With OCX Axed, Space Force Moves Forward with New GPS Ground Plan

After scrapping a long-delayed program to build a next-generation GPS ground system earlier this year, the Space Force and prime contractor Lockheed Martin are pushing toward delivery of the capability in time to support the first launch of the newest GPS satellites, currently planned for 2028.

However, a new report from the Government Accountability Office raises concerns about that timeline. Further, the Space Force still lacks a plan to operationalize a key civilian signal installed in GPS satellites already on orbit. That signal, called L5, provides higher bandwidth and is more resistant to jamming and interference than other civilian GPS signals—which is important for aviation and maritime safety.

The Space Force announced in April it would cancel its long troubled Next-Generation GPS Operational Control Segment, or OCX. The system was meant to operate “Generation 3” satellites, to include the GPS III and GPS IIIF variants. But the effort, led by prime contractor RTX, failed to meet cost and schedule targets. By the time the Space Force pulled the plug, the program was 10 years late and its cost had nearly doubled from $3.7 billion to $6.27 billion.

Erin Carper, the acting portfolio acquisition executive for positioning, navigation, and timing and satellite communications, told reporters in September the decision to cancel OCX after more than 15 years and billions of dollars was driven primarily by two imperatives: the need to deliver the ground control elements for GPS IIIF satellites on time and to contain development risk along the way.

“Can we do it faster and not perturb the IIIF schedule? That was a significant driver,” Carper said Sept. 15 at AFA’s Air, Space & Cyber conference. “And then the other thing was, do we understand the risk remaining? The test campaign for OCX and the burn down of [deficiency reports] and some of the other things, that’s where we saw risk to the schedule for OCX.”

Rather than continue with OCX, the service opted instead to funnel resources toward a series of upgrades Lockheed Martin has been delivering for the legacy GPS ground segment, dubbed the Architecture Evolution Program, or AEP. The service first put Lockheed on contract for AEP in 2016, when OCX was delayed, to ensure the ground system could support GPS III launches and, eventually, command and control them once on orbit.

Since April, the Space Force has awarded Lockheed an additional $199 million to upgrade AEP to support launch and command and control for GPS IIIF satellites—an effort it’s calling AEP-M—and to begin a full technology refresh of the GPS ground segment hardware and software. That upgrade will lay the foundation for the next generation of the GPS ground system, known as Gen4. The service envisions that architecture as more modular and distributed, and it’s considering how it might leverage commercial antennas and other capabilities to support it.

Lockheed’s Vice President for Global Communications and Navigation Christina Mancinelli said that over the last 10 years, the company has completed more than 100 projects aimed at adding new capabilities to AEP, including a capability called M-Code Early Use, which allowed the ground system to task and monitor an advanced, secure signal called M-Code.

“We’ve been modernizing along the way,” Mancinelli said. “There have been some big upgrades we’ve made on the ground, but we have also been evolving it and doing projects to keep up with things for the last decade.”

Both Mancinelli and Carper said their teams are pushing to have AEP-M ready for the first GPS IIIF launch, though they noted that they’re still negotiating a formal schedule for the effort. A Space Systems Command spokesperson said the schedule is currently under review by the Pentagon’s Cost Assessment and Program Evaluation office. They declined to give an estimate of when the timeline might be solidified and wouldn’t provide a total cost estimate for the effort.

Meanwhile, GAO said in an Oct. 7 report that to support a 2028 launch, the ground control capability must be available by early 2027.

More broadly, Carper said she’s optimistic that Lockheed’s heritage on GPS ground and the program’s more incremental approach will help it avoid some of the pitfalls of OCX, which was attempting to pull off what she described as “a big bang delivery of capability.” In modern software development, incremental deliveries are favored because if there’s a glitch in an update, it’s easier to revert, or roll back, to a more stable version of the software to address it.

“There’s significant risk in cutting an entire constellation of operational satellites over to a brand new ground system, and that meant a level of test and oversight that was becoming very challenging,” she said. “With AEP-M, we’re able to roll out incremental capabilities, roll back more easily. … That’s not to say there aren’t inherent risks; there always will be. We will run into challenges, but we understand what some of those challenges are and are managing the risk.”

Modernization Delays

While the AEP-M contracts awarded to date cover the scope of what OCX would have provided for command and control and launch support, it doesn’t include modifications needed to operationalize the L5 signal. That signal is installed today on 21 spacecraft—some older GPS IIFs as well as all 10 GPS III satellites in orbit. However, due to OCX delays, the service hasn’t yet upgraded the ground system to monitor those signals.

SSC confirmed to Air & Space Forces Magazine that it has not yet awarded a contract for the L5 signal upgrades.

“The L5 effort was not included in the recently awarded control segment contracts to Lockheed,” a Space Systems Command spokesperson said. “The Space Force is focused on delivering capability incrementally as quickly as possible and is exploring all appropriate options for delivering modernized civil signals.”

SSC noted that it’s working with the Department of Transportation and the Federal Aviation Administration to finalize a plan for that work and expects to award contracts “in the near future.”

Amid a rise in GPS jamming and spoofing incidents in recent years, experts and commercial industry have been pushing for the U.S. government to operationalize the L5 signal—a move they say would make the aviation industry and commercial receivers more resilient. In 2024, the GPS Innovation Alliance recommended the Defense Department “increase the urgency and primacy” of upgrading the GPS ground system to support more robust civil signals.

“The more you can integrate multiple different types of signals into a receiver as well as combine that with specialized antennas … the better you are at resisting attempts to jam or spoof your receiver or device,” Lisa Dyer, the alliance’s executive director, told Air & Space Forces Magazine on Oct. 7. “We see today a need for that kind of capability, and L5 is one of those signals that we’d really like to see get integrated as soon as possible.”

There are other complicating factors beyond the ground system upgrade plans, including a requirement that at least 24 satellites be broadcasting the signal before it can be declared fully operational. Some commercial firms have already integrated L5 into their operations, but more regulated industries like aviation need the FAA to certify the signal as healthy before they can follow suit.

It’s possible the FAA could approve the signal before it hits the 24-satellite threshold, but one source familiar with the discussions said the agency is unlikely to change its position or permit waivers due to safety concerns. There has also been discussion around fielding the first GPS IIIF satellites on a faster timeline, but it’s unclear if there would be room on the launch manifest to accelerate the program due to current bottlenecks in the launch industry. And according to the GAO report, even if the Space Force and Lockheed were able to accelerate IIIF deliveries, there’s no certainty that the ground segment would be ready to support an earlier launch.