3) of rotation matrices has dimension three, most attitude determination EKFs use lower-dimensional attitude parameterizations than the nine-parameter attitude matrix itself. The fact that all three-parameter representations of SO(3) are singular or discontinuous for certain attitudes has led to extended discussions of constraints and attitude representations in EKF & 719-11 These issues are now well understood, however, and the EKF, especially in the form known as the multiplicative extended Kalman filter5-7 (MEKF), has performed admirably in the vast majority of attitude determination applications. Nevertheless, poor performance or even divergence arising from the linearization implicit in the EKF has led to the development of other filters. Several of these approaches retain the basic structure of the EKF, such as additive EKF a backwards-smoothing EKF,l8 and deterministic EKF-like estimators. ”-” In particular, the backwards-smoothing EKF solves a nonlinear smoothing problem for the current and past sample intervals using iterative numerical techniques. The numerical iteration retains all of the nonlinearities of a fixed number of stages that precede the terminal stage of interest, and it processes information from earlier stages in an approximate manner. l5 Deterministic EKF-like estimators are closely related to H_infinity control design.” Usually an upper bound is derived first, and then the bound is minimized based on approaches such as Riccati equations and linear matrix inequalities. The nonlinear problem is much more difficult; which requires the solution of the Hamilton-Jacobi-Isaacs partial differential inequality. For attitude estimation, small-error approximations are used to developed a filter. 19i20 Other designs use various assumptions to derive simplified filters. These generally provide suboptimal performance characteristics in relation to the EKF, but involve linear or pseudo-linear equations that are used to estimate the states of a nonlinear dynamical system. Therefore, linear design and analysis tools can be used to construct the filter and to assess its overall performance. Some of these use a deterministic solution of the attitude] e.g. methods that are based on the QUEST attitude determination solution.23 Simple filter designs based on QUEST include filter QUEST24 and recursive QUEST.25 A more complicated but far more robust approach] called extended uses a full nonlinear propagation along with a novel measurement update. This approach can be used to estimate attitude and additional parameters as well. Interlaced filters that replace a nonlinear filter with two or more linear filters have been used for rate estimation] but not for attitude e~timation.~~-~’ Several new alternatives to the standard EKF have been recently introduced] such as sigma point or unscented filter^^'-^^ and particle filter^.^^-^^ Unscented filters (UFs) have been shown to exhibit several advantages over the EKF, including: 1) the expected error is lower than the EKF, 2) they can be applied to non-differentiable functions, 3) no Jacobian matrix calculations are required] and 4) they provide higher- order expansions than the standard EKF. Unscented filters work on the premise that with a fixed number of parameters it should be easier to approximate a Gaussian distribution than to approximate an arbitrary nonlinear function. They typically use the standard Kalman form in the post-update, but use a different propagation of the covariance and pre-measurement update with no local iterations. The attitude estimation UF derived in Ref. 33 is based on a quaternion representation of the attitude kinematics. However, straightforward implementation of the standard UF equations derives a predicted quaternion mean from an averaged sum of quaternions. Therefore, no guarantees can be made that the resulting quaternion will have unit norm. This was overcome by using a generalized unconstrained three-component vector to represent the attitude error-quaternion] leading to an unconstrained formulation in the UF design. Unscented filters are essentially based on second or higher order approximations of nonlinear functions, which are used to estimate the mean and covariance of the state vector. Though the mean and covariance are the sufficient statistics of a Gaussian distribution, they are not sufficient to represent a general probability distribution. When UF methods are applied to strongly nonlinear and non-Gaussian estimation problems] where the a posteriori distribution of the state vector may be multi-peaked, heavily-tailed, or skewed, desired performance characteristics may not be obtained. This may be overcome by using particle filter^^^-^^ (PFs). Like other approximate approaches to optimal filtering] the ultimate objective of PFs is to construct the a posteriori probability density function (PDF) of the state vector, or the PDF of the state vector conditional on all the available measurements. However, the approximation of PFs is vastly different from that of conventional nonlinear filters. The central idea of a PF approximation is to represent a continuous distribution of interest by a finite (but large) number of weighted random samples of the state vector, or particles. A PF does not assume the a posteriori distribution of the state vector to be a Gaussian distribution or any other distribution of known form. In principle,it can estimate probability distributions of arbitrary form and solve any nonlinear and/or non-Gaussian system. Reference 36 presents a PF for attitude estimation based on the bootstrap filter.35 The optimal solution of the nonlinear estimation problem requires the propagation of the conditional PDF of the state given the observation history.37 All practical nonlinear filters are approximations to this ideal. Exact finite dimensional filters38 can be found that solve some nonlinear problems by using the Fokker-Planck equation2l3’ to propagate a non-Gaussian PDF between measurements and Bayes’ formula‘? to incorporate measurement information. A recently proposed filter4’ follows this pattern, but does not solve the nonlinear attitude filtering problem exactly. We refer to it as an orthogonal filter, because it represents the attitude by an orthogonal rotation matrix, rather than by some parameterization of the rotation matrix. The PDF is a non-Gaussian function defined on the Cartesian product of S0(3), the group of rotation matrices, and the Euclidean space Rn of bias parameters. This filter entirely avoids questions about singularities of representations or covariance matrices arising in EKFS~-~~ and UFS,~~ and has the additional advantage of providing a consistent initialization for a completely unknown initial attitude, owing to the fact that SO(3) is a compact space. Nonlinear observers often exhibit global convergence, which is to say that they can converge from any initial guess.41 Several applications of observers for attitude control have been proposed Refs. 42-48. A nonlinear observer and controller using only measurements of roll, pitch and yaw has been developed in Ref. 43. Local asymptotic stability is ensured under mild hypotheses. A globally convergent, nonlinear full- order observer using quaternions and Euler’s equations for the dynamics has been derived in Ref. 44. The observer structure contains a discontinuous term, which is often associated with “sliding mode” observers. The error-quaternion is defined using a multiplicative approach and stability is proven using a Lyapunov function. A simpler, robust smoothed sliding mode observer that avoids quaternion error differentiation noise and eliminates the necessity of measuring angular rate is derived in Ref. 45. Although an additive approach is used to define the quaternion error, global stability is still provided through a Lyapunov function. Algrain and Lee develop a nonlinear observer to estimate angular rates along the third axis of a spinning spacecraft using only two-axis measurement^.^^ A pseudo-linear model is developed by decomposing the nonlinear system into linear and nonlinear parts. BoSkoviC, Li and Mehra use angular rate measurements with quaternion kinematics to derive a nonlinear bias observer, which is coupled with an adaptive sliding mode ~ontroller.~~ Stability is proven as long as the attitude never passes through f180 rotations. Thienel and Sanner develop an exponentially convergent nonlinear observer given a constant gyro bias with identification of the bias proven through a persistency of excitation argument.48 An analysis is also shown that includes gyro noise. Adaptive approaches generally fall into two categories. One category encompasses approaches that adap- tively tune the Kalman filter through the identification of either the process noise covariance or measurement noise covariance, or both simultaneously. In practice “tuning” a Kalman filter can be arduous and very time- consuming. Usually, the measurement-error covariance is fairly well known, derived from statistical inferences of the hardware sensing device. However, the process noise covariance is usually not well known and is of- ten derived from experiences gained by the design engineer based on intimate knowledge of the particular system. The approach is based on “residual whitening.” 49 Unfortunately, most noise adaptive techniques are applicable only for linear systems,’ which creates problems for attitude estimation due to the nonlinear equations involved. Still, it is possible to use these techniques with linearized equations, as demonstrated in Ref. 50. Lam and Wu further develop adaptive filters that address both colored and white noise ~tatistics.~~ The former noise is identified using a non-parametric neural network approach, while the latter noise is identified using an a-P filter. An adaptive filter is also proposed in Ref. 17 to account for inaccuracy in the knowledge of the process noise statistical model, which uses a linear pseudo-measurement model. Other adaptive approaches use adaptive methods for fault tolerant estimation 53 The other category includes approaches that adaptively estimate unknown system parameters, such as the inertia matrix. These generally fall into two basic categories: 1) parameter estimation or filter-based methods, and 2) nonlinear adaptive techniques. Least squares methods to determine the inertia matrix and other constant parameters, such as disturbance model parameters and biases, are shown in Refs. 54-56. A disturbance accommodation technique that models the unknown disturbance angular rate using a power set of time as basis functions is shown in Ref. 57. Nonlinear adaptive techniques are similar to nonlinear observers in that they usually provide global stability proofs that guarantee convergence of the estimated parameter^.^^-^' This paper will review the basic assumptions of these filters, presenting enough mathematical detail to give a general orientation. First, reviews of the quaternion parameterization and gyro model equations are given. Then, attitude estimation methods based on the EKF are shown, followed by QUEST-based approaches. Next, the two-step estimator is shown. The UF and PF approaches are then shown, followed by the orthogonal filter. Then, the predictive filter, as well as nonlinear observers and adaptive approaches are reviewed. The paper concludes with a discussion of the strengths and weaknesses of the various filters. (Thomas H. Kerr comment: Also see item [168] below for a 1971 precedent for handling estimation on a circle, SO(2),  and on a sphere, SO(3).)

