Target localization and circumnavigation using bearing measurements in 2D

This paper considers the problem of localization and circumnavigation of a slowly drifting target with unknown speed using the agent's known position and the bearing angle of the target. We first assume that the target is stationary and propose an estimator to localize the target and a control law that forces the agent to move on a circular trajectory around the target such that both the estimator and the control system are exponentially stable. Then the case where the target might experience slow but possibly steady movement is studied.