The Global Positioning System (GPS) is the most widely adopted source of positioning, navigation, and timing (PNT) services essential to critical infrastructure, supporting all modes of transportation including aviation, maritime, rail, and road. Beyond transportation, GPS serves as a foundational technology across many economic sectors, including land surveying, finance, machine control, precision agriculture, seismic monitoring, scientific research, and space operations.

By enabling accurate route planning, real-time tracking, and synchronized operations, GPS enhances safety, reduces delays—and reduces fuels cost, effective time productivity, and resilient logistics networks. Its widespread availability streamlines emergency response, supports collision-avoidance capabilities, and lays the groundwork for safe, emerging automated and connected vehicle technologies. Because GPS user equipment relies on low-power signals from Medium Earth Orbit, it is inherently vulnerable to intentional and unintentional signal disruptions, highlighting the need for complementary PNT (CPNT) systems to bolster resilience.

To address this vulnerability, the U.S. DOT Volpe Center, on behalf of the U.S. DOT Office of the Assistant Secretary for Research and Technology (OST R) Office of Positioning, Navigation, and Timing (PNT) and Spectrum Management, developed a CPNT Action Plan designed to accelerate the adoption of CPNT solutions throughout the nation’s transportation system and other critical infrastructure sectors.

The U.S. DOT Volpe Center has extensive knowledge and expertise within the PNT resilience landscape and is working closely with OST-R’s Office of PNT and Spectrum Management. Together, we are executing the CPNT Action plan including field testing of mature and commercially available technologies that could offer complementary service in the event of GPS services disruptions.

The U.S. DOT Volpe Center’s continued support includes an acquisition strategy to fast-track CPNT technology testing and adoption. This strategy led to the release of a Request for Information and a subsequent Combined Synopsis Solicitation or Request for Quotation. In June 2024, more than $7 million was awarded to nine CPNT technology vendors for Rapid Phase testing at federal, critical infrastructure, and vendor field test ranges. The U.S. DOT Volpe Center coordinated vendor site visits and technology deployments, developed test plans and documented the range of PNT services for future inclusion in the federal PNT Services Clearinghouse.

Successful testing of Rapid Award Phase I vendor technologies was completed in June 2025. Test data collection and analysis was performed, and initial test results were presented during the third U.S. DOT Interagency Complementary PNT Workshop in Washington, D.C., held in August 2025. The report on Rapid Phase Award I testing supporting the Instrument Field Test Ranges objective of the CPNT Test Plan was delivered to OST-R leadership in March 2026.

By encouraging adoption of CPNT solutions throughout the nation’s transportation system and stakeholders, this work aligns with Executive Order 13905, Strengthening National Resilience through Responsible Use of Positioning, Navigation, and Timing Services, which seeks to ensure the disruption or manipulation of PNT services does not undermine the safety, reliability, or efficiency of critical infrastructure services.

About the U.S. DOT Volpe Center

Since 1970, the U.S. DOT Volpe Center has advanced transportation innovation for the public good, providing multimodal applied research, collaborating with federal, state, and industry partners, and multidisciplinary technical leadership and expertise to solve complex transportation challenges. Learn more at www.volpe.dot.gov.