| Star sensor is a kind of high-precision attitude measurement instrument.It uses stars for three-axis attitude measurement and provides attitude information for spacecraft.It is an indispensable part of spacecraft attitude control system.The traditional star sensor generally has the problems of high quality,volume and power consumption,and the traditional star sensor system processing link is complex.This paper takes the star sensor as the research object,and mainly studies the embedded processing link of the system.The research work in this paper mainly includes the following contents:(1)The embedded physical link of the star sensor system is studied.In view of the problems of complex link processing and large circuit size in the current mainstream design scheme of star sensor system,this paper uses the "ARM+CMOS" image sensor architecture to build the star sensor system,carries out the circuit design of the system physical link,and evaluates the circuit design parameters.The correctness of physical link circuit design of star sensor system is verified.(2)The embedded algorithm link of star sensor system is studied.The algorithm realization of star map preprocessing and centroid positioning is carried out.The centroid extraction accuracy is compared by using centroid method,Gaussian fitting method and weighted centroid method.In this paper,the centroid method with higher accuracy is adopted to achieve centroid extraction.In the part of star map recognition,in order to improve the reliability of star map recognition algorithm,an improved triangle recognition algorithm is proposed.By comparing with the traditional method,it is found that the star map recognition method proposed in this paper has a strong ability to resist the interference of "pseudo-star".The proportion of pseudo-star reaches 40%,still has a recognition success rate of 98.2% and no error recognition occurs,which has good robustness.In the attitude solving part,the attitude solving algorithm is implemented,and the experiment is carried out for the attitude solving accuracy of the star sensor.The mean error of pitch Angle,yaw Angle and roll Angle is only-0.217″,0.2034″,-0.578″,respectively.A star sensor is used to measure the attitude of the star map simulated by the star simulator.The result of the algorithm is compared with the quaternion provided by the star simulator to verify the correctness of the link of the algorithm.(3)The embedded data link of the star sensor system is studied.The device tree,device driver and user layer data stream acquisition program involved in the transmission process of star map data stream are designed.Aiming at the way of processing star map data stream by data link,this paper proposes a multi-thread processing strategy.Through comparison and analysis with single-thread processing strategy,experiments show that multi-thread star map data stream processing strategy improves the overall processing efficiency by 25.08%compared with single-thread processing. |
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