Vision-based loitering over a target for a fixed-wing UAV

For a fixed-wing Unmanned Aerial Vehicle (UAV) equipped with a gimbaled camera, we consider the problem of tracking a visual target while simultaneously bringing the UAV to orbit on a circular trajectory centered above the target. To achieve this kind of loitering behavior, we propose a feedback control method that is inspired by image-based visual servoing and makes use of a backstepping technique. By this approach, we are able to obtain a control law that requires only image and proprioceptive data. A formal proof of convergence and a set of validating numerical trials are provided, including a realistic simulation on a commercial UAV.