Relative Moving Target Tracking and Circumnavigation

This paper develops observers and controllers for relative estimation and circumnavigation of a moving ground target using bearing-only measurements or range with bearing measurements. A bearing-only observer, range with bearing observer, a general circumnavigation velocity command for an arbitrary aircraft, and nonlinear velocity-based multirotor controller are developed. The observers are designed in the body-fixed reference frame, while the velocity command and multirotor controller are developed in the body-level frame, independent of aircraft heading. This enables target circumnavigation in GPS-denied environments when only a camera-IMU estimator is used for state estimation and ensures observable conditions for the estimator. Simulation results demonstrate the effectiveness of the observers, velocity command, and multirotor controller under various target motions.