Adaptive Bearing-Only Target Localization and Circumnavigation Under Unknown Wind Disturbance: Theory and Experiments

This letter addresses the problem of controlling an autonomous agent to localize and circumnavigate a stationary or slowly moving target in the presence of an unknown wind disturbance. First, we introduce a novel wind estimator that utilizes bearing-only measurements to adaptively estimate the wind velocity. Then, we develop an estimator-coupled circumnavigation controller to mitigate wind effects, enabling the agent to move in a circular orbit centered at the target with a predefined radius. We analytically prove that the estimation and control errors are locally exponentially convergent when the wind is constant and the target is stationary. Then, the robustness of the method is evaluated for a slowly moving target and time-varying wind. It is shown that the circumnavigation errors converge to small neighborhoods of the origin whose sizes depend on the velocities of the wind and that of the target. Comprehensive simulation and experiments using unmanned aerial vehicles (UAVs) illustrate the efficacy of the proposed estimator and controller.