Motion Estimation to a Failed Satellite on Orbit using Stereo Vision and 3D Model Matching

An algorithm is developed for estimating the motion (relative attitude and relative position) of large pieces of space debris, such as failed satellites. The algorithm is designed to be used by a debris removal system which would perform various operations on space debris such as observation, investigation, capture, repair, refuel and de-orbit. During these operations, the debris removal system must control its position and attitude simultaneously. Such six degree-of-freedom control becomes more difficult if the failed satellite is changing attitude, such as by nutation. The information required as feedback signals for such a controller is relative - position, velocity, attitude and angular velocity - and these are expected to be measured or estimated from image data. The algorithm uses a combination of stereo vision and 3D model matching, applying the ICP (iterative closest point) algorithm, and uses time series of images to increase the reliability of the relative attitude and position estimates. To evaluate the algorithm, a visual simulator is prepared to simulate the on-orbit optical environment in terrestrial experiments, and the motion of a miniature satellite model is estimated using images obtained from the simulator