Other topics that I routinely follow:

[153] Niu, X., Nassar, S., El-Sheimy, N., “An Accurate Land-Vehicle MEMS IMU/GPS Navigation System Using 2D Auxiliary Velocity Updates,” Navigation: Journal of the Institute of Navigation, Vol. 54, No. 3, pp. 177-188, Fall 2007.

[154] Soloviev, A., van Graas, F., “Batch-Processing of Inertial Measurements for Mitigation of Sculling and Commutation Errors,” Navigation: Journal of the Institute of Navigation, Vol. 54, No. 4, pp. 265-276, Winter 2007.

[155] Soloviev, A., van Graas, F., “Enhancement of Integrated GPS/INS Performance Utilizing Frequency Domain Implementation of INS Calibration,” Navigation: Journal of the Institute of Navigation, Vol. 54, No. 2, pp. 87-98, Summer 2007.

[156] Lee, Y. C., “Two New RAIM Methods Based on the Optimally Weighted Average Solution (OWAS) Concept,” Navigation: Journal of the Institute of Navigation, Vol. 54, No. 4, ff. 333, Winter 2007.

[157] Farrell, J. L., “Inertial Instrument Error Characterization,” Navigation: Journal of the Institute of Navigation, Vol. 54, No. 3, pp. 169-176, Fall 2007.

[158] Farrell, J. L., “Full Integrity Testing for GPS/INS,” Navigation: Journal of the Institute of Navigation, Vol. 53, No. 1, pp. 33-40, Spring 2006.

[159] Milbert, D., “Dilution of Precision Revisited,” Navigation: Journal of the Institute of Navigation, Vol. 55, No. 1, pp. 67-81, Spring 2008.

