Design and Hardware Implementation of Spaceborne Stargazing Camera System
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摘要: 为提升卫星定姿精度，采用NOIP1SN025KA型CMOS探测器设计了一款完整的观星相机。在辐照环境温度24℃、测试环境温度24℃、测试环境湿度37% RH的环境条件下利用60Co-γ辐射源进行了抗辐照实验。然后，设计了焦距为500 mm、F数为4、视场角为2.4°的光学系统。电子学系统以FPGA作为核心控制器件，控制CMOS输出数字信号，并通过TLK2711将信号传回卫星数传系统。机械结构部分主要由主镜组件、次镜组件、校正镜组件、遮光罩、支腿等部分组成。采用计量筒（殷钢）支撑次镜的设计方案，保证主次镜间隔变化在温度变化工况下满足公差要求。反射镜组件设计有径向和轴向柔性，保证光学表面在力热环境下的面形精度。校正镜组件采用压圈切向压紧镜片的安装方式，对镜片的应力小，对中性好，耐冲击和振动，能够保持良好的结构稳定性。整机通过主镜背板与卫星连接。星载观星相机具备成像和传输星点的阈值和坐标信息两种工作模式。通过外场成像实验可知，该相机成像质量良好、移植性强、可靠性高。视场角范围内，可以拍摄到约10颗星，同时可以观测到9等星，可有效辅助星敏感器工作。Abstract: A complete star-viewing camera was designed using a NOIP1SN025KA CMOS detector to improve the accuracy of attitude satellites. The anti-irradiation experiment was conducted using 60Co-γ radiation source under the environmental conditions of 24℃ irradiation temperature, 24℃ test temperature, and 37% RH test humidity. Subsequently, an optical system with a focal length of 500 mm, an F-number of 4, and a field of view of 2.4° are designed. The electronic system uses an FPGA as the core control device to control the CMOS output digital signal and transmits the signal back to the satellite data transmission system through TLK2711. The mechanical structure was mainly composed of a main mirror component, secondary mirror component, correction mirror component, baffle, and leg. The design scheme of the measuring cylinder (invar) supporting the secondary mirror was adopted to ensure that the interval change of the primary and secondary mirrors satisfied the tolerance requirements under the condition of temperature change. The mirror assembly was designed with radial and axial flexibility to ensure accuracy of the shape of the optical surface in the thermal environment. In the correction mirror assembly using pressure ring tangential pressing lens installation, the lens stress is small, good to neutral, impact, and vibration resistance, and can maintain good structural stability. The machine is connected to a satellite through the main mirror backplane. A star camera has two working modes: imaging and transmission of the threshold and coordinate information of the star point. Field imaging experiments showed that the camera exhibited good imaging quality, portability, and reliability. Approximately ten stars can be captured in the field of view, approximately 10 stars can be captured, and nine stars can be observed, which can effectively assist the star sensor.
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Keywords:
- attitude accuracy /
- optical system /
- FPGA /
- threshold
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图 1 星载观星相机光学系统结构布局
Figure 1. Layout of optical system structure for spaceborne observation camera
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图 10 CMOS成像电路板安装在基地镜筒上
Figure 10. CMOS imaging circuit board installed on the base mirror tube
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图 13 视场中与噪声灰度值相同的8.9等星
Figure 13. An 8.9 magnitude star with the same grayscale value as noise in the field of view Probability of occurrence/%
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图 14 星空不同位置观星数量的概率分布
Figure 14. Probability distribution of the number of observations at different positions in the starry sky
表 1 不同辐照累积剂量和光强条件下图像的平均灰度值
Table 1 Average grayscale values of images under different cumulative irradiation doses and light intensity conditions
TID/(krad(Si)) Light intensity/(W/m2) Dark field(0) 102 133 184 274 377 0 1.436614 139.0973 277.2640 523.7722 910.3104 1022.997 10 0 136.3080 271.7231 515.3462 899.2271 1022.995 30 8.162098 172.2558 299.8883 530.6562 893.2827 1022.997 50 0.000557 114.9043 253.6532 498.5578 876.6069 1022.997 75 0.000766 167.4559 278.3064 489.6474 822.3091 1022.986 
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表 2 光学系统设计参数
Table 2 Optical system design parameters
Parameter Parameter values Parameter Parameter values Working band/μm 0.49-0.66 Field/(°) 2.4 Focal length/mm 500 MTF(83 pairs per millimeter) 0.5 F numbers 4
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表 3 相机组件材料及属性
Table 3 Component materials and properties of camera
Material properties Lastic modulus/(GPa) Density/(g/cm3) Poisson's ratio Coefficient of thermal expansion/(10-6/K) Microcrystalline glass 91 2.53 0.3 0.05 invar 141 8.9 0.3 0.05 TC4 114 4.4 0.3 9.1
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表 4 主次镜组件模态分析结果
Table 4 Modal analysis results of primary and secondary mirror components
Main mirror Secondary mirror Order Frequency/Hz Vibration type Order Frequency/Hz Vibration type 1 391 X-axis vibration 1 791 X-axis vibration 2 391 Y-direction vibration 2 791 Y-direction vibration 3 467 Z-direction vibration 3 1067 Z-direction vibration
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[1] 何家维. 高精度全天时星敏感器关键技术研究[D]. 北京: 中国科学院大学, 2013. HE Jiawei. Study on the Key Technologies for High-accuracy and All-time Star Sensor[D]. Beijing: University of Chinese Academy of Sciences, 2013.
[2] 王军. 高动态星敏感器关键技术研究[D]. 北京: 中国科学院大学, 2019. WANG Jun. Research on Key Technologies of High Dynamic Star Sensor[D]. Beijing: University of Chinese Academy of Sciences, 2019.
[3] 罗丽燕. 基于星敏感器的星点提取与星图识别方法研究[D]. 西安: 西安电子科技大学, 2015. LUO Liyan. Research on Star Point Extraction and Star Map Recognition Methods Based on Star Sensors[D]. Xi'an: Xi'an University of Electronic Science and Technology, 2015.
[4] 段宇恒, 管亮. 基于精密星敏感器的航天器高精度姿态测量标定方法[J]. 计算机测量与控制, 2019, 27(11): 1-5. https://www.cnki.com.cn/Article/CJFDTOTAL-JZCK201911001.htm DUAN Yuheng, GUAN Liang. A high-precision attitude measurement calibration method for spacecraft based on precision star sensors[J]. Computer Measurement and Control, 2019, 27(11): 1-5 https://www.cnki.com.cn/Article/CJFDTOTAL-JZCK201911001.htm
[5] WANG W, WEI X, LI J, et al. Optical parameters optimization for all-time star sensor[J]. Sensors, 2019, 19(13): 1-17. DOI: 10.1109/JSEN.2019.2912676
[6] Moshe B. High resolution large format tile-scan camera: design, calibration, and extended depth of field[C]//2010 IEEE International Conference on Computational Photography, 2010, 5585: 5585095.
[7] 黄辉, 周进. 基于现场可编程门阵列的CCD相机自动调光[J]. 光学精密工程, 2014, 22(2): 426-433. https://www.cnki.com.cn/Article/CJFDTOTAL-GXJM201402026.htm HUANG Hui, ZHOU Jin. Automatic dimming of CCD camera based on field programmable gate array[J]. Optics and Precision Engineering, 2014, 22(2): 426-433. https://www.cnki.com.cn/Article/CJFDTOTAL-GXJM201402026.htm
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