星敏感器像平面移位误差的分析与校正(英文)

Analysis and calibration of star sensor′s image plane displacement

星敏感器在长时间工作后会产生三种像平面移位误差,即主点漂移误差、倾斜误差与旋转误差。星敏感器的像平面移位误差会严重影响其测量精度。以往关于星敏感器像平面移位误差的研究仅考虑了像平面三自由度的主点漂移误差。而文中还考虑了星敏感器像平面在剩余三个自由度下的移位误差,即倾斜误差和旋转误差,从而提出了一种新的星敏感器六自由度像平面移位误差模型。最后,利用扩展卡尔曼滤波方法在轨标定了星敏感器的六自由度像平面移位误差。仿真结果显示该方法将星敏感器的测量精度大幅提高到了0.23″,因此新的星敏感器像平面移位误差模型弥补了旧模型的不足,显著提高了星敏感器的工作性能。

Star sensor′s image plane can have three kinds of displacement after a long time working in space, and the displacements are the principal point drift, incline displacement and rotation displacement. These displacements can severely decrease star sensor′s measuring accuracy, therefore it′s necessary to analyze and calibrate them. The previous researches have only considered the principal point drift of image plane, which is three-degree-of-freedom. In contrast, the image plane displacements under the rest three degrees of freedom, that are the incline displacement and the rotation displacement, have been modeled in this paper. These two kinds of displacement′s influences on star sensor′s accuracy have been analyzed. And the necessity to calibrate them has been pointed out. At last, the Extended Kalman Filter has been used to on-orbit calibrate the six-degree-of-freedom image plane displacement. And the simulation results reveal that the on-orbit calibration algorithm can effectively calibrate the image plane displacement of star sensor. The measuring accuracy of star sensor has been increased to 0.23″ after the calibration. Therefore the new six-degree-of-freedom image plane displacement model has made up the deficiency of the conventional displacement model and enhance the performance of star sensor greatly.