COLORADO SPRINGS, Colo. — The Air Force Research Laboratory and L3Harris will begin integrated testing this summer of an experimental satellite with implications for a future hybrid precision, navigation and timing architecture.
Navigation Technology Satellite-3 (NTS-3) is being designed to showcase new PNT technology that could shape future upgrades to GPS satellites and inform a possible new acquisition program to augment today’s constellation. Once on orbit in late 2023, the satellite will conduct more than 100 experiments testing different technology, like a digital signal generator that can be reprogrammed on-orbit to broadcast new signals. The Air Force awarded L3Harris an $84 million contract in 2018 to develop the NTS-3 satellite.
AFRL has designated NTS-3 as a Vanguard program, which means it’s a high-priority effort due to the potential impact of the technology being developed.
Speaking during a media briefing at the Space Symposium, AFRL Commander Maj. Gen. Heather Pringle said this summer’s integration activity will include participating in the Army’s PNT Assessment Exercise (PNTAX), which is held annually to help inform requirements future requirements and validate concepts. That work, she said Thursday, will help the program reduce risk and develop mitigation options before next year’s launch.
Joanna Hinks, AFRL’s NTS-3 deputy program manager, said the program is wrapping up integration of the payload with a Northrop Grumman-developed bus and noted that risk-reduction efforts will run in parallel to full system testing, providing “initial baseline data” that will get the satellite “ready for primetime.”
While the current constellation of GPS satellites operation in medium-Earth orbit, the NTS-3 satellite is destined for geosynchronous orbit. The decision to send NTS-3 to a different orbit — which was actually a pivot from the original plan to fly the experiment in MEO — was made deliberately as a way to test a hybrid PNT architecture concept, Hinks said.
“The idea here is that we already understand very well how satellite navigation works in MEO,” Hinks said. “So, what we can do with NTS-3 being in GEO is look at how can you use a constellation that is truly a hybrid architecture.”
She added that running the experiment in GEO does not mean a potential future constellation of these satellites would only operate in that orbit. Rather, it allows the program to prove whether signals coming from satellites in multiple orbits can offer a complimentary and improved capability for users on the ground.
That question is key for Space Systems Command as it considers how to incorporate NTS-3 capabilities into its existing architecture. Cordell DeLaPena, SSC’s program executive officer for PNT and military communications, told C4ISRNET after the panel that the NTS-3 experiment will help his team make its case for transitioning the capability into a possible new program of record.
“That’s why we’re doing this prototyping and experimentation, is to use that to support a potential budget decision for a new program,” he said, noting that the Space Force may have the data it needs to feed into its budget submission soon after the satellite launches next year.
“I think the results are going to be fairly quick,” he said. “And then it all depends on how the priorities play out in the service’s budget for that year.”
The experiment will also feed into a Space Warfighting Analysis Center architecture review for next-generation PNT, which DeLaPena said is funded for next year.
SSC is also working with Lockheed Martin, which is building the newest version of GPS satellites, GPS IIIF, to study options for injecting new capability into those satellites, including technology demonstrated on NTS-3. The company is already on contract for the first 17 satellites, but DeLaPena told reporters new capabilities could be inserted on later space vehicles as long as it doesn’t disrupt the program’s schedule.
The PEO is particularly interested in a new clock assignment technology as a possible add-on capability for future GPS IIIF satellites, he said. The assignment technique would allow operators to draw from multiple clocks to get a more robust timing signal.
The NTS-3 experimentation will also involve ground system and receiver equipment. During the demonstration work, the satellite will be operated by a ground system developed by Parsons. DeLaPena said that if the service opts to feed some NTS-3 technologies into the GPS IIIF program, the system would likely integrate with the GPS IIIF Operational Control Segment, OCX IIIF.
The receivers used as part of NTS-3 will be software-defined, which would allow users, during conflict, to change the characteristics of a receiver’s waveform. AFLCMC’s Agile Combat Support program executive office manages PNT user equipment for the Air Force. PEO Lea Kirkwood said during Thursday’s panel said the close partnership her team has with AFRL means that once the technology is ready, “we’ll certainly be moving those wheels forward to execute a program to get it to the war fighter.”
Courtney Albon is C4ISRNET's space and emerging technology reporter. She previously covered the U.S. Air Force and U.S. Space Force for Inside Defense.