Calibration of Relative Deviation of Star-Sensor

The attitude determination precision of strap-down star-sensor restrict by its relative installation error, which must be calibrated and compensated. In this paper an algorithm for the calibration of relative deviation of star sensor is presented based on gyros and star-sensors. For the issue of relative deviation between star-sensors in the gyro/star-sensor attitude determination system, this paper sets one star-sensor as the fiducial star-sensor, relative deviation is reflected in the form of multiplicative noise in the output of the other. Extended Kalman filter (EKF) is used to estimate the state variable, which the relative deviation error is expanded into, in real time to improve the precision of attitude. Simulation results demonstrate that this on-orbit algorithm is effective to calibrate the relative deviation between star-sensors.