AURORA, Colo.—One day, U.S. military personnel might target smart weapons using location data from Chinese or Russian versions of GPS, researchers from the Air Force and Space Force said at the AFA Warfare Symposium on March 4.
Such are the benefits of using multiple Global Navigation Satellite Systems.
“If you think about dropping a bomb based on data from [China’s GNSS constellation] BeiDou, for instance, there’s an initial, and I think very healthy, gag reflex that we all probably have,” said Jeffrey Hebert, the senior scientist for positioning, navigation, and timing in the Sensors Directorate of the Air Force Research Laboratory.
But once you “muscle through that,” he said, you can weigh the pros and cons. Space-based PNT is critical to the ability of the joint force to wage war.
“We need to be able to prosecute navigation warfare better than adversaries. And multi-GNSS is one way that we can accomplish that,” explained Hebert.
Multi-GNSS means using signals like the European Union’s Galileo constellation and even China’s BeiDou, Hebert said. And it’s one of the pillars of the U.S. military’s efforts to make its PNT more resilient against high-end adversaries, who might be able to jam or otherwise interfere with the signal from GPS.
“To get to resiliency from the user perspective, we need to look at diversifying sources” of GNSS signals, he said.

The key issue with multi-GNSS, Hebert said, is trust: How can you rely on a signal you don’t control? He said the answer is to take a page from the playbook of civil aviation.
“They’ve had to basically trust all of our lives, anyone who’s in the flying public, with GPS en route navigation, with being able to do a GPS approach to an airfield,” he said.
To have that level of trust in an unencrypted GPS signal, civil aviation authorities have had to augment it. That augmentation “involves monitoring, looking at the quality of those systems, and providing side channel information to the user that enhances their trust and the ability to use those [signals and systems] for safety critical” functions.
“What we’ve got to do is basically take some inspiration from that, but then map it to the use case of the military, which is a bit different,” Hebert concluded.
Currently, the Space Force is building and launching the next generation of GPS satellites, the so-called Block III and Block IIIF spacecraft. But in the meantime, explained David Voss, the director of spectrum warfare at the Space Warfighting Analysis Center, the service is taking advantage of new acquisition authorities and technologies to augment the fleet of 30 GPS satellites in medium-Earth orbit.
The service awarded four design contracts for Resilient-GPS, or R-GPS last year. The goal is to start with eight satellites, to be launched by 2028, four years after contract award. By way of comparison, the first Black IIIF satellite is scheduled to be launched in 2027, 11 years after its contract was awarded.
“What we want to do is take advantage of a lot of these new space technologies that are coming out. How do we take advantage of rapid tech insertion? How do we take advantage of the ability to multi-launch?” said Voss. Growing concern about attacks on GPS satellites meant a need for greater “orbital diversity,” he added. R-GPS, although also in MEO, will occupy very different orbital planes.
Introducing that orbital diversity, Voss said, is an example of “resilience by design.”
“There’s a lot of advantages to being able to provide that diversification,” said Voss, “It adds to performance. Additional numbers build performance. And that’s at the heart of resilience by design, is how can we build resiliency with performance into our capability?”
While the addition of R-GPS satellites won’t necessarily solve long-standing problems like jamming, it will create more capability, especially for civil users, added Lt. Gen. Philip A. Garrant, head of Space Systems Command.