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If not GNSS, then what?

An interesting question.

To some, it means GNSS is so important and unique that without it, all is lost. They enthusiastically support only GNSS-centric research and development, believing that any issues that GNSS has today — such as lack of resilience — can be resolved given enough time and money. It includes pushing for the discontinuance of ground-based systems and the “re-purposing” of their resources to produce more satellites and more space-based signals. It demonstrates an admirable and true dedication to the belief that GNSS is the mission.

To others, these words have a different and darker meaning, warning of a clear and present danger. To them, it means “When (not if) GNSS is not available, what other source(s) of positioning, navigation and timing services (PNT) will be available to support GNSS users’ missions and goals?” For these purpose-driven individuals, GNSS is a means — not the mission, which is to provide the necessary positioning, navigation and/or timing performance, such as accuracy, availability, integrity, continuity and coverage, required to ensure the nation’s safety, security and economic well-being.

Unfortunately, some who have made GNSS their mission strive to convince others that it should be their mission, too!

GNSS is magic — but only when it works. It has played and will continue to play a crucial part in advancing our knowledge and abilities and supporting diverse use cases worldwide. It should and must be supported, but not to the exclusion of everything else. Recently, the magic has failed numerous times all around the world and, as a PNT community of suppliers and users, we must know we are capable of so much more.

We also know that the vast majority of civil PNT service needs are local, not global — based in part on the population density of users and their use cases. Over the years, GNSS’ accuracy and coverage have spoiled us. We even chose to see GNSS interference events as proverbial “black swans.” At the same time, the abandoning of well-engineered, resilient local solutions in favor of a global, one-size-fits-all mentality has been appealing to many. We know this approach is fraught with danger. Throwing away perfectly acceptable, resilient local means rather than enhancing them and bringing their technology into the 21st century may, as a PNT community, be our biggest regret. In many ways we have already gone too far.

I encourage our PNT community to commit to doing more, to open up our minds to design, develop, evolve, create, install, implement and operate more resilient PNT sources and more resilient user systems for which PNT services are critical inputs — especially by focusing on services that are not space-based, operate in different areas of the spectrum, are capable of higher power, and can be installed and evolved more quickly to mitigate emerging new threats. Most importantly, we all need to accept and support the true mission of our PNT community, the “why” that drives our innovative solutions: to ensure PNT services always will be available to support our safety, security and economic well-being.

<p>The post If not GNSS, then what? first appeared on GPS World.</p>

Jules McNeff

“President Biden on April 30 issued a National Security Memorandum on Critical Infrastructure Security and Resilience. GPS plays a vital role in the operation of critical infrastructure, and some sectors are considering their own backups. Other than conducting studies and meetings to admire the problem, the federal government has done virtually nothing to provide a comprehensive answer. In fact, the government is now dismantling the Loran system, though enhanced Loran (eLoran) is a viable and affordable GPS backup, specifically recommended for use by prior U.S. Department of Defense and U.S. Department of Homeland Security Deputy Secretaries. Given the vital role PNT and GPS play, it’s a mystery why such a viable solution is simply ignored.”

— Jules McNeff
Overlook System Technologies

Will GPS remain the Gold Standard of space-based PNT services for the foreseeable future?

“GPS led the emergence and growth of a global space-based PNT service enterprise and has been the Gold Standard since its inception. The U.S. Department of Defense and Air Force (now Space Force) have maintained that standard through stable, transparent, and consistent policies and continuous performance improvements for the services it provides to all users. Now, in the face of foreign competition, hostile threats, budgetary pressures, reorganizations and management fragmentation, dilution of corporate memory, and inconsistent leadership support, those policy and performance foundations are in danger of eroding. The outcome for GPS and its future in the global PNT Enterprise is purely in the hands of our federal leadership today.”

