UAV Tracking with a Monocular Camera

A visual servo tracking controller is developed in this paper for a monocular camera system mounted on a Unmanned Aerial Vehicle (UAV) to track a leading UAV with a fixed relative position and orientation. Specifically, by comparing the feature points on the leading UAV from a prerecorded desired image with the corresponding feature points in the live image, projective geometric relationships are exploited to construct a Euclidean homography. A theoretical framework is developed for homography based visual servo technique for the general case in which both the camera and the object are moving relative to an inertial coordinate frame. This technique can also be applied to visual estimation of velocity or Euclidean struction of a moving object by a moving camera. The information obtained by decomposing the Euclidean homography is used to develop a robust kinematic controller which eliminates the knowledge of the leading UAV's velocities. A Lyapunov-based analysis is used to show that the proposed control strategy achieves global uniformly ultimately bounded (GUUB) position and orientation tracking.