[160] Pulford, G. W., “A Proof of the Spherically Symmetric Overbounding Theorem for Linear Systems,” Navigation: Journal of the Institute of Navigation, Vol. 55, No. 4, pp. 283-292, Winter 2008.

[161] Li, Y., Rizos, C., Wang, J., Mumford, P., Ding, W., “Sigma-Point Kalman Filtering for Tightly Coupled GPS/INS Integration,” Navigation: Journal of the Institute of Navigation, Vol. 55, No. 3, pp. 167-177, Fall 2008.

[162] “Algorithm Aligns Gyrocompass in Twisting and Swaying Vehicle,” NASA Tech Briefs MFS-28671, George C. Marshall Space Flight Center, Alabama 35812, Gyrocompass FDR Version 6.0.6/MO (from Specification CP-830100A, Appendix 1, Rev. A, 28 July 1989 for TOS on Titan), pp. 1-87, 18 June 1991.

[163] Shively, C. A., Hsio, T. T., “Error and Availability Analysis of CAT IIIb LAAS Augmented by Radar Altimetry,” Navigation: Journal of the Institute of Navigation, Vol. 52, No. 3, pp. 155-162, Fall 2005.

[164] Mason, J., “Algebraic Two-Satellite TOA/FOA Position Solution on an Ellipsoidal Earth,” IEEE Trans. on Aerospace and Electronic Systems, Vol. 40, No. 7, pp. 1087-1092, July 2004. 

[165] Mason, J., Romero, L., “TOA/FOA Geolocation Solutions Using Multivariate Resultants,” Navigation: Journal of the Institute of Navigation, Vol. 52, No. 3, pp. 163-177, Fall 2005.

[166] Jekeli, C., “Navigation Error Analysis of Atom Interferometer Inertial Sensing,” Navigation: Journal of the Institute of Navigation, Vol. 52, No. 1, pp. 1-14, Spring 2005.

[167] Ristic, B., Arulampalam, S., Gordon, N., Beyond the Kalman Filter: Particle Filters for Tracking Applications, Artech House, Boston, MA, 2004. [One of the clearest discussions of both historical and recent estimation algorithms (including EKF, UKF, MMM, IMM, and Particle Filters), their underlying assumptions/mechanization equations and that also provides extremely useful insight into important aspects and distinctions in their implementations is offered in Chapters 1-3.]

[168] Li, J. T.-H. Lo and A. S. Willsky, “Estimation for Rotational Processes with One Degree of Freedom-Part 1,” IEEE Trans. on  Automatic Control, Vol. 20, No. 1, pp. 10-21, Feb. 1975. [They explicitly handle estimation on a circle, SO(2), rather than estimation on a sphere, SO(3), as NASA's F. Landis Markley, et al deal with above in their extensive survey and comparison between approaches and techniques in [152]. However, Willsky and Lo are particularly lucid in their development and exposition and, moreover, within the last sentence of their conclusion, provide specifics of their suggested generalization to estimation results on arbitrary Abelian Lie groups, such as SO(3).] 5_pub_IEEE.pdf  

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For the following navigation textbooks:
[172] Rogers, R. M., Applied Mathematics in Integrated Navigation Systems, AIAA Education Series, AIAA, pp. 99-108, Reston, VA., 2000.
[173] Titterton, D. H., and J.L. Weston, Strapdown Inertial Navigation Technology, Peter Peregrinus Ltd., Stevenage, Herts, England, UK, 2004.
[174 ] Farrell, J. A., Aided Navigation: GPS with High Rate Sensors, McGraw-Hill, NY, 2008 (very well written but uses lower case Greek epsilon in a role that was NOT gyro drift-rates, contrary to the standard convention of the last 3 decades)
all three of these textbooks are not totally self-contained but, instead, defer to the following textbook at  exactly the same point in their discussions for completion of the proper handling of components of gyro drift-rate to be used in mathematical model to be eventually used in the corresponding navigation Kalman filter, as discussed in detail in:
[175] Kenneth R. Britting, Inertial Navigation Systems Analysis, Wiley-Interscience, NY, 1971. [Surprisingly, a new edition of this book and its 2010 sequel are now available from Artech, Boston, MA. The reason that it is surprising to me is that Kenneth R. Britting died from M.S. in the 1980's while he was with Nortronics at Northrop in Norwood, MA. A burning question is whether Fred J. Marcus is helping Kenneth R. Britting to publish from the grave AGAIN?]

[176] Chatfield, A. B. (Ed.), Fundamentals of High Accuracy Inertial Navigation, Paul Zarchan, Editor-in-Chief, AIAA Progress in Astronautics and Aeronautics Series, AIAA, 1997.

[177] Savage, P. G., “Strapdown Sculling Algorithm Design for Sensor Dynamic Amplitude and Phase-Shift Error,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 35, No. 6, pp. 1718-1729, Nov.-Dec. 2012.

[178] Jaewon Seo, Jang Gyu Lee, Chan Gook Park, “A New Error Compensation Scheme for INS Vertical Channel,” IFAC Proceedings, Vol. 37, No. 6, pp. 1119-1124, 2004.

