Study On Key Techniques Of Star Map Simulation In Dynamic Star Simulator

Star sensor is a kind of high-precision attitude measurement device that takes stars as a reference system.It determines the carrier attitude by detecting stars at different positions on the celestial sphere.Due to the difficulties in air calibration,low reliability and extremely high price,it is particularly important to test and calibrate the star sensor on the ground.The simulation level of the dynamic star simulator determines whether it can effectively test and calibrate the performance and indicators of the star sensor on the ground.To the ground in the face of star sensor function test,high precision star simulator,a smaller field of view requires large distortion of optical system,however,due to the limitation of the liquid crystal light valve resolution,a liquid crystal light valve after the precision of calculation can't meet the requirements of indicators,this paper puts forward a method of adopting physical joining together to joining together of two pieces of liquid crystal light valve,and the corresponding optical system design.In this paper,the star map simulation software is designed,and the design of each part of the software module is given,and finally the star map simulation system and the star sensor test system closed loop test is realized,and the star sensor quasi-certain attitude test experiment is completed.The star map simulation system of the dynamic star simulator USES an SAO catalog of 58928 stars for retrieval.According to the original star traversing algorithm,the total time of star point retrieval and star map refresh is about 200 ms,which does not meet the index requirement that the star map refresh time is higher than 10 Hz.In this paper,the original catalog was divided into 16 sub-regions according to longitude and latitude by the method of partitioning the whole catalog.The average number of stars in each sub-region was less than 4000.The software imported the corresponding sub-regions according to the optical axis and generated the corresponding star map,which greatly reduced the time required for star traversal.The experimental results show that the refresh time of simulated star map can be improved to more than 40ms(25Hz)after catalog partition retrieval,and the high dynamic attitude test function of star sensor can be realized.Finally,the simulation accuracy of the star map of the dynamic star simulator was analyzed.The maximum position error of the single star simulation was 7.7 "< 10",17.4 "<18",and the maximum angular distance error of the simulated star map was 34.84 "< 35",both of which met the requirements of the star map simulation of the dynamic star simulator.