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传统的星敏感器预报方法是利用当前四元数和陀螺输出角速度来预测下帧姿态四元数,再通过预测的四元数计算视场内恒星的理想星像坐标,最后在这些理想坐标为中心的范围内来获取实际的星像坐标。但是,由于陀螺漂移的存在,随着时间的增加,预测的理想坐标与实际坐标偏差越来越大,获取实际星像坐标扫描的区域越来越大,星敏感器的数据更新率也随之降低。为此,本文提出了一种适用于星敏感器的大角速度下星跟踪算法。首先根据连续两帧的姿态偏差计算星敏感器的角速度,利用角速度来计算星敏感器当前时刻与最近上一帧的姿态偏差。然后以该姿态偏差来预报当前时刻的星敏感器姿态输出,这样不仅提高了数据更新率,而且满足飞行器在大角速度机动时单纯采用星敏感器进行姿态测控的要求。最后,采用2010年外场试验实际观星数据对该算法进行了仿真验证。
The traditional method of star sensor prediction uses the current quaternions and gyroscopic angular velocities to predict the quaternion of the next frame, and then calculates the ideal astronomical coordinates of the stars in the field of view through the predicted quaternions. Finally, at these ideal coordinates of Center to get the actual star coordinates. However, due to the existence of gyro drifts, as the time increases, the deviation between the predicted ideal coordinate and the actual coordinate becomes larger and larger, and the area for acquiring the actual star image coordinate scanning becomes larger and larger, and the star sensor data update rate also follows reduce. To this end, this paper presents a star sensor for high-speed star tracking algorithm. Firstly, the angular velocity of the star sensor is calculated based on the attitude deviation of two successive frames, and the angular velocity is used to calculate the attitude deviation between the current time of the star sensor and the last frame. Then, the attitude deviation of the star sensor is used to forecast the attitude output of the star sensor at the current moment, which not only improves the data updating rate but also meets the requirements of the star sensor for attitude measurement and control at high angular velocity maneuvers. Finally, the algorithm is verified by using the actual star-observing data from field experiments in 2010.