Navigation Stars Correction Method of Rolling Shutter Exposure Star Tracker Based on Time Domain Constraint

Aiming at the problems of reduced navigation star points positioning accuracy and increased attitude error caused by dynamic star points imaging shape distortion and imaging position error of the star tracker in the rolling exposure mode,a navigation star points correction method based on time domain constraints is proposed. Based on the time asynchronous characteristics of rolling shutter exposure,combined with the optimal estimation of navigation star points positions and inter-frame velocity based on Kalman filter,the navigation star points at different moments in the time domain are corrected to the same time,thereby effectively solving the problem of star points distortion and position offset. The simulation experiments under different conditions were carried out. The experimental results show that when the angular velocity of the star sensor is within the dynamic range of 0～3°/s,the distance accuracy of the star pair after correction is higher than 0.1 pixels,attitude angle accuracy is higher than 10″.

A star correction method based on time-domain constraints is proposed to address the problem of star distortion and position shift after imaging caused by the asynchronous exposure time of the roller shutter. By combining the optimal estimation of position and velocity based on Kalman filtering, navigation stars in different time domains are corrected to the same time. When the angular velocity is less than 3 °/s, the corrected star to star distance accuracy is higher than 0.1 pixels, and the attitude angle accuracy is higher than 10 ″, effectively solving the problem of star point distortion and position deviation caused by rolling shutter imaging, and improving the star sensor’s star point centroid positioning accuracy and attitude accuracy.