基于EKF的航天器姿态确算法定及精度分析

采用陀螺和星敏感器组合的方式来进行航天器姿态确定。首先建立了陀螺和星敏感器的测量模型，选择以四元数作为描述航天器姿态的参数，详细推导了在小偏差下以误差姿态角和陀螺常值漂移误差为状态量的滤波状态方程，并且以星敏感器的测量残差作为量测量，采用扩展卡尔曼滤波（Extended Kalman Filter, EKF）算法进行姿态确定；然后进行了仿真分析，仿真结果表明：该算法可以达到较高的姿态确定精度；最后对影响姿态确定精度的硬件因素和软件因素进行了定量的数据分析，得出了有一定意义的结论，从而为工程实践提供理论支持。

Spacecraft Attitude Determination Algorithm and Precision Analysis Based on EKF

The combination of gyro and star sensor is used to determine the attitude of the spacecraft. Firstly, the measurement model of gyro and star sensor is established with quaternion as a parameter to describe the attitude of a spacecraft. The filtering state equation with error attitude angle and gyro constant drift error as the state quantity under small deviation is deduced, and the Extended Kalman Filter (EKF )algorithm is used to determine the attitude of the star sensor. Secondly, the simulation results show that the proposed algorithm can achieve high accuracy of attitude determination. Finally, the hardware factors that affect the accuracy of attitude determination and software factors for quantitative data analysis, some meaningful conclusions is achieved, so as to provide theoretical support for engineering practice.