Why the U.S. doesn’t have a terrestrial backup for GPS – by Claude AI

July 2, 2025

Written by Editor

Image: Shutterstock

What’s new: An explanation by Claude AI of one of our most pressing PNT issues in the U.S. Certainly it is something the Deputy Secretary of Transportation and the Chair of the FCC are concerned about.

Why it’s important: We are wary of AI, as we suppose everyone is and should be. But it does seem that these engines can do a pretty good job of summarizing what is likely a broad consensus on an issue. 

What else to know:

  •  Last week we were on the road for a couple speaking engagements and we got this question often.
  • We like a lot of what Claude has to say. For example, regarding discussions about which technology is the best alternative/backup: “…while the perfect solution is debated rather than deploying an adequate one.”
  • Most all IT and networking depends on GPS timing and most applications require full PNT from GPS. So Claude should probably be as worried about this as we are. 

 

The US lacks a terrestrial backup for GPS despite its critical importance due to several interconnected reasons:

Historical Shortsightedness and Bureaucratic Inertia A total outage of GPS could cost the country at least $1 billion a day. And there’s no backup. Russia and China have backups, but the U.S. doesn’t. Losing GPS would cost the U.S. $1 billion a day. So why is there no backup? : NPR The US actually had a potential backup system called LORAN-C that could have been upgraded to eLORAN, but in October 2009, Congress enacted a DHS appropriations measure allowing LORAN-C termination GPS.gov: LORAN-C Infrastructure & E-LORAN, shutting down the infrastructure just when it could have been modernized into an effective GPS backup.

Cost and Budget Constraints While Congress has mandated backup systems, funding has been inadequate. The act tasks the Secretary of Transportation with establishing a terrestrial backup timing system for GPS within two years GPS to get terrestrial backup system – GPS World, but implementation has been slow. Recent appropriations show only modest funding – $15M for “Position navigation and timing technologies and global positioning system backup” GPS backup funding continues Trump’s admire-the-problem approach – GPS World in fiscal year 2022, which is insufficient for a comprehensive national backup system.

Technological Overconfidence There’s been a persistent belief that GPS is sufficiently robust and that satellite-based solutions can be hardened against threats. This overconfidence led to decades of neglecting terrestrial alternatives while other nations like Russia and China developed comprehensive backup systems.

Jurisdictional Complexity GPS spans multiple government agencies – the Department of Defense operates the satellites, the Department of Transportation handles civilian GPS policy, and the Department of Homeland Security manages critical infrastructure protection. This fragmented responsibility has hindered coordinated backup system development.

Political and Economic Priorities Despite the enormous economic risks, backup systems don’t generate immediate political benefits. Politicians often prioritize visible, short-term projects over long-term infrastructure resilience investments that may never be needed.

Technical Debates and Standards Issues There’s been ongoing debate about which terrestrial technology to deploy – eLORAN, cellular-based systems, or newer alternatives. These technical disagreements have delayed implementation while the perfect solution is debated rather than deploying an adequate one.

Industry Resistance Some sectors have been reluctant to invest in backup systems, preferring to rely on GPS hardening and alternative satellite constellations rather than supporting terrestrial infrastructure that requires additional equipment and training.

Timing of Threat Recognition The vulnerability of GPS to jamming, spoofing, and space weather has only become widely recognized in recent years. The threat landscape has evolved faster than policy responses, leaving the US playing catch-up rather than being proactive.

The result is a dangerous gap where the United States has no terrestrial backup system Global Positioning System – Wikipedia despite clear awareness of the risks and legislative mandates to create one. The combination of bureaucratic inertia, insufficient funding, and competing priorities has left critical infrastructure vulnerable to GPS disruption.

Claude can make mistakes.
Please double-check cited sources.

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