| The satellite borne infrared imager with ultra-large swath and high-resolution can provide high temporal resolution and high spatial resolution image data.It has many advantages in the field of global vegetation observation and fine agriculture research.Due to the limitation of infrared optical system design and infrared detector technology level,infrared imager needs to use opt-mechanical scanning to achieve ultra-large swath infrared imaging.The conventional scanning imaging of constant velocity rotation has the disadvantage of low scanning efficiency.The bidirectional swinging imaging with high scanning efficiency needs to assemble scanning line corrector and spring shock absorber,which has complex scanning mechanism and low reliability.The images obtained by infrared imager have large ground distortion when infrared imager performs ultra-large swath scan imaging,which is not conducive to quantitative research and application of remote sensing data.In order to improve the detection precision of infrared imager and obtain the low distortion infrared image data,this paper studies the scanning and zoom control technology of satellite borne ultra-large swath infrared imager.The main contents of the paper include the following two aspects:(1)This paper introduces the typical payload of satellite borne wide swath infrared imaging and their scanning imaging mode,and elaborates two key technologies of infrared imager with ultra-large swath and high-resolution.This paper also designed the software and hardware of the scanning and zoom control system based on the theoretical analysis of the ultra-large swath infrared scanning imaging control system.The preliminary performance of the control system is tested.The test results show that the peak error of the positioning of scanning control system isħ0.154?,the peak velocity error of 3~o/s is withinħ1%,the maximum acceleration is 386~o/s~2,and the reorientation precision of zoom motor isħ0.001mm,which meet the requirements of the control system.(2)In this paper,two key technologies of ultra-large swath and high-resolution infrared imaging are emphatically studied.For low distortion,high scanning efficiency and high reliability imaging requirements,this paper studied the slow speed change scanning and sine acceleration fast echo control technology,and carried out the simulation and experimental test of control technology.The results show that the velocity stability of scanning imaging process is withinħ0.5%,the peak error of start and stop angle of scanning imaging is 1.44?,the state switching is stable for the state switching speed error of slow scanning and fast return is within 0.5%,the peak error of slow scanning time,fast scanning time and scanning period time is 0.083ms,0.25ms,0.333ms,the scanning efficiency of scanning control system reaches 86%.The scanning motion has no impact and vibration on the scanning mechanism,and improve the reliability of scanning mechanism.In view of the distortion requirement of ultra-large swath infrared imaging,this paper studied the position synchronized control technology of the scanning and zoom control system,and carried out the experiment of synchronous control and exterior view imaging.The experimental results show that the scanning control system has a good time synchronization with the zoom control system.The position synchronization control accuracy of two zoom motors is up toħ0.003mm,which made imaging clear in continuous zooming process.The zoom scanning imaging method can eliminate the distortion of the infrared image in ultra-large swath scanning imaging.The main innovations of this paper are as follows,studied the infrared imaging scanning control technology with low distortion,high scanning efficiency and high reliability and the multi motor nonlinear position synchronous control technology of the scanning and zoom control system.It proves that the zoom scanning imaging method can eliminate the distortion of the infrared image in ultra-large swath scanning imaging.The research results of the above two technologies provide a good technical accumulation for future space applications. |
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