— Jules McNeff
Overlook System Technologies

<p>The post EAB Q&A: GPS use in US infrastructure, PNT services first appeared on GPS World.</p>

“With the proliferation of commercial SATCOM services being launched to provide global broadband services, there is an opportunity to leverage these capabilities to also augment positioning, navigation and timing (PNT). The Defense Science Board has been directed to consider this and is evaluating how these commercial alternatives, such as PNT signals-as-a-service, could supplement GPS if technical and logistical challenges could be overcome.

With the recent announcement of Iridium buying out Satelles for $115M and the apparent interest in the U.S. Department of Defense (DOD) to consider using commercial alternatives to provide backup PNT, this is likely to spur other innovations in this space and bring more players (and investors)  to the market. This has the potential to significantly increase PNT resilience around the world by enabling the use of existing SATCOM services, with a wide diversity of spectrum allocations separated from GPS, allowing operation

in a GPS-denied environment.

Deployment also can be accelerated by leveraging commercial manufacturers of SATCOM equipment who can rapidly release commercial products with alternative embedded PNT capability that can provide aiding data through the Modular Open Systems Approach (MOSA) standards already developed for A-PNT devices in the DOD acquisition process.

The major barrier to adoption of these services, however, could be the anemic funding being provided for adoption of commercial space services to Space Systems Command’s new Commercial Space Office (COMSO).”

–Alison Brown, NAVSYS Corp.

<p>The post EAB Q&A: Bridge the GPS vulnerability gap first appeared on GPS World.</p>

Greg Turetzky

“It’s more consequential than most people realize. The first and most impactful consequence is the limitation of the GPS constellation to
32 satellites. There are more healthy satellites in the sky and, more importantly, Block III satellites sitting in the barn. These additional satellites and their modernized signals would improve navigation globally with improved accuracy and resilience. Additionally, without OCX the L5 signals are labeled ‘unhealthy’ and therefore the constellation is labeled ‘pre-operational.’ Without OCX, L5 cannot reach initial operational capability (IOC), which prevents certain market segments from being able to officially use them. GPS will remain in third place if the delay continues.”

— Greg Turetzky
Consultant

Michael Swiek

“OCX seems more than seven years behind when you consider that we have been hearing about it as a concept and then a proposal for years before it became an actual program. In the Hope and Crosby movie, “The Road to Rio,” Jerry Colonna leads a cavalry charge to rescue the heroine across several brief scenes. He never arrives, and the heroine is saved by other means. Colonna then proclaims, ‘Well, we didn’t make it, but we sure added some excitement!’ While waiting for the heroic arrival of OCX, might the evolution of technology, and regular updates to the current system, already provide some of the improvements promised by OCX? The OCS is already upgraded to accommodate Contingency Operations for GPS III satellites, M-Code early use and incorporated cyber security protections. Is it, maybe, time to just move beyond OCX and start anew with today’s context and assessment of future needs?”

— Michael Swiek
GPS Alliance

<p>The post EAB Q&A: OCX is more than seven years behind schedule. What are the consequences? first appeared on GPS World.</p>

Bernard Gruber

“No. As Peter Lynch once said, ‘Know what you own, and know why you own it.’ Although this sage advice was for individuals buying equities, I would offer the same for GPS investing in or ‘guaranteeing’ high-accuracy service. Myriad differential GPS solutions currently exist, next generation atomic clocks are in orbit now, internet-based corrections are available. Evolution will improve accuracy, and techniques for higher accuracy will develop when they are needed by the market. I would rather see investment continue in Alt Nav and compatible GPS solutions. As for Galileo and BeiDou authentication plans, I may provide a different answer.”
— Bernard Gruber
Northrop Grumman

Jules McNeff

“What’s in a name? For most people, GPS already provides a high-accuracy service. Depending on how one uses its signals, you can already track the movement of tectonic plates and changes in Earth reference frames — that’s pretty high accuracy. There are always those who want more, but it’s unreasonable to expect GPS to be the only source, given performance and resilience gains with positioning, navigation, and timing (PNT) augmentations and complements along with GPS basic services. The GPS providers need to focus on Job One, a robust set of GPS services for all its users, and not have that mission complicated further.”
— Jules McNeff
Overlook Systems Technologies 

<p>The post EAB Q&A: Satellite-based high-accuracy services first appeared on GPS World.</p>

John Fischer

What is the most promising innovation in satellite navigation being introduced by BDS, Galileo, QZSS, or NavIC?