[179] Viterbi algorithm being equivalent to Dynamic Programming: https://scholar.google.com/scholar?q=viterbi+algorithm+dynamic+programming&hl=en&as_sdt=0&as_vis=1&oi=scholart&sa=X&ved=0ahUKEwiwhOicsejaAhVGc98KHScLD1UQgQMIJTAA 

[180] Uwe D. Hanbeck, “Recursive Nonlinear Set-Theoretic Estimation Based on Pseudo-Ellipsoids,” Proceedings of the IEEE Conference on Multisensor Fusion and Integration for Intelligent Systems, pp. 159–164 (MFI2001), Baden–Baden
Their patent abandoned by Siemens AG (perhaps because of prior art: me): https://patents.google.com/patent/US20060234722A1/en 

[181] Fuqiang You, Hualu Zhang, Fuli Wang, “A new set-membership estimation method based on zonotopes and ellipsoids,” Transactions of the Institute of Measurement and Control, Vol. 40, issue 7, pp. 2091-2099, Article first published online: 27 July 2016; Issue published: 1 April 2018

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Abstract: In this paper, a theory of optimal nonlinear estimation from sampled data signals where the a posteriori probability densities are approximated by Gaussian sums is adapted for application to phase and frequency estimation in high noise. The nonlinear estimators (demodulators) require parallel processing of the received signal. In the limit as the number of parallel processors becomes infinite the FM demodulators become optimum in a minimum mean square error sense and the PM demodulators become optimum in some well defined sense. For the clearly sub-optimal case of one processor, the demodulators can be readily simplified to the familiar phase-locked loop. On the other hand, for the intermediate case, significant extension of the phase-locked loop threshold is achieved where (say) six parallel processors are involved. 

[203] Raytheon-UTC merger wins approval, pending divestitures:
The Biggest Defense Merger Ever Gets Key Antitrust Approval — With These Conditions:
US Coast Guard protests GPS disruption to UN body: ‘urgent issue’ - GPS World | RNTF:

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[294] Mahmood R. Azimi-Sadjadi, Tongxin Lu, Eduardo M. Nebot, "Parallel and Sequential Block Kalman Filtering and Their Implementations Using Systolic Arrays." IEEE Trans.
on Signal Processing
, Vol. 39, No. 1, pp. 137-147, Jan. 1991.

[295] Jeff B. Burl, "Reduced Order kalman Filtering of Moving Images," Conference Record of Twenty-Second Asilimar Conference on Signals, Systems & Computers, Pacific Grove, 
CA, Vol. 2 of 2, pp. 565-567, 31 Oct.-2 Nov. 1988.

[296] Thomas Joseph Green, Jr., Three-Dimensional Ohject Recognition Using Laser Radar, Doctor of Philosophy, Dept. of Electrical Engineering and Computer Science, Jan. 1992.

[297] Joseph L. Doob, "The Development of Rigor in Mathematical Probability (1900-1950)," The American Mathematical Monthly, Vol. 103, No. 7, pp. 586-596, Aug.-Sept. 1996.

[298] Panos M. Pardalos, Leonidas S. Pitsoulis, Mauricio G. C. Resende, "Algorithm 769: Fortran Subroutines for Approximate Solution of Sparse Quardratic Assignment Problems 
Using GRASP," ACM Trans. on Mathematical Software, Vol. 23, No. 2, pp. 196-208, Jun. 1997.

[298] Pei-Chi Wu, "Multiplicative, Congruential Random-Number Generators with Multiplier ± 2K1 ± 2K2 and Modulus 2p-1," ACM Trans. on Mathematical Software
Vol. 23, No. 23, pp. 255-265, Jun. 1997.

[299] Gustaf Hendeby, Performance and Implementation Aspects of Nonlinear Filtering, Linköping studies in science and technology. Dissertation. No. 1161, Department of Electrical Engineering Linköping University, SE–581 83 Linköping, Sweden Linköping 2008.

[300] Shyam MohanM, Naren Naik,R.M.O.Gemson, M. R. Ananthasayanam, Introduction to the Kalman Filter and Tuning its Statistics for Near Optimal Estimates and CramerRao Bound, Technical Report: TR/EE2015/401, DEPARTMENT OF ELECTRICAL ENGINEERING INDIAN INSTITUTE OF TECHNOLOGY, KANPUR, FEBRUARY 2015.

[301] William S. Widnall, Stability of Alternate Designs for Rate-Aiding of Non-Coherent Mode of a GPS Receiver, Intermetrics Report No. IR-302, 25 Sept. 1978.

[302] Boris Danik, "A Low-Cost Velocity Reference System for Rapid Alignment of Aircraft Inertial Platforms on a Moving Base," Proceedings of the IEEE 1980 National Aerospace and Electronics Conference (NAECON), pp. 608-615, 1980.

[303] Gelb, A., Course Notes Marine Inertial Navigation, The Analytic Sciences Corporation (TASC), TASC TR-119-1, Reading, MA, January 1967. (Handles Monitor Gyro in alignment procedure for SINS/ESGM)

[304] John E. Bortz, Micron Analysis, Vol. 1. MESGA Attitude Readout Error, The Analytic Sciences Corporation (TASC), Technical Report AFAL-TR-72-228, Air Force Avionics Laboratory, Air Force Systems Command, Wright-Patterson Air Force Base, Ohio 45433, August 1972.

[305] When to Use MLP, CNN, and RNN Neural Networks https://lnkd.in/gGqE_mC  

Click this link to return to the start of these reference citations.

USS Cobra Judy Radar Ship is the sister ship of the U.S.S. Compass Island. The Compass Island had been used in the early and mid 1970s as a test suite for demonstration and shake down of SSBN Navigation changes and upgrades before deploying within the submarine fleet. Both sister ships had little lateral fins on the bottom of the hull below the water line that could be extended out horizontally from the hull to stabilize the platform in rough seas (of a high sea state). A complete SSBN Navigation Room was present on the Compass Island, but intentionally installed backwards from its orientation aboard SSBNs. A prior NASA observation ship, the U.S.S. Vangard, replaced the Compass Island in this role in the late 1970s.

