Circular-Feature-Based Pose Estimation of Noncooperative Satellite Using Time-of-Flight Sensor

This paper develops an end-to-end circular-feature-based pose estimation using the time-of-flight (TOF) camera for capturing serviced satellite. First, the docking ring is chosen as the recognized object for pose measurement. Second, a new ellipse detection method is proposed to detect the docking ring. Third, the circular feature is used to estimate the six-degrees-of-freedom pose with the aid of a reflective block. Combined with the range at each pixel location from TOF, the pose duality can be eliminated, and the roll angle is recovered through the geometric constraint. Ground physical experiments validate the effectiveness and efficiency of the proposed method. The on-orbit application demonstrates that the proposed algorithm can accurately and robustly estimate the relative pose of the noncooperative satellite, providing reliable navigation information for the chaser spacecraft with the relative pose estimation errors less than 2 deg and 5 cm.