Cooperative Target Tracking with Time-Varying Formation Radius

This paper extends our previous results on cooperative target tracking of a moving ground vehicle using multiple unmanned aerial vehicles with constant 2D horizontal range to a time-varying horizontal range. An early-designed guidance law that orbits one UAV around the target is modified to handle time-varying horizontal range given by a prescribed reference. Cooperative target tracking is achieved by combining two control efforts together, where one brings each UAV to orbit above the target and the other spreads all UAVs evenly on a circle. Three communication topologies are considered, i.e., an all-to-all communication, a ring topology, and a cyclic pursuit topology. The effectiveness of the proposed cooperative target tracking control laws is demonstrated by numerical simulations under the cyclic pursuit communication topology as an example.