It said policymakers “could consider selecting the most resilient technologies as the cornerstone of the PNT suite for military missions, rather than defaulting to GPS.”

The 51-page report takes a comprehensive view of alternative PNT policy and leadership across the department. Its findings are an interesting and informative look at issues and efforts.

Increasing demands

The report comes at a time when U.S. forces have been seeing increasing interference with their own and allied GPS-enabled systems. The Organization for Security and Cooperation in Europe has regularly reported that its surveillance drones in the Ukraine have been jammed. Chinese press recently bragged that jamming caused U.S. Navy ships in the South China Sea to switch from using GPS to the Chinese BeiDou system. Additionally, U.S. military commanders have regularly described the Middle East as the most contested electronic warfare area on the planet, in large part because of regular interference with GPS signals.

The GAO study also comes on the heels of a provision in the National Defense Authorization Act (NDAA) for this year which directs DOD to provide non-GPS PNT to combatant commanders by 2023. The act says this timeline is consistent with responding to Joint Urgent Operational Needs, a formal method for commanders to communicate with department leadership. According to some sources, this suggests that the Pentagon has been receiving such requirements from field commanders, but has not responded to them in what Congress considers a timely manner.

Alternative PNT “not a priority,” resisted

Despite chronic GPS signal interference across the globe, outside experts and officials across the DOD told the GAO study team that developing alternative sources of PNT was not a priority for DOD. One example cited was the lack of a central program office.

One expert said, “PNT — It’s everyone’s need, but nobody’s business.” Another expert said, “Everyone wants to use [PNT], no one wants to pay or care for [PNT].” One DOD official characterized alternative PNT as an afterthought. DOD’s PNT Roadmap states that PNT capabilities, despite being mission critical, are not normally considered a key requirement, but rather may be treated as “a second-tier requirement.”

Worse, the report indicated that some forces within the department resist alternative PNT efforts.
According to one DOD official cited anonymously in the report “bureaucratic and political obstacles [represent] the biggest challenges for alternative PNT” and “anything that threatens GPS, such as alternative PNT technologies, faces pushback.”

The report cited another DOD official as agreeing that “there is an impression that the GPS program has a lot of political clout within DOD, and that those trying to develop alternative PNT technologies may face political challenges.”

Realistic requirements

Many missions do not need the accuracy provided by GPS, according to the report. Nevertheless. DOD programs often default to GPS performance standards when developing requirements. Many alternative technologies, while more resilient, are unable to achieve the same accuracy as GPS and therefore fail to meet the over-stated requirements.

Open architecture

Both DOD and GAO see development of modular open system architecture (MOSA) as key to PNT success in the future. This will allow addition of new PNT sources to a platform without the need for a major retrofit. With MOSA, all that would be needed is a new sensor module for the desired PNT source.

The GAO report endorsed this approach and encouraged DOD to institutionalize it with dedicated funding.

Working with industry

Decades of civil GPS use have benefited DOD in many ways. Broad academic and commercial research has resulted in a host of applications and improvements in the size, weight, and power requirements of equipment, as well as lowered costs. These benefits would almost certainly not have been realized at the current scale if the market for GPS equipment and apps had been restricted to military users.

The 2021 NDAA directs the department to “…enable civilian and commercial adoption…” of the GPS alternative technologies it develops for field commanders. The GAO report suggests DOD also work to leverage industry advances in technologies.

Scope and recommendations

GAO’s tasking for this effort did not include examining efforts to make GPS signals and equipment more resilient to disruption, nor use of non-U.S. satellite navigation systems. Neither were non-defense uses of PNT, nor improvements in such things as tactics, techniques, and procedures considered.

The study focused solely on department efforts to complement GPS services.

Six recommendations for policymakers are included in the report:

1. Increase Collaboration — Consider mechanisms to coordinate across DOD to clarify responsibilities and authorities in prioritizing the need for alternative PNT technologies.
2. Focus on Resiliency — Consider selecting the most resilient technologies as the cornerstone of the PNT suite for military missions, rather than defaulting to GPS.
3. Clarify Requirements — Consider opportunities to clarify what level of PNT performance is actually needed for missions, rather than defaulting to requirements that match GPS performance.
4. Coordinate with Industry — Consider ensuring that DOD and commercial industry coordinate so that industry is prepared to meet DOD’s needs, and DOD can leverage industry advances.
5. Institutionalize Open Architecture — Consider making the open architecture initiative more permanent, including providing funding.
6. Analyze Vulnerabilities — Consider having DOD conduct ongoing analysis of vulnerabilities of different PNT systems.

The May 2021 GAO report “Defense Navigation Capabilities: DOD is Developing Positioning, Navigation, and Timing Technologies to Complement GPS” is available here.

Dana Goward is president of the Resilient Navigation and Timing Foundation.