In case you missed it, the European Union Agency for the Space Program (EUSPA) recently issued its first ever User Technology Report addressing both GNSS and Secure SATCOM. Though they seem to be different and distinct topics, EUSPA does a reasonable job of drawing them together with an “Editor’s Special — Synergies from Space” at the end of the document.
The first half of the report deals with GNSS and is an exploration and celebration of how far we have come with GNSS. While the report is aimed at “users” and is designed to be “technical,” it is written to be accessible by most who are generally familiar with the topic.
Also, a careful reading reveals several messages for policymakers.
Protecting Frequencies
The report opens with a celebration of what has now become a multi-constellation, multi-frequency, open positioning, navigation and timing (PNT) system with 110 satellites, two regional augmentation systems (Japan’s QZSS and India’s NavIC), and Satellite Based Augmentation Systems (SBAS). All of this depends, of course, on clear and uninterrupted signals.
One of the first cautions policy makers should note is a subheading in the section that reads “Frequencies: a scarce resource to be protected.” This is the first of many mentions of the need to protect signals and users from accidental and malicious interference.
From 2016 to 2019, the European Union’s STRIKE3 project deployed equipment to monitor L1/E1 signals in 23 countries across the globe. They found more than 450,000 signals that could interfere with GNSS, 59,000 of which were assessed to be intentional jamming or spoofing.
This was well before the current wars in Ukraine and the Middle East and before Russia’s malicious ongoing electronic warfare in the Baltic. So, even in the absence of aggressive nation-state actions, which could flare up at any time, STRIKE3 showed that GNSS interference was a significant problem threatening users’ reliance on GNSS.
Both the European Union and the United States have undertaken projects in response to widespread jamming and spoofing.
In Europe, EUSPA has begun the EGIPRON project, or European Global Interference PROtection Network. It aims to develop and deploy “…an interference monitoring system covering all European territories and worldwide areas of European interest” working with contractors Qascom and Leonardo.
The U.S. Department of Transportation (DOT) announced the “GNSS Situational Awareness Common Operational Picture GovCloud Environment” at the December 2024 National PNT Advisory Board meeting. The government version was described as operational, with a public version to be available in mid-2025.
These detection — and hopefully geolocation — systems will be great tools. Policy makers must remember, though, that better understanding the scope of the problem will not solve it.
Better laws and regulations to empower enforcement, along with improved enforcement capability, will both be needed if even a dent is to be made in the problem. Getting these in place will be significant legislative and budgetary challenges. Even then, the problem of accidental and malicious GNSS interference will not be solved. Authorities will just be able to manage it a bit better.
Toughen Receivers
A great majority of the GNSS portion of the document is appropriately devoted to receivers. They are, after all, the only part of the GNSS system over which users have any discretion and control.
Receiver design, signal processing, antennas and PNT processing are all discussed. The most attention is paid to describing the characteristics and appropriate uses of five different families of GNSS receivers:
- Mass Market Entry-Level
- Mass Market Premium
- Professional Non-Regulated
- Professional Regulated
- Special Applications
Using the right kind of GNSS receiver for a given application is essential for safety and effectiveness.
The question for policymakers, though, is not whether the right technology exists to mitigate risks — it does. Rather, the issue is whether that technology is being used appropriately.
Most GNSS users are uninformed about GNSS issues and tend to purchase equipment based upon price rather than resilience. Policymakers must consider how to motivate users, especially in critical applications, to purchase and use more expensive equipment. Government leaders have many levers of influence at their disposal, from education to regulation and requirements. As of yet, however, we have seen few in use.
Alternative & Complementary PNT
The booklet devotes a page to “Complementary PNT Technologies” with the subhead “Complementary PNT technologies are redefining navigation solutions.” Saying “one size does not fit all” — which can also be said for GNSS — includes a graphic from the most recent European Radionavigation Plan of a conceptual, system of systems PNT architecture.
Perhaps more significantly, other pages have mentions of the desirability of “diversifying” PNT sources and “hybridizing” PNT sources.
Safety-Critical Applications
Overall, the GNSS section of the User Technical Report is an excellent general overview and reference document.
Its description of SBAS, however, might give a misimpression to the uninformed reader.
The title on page 12 reads “SBAS enhance GNSS performance and enable safety critical operations.”
SBAS improves GNSS accuracy with corrections and ionospheric models and helps with integrity. However, it does little to prevent service disruptions due to interference.
The title for SBAS conflict on page 12, with a comment on page 17, discusses “GNSS Vulnerabilities and Mitigation Measures.” The very last note on the page and in the tiniest type reads, “For critical applications, implement alternative (non-GNSS) technologies as a backup to ensure continuous PNT information.”
This latter statement is very much in keeping with the most current, 2023 version of the European Radionavigation Plan, which says:
“Thus, for critical applications or critical infrastructure protection, it is broadly accepted that GNSS, even in a multi-constellation and multi-frequency environment, should not be the unique source of PNT information. For those applications, an alternative PNT solution (back-up but also complementary) should be developed and maintained, not necessarily based on radio frequency technologies.”
To a certain extent, this has been echoed in the United States as well.
In 2020, a Presidential Executive Order warned against over-reliance on GPS/GNSS, saying the government “must ensure critical infrastructure can withstand disruption or manipulation of PNT services.”
Following this, in its January 2021 report on a PNT demonstration project, the DOT said:
“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.”
Additionally, a 2023 presentation to an international group by the Office of the Assistant Secretary of the Air Force was titled “Alt. PNT — the Pathway to Resilience.”
GNSS are great systems, but we cannot let our understandable enthusiasm for what are truly miracles of technology unintentionally mislead others. Policymakers must be constantly on the lookout for such missteps and help us all maintain a broader, user-focused perspective.
