星敏感器模型参数分析与校准方法研究

Star sensor model parameter analysis and calibration method

以星内角统计偏差为校准精度评价指标,分析了高解析度面阵 CMOS 星敏感器模型中主要参数,得出焦距对精度影响最大,畸变次之,主点位置影响最小。由此提出了一种星敏感器校准方案,利用高精度 2 维轴向转台和单星星光模拟器采集数据,采用最小二乘参数估计算法计算主点焦距偏差,并且用 10 参数的二维多项式基函数拟合焦平面畸变。仿真结果表明在 0.03 像素误差的噪声水平下该方案能够达到 1″精度,可以满足现代空间飞行器的高精度姿态测量要求。

With the interstar angle statistical residual as an evaluation standard for accuracy calibration, the geometry parameters of a high-resolution planar-array CMOS star senor model are analyzed with a conclusion of that the influence of focal length on accuracy is the largest and then the distortion, and finally the principal point. Based on the analysis, a star sensor calibration scheme is proposed. In the scheme, data are sampled by a high-accuracy 2-D axial rotating platform and a single starlight simulator, the focal length offsets of principal point are calculated with least square parameter estimation methods, and the focal plane distortion is fitted by a 2-D polynomials of 10th degree. The simulation results show that under the noise level of 0.03 pixels error the calibration accuracy of 1 arc-second can be obtained by the scheme and it can meet the demand of high-accuracy attitude-measurement of modern space spacecrafts.