Research On Wide Field And Broad Spectrum Push-broom Optical System

The remote sensing monitoring of water environment is a powerful means to obtain water pollution information.The spectral response of suspended solids in water is mainly concentrated in the visible and shortwave infrared band,the spectral range is wide.In addition,the wider the field of view of the remote sensing camera can cover the wide surveillance area,which is of great significance to improve the time resolution,shorten the resetting cycle and achieve high density observation.Therefore,it is very important to carry out the research of large field of view,wide spectrum and medium and high resolution optical system in order to realize the monitoring of chlorophyll content,sediment content,shallow water terrain and pollution,with 100 meters level of spatial resolution in 800 km sun synchronous orbit.In this paper,we study the status quo of some typical remote sensing satellite loads at home and abroad.In order to realize high spatial resolution,wide spectrum and large field coverage at the same time,most of the satellites at home and abroad are carrying multiple loads such as CCD camera and infrared camera.This paper also discusses the characteristics of refraction,refraction and total reflection optical systems,and their respective application areas.Aiming at the characteristics of water environment remote sensing system,this paper designs an off-axis three-reverse system.The operating wavelength of the system is 0.4 ~ 1.26?m,the diameter is 30 mm and focal length is 120 mm.The long field of view is 30 ° × 4 ° through the off-axis of the field of view,and the system can meet the needs of large field of view,wide spectrum and medium and high resolution.In this paper,the machining and fitting tolerances of the system are analyzed.The relative refraction system of the off-axis three-mirror system is loose and susceptible to stray light.So the stray light is analyzed for the off-axis trio.According to the general analysis procedure of spurious,the system point source transmission function(PST)curve is obtained,and the result of the PST curve shows that the system is stray light suppression ability to meet the requirements.Another difficult point of the off-axis three-mirror system is that the mirrors are aspherical,and even high-order aspheric surfaces are used.This paper summarizes the commonly used processing and inspection methods of the mirrors.For the system of this paper,a compensation test scheme and processing equipment to adjust the program for three mirrors are designed,and reduced the difficulty of test and adjust of the off-axis three mirrors.Through the research of this subject,the feasibility of high-field,wide-spectrum and medium-high resolution is demonstrated.