一种基于天体运动学的星敏感器精度测量方法

星敏感器是目前应用在航天飞行器中精度最高的姿态测量器件,因此其精度的标定显得尤为重要。该文提出了一种基于天体运动学规律的星敏感器精度测量方法,利用地球自转的精密性,将星敏感器与地球固连,对天顶邻域拍摄星图。同时将存储在星敏感器内的导航星表由J2000.0坐标系在考虑恒星自行、岁差、章动及地球自转影响后变换到地固坐标系,经过星点提取、星图识别和姿态解算,得到星敏感器俯仰、偏航和滚转三轴在地固坐标系中的变化,根据统计规律得出星敏感器的指向精度和滚转精度。该测量方法方便易实施,可以避免传统测试方法操作复杂、需要精密转台和星模拟器的困扰,测量精度满足星敏感器要求,具有准确性和真实性。

Accuracy measurement of star trackers based on astronomy

Star trackers are the highest accuracy attitude measurement devices used in spacecraft.The star tracker’s accuracy is especially important.A method was given to measure the accuracy of a star tracker based on astronomical principles using the earth’s rotation.The star tracker’s position is fixed to the earth while taking photographs of stars.The celestial coordinates in the star catalogue stored in the star tracker are transformed from the J2000.0 coordinate system to an earth fixed coordinate system taking into account axial precession,nutation,proper motion and the earth’s rotation.Pointing and roll accuracy curves are acquired after the star extraction,star map recognition and attitude solution.This method conveniently,efficiently and accurately measures the star tracker’s accuracy while avoiding traditional complex operations.Tests using a precise star simulator and a three-axis table verify the system’s accuracy.