Safe-circumnavigation of one single agent around a group of targets with only bearing information

This paper investigates the safe-circumnavigation problem of a single agent along a group of static targets. We assume in this paper that the distance information cannot be measured directly and only bearing measurements are available. In order to localize the targets, we design the positional estimator where the bearing measurements of the targets are used to construct the system matrix of the state equation of the estimator. To guarantee that the bearing angles are meaningful and with enough precision, we build the condition keeping safe distance between the agent and the targets. Furthermore, a gradual relaxed method is provided to reduce the limitations brought by the mutual restraint between the accuracy of the initial estimation and the desired encircling radius, so as to make the proposed method easy to apply. The performance of the proposed algorithms is verified through an experiment based on a wheeled robot platform.