Cooperative Circumnavigation of a Moving Target Using Discrete-Time Bearing Measurements

This paper investigates the cooperative circumnavigation problem of an unknown, non-cooperative dynamic target for a multi-agent system using discrete-time bearing-only measurements. Each agent can only obtain the target's bearing information. Focusing on the discrete-time bearing data, the unscented Kalman filter (UKF) is introduced to estimate the state of the target. Afterward, leveraging the estimates and control objectives, a discrete-time controller is developed to steer the multiple agents to follow and circumnavigate the target with a prescribed configuration that includes desired radius, angular velocity, and angular spacing pattern. Compared to existing coupled architectures of continuous-time observers and controllers, the proposed method eliminates the need for discretizing continuous-time systems in practical implementations, thereby circumventing the noise sensitivity inherent in continuous-time observers and avoiding the potential risk of system instability arising from discretization. Finally, a numerical experiment validates the performance of the theoretical result.