一种大角加速度下的星跟踪算法

Star tracking algorithm under large angular acceleration

在飞行器大角加速度机动情况下,星敏感器星跟踪算法预测坐标的偏差变大导致星点扫描范围变大,星点识别时间变长,数据更新率降低,为此提出了一种采用联合星敏感器和陀螺信息预测星像坐标的星跟踪算法。该方法首先由组合导航输出的上一时刻的姿态数据和一个周期内修正后的陀螺数据积分推算下一时刻的飞行器姿态,然后通过坐标转换计算出已知恒星下一时刻在星敏感器坐标系上的星图坐标。理论分析和仿真结果表明,该方法飞行器最大角加速度30(°)/s2,最大角速度30(°)/s的情况下,预测星敏感器视场内恒星的星像坐标的偏差在10个像素以内,可使星图扫描和星点匹配快速完成,提高星敏感器的工作效率。

When the aircraft is under large angular acceleration maneuvering,the predicted deviation in the star-tracking algorithm of star sensor will be enlarged due to the widened scanning region,longer identification time and lower data update rate.In this paper,a new star-tracking algorithm is presented which exploits the information of the star sensor and gyro to solve these problems.First,the aircraft attitude at next time is calculated out by using the attitude data from integrated navigation and the angle velocity data from gyro.Second,star coordination in star image at next time is achieved by coordination transformation.The theoretic analysis and simulation indicate that the predicted deviation is within 10 pixels when the aircraft is under extreme situations with a maximum angular acceleration of 30°/s2 and a maximum angular velocity of 30°/s.Therefore star scanning and star pattern recognition can be rapidly finished,and the performances of star sensor are improved.