MUTUAL RELATIONS OF INTERNAL COORDINATE SYSTEMS OF STAR SENSORS IN THE PROBLEM OF ACCURATE DETERMINATION OF SPACECRAFT ORIENTATION

We consider the problem of estimating the relative angular position of internal coordinate systems of star sensors for accurate determination of spacecraft orientation. The relative angular position of the internal systems is determined by the comparison of calculated and measured angular distances between stars which were identified with the star sensors. Our algorithm to determine the relative angular position uses guaranteed approach to solving the problem of estimating the state of a dynamic system. A model to determine the relative angular position of internal coordinate systems was developed. Based on the model, a regularized ellipsoidal observer was build for estimating the quaternion determining the relative angular position of the internal coordinate systems. Our results of simulations of the algorithm are given.