Parameter calibration and error compensation of star sensor
摘要
A star sensor model is established by geometrical method on the basis of an ideal pinhole model in consideration of the error factors such as inaccurate focal length of the optical system of star sensor,plane tilt and rotating of CCD,and optical lens distortion etc.Based on the ground experimental data,the mathematical model is solved by least square method,the calibration parameters such as focal length,plane tilt and rotating factors of CCD and distortion factors etc can be obtained.The incident ray vector can be directly calculated and corrected from the measured star coordinates through substituting the calibration parameters into the mathematical model,thus the errors of the optical system can be compensated.The calculation results show that the statistical error of interstellar angular distance is reduced from 41 before calibration to 17,the calculation accuracy is improved.