Low-Frequency Error Extraction and Compensation for Attitude Measurements from STECE Star Tracker.

The low frequency errors (LFE) of star trackers are the most penalizing errors for high-accuracy satellite attitude determination. Two test star trackers- have been mounted on the Space Technology Experiment and Climate Exploration (STECE) satellite, a small satellite mission developed by China. To extract and compensate the LFE of the attitude measurements for the two test star trackers, a new approach, called Fourier analysis, combined with the Vondrak filter method (FAVF) is proposed in this paper. Firstly, the LFE of the two test star trackers' attitude measurements are analyzed and extracted by the FAVF method. The remarkable orbital reproducibility features are found in both of the two test star trackers' attitude measurements. Then, by using the reproducibility feature of the LFE, the two star trackers' LFE patterns are estimated effectively. Finally, based on the actual LFE pattern results, this paper presents a new LFE compensation strategy. The validity and effectiveness of the proposed LFE compensation algorithm is demonstrated by the significant improvement in the consistency between the two test star trackers. The root mean square (RMS) of the relative Euler angle residuals are reduced from [27.95'', 25.14'', 82.43''], 3σ to [16.12'', 15.89'', 53.27''], 3σ.