Optimal time segmentation algorithm of yaw steering for three-axis stabilized geostationary satellite

The three-axis stabilized geostationary satellite employed sun sensor to determine yaw attitude needs to input the yaw coefficient on ground, which is calculated according to theorbit data and solar ephemeris on line. Method of fitting is chosen to calculate currently, for it is complex to compute directly on orbit. This paper studies optimal time segmentation fitting algorithm of yaw steering for three-axis stabilized geostationary satellite on the basis of theory of yaw steering by sun sensor. As the errors of yaw steering are mainly from fitting-errors of sun sensor measurement angle, and the method of uniform time segmentation of sun sensor measurement angle could not deal with the relationship between segmentation number and fitting accuracy very well, a constrained least squares algorithm using non-uniform time segmentation is proposed. This algorithm could effectively reduce the number of segmentation and ensure the calculation accuracy at the same time. It has practical significance in the research of high precision yaw attitude determination of three-axis stabilized geostationary satellite.