In separate letters to the Office of Management and Budget (OMB) and new Secretary of Transportation Buttigieg, influential members of Congress have urged the Biden administration to take prompt action and establish a backup timing capability for GPS.

Danger and Benefits, Solution in Hand

On March 1, Republican representatives Sam Graves and Bob Gibbs wrote to the acting OMB director citing the dangers of not having a backup, and the benefits one would bring. Graves is the ranking member of the House Transportation and Infrastructure Committee.

Calling backup timing for GPS “important telecommunications infrastructure,” they said the capability is essential. Without a backup “… it is not a question of if our transportation, financial, and telecommunications infrastructure systems will fail, it is a question of when.”

After describing some of the threats to GPS, they observed that America will suffer from an outage more than many of its adversaries. Russia and China were cited as examples of nations that already have terrestrial backup systems for space-based PNT.

The letter to OMB also cited the benefits to safety, autonomous and intelligent transportation systems, along with “5G & Future Telecommunications.” GPS interference has led to a near crash of a commercial passenger aircraft, drone accidents, and allowed white-hat hackers to force cars off the road. The letter also referenced a report by the Alliance for Telecommunications Industry Solutions (ATIS) calling for a national timing solution to complement GPS. Such a solution would “…allow faster 5G implementation and enable it to reach more Americans.”

Graves and Gibbs also mentioned the Department of Transportation’s (DOT) January report to Congress on its GPS Backup Technology Demonstration. The report called for an architecture that included signals from space in the L band, terrestrial broadcasts in the Ultra High Frequency and Low Frequency spectra, and a fiber backbone to synchronize and feed precise time to terrestrial transmitters.

Studies and Broken Promises

By contrast, a letter signed by Democratic House members focused on decades of administration studies, a broken promise, and failure to follow the law.

Transportation and Infrastructure Committee Chair Peter Defazio, along with Representatives Garamendi and Carbajal, wrote to DOT Secretary Buttigieg on Feb. 25. The letter noted that the need for a GPS backup was first identified in a 2001 DOT report. Since then, “…there have been over 18 studies and recommendations by the Federal Government calling for a land-based, wireless nationwide backup system.” Also mentioned were comments in 2014 by DHS officials calling the nation’s over-dependence on GPS “a single point of failure” for critical infrastructure.

Congress was encouraged in 2015 when the Obama administration said it would establish an eLoran timing system and follow it with a broader approach to GPS vulnerability. “This well-reasoned approach gave Congress encouragement that this national security problem would finally be addressed.”

“However, in 2018, after no additional action was taken, Congress took responsibility to codify the commitments outlined in the 2015 letter, and on a nearly unanimous bipartisan basis in both Houses, passed the National Timing Resilience and Security Act (NTRSA) to implement the land-based timing back-up system.”

The letter also notes that Congress further nudged the administration on this issue in last year’s appropriations. The act for 2021 provided funding for six new DOT staff positions to support the project and directed the department to make the hires.

Timing and Positioning

Observers say that it is almost certain the capabilities implemented to satisfy the terrestrial timing requirement in NTRSA will also provide a positioning capability independent of GPS.

NTRSA requires DOT to “… incorporate the recommendations from any GPS back-up demonstration program” into the solution set. The combination of technologies recommended by the demonstration report will provide users one or more terrestrial services from which location can be derived.

Also, mobile devices must know their locations to use wireless timing signals. Location information independent of space-based signals is needed to provide these users resilient timing service.