“Two things are having an immediate impact: authentication methods, such as Galileo’s Open Service-Navigation Message Authentication (OS-NMA), and the proliferation of correction services for high accuracy. Navigation message authentication offers a practical, easy-to-implement defense against several (though not all) types of spoofing attacks. QZSS and NavIC offer this too. And though paid correction services have been available for some time, Galileo’s High Accuracy Service (HAS) will bring it into the mainstream. Sometimes innovation is just applying simple techniques in a useful, efficient manner.”

— John Fischer
Safran Navigation & Timing 

For critical infrastructure, how good a remedy are multi-constellation receivers to GNSS vulnerability?

“Multi-constellation receivers do not do much to combat jamming and spoofing; they only detect failures in a constellation itself through comparison. Since they all are open standards, a good spoofer can fake all the systems simultaneously. Multi-frequency receivers are a bit more resistant to jamming, since one must jam multiple bands, but since all the bands are relatively close, the barrier is not high. To be truly resilient, you need diverse, redundant PNT sensors — IMUs, CRPAs, strong signals of opportunity, lidars, etc. — in addition to GNSS receivers.”

— John Fischer
Safran Navigation & Timing 

<p>The post EAB Q&A: What is the most promising innovation in satellite navigation? first appeared on GPS World.</p>

Michael Swiek

“This reminds me of the questions that arose many years ago over whether the U.S. Coast Guard differential correction service (DGPS) would unfairly compete with commercially provided augmentations. I don’t know whether there is a single rigid number that fairly separates publicly provided augmentations from commercially provided ones, or if such a number could be set for all time. It would probably need to be flexible, and evolve over time as needs change and technological improvements come to pass. In the end, the public-provided service should be at a reasonable minimum level to address an identifiable broad public need — such as safety of life requirements — but not so fine as to undercut finer levels of accuracy for which there is a market of users willing to pay for such services from the private sector. This could ensure a responsible service provision for the public good, as well as a healthy competitive environment for commercial technological development.”

— Michael Swiek
GPS Alliance

<p>The post EAB Q&A: What accuracy level should public services end and private ones begin? first appeared on GPS World.</p>

John Fischer

“Yes! And there are several CSAC suppliers, each with varying accuracies, power consumptions, and price points. These atomic clocks are no longer exotic scientific instruments but rather commercialized, proven devices that can be mounted on a circuit card at a reasonable cost. They offer extended holdover time in the absence of GNSS and help with spoofing detection by verifying the incoming signal. They provide exact frequency recovery on power-up (re-trace) for power saving modes. Defense, telecom, financial transactions, and autonomous navigation for cars and drones are all applications that can be made more resilient by these clocks.”

— John Fischer
Safran Navigation & Timing

Jean-Marie Sleewaegen

“Atomic clocks, including CSAC, are frequently used in GNSS timing applications, for example to keep accurate time during GNSS outages or to assist in identifying spoofing attacks targeting the time component. On the other hand, the long-term stability of atomic clocks is not particularly relevant in navigation applications where time is not the main output, and the additional cost, power consumption and size of CSAC are not justified.”

— Jean-Marie Sleewaegen
Septentrio

Ismael Colomina

“Indeed. After the DARPA-NIST initiative and subsequent commercialization, affordable, accurate and stable chip-scale oscillators can be easily integrated into circuit boards providing additional measurements to PNT systems to improve positional vertical accuracy, as well as reliability and integrity. For example, in high-end mobile mapping systems operating in complex urban scenarios, their use helps detect GNSS outliers at a relatively negligible additional cost.”

— Ismael Colomina
GeoNumerics

<p>The post EAB Q&A: Is the GNSS community failing to exploit the potential of CSAC? first appeared on GPS World.</p>