White House, DoT Promote More Dough For GPS Alternatives

WASHINGTON: No currently available commercial alternative can provide a stand-alone backup to GPS, concludes a long-awaited study led by the Transportation Department. While some systems can stand in for GPS’s timing function, none provide robust enough positioning and navigation capabilities, the study concludes.

The study, Complementary PNT and GPS Backup Technologies Demonstration Report, was released Friday — the same day the White House issued a new policy to improve GPS as well as kick-starting investment in alternative PNT systems. Space Policy Directive 7 (SPD-7) replaces the 2004 PNT policy issued by the George W. Bush administration. In particular, the directive focuses on the need for increased  Pentagon focus on making GPS signals more jam resistant, as well as improving cybersecurity — such as the roll out of Lockheed Martin’s next-generation GPS III satellites and full implementation of the long-delayed M-Code encrypted signal.

SPD-7 also contains new language urging US government agencies to “Invest in domestic capabilities and support international activities to detect, mitigate, and increase resilience to harmful disruption or manipulation of GPS, and identify and implement, as appropriate, alternative sources of PNT for critical infrastructure, key resources, and mission-essential functions.”

“In my opinion, the focus on augmentation and non-space PNT alternatives is significant, as I think it symbolizes a shift away from the previous ‘gold standard’ approach of getting everyone to use and rely on GPS,” Brian Weeden, head of program planning for the Secure World Foundation said in an email yesterday.

“The original goal of that gold standard approach was to undermine any foreign GNSS competitor, which didn’t work, and also conflicted with the DOD’s requirement to be able to deny GPS to adversaries,” he explained. “I think the latter is why we haven’t seen more effort put towards shoring up civil GPS signals against jamming and spoofing, and instead you see a policy shift to encourage alternative sources of PNT.”

DoT reviewed 11 commercial available PNT systems, based on a variety of technologies, finding that “there are suitable, mature and commercially available technologies to backup or complement the timing services provided by GPS.”  However, the study also found that “none of the systems can universally backup the positioning and navigations capabilities provided by GPS and its augmentations. The critical infrastructure positioning and navigation requirements are so varied that function, application, and end-user specific positioning and navigation solutions are needed. This necessitates a diverse universe of positioning and navigation technologies.”

Nonetheless, the study says the US government should promote use of currently available tech and investment in emerging capabilities “that show strong performance, operational diversity, operational readiness, and cost-effectiveness is worthwhile. Based on this demonstration, those technologies are LF [low frequency, with a range of 30–300 kHz] and UHF [ultra-high frequency, with a range of 300–3,000 MHz] terrestrial and L-band [1-2 GHz, and used by GPS] satellite broadcasts for PNT functions with supporting fiber optic time services to transmitters/control segments,” it finds.

The DoT study was mandated by Congress in the 2018 National Defense Authorization Act. That bill also ordered DoT, DoD and the Department of Homeland Security to jointly develop a plan for ensuring that back-up GPS capabilities are widely available in case GPS signals are degraded or lost for any reason. Outages can be caused by anything from inability of signals to reach receivers in dense urban environments or remote locations, signal interference from wireless broadcasts (hence, DoD fears about the controversial 5G wireless network being developed by Ligado) or deliberate jamming.

However, that effort “remains a work in progress,” one US government official involved said yesterday. The National Security Council is leading a broad interagency effort to figure out how to tackle what is a Herculean task, the official explained. “The challenge is there just is no one size fits all [solution.] So, each agency has to really figure out for themselves and their users what they would recommend,” the official said.

DoT’s four key findings made the lack of a comprehensive GPS alternative clear:

1. All the vendors “demonstrated some PNT performance of value, but only one vendor, NextNav, demonstrated in all applicable use case scenarios.” (Although even that system was not deemed a “universal’ solution.)
2. Neither of the eLORAN solutions tested were able to produce accurate timing signals when receivers were located underground in what the study called a “Static Basement Test.” Systems using eLORAN (for enhanced Long Range Navigation) rely on radio towers to transmit signals, and are being used by some US allies such as South Korea.
3. One technology, so-called R-Mode in the medium frequency (MF) band, with a range of 300 kilohertz (kHz) to 3 megahertz (MHz)], “did not meet the minimum technology readiness level (TRL) of six.”
4. “Deployment effort and coverage (infrastructure per unit area) are both significant cost factors.” The study did not go into enough depth to project costs for any one system, but stressed that “cost is a central consideration in any PNT investment decision.”

Weeden concurred that costs will be an issue for widespread use of alternatives to GPS — which is provided for free by DoD (although of course receivers made by commercial firms are not.) “I think one major thing to point out is that using many (all?) of them will require new receivers, which means they will require a pretty significant investment and adopting phase to implement widely.”

Even the system that was shown to be adequate (though, again, not a comprehensive solution) to serve now as a GPS alternative, NextNav’s terrestrial PNT system TerraPoiNT, ranked high on the DoT study’s “deployment effort” scale — meaning that it would require significant investment in materials and time to deploy.

In a press release touting the DoT study, NextNav says TerraPoiNT’s “signal which is over 100,000 times stronger than GPS, combined with its ability to operate independent of GPS and its cybersecurity protections overcomes the limitations of GPS.”

“The DOT report highlights the fact that viable, market-ready PNT solutions can increase the resilience and security of location and timing services,” said Ganesh Pattabiraman, NextNav CEO, in the release. “These solutions will play a vital role in addressing both the immediate need to secure our critical infrastructure, but will also enable modern applications such as autonomous vehicles and 5G telecommunication systems. We are thrilled that the DOT report both validates the TerraPoiNT technology and recognizes NextNav’s vision for the future of PNT.”

The US government source noted that part of the problem for companies developing alternative PNT technologies is the current lack of government investment, as agencies scramble to identify their own needs. Without better guidance on what government buyers want, it obviously is difficult for companies to commit internal research and development funds.

The DoT study, in fact, makes two recommendations aimed at its own future work to promote alternative PNT systems for use in the transportation sector, which relies heavily on GPS, that would go some way toward helping industry determine where to put its own money:

1. DOT should develop system requirements for PNT functions that support safety-critical services.
2. DOT should develop standards, test procedures, and monitoring capabilities to ensure that PNT services, and the equipage that utilizes them, meet the necessary levels of safety and resilience identified in Recommendation 1.