Air Force Research Lab tests new radio tech for GPS-denied environments

A new handheld device for ground forces aggregates radio signals to provide force location data in combat, without GPS.

The Air Force Research Laboratory (AFRL) is working with industry to test and refine an emerging radio frequency force-tracking technology able to identify ground forces’ location without needing to rely upon GPS.

The technology utilizes a ground operated handheld device which uses an algorithm to aggregate signals of opportunity from various radio frequencies,  said Mark Smearcheck, AFRL electronics engineer, in a written statement.

“By receiving and processing various radio frequency sources not designed for navigation purposes, the new system connects to a smartphone and is designed to pinpoint a user’s location without relying on GPS,” he said.

The concept, a combined effort between the AFRL and Virginia based Echo Ridge, is to identify and develop position, navigation and timing technologies able to operate in a GPS-denied environment wherein commonly relied upon GPS signals are jammed, attacked or compromised. In particular, China is known to be testing high tech ASAT, or anti-satellite, weapons intended to knock out or destroy enemy GPS systems.

As a result of this and other threats, the Air Force has been vigorously pursuing resilient, cyber hardened, combat capable communications technology to sustain combat operations and preserve force networking without GPS.

The device connects to a smartphone running the Android Tactical Assault Kit, a device typically carried by Air Force ground operators  to display the navigation solution on a map.

With the process developed by Echo Ridge, the errors do not accumulate over time, as they might with a traditional dead reckoning approach, so a valid position can be produced indefinitely, officials explained.

“Multiple signal sources are used simultaneously, which provides redundancy and increased immunity to adversarial attack,” an Air Force statement said.

“We’re measuring signals that have known or discovered geographical locations,” said John Carlson, chief technical officer at Echo Ridge. “Because we’re able to precisely measure those signals, we can accurately estimate position without error growth over time or distance traveled.”
Echo Ridge and the AFRL Sensors Directorate recently completed a field test and demonstration of the technology at Fort Bragg, North Carolina.

Developers are now working on improving ruggedness for the device to expand the mission scope of its potential combat uses.

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