星敏感器标定方法研究

Calibration Method of Star Sensor

星敏感器标定是对其内部各种参数的估计,能有效减小星敏感器的系统误差,提高其姿态输出精度。根据待定系数标定和内部参数标定参数的不同,建立了星敏感器标定参数模型。并针对不同标定模型,分别介绍了各种标定参数的地面标定方法和计算方法。在分析现有在轨标定方法、比较在轨标定和地面标定的差别的基础上,重点分析了星敏感器焦距和主点等内部参数的在轨标定方法,采用扩展卡尔曼滤波对在轨星图进行处理。仿真结果表明,焦距和主点估计值的扩展卡尔曼方法较最小二乘估计法,其收敛速度快、稳定性好且精度高,在5000幅星图后输出即可稳定,可有效去除星点随机误差影响,提高标定精度。

Calibration is the estimation of the internal parameters of star sensor,which can decrease the system error and improve the pointing precision.Based on the different calibration method between coefficients to be determined and internal parameters,the calibration models are established.The different approaches of ground calibration and data processing are summarized according to different calibration models.The on orbit calibration method of focal length and optical center offset is analyzed,and the on orbit star images are processed with extended Kalman filter.The simulation results indicate that the new method can converge more quickly and eliminate the random centroiding measurement errors more efficiently than the nonlinear least squares estimation.