Drones give us a unique perspective of the world around us. But just imagine what these small, agile, unmanned aircraft could do if they weren’t completely dependent on GPS to navigate. They could assist in underground search efforts or even deliver your next package without worrying about their proximity to buildings and other obstacles that can block GPS signals. NSF-funded researchers at Brigham Young University are producing a new breed of fixed-wing UAV’s that can navigate effectively when GPS signals are interrupted, weak or nonexistent.
The team’s system uses onboard devices like cameras, depth sensors and other types of sensors with sophisticated algorithms to overcome the dependence on GPS. The aircraft uses relative navigation, which estimates the UAV’s position, velocity and attitude-so it can navigate relative to local surroundings. To test the method, the team’s UAV traveled 1 mile successfully for two and a half minutes with an error of less than 3 percent of the distance traveled. The relative navigation approach allows the onboard algorithm to readily incorporate information from other aircraft or known landmarks to further improve its estimate of its location. While additional development is needed, advances such as these will lead to safer, more reliable UAVs when GPS is degraded or unavailable.