Space Development Agency Plans to Create an Alternative GPS Constellation

The director of the Department of Defense’s new Space Development Agency (SDA) said Friday that one of his priority projects is to create an alternate GPS capability using frequencies different from those of the current constellation.

“When I say alternate I mean truly alternate,” Fred Kennedy told a breakfast meeting of the Mitchell Institute for Aerospace Studies. “I don’t mean one that relies on GPS. I mean that it’s independent of GPS.”

Established in March 2019 the SDA is part of the DOD’s response to the emergence of near-peer adversaries in space—competitors like China and Russia who are working on capabilities to both rival and counter those of the U.S. To create its Alt-GPS system SDA intends to draw on the large commercial communications constellations now being developed. One approach would be to add a timing capability to one of the constellations.

“Imagine optically cross-linked satellites on orbit,” Kennedy said. “You get the delay between the satellites nailed down, you get a good clock into that constellation so I have de facto navigation satellites throughout my constellation—and I push that data down, that nav data. I push that nav signal down multiplexed in with the comm signal that’s already going to everybody with a handheld. …They’re going to get the nav signal; as long as they’re a subscriber to the network they’re going to get it. There’re some broadcast issues we could talk about but the bottom line is the networks that the commercial sector is going to put up actually help us get there very quickly.”

SDA could also adapt the satellites the private sector is building for military use, benefiting in the process from the economies of scale enjoyed by the communications projects. “We just take (the satellites) pull some of the commercial equipment, throw on some nav gear and go,” Kennedy said.

Kennedy ackowledged that there are other constellations like Russia’s GLONASS and China’s BeiDou that could provide additional signals, but said the U.S. is unlikely to want to rely on them. Moreover, with the approach he is suggesting it might be possible to have more than one alternative PNT system. “If GPS is denied—and it will be denied—that’s OK because I’ve got one, two or three alternate sources.”

Thecommercial constellation might even be in a position to charge for a new navigation service, he said. “I don’t know if there’s a business case for that or not but I imagine there may be car companies with, I don’t know, auto pilots that may want to know more about where they are and things like that. There could be reasons why people want to sell that kind of hyper-fidelity GPS navigation.”

SDA’s new navigation network will use non-GPS satellite frequencies, he confirmed to Inside GNSS. “It will be Alt-GPS coming down at Ka or Ku band. So have fun, Chinese, jamming Ka and Ku now—and whatever other band I decide I want to broadcast on.”

Former Air Force Secretary Whit Peters, who was in the Washington audience, asked about the issue of integrating new receivers across the vast array of military equipment. “What is the end-to-end from what you’re doing to the user terminals and the airplanes? And who is going to put up the money to put your radios in the F-16, which costs $5 million or $6 million bucks up front just opening up the software?”

“I don’t mean it to sound like a cop out,” said Kennedy. “I do not want to build those terminals and I don’t want be responsible for going to every one of those SPOs (Special Programs Offices) and figuring out how to slap on a radio. What I do want to do is ensure that the protocols and standards are there so that when the services do go buy a formal phased-array antenna they know enough about it to be confident they can put it on a B-21. So that discussion has to be ongoing.”