Optimal search strategies for Unmanned Aerial Vehicles

This work presents a method for deriving efficient search strategies for an autonomous unmanned aerial system (UAS). First the method is used to optimize flight path for an airplane with a simple downward-pointing fixed camera. The aircraft performs banking maneuvers in order to expand the search area. In that case, the optimizer solves for the best airplane speed, bank angle, maximum heading change, and average flight path separation subjected to the constraints of the airplane, the camera, and the relative size of the target on the ground. Next, the method is used to maximize the amount of ground area viewed by a pan-tilt-zoom camera mounted to an airplane subjected to constraints of the camera, airplane performance, and the relative size of the target on the ground. An optimizer solves for the best camera angles, zoom setting, and the flight path separation between parallel searches. The input parameters used in the simulation results of this paper are specific to a low-cost / low-altitude UAS, but the method can be generalized for application with different aircraft and camera systems. As expected, the gimbaled camera configuration is capable of searching more area than the fixed downward-pointing camera configuration, however, the fixed camera is more competitive than expected. Finally, a flight test with the fixed camera is flown to compare with the simulation results.