| Space science and technology has important strategic significance for all thecountries in the world to compete for space resources. And the space-to-groundimaging technology is one of the core purposes of developing space science andtechnology. The space-to-ground imaging is able to carry out the multi-level,all-round and three-dimensional observation activities for the targets of land, sea, airand so on. It plays increasingly important effect in many aspects such as safeguardingnational security, promoting technology advancement, accelerating related industriesdevelopment and so on.With the technology mature of aeronautical and space, optical, microwave and soon, the space-to-ground imaging is developing rapidly for the target of wide view andhigh resolution. However, the domestic research starts lately in this field, and thetechnology level has fallen behind the United States as the representative of thedeveloped countries in the west. Based on the current status of the research, the mainresearch content of the paper focuses on solving two key technologies in thespace-to-ground imaging large inertia scanning control and synchronal imagemotion compensation by means of the technology foundation of Shanghai Institute ofTechnical Physics in the field. The large inertia scanning is used to expand the field ofview, and the synchronous image motion compensation resolves the image motionproblem in the space-to-ground imaging in order to improve the image resolution.And it will achieve the technological requirements of wide view and high spatialresolution in the process of the space-to-ground imaging.A scanning imaging scheme of "frame imaging+whole mechanism+pendulumscanning" is proposed. The advantages of the design scheme and thetechnological difficulties it bring are discussed in theory. According to the controlrequirements of the large inertia and high precision in this paper, the keycomponents of system are analyzed in detail. Through analyzing themathematical model of the selected operating motor in different coordinatesystems, the current control strategy and control method of space vector havebeeen determined ultimately.It has made the modeling and simulating of above-mentioned scanning imagingscheme, proving the reasonableness and achievability of the design scheme. The particularity of "pendulum scanning" and "large inertia" are analyzed in theory,and the corresponding solutions are proposed. Ultimately the scanning imagingsystem is fulfilled specifically by the software system and hardware circuit. Andthe PC interface based on LabVIEW is designed, achieving the real-timecommunication between the PC and scanning system.In order to calculate the image motion accurately, the ground, camera and focalplane coordinate systems are established. Based on the coordinate systems, theimage motion calculation formulas are deduced. And it has made the statisticalerror analysis and simulating of image motion compensation. The compensationformulas of flight direction and scanning (roll, pitch, yaw) direction are obtainedby the detailed calculation. According to above-mentioned compensationformulas, the real-time image motion compensation is fulfilled by thegalvanometer compensation system in engineering, obtaining the actual imagingeffect images of the simulated flight, roll, pitch, yaw and scanning direction. Andeach compensation error is obtained by the separate calculation.The scheme that using one-dimensional method fulfills two-dimensionalcompensation is proposed innovatively. Through rigorous mathematical deducing,the reasonableness and achievability of the scheme is proved in theory. And theformulas corresponded with the compensation method are deduced. Finally, thetwo-dimensional compensation system is designed by the scanning imagingsystem and cam compensation system. The thinking and method have a certainreference function for the related research on image motion compensation. |
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