Pre- (and post-)GPS Relative Navigation (RelNav) enabled networks of different platforms to reference both friendlies and enemy targets with respect to a single common (virtual) grid using the L-band JTIDS (time-slotted and frequency hopped from 960 MHz to 1215 MHz, with gaps imposed for TACAN and IFFN). This capability was especially useful when all participants were at sea and far from any geographic landmarks of absolute location. The grid tended to move and rotate slightly. Its location was dictated by the Navigation Controller (NC), the platform having the best navigation accuracy (as a self-assessment), but in lieu of the demise of the original NC, the NC was replaced by the next best platform in this role to avoid possessing a single point vulnerability. JTRS (pronounced Jitters) is slated to replace JTIDS as an entirely software radio system (with its own unique set of problems yet to be solved). JTIDS included NTDS/ATDS. Air Force JTIDS used DTDMA protocol without RelNav. Navy version was TDMA with RelNav. Marine version of JTIDS was PLRS. Reed Solomon Code throughout. GPS uses Gold Code in two flavors or cycle lengths (to be upgraded).

Hybrid High-Rate Output Candidate Design for JTIDS/GPS/INS Integration and INS Navaid Selection.

Sam Blackman (Raytheon/Hughes), the (late) Oliver Drummond, Yaakov Bar-Shalom (UCONN), and Rabinder Madan.


Blazers of the exciting area of multi-sensor\multi-target tracking (sometimes pursued even in clutter) [related to optimal resource allocation and solved by invoking Munkres or the Hungarian or Jonker- Volgenent- Castanons (J-V-C) or Murtys (1968) or Sam Blackman's Multi- Hypothesis Testing (MHT) algorithms. The first 3 techniques are all from the Operations Research area; the last is based on Bayesian Statistical analysis.

Not shown here: Prof. David Castanon (Boston University) and Charles Morefield (originally of Aerospace Corporation in the 1970s when he posed multi-target tracking as a 0-1 Integer Programming Problem, more recently Chairman of the Board at Alphatech (after Michael Athans stepped down and went to Portugal) before Alphatech became part of BAE in Burlington, MA), and Thomas Kurien (Raytheon). Also see Particle Filter variations in: Vermaak, J., Godsill, S. J., Perez, P., Monte-Carlo Filtering for Multi-Target Tracking and Data Association, IEEE Trans. on Aerospace and Electronic Systems, Vol. 41, No. 1, pp. 309-331, Jan. 2005. Also see Miller, M. L., Stone, H, S., Cox, I. J., Optimizing Murtys Ranked Assignment Method, IEEE Trans. on Aerospace and Electronic Systems, Vol. 33, No. 7, pp. 851-862, July 1997. Another: Frankel, L., and Feder, M., Recursive Expectation-Maximizing (EM) Algorithms for Time-Varying Parameters with Applications to Multi-target Tracking, IEEE Trans. on Signal Processing, Vol. 47, No. 2, pp. 306-320, February 1999. Yet another: Buzzi, S., Lops, M., Venturino, L., Ferri, M., Track-before-Detect Procedures in a Multi-Target Environment, IEEE Trans. on Aerospace and Electronic Systems, Vol. 44, No. 3, pp. 1135-1150, July 2008.

Fourth ONR/GTRI Workshop on Target Tracking and Sensor Fusion, Naval Postgraduate School, Monterey, CA, 17 May 2001.Notice the guy (i.e., THK III) apparently in sun glasses (actually transitions) in the back row there (left of center, as always).

Lockheed Martins Paveway II Dual Mode Laser-Guided Bomb (DMLGB), which uses both laser-guided and inertial/GPS guidance, has achieved the U.S. Navy's initial operational capability and is now preparing for operational employment.


The DMLGB is designed to execute precision strike missions against stationary and mobile targets in all stationary and mobile targets in all weather conditions, according to Lockheed. The kits can operate in laser only, inertial/GPS, or dual-mode to provide pilots with flexibility to engage various types of targets in a single mission, says Lockheed Martin.

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Extra! Extra! Read all about it!

JAVAD GNSS has announced that its customers with JAVAD GNSS triple-frequency type OEM boards (TR-G2T, TR-G3T, TRE-G2T, TRE-G3T, TRE-G3TAJ) and receivers (TRIUMPH-1, Alpha TR-G2T/TR-G3T, DeltaS TRE-G2T/TRE-G3T/TRE-G3TAJ, SigmaS TRE-G2T/TRE-G3T/TRE-G3TAJ) can now track the L5 demonstration signal.

The first GPS satellite with the L5 signal [Block IIR-20(M)] was successfully launched on 24 March 2009 and its L5 = 1176.45 MHz payload activated on 10 April 2009.

The signal characteristics clearly indicate that JAVAD GNSS receivers allow high-quality code and carrier-phase measurements of the L5 signal. The signal-to-noise ratio typically varies from about 30 dB*Hz at low elevations up to 57 dB*Hz at zenith (see figures below: top is SNR for L5; bottom is SNR for GPS PRN 1).

The white-noise and multipath tracking errors are comparable to what is normally seen for the L1 and L2 signals.

