An Image Registration Approach for Accurate Satellite Attitude Estimation

Satellites are controlled by an autonomous guidance system that corrects in real time their attitude according to information coming from ensemble of sensors and star trackers. The latter estimate the attitude by continuously comparing acquired image of the sky with a star atlas stored on board. Beside being expensive, star trackers undergo the problem of Sun and Moon blinding, thus requiring to work jointly with other sensors. The novel vision based system we are investigating is stand alone and based on an earth image registration approach, where the attitude is computed by recovering the geometric relation between couple of subsequent frames. This results in a very effective stand alone attitude estimation system. Also, the experiments carried out on images sampled by a satellite image database prove the high accuracy of the image registration approach for attitude estimation, consistent with application requirements.