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There are growing concerns in the US that GPS satellites might become enemy targets in a future war. The Pentagon and intelligence agencies have warned that China and Russia have developed advanced electronic weapons that could be used to jam or interfere with GPS signals.

Military operations are hugely dependent on having access to assured positioning, navigation and timing (PNT) services. The US Air Force has begun deploying more-advanced GPS satellites, called GPS 3, designed to be more resistant to jamming and spoofing.

The Air Force Research Laboratory in 2022 will launch an experimental PNT satellite called NTS-3 (Navigation Technology Satellite 3), in order to examine how the military’s PNT architecture could be made more resilient, according to

NTS-3 will integrate several advanced technologies to demonstrate resiliency and new concepts of operation to include experimental antennas, flexible and secure signals, increased automation, and use of commercial ground assets. Technologies matured and knowledge gained from NTS-3 are expected to transition to future generations of GPS, according to

NTS-3 would be a “persistent capability” that is always directly above the same spot on the ground. The military’s current constellation of 31 operational GPS satellites, in contrast, orbit the Earth twice a day.

At 1,250 kilograms, NTS-3 is far smaller than the 4,400-kilogram GPS 3 satellites being built by Lockheed Martin Space Systems.

The NTS-3 mission will also demonstrate new tactics and procedures — in space and on the ground — that will help advance the state of space-based PNT, including increased automation, greater use of commercial ground assets, and novel cybersecurity procedures. The Air Force still has 31 GPS 2 satellites in service and has only just begun to deploy its GPS 3 constellation.

Another goal in the NTS-3 experiment is to figure out how to better synchronize the space, ground and user equipment segments. The lack of coordination among the three segments has been blamed for setbacks and schedule delays in the GPS 3 program.