DARPA Pursuing Global Positioning System Alternatives
The Defense Advanced Research Projects Agency is looking to develop alternative positioning, navigation and timing capabilities.
Dave Tremper, a program manager at the agency’s strategic technology office, said relying solely on GPS provides users with a single point of failure.
“GPS is so good that it’s kind of knocked all of the other players off the field,” he said. “What happens when it’s not there and what happens when your system still needs that degree of timing and you still need that degree of position? … We’re going back and scrubbing systems and saying, ‘We need to really think about having that redundancy to GPS.’’’
One of the agency’s projects is the Spatial, Temporal and Orientation Information in Contested Environments program, he said. The effort, known as STOIC, is focused on developing a GPS backup, Tremper noted.
Part of the STOIC project leverages information gathered from a former program called Adaptable Navigation Systems, he said, which examined different types of signals for positioning, navigation and timing. One of these signal types included very low frequency transmissions, he said.
These signals allowed for gathering location information that was about one to two kilometers off because it did not account for changes in the ionosphere, which is a layer of the atmosphere that can reflect and modify radio waves, he noted.
“The ionosphere moves, and if you don’t account for how the ionosphere moves, then what you measure at your location changes because the length of the signal changes,” Tremper explained. “What STOIC is doing is it’s revisiting that ... positioning [signal], but now accounting for what the ionosphere was doing.”
The program, which began in 2015, is now in phase three and has started field testing, according to the agency. DARPA plans to begin testing the receivers on platforms in the air and on the water, Tremper said.
“If you’re on the Earth, you’ll be affected by things like bridges and pipes that are underground, and all those things will cause some shifts in your measurements,” he said. “It’s easier to start in the air … where you don’t have those little anomalies impacting your measurement.”
DARPA is examining low-frequency commercial receivers that can be used for military platforms. The antennas for the project are small enough to be used on ships and vehicles, he added.