After years of talking about the issue and a few fits and starts, the Space Force is refining its plans to bolster its legacy GPS architecture amid fears that its satellites and ground systems are increasingly vulnerable to threats like jamming, spoofing, and even kinetic attack.
The service has equipped its newest GPS satellites with more powerful military signals and defenses against signal jamming and spoofing, but new threats to the system—as essential to modern warfare as it is to the U.S. economy—have leaders weighing how to make the system more resilient.
Col. Neil Barnas, who leads Navigation Warfare and PNT acquisition as commander of Systems Delta 831, said that although GPS continues to be the foundation of the U.S. military’s PNT capabilities, it was designed for a different time.
“Everything we’re putting in orbit today, all of that was really envisioned in the early 2000s. [The current generation of] GPS III was put on contract in 2008,” Barnas told Air & Space Forces Magazine. “And so, the world has changed a lot.”
The Defense Department views GPS as the foundational layer of its broader PNT architecture. U.S. leaders have sounded the alarm about vulnerabilities and capability gaps across the GPS enterprise with increasing frequency in recent years, from satellites on orbit to the terrestrial operations segment to the terminals that receive GPS signals for users on the ground.
Signal jamming and spoofing—ubiquitous in Ukraine and Russia as well as in recent operations in Iran—is of particular concern to the Pentagon, which is highly dependent on GPS for precision targeting, communications, and navigation.
The Space Force’s roadmap for modernizing the system includes near-term upgrades to the constellation, including fielding 12 more GPS IIIF satellites, part of what the service refers to as its “Generation 3” architecture. Those spacecraft, expected to start launching in 2028, will be equipped with stronger signals and accuracy than previous spacecraft. Barnas said the service is weighing potential modifications to those satellites, including adding an antenna to strengthen its military signal.
The Space Force is also working with the Air Force and the other services to improve the terminals and devices that allow users to access GPS signals and is eyeing improvements to the control segment that operates those satellites.
At the same time, Barnas said, the Space Force is looking ahead and crafting concepts for what it calls a Generation 4, or Gen4, GPS capability—from redundant ground systems that can withstand or adapt in response to targeted kinetic attacks, to proliferated constellations distributed across multiple orbits, to new protected signals for small drones.
“We’re broadly thinking about an integrated resilience strategy across space, ground, and user,” Barnas said. “We’re really trying to come at space-based PNT very holistically.”
Ground First
The Space Force’s fiscal 2027 budget requests $115 million for GPS Gen4 and projects it will need another $1.8 billion through fiscal 2031. Barnas said most of the near-term Gen4 funding is focused on designing a ground segment.
That “ground-first” approach follows years of challenges in the GPS enterprise–and really, across the entire space portfolio—to deliver capable, secure ground systems before the satellites they’re meant to operate are in orbit. The most recent, high-profile example of this is the Next-Generation GPS Operational Control Segment, or GPS OCX, which the Space Force canceled in April. Developed by RTX, the system was already 10 years late by the time the service pulled the plug.
For the Gen4 ground segment, the service is looking first at the commercial market to see what technology is available now that could help make the system more resilient.
“We’re doing market research currently with industry to look at what are the technologies that they offer, which I think are going to be considerable, and so we’ll see those results shortly,” he said, adding that the service is looking at more near-term options to tap into the commercial antenna marketplace to support the Gen3 ground architecture.
It’s also considering how that future architecture might be able to integrate with GPS-like systems from other countries, like Europe’s Galileo or Japan’s QZSS, and is exploring options for ingesting space domain awareness data that it could use to optimize GPS satellite operations.
“We’re thinking about PNT situational awareness, and how does GPS actually become a user of that data, which is actually becoming incredibly prolific,” Barnas said.
Resilient Satellites
Beyond the ground segment, the Space Force is exploring options to make the next generation of GPS satellites more resilient.
In 2024, it kicked off a program called Resilient GPS and chose three companies to design a constellation of smaller, low-cost satellites to augment the larger constellation. When it later attempted to defund the effort in fiscal ‘26, Congress appropriated $15 million to keep it alive.
The service is using that money to fund the next phase of R-GPS and has tasked the three companies who participated in the first increment—Sierra Space, L3Harris, and Astranis—to conduct studies on things like crypto devices and GPS monitoring. That work, he said, will feed into the future Gen4 architecture.
Barnas and his team are also closely monitoring the commercial PNT satellite market and the new crop of companies that are planning to launch dual-use PNT constellations in low-Earth orbit. The Commercial Space Office and the Air Force Research Laboratory are working with at least two of those firms, Xona and TrustPoint, to explore how their fleets could augment GPS.
Both companies have launched initial demonstration satellites and plan to start providing an operational PNT service in 2027. In interviews with Air & Space Forces Magazine, executives said they’ve seen interest from the government in a turnkey solution that they can offer as a service and potentially integrate with existing systems. That interoperability is particularly important given the high cost and technical challenges that come with developing and fielding satellites, ground systems, and user equipment that all work together seamlessly.
“The cost of building the satellites is relatively small in comparison to the cost of deploying all the user equipment,” Xona CEO Brian Manning said. “And that’s why it’s really critical to have services and capabilities that can be integrated easily with equipment that is either already deployed or the equipment that they are deploying now.”
TrustPoint CEO Patrick Shannon said he expects that one day the Pentagon and other government customers will buy capacity from commercial PNT providers in the same way they procure imagery and SATCOM from commercial firms.
“The long-term goal is to essentially be a provider of sort of an enterprise-level subscription to the government, where they pay annually and their user base is supported,” Shannon said. “I think the economics have already been proven out by those other two use cases, and the specifics of how to implement it and who should own it, who should be accountable for PNT is what’s in development.”
Barnas said the Space Force’s work with these companies is nascent today, but he expects they’ll be conducting demonstrations and crafting acquisition strategies for commercial PNT in the not-too-distant future.
“We don’t have any plans for this at the moment, but certainly we’re engaged with those companies,” he said. “In the near term, we’re looking at their technical approach, their cyber approach, to make sure that it’s something that we can use for national security purposes.”