多探头星敏感器星图融合姿态确定精度

Attitude determination accuracy of multi-head star tracker based on star-image fusion

针对多探头星敏感器星图融合姿态确定精度问题做了研究。首先提出多探头星敏感器星图融合方法;其次在此基础上以三个探头为例,推导了三探头星敏感器星图融合姿态确定误差协方差矩阵公式;然后利用协方差椭球对该协方差矩阵的性质做了详细分析,明确了探头间构型、星图融合参考系选择以及各探头星点选取等因素对星图融合姿态确定精度的影响关系;仿真结果表明,最优构型的多探头星敏感器通过星图融合可输出同精度的三轴姿态,并且光轴精度较单探头星敏感器提升了30%。研究成果对多探头星敏感器的工程研制具有理论指导意义。

The attitude determination accuracy of a multiple-head star tracker is studied based on the star-image fusion. Firstly, a star-image fusion method with multiple-head star sensor is proposed. Based on the method, a star-image fusion covariance matrix of a three-head star tracker is derived. Then, the properties of the covariance matrix are analyzed by using a covariance ellipsoid, and the main influencing factors is figured out, which include optical head separate angle, star-image fusion reference frame and the star points chosen by star-image fusion. Simulation results show that the multiple-head star tracker with optimal structure allows full accuracy on all axes based on the proposed star-image fusion method, and the attitude determination performance is increased by 30% compared with single-head star tracker. The research results lay a theoretical foundation for the engineering development of the multiple-head star tracker.