Those interested in sample raw data with the triple-frequency(L1-L2-L5) code and carrier phase measurements from IIR-20(M), can download sample data from GNSS Almanac Archive (see the ADVANCED section on www.javad.com). Note that these sample raw data are available in the JAVAD GNSS proprietary binary format as well as Rinex 3.0. http://sc.gpsworld.com/gpssc/data/articlestandard/gpssc/182009/595183/javad-1.jpg


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Air Force Successfully Transmits an L5 Signal From GPS IIR-20(M) Satellite

4/13/2009 - LOS ANGELES AIR FORCE BASE, Calif. -- The U.S. Air Force GPS IIR-20(M) satellite successfully transmitted for the first time a GPS signal in the L5 frequency band today. L5, the third civil GPS signal, will eventually support safety-of-life applications for aviation and provide improved availability and accuracy.

This broadcast brings into use the GPS International Telecommunication Union filing at 1176.45 MHz in the highly protected and co-allocated Radio Navigation Satellite Service and Aeronautical Radio Navigation Service band. A joint team consisting of the GPS Wing, Lockheed Martin, ITT and The Aerospace Corporation developed the L5 Demonstration signal payload and integrated it onto the GPS IIR-20(M) spacecraft, which launched March 24, 2009.

The initial broadcast of the L5 Demonstration signal was monitored and validated by SRI International in Menlo Park, Calif, in cooperation with the GPS Wing, 2nd Space Operations Squadron, Lockheed Martin, Draper Laboratory and The MITRE Corporation.

Thanks to the men and women of the Air Force, our industry partners and national research institute, this mornings successful L5 transmission marks an important milestone in GPS civilian applications. This new third civil signal will make possible the research and development of safety-of-life applications for the commercial transportation sector, and in the future, will play a vital role in improving safety, fuel efficiency, and capacity in our airspace, waterways, highways, and railroads. Todays event marks another important step in the ongoing effort to maintain and modernize GPS as the global standard for space-based positioning, navigation, and timing, said Joel Szabat, Deputy Assistant Secretary for Transportation Policy, U.S. Department of Transportation.

The L5 demonstration payload effort shows the can-do spirit and dedication of all who work in this industry and is an example of a government/industry team working together to meet a significant challenge in a very short time. Development of a solid plan and schedule, adherence to that plan, and consistently looking ahead allowed for a timely and successful completion of the L5 effort, said Col. Dave Madden, Commander, and Global Positioning Systems Wing.

Air Force Space Command
s Space and Missile Systems Center, located at Los Angeles Air Force Base, Calif., is the U.S. Air Forces center of acquisition excellence for developing, acquiring, fielding and sustaining the worlds best space and missile systems for the joint warfighter and the nation.

L5 Signal

Time series and power spectrum of the L5 demonstration signal

New GPS Satellite’s Problems Indicated on 4 May 2009

Lt Col David Goldstein, chief engineer for the GPS Wing, told the plenary session at the European Navigation Conference in Naples, Italy, that the Wing is experiencing some out of family measurements from the recently launched IIRM (20) satellite. This appears to corroborate some unofficial rumors that have circulated recently about problems with legacy signals from the satellite, that is, L1 and L2. The April 10 broadcast of the first L5 signal secured that frequency for the U.S. GPS program; since that signal contains no navigation message at present, it is presumably not affected by these problems.

Goldstein told the ENC opening session, Monday 4 May 2009, that the Air Force will not launch any further satellites until this issue is resolved. IIR(M) 21, the last of the IIR(M) series, is currently scheduled to rise sometime in August, with the first of the IIF generation to follow in late 2009 or early 2010.

Normally, a satellite is set healthy within 28 days of launch, after extensive testing, but this has not occurred with the satellite launched on 24 March 2009. The U.S. Air Force has formed a response team and is working nearly round the clock to resolve the problem, but according to Goldstein is not rushing the issue, seeking a thorough solution since the overall constellation is robust at 30 satellites.

We are currently examining data from the satellite that is not consistent with data from the other IIR(M)s, he stated, characterizing the variances as measurements with larger than expected pseudorange errors that are elevation-dependent, and that we have not seen before. We have experimented with a few fixes and it looks very promising.

He described the response team’s approach as making a fishbone diagram of all potential failure mechanisms, and working through them methodically. We think we have identified the failure but it may be several more months before the analysis is complete, and the situation is fully resolved.

The big delay in preventing GPS from being completed by the planned date of 1984 was the Space Shuttle Challenger disaster. Most GPS satellites were planned to be inserted from a Space Shuttle but instead had to be inserted from Delta rockets as a fall back that delayed a full GPS satellite constellation from existing until 1994.

The open literature discussion of L3 in the early 1980s for GPS was that like L2 (=1227.5 MegaHertz) and L1 (=1575.42 MegaHertz), it was also an integer multiple of a single onboard clock frequency being L3 (= 1381 MegaHertz). It was speculated that L3 was used to cross-communicate between GPS satellites like a JTIDS RelNav network in the sky. Some have speculated that it had related to autonomously maintaining proper satellite ephemeris of the network since in the bad old days of Mutually Assured Destruction (MAD) as a policy strategy, he who had the last accurate weapon fired won. Land-based Minuteman ICBMs (with AIRS navigation systems) utilized GPS for a midcourse nav fix. Ship launched SLBMs did not (at least not in the 1970s). GPS supposedly had sufficient untended (by human intervention) ephemeris to last for 6 months unaided, according to NADC in the early 1980s. 

L3  is now both known by the private sector and is controversial in the civilian Radio Astronomy community, as seen below.

The Global Positioning Satellite system has a mode, L3 at 1381 MHz, which is used for global alarm. If it is within your observing band, then all astronomical signal gets swamped. With advanced notice, the observatory is in a position to alert the responsible authorities and request rescheduling GPS L3 transmission. 

