2007 Volume 50 Issue 167 Pages 27-33
An initial quaternion estimation method for the attitude determination of a spacecraft using an onboard star sensor is presented. In this method, we use a sequence of the number of stars in the field of view (FOV) of the star sensor as the measurement instead of the direction vector pairs of stars. A new statistical observation model is derived and coupled with the kinematics model of attitude to develop a cost function of the estimated initial quaternion. The attitude acquisition method proposed herein exploits generalized simulated annealing to optimize the cost function and find the initial quaternion. In addition, a virtual sub-FOV and its shuffling procedure for a more accurate estimation are presented. The performance of the proposed method is quantified using an extensive simulation.