The Study On Off-axis Optical System With Wide Field Of View For Space-Based Detection Camera

For the occupation and use of space resources,the monitoring of space targets has a wide range of application and requirements,both in terms of space utilization and space control.With the development status and future space plan of different countries showing,the wide field of view space-based monitoring satel ite with flexible shooting and strong ability of overall observation,has gradually become the inevitable trend.The development of wide FOV and high resolution Space-based monitoring camera in our country is at the start stage.With the continuous development of domestic satel ite technology and the future development of the growing number of satel ites,the research of wide field of view camera is imminent.In this paper,the design scheme of the optical system of the camera and the detection scheme of the optical system are studied,to lay the foundation for the further development of space surveillance cameras.Firstly,this paper makes a survey of the development of the domestic and international space target surveil ance cameras,and introduces in detail the space target surveil ance satel ites and their cameras in the United States,Canada and other countries,and discusses the future development trend of space surveil ance satel ite in several countries and the current domestic development condition.The target of the space surveil ance camera is a space object,and its environment has a great influence on the technical parameters of the camera.According to the characteristics of the detector and the target,a series of calculation schemes are proposed for the camera’s field of view,focal length and working spectrum.At the same time,considering the working environment,the camera must have the ability to eliminate stray light.Therefore,according to sources of stray light and different target magnitude,detector signal-to-noise ratio,optical system effective aperture,exposure to different target magnitude,this paper analyzes the ability of the optical system to eliminate the stray light.Finally,the main form of space monitoring optical system is off-axis three mirror optical system with intermediate imaging plane and the real entrance pupil.Based on the known parameters of the system,the traditional Seidel aberration theory is used to design a wide field of view off-axis reflection system with a real pupil and an intermediate image plane.Then,introduces the design method based on differential equations,which combining with geometric ray tracing,establishes the differential equations based on Fermat’s principle and sine condition,used for designing the free-form off-axis system.And then to design an off-axis reflection system with wide field of view by this method,and obtain excel ent image quality in the field of view 16o×4o.Meanwhile,this paper presents a detection scheme for the off-axis reflection system with the real entrance pupil and exit pupil.The method is a grating detection method based on sine condition,can detect the linear correlation aberration of the axis and off-axis field of view by the violation of the sine condition,which will be used to guide the adjustment.According to this test method,the single lens verification test and the off-axis reflection system simulation experiment are carried out.