As circulated in unclassified literature in the 1980s, L3 is a part of NUGET, GPS satellites monitor and report on whether they have detected a nuclear blast anywhere in the world.

GPS L3 Interference and Radio Astronomy

European radio astronomy stations operating in the frequency band 1330 - 1400 MHz are experiencing harmful interference at a frequency of about 1381 MHz, which is so strong that it ruins the observations in this frequency range when it occurs. This interference is generated by transmissions from the GPS L3 channel.

An example of this type of interference observed with the Westerbork Synthesis Radio Telescope, WSRT, in the Netherlands is shown in Figure 1 for the amplitude and Figure 2 for the phase of the observed signal. The radio astronomical observation concerns a radio source at 23h36m35.20s right ascension and 26o40’36.00” declination (epoch J2000). The absolute scale for the amplitude of the interference signal is not calibrated since the antenna gain into the direction of the satellite, which was emitting in the far sidelobes of the antennas, is not known.

The indicated level of detrimental interference for the observations presented in the figures below is -239 dB(W/m2/Hz), which was determined using the methodology of Recommendation ITU-R RA.769. This methodology includes the assumption that the interference is received through the far antenna sidelobes, where an antenna gain of 0 dBi applies.

Fig.1: Intensity of the interference signal from GPS L3 observed through the far sidelobes at the WSRT on August 25/26, 2002. The figure shows a detailed spectrum in two linear polarization channels (noted as XX and YY) for an integration time of 0.8 minutes. The amplitude scale is in arbitrary units (see text); the astronomical signal of interest occurs at a level of 0.005 (!) only on this scale. Note that the signal rings throughout the entire 20 MHz band that is displayed.

Fig.2: Signal phase corrupted by GPS L3 interference at the WSRT during the same observation as for Figure 1. The spiky comb in the phase is due to the interfering signal, again in two polarizations.

The L3 spread spectrum transmissions centered at 1381 MHz also transgresses into the frequency range 1400 - 1427 MHz, a spectral band where the radio astronomy has a primary allocation to which RR footnote 5.340 applies, which states that all emissions are prohibited. Using a band-stop filter the signal could be suppressed to a level of -252 dB(W/m2/Hz), i.e. still 3 dB above the level of interference detrimental to radio astronomy continuum observations as given in Recommendation ITU-R RA.769.

The fundamental problem remains that the GPS L3 emission is intentionally produced in the band 1400 - 1427 MHz and is therefore in conflict with footnote 5.340 of the ITU-R Radio Regulations.

It should be noted that in the ITU Radio Regulations for Region 1 the band 1300 - 1350 MHz includes a primary allocation to RADIONAVIGATION-SATELLITE (Earth-to-space) and no allocation to a space service in the band 1350-1400 MHz. Thus no space-to-Earth transmissions are allowed according to these Regulations. For the frequency band 1330-1400 MHz footnote 5.149 applies, which states that administrations are urged to take all practicable steps to protect the radio astronomy service from harmful interference. Emissions from spaceborne or airborne stations can be particularly serious sources of interference to the radio astronomy service (...).

CRAF considers that a regulatory solution for this issue is required, in order to avoid the creation of an undesirable regulatory precedent, where the operation of an application is allowed in conflict with the ITU Radio Regulations.

On this matter CRAF is currently in the process of negotiation with concerned Administrations and expects that it can be solved in due course.

Recent solutions to GNSS incursions into frequencies reserved for Radio Astronomy have been advertised (but the band of concern apparently differs from what is complained about above): Julien, O., Issler, J.-L., "Mitigating the Impact of GNSS Signals in the Radio Astronomy Band 1610.6-1613.8 MHz,"  Navigation: Journal of the Institute of Navigation, pp. 229-240, Vol. 56, No. 4, Winter 2009.

In 1957, Walter Marrow (Lincoln Laboratory of MIT), who later became its head but retired from that position early in the new millennium, launched a missile full of thousands of small metal space needles http://nowiknow.com/space-needles/  into LEO, which took about six months to decay out of orbit and burn up in the atmosphere. The entire event was viewed by Lincolns Haystack radar. Other Radio Astronomers were livid since reception was impossible during that time period. 

The activation of the L2C signal in January 2006 will be of great benefit to the civil community, said Colonel Jester, Chief, Space Operations Branch, Air Force Space Command. But they will be using this signal at their own risk until the command and control of L2C is realized in the Fiscal Year 2013 timeframe. Receivers able to fully utilize the L2C signal will be the responsibility of the civil community. The military will build receivers focused on the new M-code signal.

L2C is stronger than L1.

The premiere civilian GPS manufacturer (TomTom GPS internationally headquartered in the Netherlands, US headquarters in Concord, MA) had been stiffed by ~ $8 million when Circuit City went out of business. Negotiations between Microsoft and TomTom GPS about licensing Microsoft patents broke off around March  2009 and Microsoft was starting to sue TomTom GPS. TomTom GPS subsequently formed a collective with other European companies that held a number of patents similar to Microsofts in order to counter-sue Microsoft over the same issue. It will be interesting to see how this one plays out....

