Blog Editor’s Note: This is the most recent of several requests for information (RFIs) that the federal government has issued on this topic in the last few years. While the title says “Alternative Technologies” the text states the goal as “complementary and backup systems for GPS”

Here is a link to a similar DoT RFI that closed last year.

Here is a link to the 16 responses to the DoT RFI from last year. Note that some of the responses are proprietary and cannot be fully accessed by the public.


Alternative Technologies for Position, Navigation, and Timing in a Degraded GPS Environment


Solicitation Number: HSHQDC-18-RFI-00015
Agency: Department of Homeland Security
Office: Office of the Chief Procurement Officer
Location: Office of Procurement Operations
Added: Feb 21, 2018 2:09 pm

The Department of Homeland Security (DHS), National Protection & Programs Directorate (NPPD), Office of Infrastructure Protection (IP) is seeking information from industry on alternative technologies for Position, Navigation, and Timing (PNT) in a degraded GPS environment.

DHS anticipates analyzing a broad range of alternatives to identify the most appropriate set of backup or complementary PNT methods for various critical users. The maturity of such alternatives may range from concept to prototype to commercially-available products.

Blog Editor’s Post Script:  Here are some quotes from the RFI:

  • “A wide variety of events, both intentional and unintentional, can interfere with GPS signals. Among these are environmental disruptions, such as by a major solar storm, accidental errors, such as programming errors in satellite software, and jamming, such as from personal privacy devices. Interruptions of GPS service from such events might be brief and highly localized, but in the most extreme situations could last many days or longer and have national or global impact. For many users, the quality of PNT data begins to significantly degrade after a few minutes to a few hours following loss of GPS.” (Editor – Transportation and first responder systems begin to significantly degrade immediately.)


  • “The National Security Presidential Directive (NSPD) 39 of 2004 requires DHS and the Department of Transportation (DoT) to “…develop, acquire, operate, and maintain backup position, navigation, and timing capabilities that can support critical transportation, homeland security, and other critical civil and commercial infrastructure applications within the United States…” in the case of GPS outage.”


  • “…appropriate alternatives will most likely require compromises in terms of accuracy (e.g., millisecond, microsecond, or nanosecond timing), area coverage (local, regional, national, or global), and ability to support GPS outages of various durations (1 to 30 days). Appropriate backup or complementary PNT technologies may differ by sector according to the needs of each.”