Research On Measuring Method Of Star Simulator Accuracy

Star simulator is an important equipment for ground calibration and functional verification test of star sensor precision.The measuring level of accuracy of single star position error,a major technical index of star simulator,directly affects the calibration accuracy of star sensor,which will affect the accuracy of attitude determination of satellite in orbit finally.Therefor,aiming at the measuring problem of single star position error of star simulator within ? 35.5° view field,this paper does some research about the measuring methods of star simulator accuracy.That is of great significance for improving the measuring level of star simulator accuracy and the study of star sensor with high precision.Based on the analysis,research and summary of the existing star simulator precision measuring methods,this paper presents a measuring method combining theodolite and plane array CCD,and studies the corresponding measuring system.An star imaging optical system with high imaging quality is used to image the star image in the view field of theodolite on CCD.The star image is collected and sent to PC by a CCD image acquisition system.Finally,the measure of accuracy of single star position error is realized by using sub-pixel centroid extraction algorithm to determine star position.According to the star point imaging requirements,a high imaging quality star imaging optical system is optimal designed by ZEMAX software.The analysis results of image quality evaluation show the star image is good;A computer CCD image acquisition system is designed to collect star image,process signal and transmit data;By the study of sub-pixel square weighted centroid extraction algorithm,a software for extracting star centroid is designed by MATLAB.The simulation experiment of algorithm proves the position measure accuracy can reach sub-pixel level.Finally,through the error analysis and experimental verification of the whole test system,the results show that the range of the test system is ? 35.5°,and the measuring precision is better than 5''.