面向微小卫星的星敏感器研究

Research on Star Tracker for Micro-Satellites

研制了一款新型面向微小卫星的星敏感器,采用商用器件构成以满足微小卫星对小型化的要求。星敏感器由工业镜头、DSP、低功耗CPLD和灰度型CMOS图像传感器组成。为进一步提高测量精度以满足卫星的需求,针对星敏感器的成像模型进行了分析,并用恒星校准的方式补偿了光学参数;对恒星处理算法进行了分析,在图像处理环节特别地采用了中值滤波技术,解决了孤立脉冲噪声对星点提取的影响。基于地球自转的星座跟踪实验表明,所研制的星敏感器样机欧拉角回归标准差为30″,已可实际应用于微小卫星平台。

A new design of star tracker(ST) is proposed. The STisbased on the using of commercial devices,to match Micro-satellites' compact size. The STconsists of an industrial lens,a DSP processor,a low power CPLD and a grayscale CMOS sensor. To improve the measurement accuracy,theimaging model of the STis analyzed,andthe optical parameters are compensated by in-field star calibration. The algorithm of star photoprocessing is also analyzed,anda median filter is applied to reduce the effect ofimpulse noise during star point extracting. A ST prototype is tested with field experimentsbased on the earth's rotation and constellation tracking,the results show that the prototype's RMSE( Root Mean Square Error) of Euler angleis 30″. The prototype,whichis in compact size and low power consumption,can be exactly applied to Micro-satellites.