Optical System Design And Stray Light Research Of A Space-based Detection Camera

With the rapid development of space technology,the competition in the field of space resources is increasingly fierce.At the same time,the more man-made satellites are launched into space,the larger the number of invalid spacecraft and space debris is.In order to meet the requirements for the safety of space environment and the increasing demand for the detection of faint targets in deep space,the space-based detection optical system with wide field of view has become a major trend.Since such space optical systems are used for the detection of faint targets,the effects of stray light are very serious.Once the stray light hits the surface of the detector,it will reduce the image contrast and the signal-to-noise ratio of the system,affect the image quality,and even lead to the failure of the system.Therefore,in order to ensure the function of space-based detection load,the effective suppression of stray light is absolutely necessary.Based on the above background,the theoretical basis of stray radiation transmission and surface scattering properties are studied in this paper,and the basic means of stray light suppression are summarized from different aspects.The following research work has been completed:(1)Design a space-based detection optical system.Through the comparison of various types of optical system structures,combined with the demands of a wide FOV and a compact structure,the optical system based on monocentric lens is selected.According to the subject index,the related parameters of the optical system were calculated.Finally,the design of the optical system with 30°×60°of FOV used the Zemax software and the image quality evaluation are completed.(2)Complete the analysis and suppression of the stray light in the system.Described the specific steps of stray light analysis in detail,and based on the designed optical structure and requirement for light and small systems,designed the baffle,vanes,and aperture stop under the limit of the size of the structure.Furthermore,thestray light analysis model is established by the Trace Pro software,and simulated analysis was performed.The PST results of the system under the influence of stray light at different off-axis angles were obtained.In combination with the calculated index of stray light suppression,the system was evaluated for the ability of stray light elimination.(3)Further improve and optimize the light shielding structure.Two new baffles is designed based on the tilting vanes.At the same time,a diaphragm is added to solve the increasing of the stray light illumination on the image surface of the system at partial angles.The simulation was performed again,and the comparative analysis of the expanded results showed that the PST values of the two improved structures all achieved reductions of 1-2 orders of magnitude.The improvement scheme better meets the requirement of indicators,and improves the overall detection capability to at least 6.5M stars.Finally,the most suitable shading structure was selected through comprehensive analysis.The research work in this paper has achieved the effective suppression of stray light of the space optical system with wide FOV under the limitation of short baffle,and improved the system's ability of stray light suppression by improving the structure.