The U.S. Department of Transportation (USDOT) released the Complementary Positioning, Navigation, and Timing (PNT) and GPS Backup Technologies Demonstration Report to Congress final report.  USDOT’s Volpe National Transportation Systems Center (Volpe Center) conducted field demonstrations of candidate PNT technologies that could offer complementary service in the event of Global Positioning System (GPS) disruptions.  The purpose of the demonstrations was to gather information on PNT technologies at a high Technology Readiness Level that can work in the absence of GPS. 

“The results of the thorough scientific research conducted by this demonstration effort indicate that there are suitable, mature, and commercially available technologies to back up or to complement the timing services provided by GPS.  However, the demonstration also indicates that none of the systems alone can universally back up the positioning and navigation capabilities provided by GPS and its augmentations.  This necessitates a diverse universe of positioning and navigation technologies,” said Diana Furchtgott-Roth, USDOT’s Deputy Assistant Secretary for Research and Technology.

The Volpe Center, through a competitive acquisition process, selected 11 candidate technologies to demonstrate positioning and/or timing functions in the absence of GPS.   

The demonstrations were conducted in March 2020 at NASA’s Langley Research Center (Hampton, VA) and Joint Base Cape Cod (Bourne, MA).  The results from the demonstrations were evaluated against 14 measures of effectiveness.  The findings indicate that the best strategy for achieving resilient PNT service is to pursue multiple technologies to promote diversity in the PNT functions that support transportation and other critical infrastructure sectors in urban, rural, and maritime areas. 

The report details the results of USDOT activities covering GPS backup demonstration planning, the PNT technologies demonstrated, the government reference system used to collect and verify results, and an information framework to convey measures of effectiveness of the demonstrated technologies.

More information on GPS Backup/Complementary PNT Demonstrations can be found here