【作者】 谭迪；

【导师】 张新；

【作者基本信息】 中国科学院长春光学精密机械与物理研究所 ， 光学工程， 2017， 硕士

【摘要】 星敏感器是实现飞行器惯性空间三轴姿态高精度测量的设备,具备高可靠性、轻小型化、低功耗等特点,已经成为天文导航中姿态测量精度最高的仪器,其精度水平的提升对我国空间技术水平的发展有着重要意义。在秒级甚至亚秒级高精度星敏感器系统中,通常采用亚像元质摘心定位技术完成星点提取过程,以使单星星点质心定位精度达到亚像元甚至更高的精度级别,决定了星敏感器系统姿态测量精度的极限。在亚像元质心定位技术中,影响其星点质心定位精度的误差源之一是星点弥散斑模型的选取。传统的方法采用高斯函数描述星点弥散斑的分布,忽略光学像差的影响,已经无法满足实现甚高精度星敏感器的要求。作为决定星敏感器工作性能的第一要素,星敏感器光学系统对探测口径和视场有较高的诉求,光学像差的客观存在性与复杂多样性,将导致星点弥散斑分布的差异性,从而进一步改变星点质心定位误差分布。所以,本文针对甚高精度星敏感器的实际需求,将理论分析与数值仿真有机结合,重点研究了光学像差对亚像元质心定位精度的影响机理与分布规律,并完成大视场、无热化、高精度星敏感器光学系统设计,具体工作内容包括:1.对亚像元质心定位技术进行了研究,包括应用机理、部分细分算法、噪声源等方面。探讨了亚像元质心定位技术对星敏感器探测能力与测量精度的影响,采用解析推导与数值分析结合的方式,证明传统星点高斯弥散斑模型已不能满足星敏感器秒级甚至亚秒级精度的要求,研究光学像差对亚像元质心定位技术的影响是追求甚高精度星敏感器的必然选择;2.基于光学像差理论,借助夫琅禾费衍射理论、Zernike像差多项式分析像差光学系统中星点弥散斑分布的空间特性,并辅以光学设计软件Zemax完成了验证;3.采用数值分析与程序编写相结合的方法,揭示各类光学像差对亚像元质心定位精度的影响机理和分布规律,推导出光学像差与质心定位误差的函数关系,为抑制或消除光学像差对亚像元质心定位精度的影响提供理论依据;4.综合各类光学像差对亚像元质心定位精度影响程度的差异性,提出了星敏感器光学系统设计时的像差控制准则,用于指导高精度的星敏感器光学系统设计;5.采用的光学设计软件CODE V,依据像差控制准则及其他星敏感器光学系统技术指标的要求完成了大视场、无热化、高精度星敏感器光学系统设计,为F/1.5、FOV/26°的折射式复杂双高斯系统,并对系统进行了像质评价、光谱分析、热适应分析与质心定位精度分析。更多还原

【Abstract】 Star sensor is a spatial measurement instrument with the highest the three-axis attitude accuracy of spacecraft in the inertia space,and notable characteristics of the new generation of star sensor includes high reliability,well environmental adaptability,miniaturization,less power consumption etc.Achieving higher accurate star sensor is of great significance to enhance the development of country space technology.In the star sensor system with ultra-high precision,sub-pixel centroid positioning technology is generally used to single-star centroid location accuracy to achieve sub-pixel or even higher centroid location accuracy during the star point extraction process.Single-star centroid location accuracy directly affects the success rate of pattern recognition and output attitude-angle accuracy,and determines the star sensor attitude measurement limit accuracy.In research on the sub-pixel centroid location technique,one centroid location error is selection of spot model of star image energy in the subdivision algorithm.The traditional method ignored the influence of optical aberration,and used the Gauss function to describe the distribution of star spot,which has been unable to meet the requirement of realizing the ultra-high precision star sensor.As the primary factor of constraining star sensor performance,optical system has high demands on the detection aperture and field of view,so the objective existence of optical aberration and complex diversity will lead to differences in the star spot distribution,so as to bigger centroid location error.Therefore,in this paper,the theoretical analysis and numerical simulation are combined to exploring the influence of optical aberrations on centroid location error,and the large field of view,athermal,high-precision star sensor optical system is designed.Main studying tasks are as follows:1.Sub-pixel centroid location technology is studied in details,including its working process,partial subdivision algorithm,noise source and so on.According to discussing the influence of sub-pixel centroid location on the detection capability and measurement accuracy of star sensor,this paper proves the irrationality of Gauss function spot mode and concludes that exploring the effects of optical aberration is the inevitable choice to upgrade the centroid location accuracy.2.Based on the Fraunhofer diffraction theory and Zernike aberration polynomial,this paper analyses the spatial distribution characteristics of star spot in aberrated optical system,and supplements the verification with optical software Zemax.3.By means of numerical analysis and programming,this paper reveals effect mechanism of optical aberration on sub-pixel centroid location accuracy,and The analytical expression of location error is calculated combining with the physical process of centroid location.The result will provide a theoretical basis for suppressing or eliminating the centroid location error for aberration;4.This paper integrates different influence of various aberrations,and the analysis of error will help to guide the latter systematic error compensation,and principle of controlling optical aberration will guide the optical system design of star sensor.5.This paper chooses a complex double-Gauss optical system as the basic structure,including eight optical elements,and then optimizes the design based on the use of CODE V optical software until achieving a high precision optical system of star sensor,which meets a view field of 26°,an F-number of 1.5.更多还原