Research And Design Of Multimode Satellite Imaging Simulation System

With the development of aerospace technology,the use of optical remote sensing satellites for earth observation is becoming more and more common.The development of satellite industry is crucial to the development of the country.The country has high hopes for the development of satellite industry and invested a lot of funds.In order to ensure the normal operation of each part of the function when the satellite is in orbit,it is necessary to carry out ground simulation experiments before the satellite goes to the sky,to accurately evaluate the image quality that may be obtained after launch,and to optimize the design parameters to obtain higher quality images.In this paper,the basic principle of in orbit imaging of optical remote sensing satellite is studied,and the imaging geometry model of optical camera is established.According to the imaging characteristics of different imaging modes of remote sensing satellite,a multi-mode satellite imaging simulation system is constructed based on the Visual Studio platform,and the imaging system semi physical simulation experiment is carried out.The specific work and innovations of this paper are as follows:1.The imaging process of satellite is studied,and the conversion relationship between multiple coordinate systems involved in the imaging process is deduced.Based on the collinear equation,the geometric model of imaging observation is established,and the representations of pixel vector in different coordinate systems are calculated,and the positioning of image point on the earth is realized.The MTF method for image quality evaluation is introduced,and the calculation method used in this paper is determined according to the specific situation.2.The design and verification of staring video imaging are carried out.Attitude planning of pitch and roll angle in staring process is carried out to realize the dynamic observation of specific area;in order to solve the image rotation phenomenon during imaging process,the yaw angle planning is innovatively carried out based on the principle that the angle between vector in the ground imaging area and the image coordinate axis remains unchanged after converting to same system during imaging process.According to the characteristics of staring imaging,a fast simulation algorithm combining traditional simulation method and two-dimensional Lagrange is proposed for imaging in flat area.At last,the MTF analysis of the simulation image is carried out by using the edge method.3.In view of the most widely used point push scan imaging mode,the imaging characteristics of TDICCD are analyzed,and the effects of integral series and attitude flutter on the imaging quality are studied.On this basis,a new generation of highefficiency imaging mode,non orbit imaging,is studied.The imaging principle and the difference between the imaging process and traditional point push scanning imaging are analyzed.The imaging analysis of non-orbiting targets was carried out,and the MTF curves under different integration series were calculated by the edge method.In view of the attitude error of yaw angle,the influence of different flutter amplitude and frequency on image MTF is analyzed.4.Preprocessed the original image source used in the simulation.Aiming at the problem that the size of a single image source is too large to read at one time for a computer,the work of block cutting and image coding is carried out according to the characteristics of the original image.5.Based on the above research,the imaging simulation system is constructed.The software of the simulation system is based on the Visual Studio platform,and designed with C++ language.Different parameters can be selected to simulate different imaging modes.In order to realize communication with attitude and orbit control platform,UDP protocol is used to build communication link with Socket interface,and multi-thread technology is used to realize independent work of different functional modules of the system,so as to ensure that the communication process is accurate and efficient without interference.The Camera Link high-speed image interface is used to interconnect with the image processing board,and the acquired image sequence of specific scene is injected into the hardware data link to meet the needs of algorithm debugging of image processing system with different hardware interfaces.In conclusion,for the purpose of designing and constructing a satellite imaging simulation system,this paper focuses on the simulation research of three imaging modes: staring video imaging,traditional point push scanning imaging and non orbit push scanning imaging,including attitude planning of imaging process,corresponding positioning of image point and object point,original image processing,simulation image generation,image quality evaluation,etc.The research results of this paper are of great significance to the development of imaging simulation platform and the promotion of engineering and integration of simulation technology.