Using signals of opportunity as substitute for GPS
BAE's Navigation via Signals of Opportunity (NAVSOP) doesn’t depend on satellite signals, instead using a wide range of common signals readily available to sidestep jammers.
It can even use the GPS jammer signal itself. And it’s just as accurate, BAE says.
In BAE’s system, everyday signals like TV, Wi-Fi, radio or cell phone are used to triangulate the location of a person or vehicle. NAVSOP gets the position exact within several feet with this signal-scavenging approach.
It uses all sorts of other signals as well, from GPS satellite to air traffic control. The system can even learn and evolve by taking signals that were originally unidentified and using them to build increasingly reliable and more exact fixes on location.73 de Mark N9XTN