Target localization and enclosing control for networked mobile agents with bearing measurements

The problem of localization and enclosing control of an unknown moving target by networked mobile agents in a plane is considered in this paper. Each agent is supposed to be able to only measure the bearing angle to the target. Based on the bearing measurements of each agent and its neighbors, an estimator is proposed for each agent to localize the target. A distributed control law is then designed for the agents to travel along a common circle of the prescribed radius centered at the target and simultaneously achieve any desired spacing pattern along the circle. For a moving target with a bounded and unknown velocity, networked mobile agents globally converge to a neighborhood of the desired circular formation around the target by the proposed control law. Under the further assumption that one of the agents has access to the velocity information of the target, the localization algorithm and control law are modified by utilizing the estimate of the target's velocity for each agent. It is shown that under the proposed control strategy the agents globally converge to the desired circular formation around the moving target. The effectiveness of the proposed algorithms is illustrated via simulations.