摘要
为实现星敏感器在J波段对3等恒星进行全天时高精度探测,采用被动消热差设计方法,根据光学系统与结构材料的热差性能差异,进行匹配优化实现镜头消热差,设计完成了一种大相对孔径全天时星敏感器光学系统。针对恒星在该波段下的指标进行分析,确定光学系统焦距为84 mm,F数为1.4,工作谱段范围为1.1~1.4μm,视场角为8.4°。在光学系统设计过程中选取常用光学材料和镜筒材料,通过改变各透镜形状,合理匹配各镜片之间的光焦度,从而实现被动补偿无热化设计。优化设计完成后的光学系统在高低温(-40℃~+60℃)及真空条件下,当离焦0.02 mm后,弥散斑尺寸优于30μm,色畸变小于0.018 mm。星敏感器内部采用表面发黑处理,遮光罩采用非等间距布局设计,表面采用一款具有较高太阳吸收率的SB-3A国产消光漆进行涂黑,可以在保证效果的情况下有效减轻重量,遮光罩内档光环采用16°斜角,可以保证较好的杂散光抑制能力。利用Tracepro软件对光机系统的杂散光进行了仿真分析,分析结果表明,视场内由目标产生杂散光是目标强度的3×10^(-5),视场外杂散光强度由10^(-2)量级迅速下降,18°以外杂散光强度为视场外强光的10^(-4)以下。地面观星试验实现了对3等星全天时探测,验证了该光学系统设计的合理性。
Star sensor is a high-precision space attitude measurement instrument with high precision,good autonomy and independent existence of other systems.It takes the starry sky as the working background and stars as the benchmark to obtain the attitude information of the spacecraft by detecting stars in different positions in space.Therefore,its accuracy is the key factor affecting the overall performance of the whole system.The all day star sensor is a star sensor that can still detect stars under the strong background in the daytime and has the anti-interference ability to the strong sky background.As the most important part of the optical system,its imaging quality is very important to improve the star detection ability of the star sensor.However,with the development of aerospace technology,space science has higher and higher requirements for the attitude accuracy of spacecraft.Therefore,in order to meet the needs of all-time highprecision detection,the lens of the star sensor optical system must adopt a large relative aperture to improve the star detection ability.In order to realize the all-time high-precision detection of class 3 stars by star sensor in J-band,this paper adopts the method of passive thermal difference design,carries out matching optimization according to the thermal difference performance difference between the optical system and structural materials,and then realizes lens thermal difference elimination.An all-time star sensor optical system with a large relative aperture is designed and completed.Firstly,the irradiance and signal-to-noise ratio of class 3 stars in the J-band are analyzed to determine the main parameters of the optical system,in which the focal length is 84 mm,the F number is 1.4,and the working spectrum range is 1.1~1.4μm.The field angle is 8.4°.Secondly,considering that the optical system of the star sensor has the characteristics of a large relative aperture,long focal length and the influence of optical system distortion on the accuracy of star point extraction,the distortion free telephoto objective is selected as the initial structure of the optical system for optimization.In the process of optical system design,common optical materials and lens barrel materials are selected.By changing the shape and thickness of each lens,the focal power and air gap between each lens are reasonably matched,so as to realize the passive compensation non-heating design.After the optimized design,the dispersion spot size of the optical system is better than 30 when the defocus is 0.02 mm under the conditions of high and low temperature(-40℃~+60℃)and vacuumμm.The color distortion is less than 0.018 mm,and the design results meet the design requirements.The inner surface of the star sensor is blackened,the light shield is designed with nonequidistant layout,and the surface is blackened with an SB-3A domestic extinction paint with high solar absorption,which can effectively reduce the weight under the condition of ensuring the effect.The inner baffle ring of the light shield adopts a 16°oblique angle,which can ensure good stray light suppression ability.The stray light of the optical mechanical system is simulated and analyzed by using TracePro software.The analysis results show that the stray light generated by the target in the field of view is 3×10^(-5) of the intensity of the target,the stray light intensity outside the field of view decreases rapidly from the order of 10^(-2),and the stray light intensity outside 18°is less than 10^(-4) of the strong light outside the field of view.Finally,the actual ground star observation test is carried out on the principle prototype.Through the star photos and three-dimensional energy diagram taken by the principle prototype,it can be seen intuitively that the signal intensity of the class 3 star target is much greater than the background intensity.After subsequent image processing,a clearer star observation effect can be obtained.Through theoretical analysis and design and practical observation experiments,it is verified that the optical system designed in this paper can meet the requirements of all-time high-precision detection of class 3 stars in J-band,which also shows the rationality of the design of the optical system.
作者
张凯胜
苏秀琴
叶志龙
ZHANG Kaisheng;SU Xiuqin;YE Zhilong(Xi’an Institute of Optics and Precision Mechanics,Chinese Academy of Sciences,Xi'an 710119,China;University of Chinese Academy of Sciences,Beijing 100049,China;Shanghai Aerospace Control Technology Research Institute,Shanghai 201109,China)
出处
《光子学报》
EI
CAS
CSCD
北大核心
2022年第11期274-284,共11页
Acta Photonica Sinica
基金
中国科学院战略高技术创新基金(No.GQRC-19-19)。
关键词
大相对孔径
全天时
星敏感器
光学系统
无热化
Large relative aperture
All day
Star sensor
Optical system
Athermalization
