Abstract: This paper studies the star sensor low frequency error (LFE) inflight calibration problem. The star sensor LFE, which is caused primarily by the periodic thermal distortion, has a great impact on the satellite attitude determination accuracy. To cope with this problem, we propose a novel LFE calibration method. An augmented Kalman filter (AKF) is adopted to estimate the satellite attitude and the LFE parameters simultaneously. It is specified that the attitude determination accuracy can be improved by using the proposed LFE calibration method. The star sensor LFE model for numerical simulation is established based on the telemetry data from real star sensors operating under inorbit conditions. The simulation results illustrate the efficiency of the proposed method.