Navigating the globe was once done using the sun, moon and stars as reference, but modern times bring modern methods, and the majority of the world now relies on GPS for its navigation needs.
But what happens when GPS isn’t available?
A collection of Department of Defense units and U.S. universities found out when they gathered at Edwards Air Force Base, Calif., to evaluate various aerial platforms in a degraded GPS environment recently.
The week-long test event called DT NAVFEST – short for Developmental Test Navigation Festival – was the first large-scale program of its kind, according to James Cook, KC-46A project manager with the 418th Flight Test Squadron.
“DT NAVFEST was established to provide a locally more realistic GPS jamming environment in which aircraft platforms and unmanned aerial vehicles could evaluate their performance under a degraded GPS signal,” Cook said.
“Other locations around the U.S. provide such environments, but having it locally allowed for direct program input and cost savings to customers by not having to deal with the logistics costs of deploying to those locations.”
Cole Johnson, technical lead for NAVFEST, explained how they create a degraded GPS environment.
“GPS signals are super faint,” he said. “Imagine a 30-watt lightbulb 12,000 miles in space. So it doesn’t take much interference for your smartphone’s GPS to lose lock on such a low power signal. Interference could occur from walking in a dense forest, through a canyon, inside a building, driving among skyscrapers, or from GPS jammers. The end effects of GPS jammers aren’t much different than the other causes of interference, they all make it harder for your GPS receiver to pick out faint GPS signals from the air, except jammers do it by adding noise to the environment.”
Units that tested assets at Edwards included the Emerging Technologies Combined Test Force, the 411th 416th, 419th and 461st Flight Test Squadrons. Two universities – Stanford University and the University of Illinois – and the U.S. Army’s Special Operations Command also participated.
The GPS jammers and support came from the 746th Test Squadron at Holloman Air Force Base, N.M.
According to Wei Lee, test safety engineer with the 412th Test Wing, the universities were invited to participate in DT NAVFEST on a trial basis with the hope of expanding to other institutions in the future.
“Live GPS jamming data is extremely difficult for academic labs to obtain due to the complexity of working with the Federal Aviation Administration and regional first responders,” Lee said.
“It is crucial that the Department of Defense support basic research and development that is ongoing in our nation’s top academic institutions. Many of the low technology readiness level projects will eventually migrate from academic labs to defense industry and military applications. Allowing the labs to participate on a non-interference basis is a win-win situation.”
