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.