Star sensor model parameter analysis and calibration method

With the interstar angle statistical residual as an evaluation standard for accuracy calibration, the geometry parameters of a high-resolution planar-array CMOS star senor model are analyzed with a conclusion of that the influence of focal length on accuracy is the largest and then the distortion, and finally the principal point. Based on the analysis, a star sensor calibration scheme is proposed. In the scheme, data are sampled by a high-accuracy 2-D axial rotating platform and a single starlight simulator, the focal length offsets of principal point are calculated with least square parameter estimation methods, and the focal plane distortion is fitted by a 2-D polynomials of 10th degree. The simulation results show that under the noise level of 0.03 pixels error the calibration accuracy of 1 arc-second can be obtained by the scheme and it can meet the demand of high-accuracy attitude-measurement of modern space spacecrafts.