太阳矢量在行星际探测器姿态估计中的应用研究

在基于矢量观测的行星际探测器姿态确定中,参考矢量的几何关系是影响姿态估计精度的一个重要因素。针对这一问题,本文提出了一种利用太阳矢量来提高探测器姿态估计精度的最优算法。该方法在引入太阳矢量的基础上,将星敏感器测得的姿态四元数转化为两个互相垂直的参考矢量,并根据敏感器的测量精度计算相应的规范化权值系数;结合姿态四元数估计算法,给出最小二乘意义下的探测器最优姿态估计。最后,以深度撞击任务的实际飞行数据对本文所提算法进行验证。仿真结果表明,引入太阳矢量后的三轴姿态角估计误差小于150μrad,完全满足深度撞击任务的要求。

Research of Sun Vector in the Attitude Estimation of Interplanetary Spacecraft

In the interplanetary spacecraft attitude determination based on vector observation, the geometric relation between the reference vectors is an important factor which influences the accuracy of attitude estimation. This paper proposes an optimal algorithm using the Sun line-of-sight vector to improve the attitude estimation accuracy. With the introduction of the Sun vector, the attitude quaternion obtained from the star-tracker is converted into a pair of mutually perpendicular reference vectors perpendicular to the Sun vector. The normalized weights are calculated according to the accuracy of the sensors. Furthermore, the optimal attitude estimation in the least square sense is achieved with the quaternion estimation method. Finally, the practical data of the Deep Impact mission is used to demonstrate the presented algorithm. The estimation error of attitude angles are within 150μrad, which meets the requirements of the Deep Impact mission.