GPS at Risk: Doomsday 2010

The United States Government Accountability Office (GAO) issued on 7 May 2009 an alarming report on the future of GPS, characterizing ongoing modernization efforts as shaky. The agency appears to single out the IIF program as the weak link between current stability and ensured future capability, calling into doubt whether the Air Force will be able to acquire new satellites in time to maintain current GPS service without interruption. It asserts the very real possibility that in 2010, as old satellites begin to fail, the overall GPS constellation will fall below the number of satellites required to provide the level of GPS service that the U.S. government commits to. read more»

L5 and Rorschach Shock

“There is a very minor problem with the L1, L2, and M-code navigation signals. Any causes would be pure speculation at this point, but the issue is the satellite will not be set healthy until these problems are fixed…. The ITT, LMCO and GPS Wing teams are working the problem hard. It may be a few weeks before the satellite is set healthy, but when that time comes I am sanguine that all the signal issues will be mitigated and the navigation message will be on par with the other IIR(M) payloads.” — Colonel Mark Crews

BY DON JEWELL | djewell@questex.com

I am sure that many of you remember Colonel Mark Crews when he served with distinction as the chief engineer for the GPS Wing at SMC. Mark made some legendary and landmark contributions to the future of the GPS constellation as we know it, nationally and internationally. After you read what Dr. Crews has to say about the L5 payload, I will launch into an issue concerning user equipment that has been on mind for sometime — with a trip to the shrink’s couch. read more»



Parkinson Prescribes Remedy for GAO Report Alarm

Brad Parkinson, the first GPS Program Office director, chief architect and advocate for GPS, submitted written testimony to Congress on mitigation options for possible GPS brownouts. His presentation comes in reference to the recent GAO report highlighting the risk that the GPS constellation may fall below the minimum level of 24 satellites required for full operational capability. In his opening, Parkinson states that ”GAO correctly points out the possibility that the GPS constellation will be reduced to less than the current number of 30 to 32 satellites. In fact, it is possible that the constellation will be at a level of less than 24 satellites. I would like to focus on the options that would help reduce this risk." read more»  Click here to download a 91KByte pdf file conveying Sir Brad Parkinsons excellent 10 side PowerPoint presentation to Congress.                    Prof. Parkingsons original 228KByte PowerPoint is here, including his speaker's notes as prompters.

Calling the Real Race in GNSS

Andrew Sage, a director of UK-based transport consultancy Helios, delivered a presentation at the European Navigation Conference entitled: The race to be the partner of choice for GPS. read more» 

Analyses of a Drop in GPS Satellite Numbers 

Professor Richard Langley of the University of New Brunswick (also GPS World Innovation editor) has done several analyses to see how the use of GLONASS satellites could help compensate for a potential reduction in the number of available GPS satellites. These studies came in response to a warning from the U.S. Government Accountability Office about the potential drop in the number of healthy satellites in the GPS constellation as a result of delays in both the Block IIF and Block III modernization programs. read more>>

The SVN-49 Story: What Went Wrong, How It Got Found, and Fixed 
During a very reassuring teleconference today with Colonel David Madden (GPSW/CC) and Colonel David Buckman (AFSPC - GPS Command Lead), we learned the true story of exactly what happened to SVN-49 , aka IIR-20(M), launched March 24, and why it has not been set to a healthy status. This teleconference should put an end to all the speculation concerning SVN-49 and its future status. In sum, there is nothing wrong with the L1, L2, or L5 signal transmitters, and they will not have to undergo expensive re-testing. 

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Latest GPS Satellite Early Orbit Checkout Extended 
The U.S. Air Force is investigating the cause and effects of signal distortions observed from the GPS IIR-20(M) spacecraft launched on March 24, 2009. Routine early orbit checkout procedures determined that GPS IIR-20(M) signals were inconsistent with the performance of other GPS IIR-M satellites. The signal distortion was initially observed as an elevation-dependent bias in ranging measurements from GPS monitor stations. read more>>

Coast Guard Directed to Maintain and Upgrade Loran
The U.S. Senate, in a Coast Guard Authorization Act for Fiscal Years 2010 and 2011 currently before the Committee on Commerce, Science, and Transportation, directs the Secretary of Transportation to maintain the current Loran-C navigation system and prepare for modernization to eLoran, and authorizes $37 million per year for 2010 and 2011 towards that purpose. Similar action is also currently pending in the House. 


Resource for Comparing Precise Point Positioning (PPP) Solutions
GNSS researchers at the University of New Brunswick, Canada, have created a Precise Point Positioning (PPP) Software Centre website to offer an easy means of comparing solutions from online PPP applications. Users are invited to send a RINEX observation file that will be simultaneously processed by three online PPP applications. 

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Final Modernized GPS IIR Satellite to Lift off from Cape Canaveral The last in a series of eight modernized Global Positioning System Block IIR (GPS IIR-M) satellites built by Lockheed Martin for the U.S. Air Force is set to launch aboard a Delta II rocket on Aug. 17 from Cape Canaveral Air Force Station, Florida. More....

Summary of SDI

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GPS IIR-21(M) Satellite Declared Operational

The last in the series of eight modernized Global Positioning System IIR satellites, GPS IIR-21(M), was declared operational Thursday for military and civilian users worldwide, just 10 days after launching from Cape Canaveral Air Force Station. More....

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PRN01/SVN49: Another GPS Satellite Anomaly

From monitoring at the University of New Brunswick and elsewhere around the globe, it appears that normal signals from the L1 and L2 transmitters on the GPS satellite PRN01/SVN49 were unavailable for more than two hours on the morning of September 4. More....

More problems with GPS and the end for Loran (not too wise since redundant navaids enable easy detection by comparison when GPS is being interfered with) can be found at the following link: http://www.gpsworld.com/gnss-system/out-front-rocky-road-robustness-9424 .


An INS-based Tracking device the size of a pin head:


Please click here to see the future of GNSS and the current status (as of August 2012) of the LightSquared Controversy, which had threatened GPS reception if it had been allowed to proceed.

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