一种星敏感器-陀螺组合定姿的实时在轨标定方法

研究了一种星敏感器一陀螺组合定姿方式中的姿态敏感器误差的实时在轨标定方法。首先，选择直观的欧拉角作为姿态描述参数，根据星敏感器和陀螺的测量原理建立星敏感器一陀螺在轨标定的测量方程和状态方程，并以此建立数学模型。其次，采用简单高效的EKF（ExtendedKalmanFilter，扩展卡尔曼滤波）作为估值算法，进行了在轨标定数值仿真。对于航天器姿态定向中出现的姿态角和星敏感器安装角之间的耦合问题，通过在特定姿态通道上施加简单姿态机动实现了解耦。数值结果表明，该实时在轨标定方法，尤其是所提出的姿态角和星敏感器安装角解耦策略，可以实现对航天器姿态的实时精确估计以及对星敏感器安装误差、陀螺常值漂移和相关漂移等误差的实时在轨标定。该方法可用于航天器姿态测量设备的实时在轨标定和航天器姿态的高精度实时确定。

A Realtime On-Orbit Calibration Method for Integrated Attitude Determination by Gyros/Star Sensors

A realtime on-orbit calibration method for attitude sensor errors by gyros/star sensors is studied. First, simple Euler angle is chosen to be an attitude parameter and a mathematic model of on-orbit calibration is construc- ted. The model consists of measurement equations and state equations derived from the measurement principles of star sensors and gyros. Then, efficient extended Kalman filter （EKF） is used as an evaluation algorithm and numer- ic simulation is done for the proposed method. Furthermore, coupling between attitude angles and installation angles of star sensors is observed and simplified maneuver is applied on specific attitude channel to fulfill decoupling. The numeric simulation results show that the above on-orbit calibration method and the decoupling strategy are effective to precisely estimate spacecraft attitude and they are efficient for calibration of the installation errors of star sensors and constant and relative gyro drift. The method in the paper can be used in realtime on-orbit calibration of attitude sensors and realtime precise spacecraft attitude determination.