由于S曲线误差是星敏感器质心定位系统误差的重要组成分, 本文结合质心定位的物理过程及仿真对S曲线误差来源进行了分析。 研究了各项误差来源产生的影响, 并采用频域分析法得出了S曲线误差的理论解析式。用星敏感器产品进行了实验, 采集视场中心S曲线误差并用正弦模型进行补偿, 分析了同一补偿模型对全视场S曲线误差的补偿效果, 并对标定数据进行了S曲线误差补偿。实验结果表明: 视场中心S曲线误差的标准差为0.048 pixel, 补偿后标准差为0.027 pixel, 质心定位精度提高了43.8%; 进一步采用视场中心正弦补偿模型对全视场S曲线误差进行补偿后, 全视场质心定位精度提高了35.7%以上, 全视场标定精度提高了31.7%。由实验结果可知: S曲线误差是星敏感器的一项重要误差源, 采用正弦模型对S曲线误差进行补偿能够取得显著的补偿效果。

As the S-curve errors are important parts of centroid location errors for star sensors, this paper explored the sources of S-curve errors combining with the physical process of centroid location and a simulation. The specific effect of each error source was analyzed and an analytical expression of S-curve errors was calculated by a frequency domain method. The experiments using a star sensor were performed and the S-curve error in the center of the Field of View (FOV) was collected and was compensated using a sine model. The compensation effects on the S-curve errors in the whole FOV were analyzed by the same compensation model and the calibration data were also compensated. Experimental results show that the standard deviation of S-curve error is 0.048 pixels in the center of the FOV, and 0.027 pixels after compensation, therefore the precision of centroid location is improved by 43.8%.Furthermore, after compensating with the same sine model in the center of the FOV for whole field-curve errors, the precision of centroid location in the whole FOV is improved by 35.7% at least and the precision of calibration is improved by 31.7%. It concludes that the S-curve errors are important errors of star sensors and they can be significantly compensated by using the sine model.