Relative Alignment Error Calibration Method for Star Sensors of Spacecraft in Orbit

The problems of star sensors relative misalignment calibration and its performance evaluation are investigated. First, an integrated star sensor model including misalignment and measurement error is established. Then, measurement equations for alignment calibration are deduced individually for two different misalignment descriptions, and corresponding estimators are also designed based on Kalman filtering method. Meanwhile, the comparison is present between these estimators when applied to inflight spacecraft calibration. Furthermore, an evaluation method is developed by angle between optical axes of dual star sensors. Finally, the effectiveness of the proposed calibration method is demonstrated by numerical simulations, and the characteristic of inorbit star sensors misalignment relative to each other are also obtained by applying the proposed method with telemetry data．