GAO: Pentagon GPS Modernization Still Behind Schedule, OCX Cancellation Raises Risk

The Pentagon’s long-running effort to modernize GPS is still behind schedule, and the April cancellation of its replacement ground control system has introduced new risk to bringing the next generation of satellites online, according to a new Government Accountability Office report released Wednesday.

“The Department of Defense’s (DOD) efforts to modernize GPS continue to face delays,” the congressional watchdog said in report GAO-27-107676, “Precision Navigation Systems: Challenges Remain with Fielding New Capabilities,” published Oct. 7.

A central change since GAO’s last review is the Pentagon’s decision to scrap the Next Generation Operational Control System, known as OCX, which was meant to replace the aging GPS ground control system. The Defense Acquisition Executive canceled OCX on April 17, 2026, and the Department of the Air Force and Space Force said at the time that the program “was unable to deliver needed capabilities on an operationally relevant timeline at an acceptable level of risk to meet the GPS constellation modernization needs.”

In place of OCX, the Defense Department is upgrading the existing GPS Operational Control Segment, also known as the Architecture Evolution Plan, rather than fielding a new control system. GAO said that transition creates risk for the launch, checkout and operation of new GPS satellites. Program officials told auditors the needed ground-control capabilities will be required by early 2027 to support a planned GPS IIIF launch in 2028.

GPS provides positioning, navigation and timing data used by the U.S. military and civilians, including systems that depend on precise timing as well as navigation. The Space Force operates GPS for the Defense Department, and the modernization push has been underway for years as military officials try to improve resilience against threats such as jamming and spoofing.

The canceled OCX program had cost about $6.27 billion as of January 2026, according to the Department of the Air Force, including contractor funding and government testing and support costs. In announcing the cancellation in April, Acting Service Acquisition Executive Tom Ainsworth said, “It’s important we refine and update acquisition processes to prioritize rapid, incremental capability delivery versus complex ‘all or nothing’ system deliveries.”

GAO said progress on fielding M-code — the military’s encrypted, jam-resistant GPS signal — remains uneven across the services. The Air Force has made progress on receiver cards but still faces development, software, funding and integration challenges, particularly for aviation platforms. The Navy is pursuing an interim aviation approach so some aircraft can use M-code sooner.

By contrast, the Army and Navy are already fielding M-code-capable or multi-PNT receivers on some ground vehicles, ships and Army aircraft, GAO said. PNT stands for positioning, navigation and timing, and the department is developing complementary tools because GPS signals can be disrupted or manipulated. Those efforts include satellite-based alternatives, non-satellite systems and backup timing solutions.

But GAO said the broader PNT portfolio is fragmented across the military services, making it harder to line up budgets, schedules and requirements. Congress created a PNT Oversight Council to help oversee those efforts, but GAO said the council can only make budget recommendations. The individual services still control their own budgets, limiting the council’s ability to enforce alignment.

That fragmented structure has contributed to slower coordination between GPS modernization and backup navigation and timing efforts, the report said. The result is a portfolio in which some protected capabilities are moving ahead, while other pieces — especially aviation-related M-code fielding and the ground segment transition after OCX — remain at risk of delay.

GAO made three recommendations aimed at identifying opportunities to consolidate and better align GPS modernization and complementary PNT efforts across the services. The Defense Department concurred with the recommendations.

Congress is also pressing for a clearer plan on what comes next. Committee report language for fiscal 2027 directed the secretary of the Air Force to submit a GPS ground-system transition plan within 90 days of enactment, including an estimate of OCX termination liability, an Architecture Evolution Plan upgrade schedule to support GPS IIIF, and a timeline for full M-code capability on existing GPS III satellites.