Research On Relationship Of Satellite Flutter On-orbit Versus Positioning And Imagery Quality

With the successful launch of ZY-3satellite, the process of survey and mapping in China reaches a new high level with a steady step. Many problems after the launch concern the core of potential of satellite application and specification certification of satellite design, which also symbolize whether the purpose is reached. The problems of imaging on-orbit、calibration on-orbit and et al are the key to surveillance whether the satellite is matched to the expected satellite indicators. The satellite flutter on-orbit is the main factor of low quality of CCD imaging system on-orbit and the change of systematic parameters. On the organic synthesis of photogrammetry, remote sensing, spatial dynamics, space geometry, and many other disciplines, this paper research on the effect of satellite flutter on-orbit to imaging quality of survey and mapping satellite and geometry positioning.Satellite flutter on-orbit result in dispersed spots、imaging dislocations、imaging distortion and low quality of satellite images when CCD imaging system on-orbit photography. Meanwhile, they will cause the change of focal length、the deviation of principal point、the change of optical distortion parameters when it achieves geo-referencing. On summary, satellite flutter causes deviations of above problems concerning whether is successful of satellite imagery on-orbit. In this paper, we systematically study the effect of satellite flutter on-orbit to satellite imaging on-orbit from the conception of satellite flutter、detection of satellite flutter、the simulation of satellite flutter、geometric calibration on-orbit of satellite flutter、he assessment of image quality of satellite flutter、the compensation of imaging quality of satellite flutter by means of quantitative inversion and digital simulations.In this paper, the main content:1、The conception of satellite flutter on-orbit.Satellite flutter is different from satellite vibrations, which cause deformation of rigid body of satellite imaging system and can be detected by the instruments. The problems of satellite flutter are more complicated. They can not yet be acquired by position or attitude sensors now. And this is why we use the quantitative inversion method.2、The detection of satellite flutter on-orbit.Nowadays, there exists no way to get amplitude and frequency of flutter by measure system with real-time. But we can use high speed small area-array CCD to do the inversion of satellite flutter and acquire imaging positioning and attitudes of CCD (Charge Coupled Device, CCD) imaging system by the contrasting to the image of extraction of every frame and reference image with imaging motion model.3、The problem of calibration of satellite flutter on-orbitIn this paper, we derive the geo-referencing model of satellite flutter when the flutter occurs. This paper simulates the change of intrinsic and extrinsic parameters to accuracy of geo-referencing by intrinsic model of satellite imaging system. This paper validates the calibration of single image and self-calibration on the basis of simulation data of SPOT5.4、The MTF calculation of satellite flutter on-orbitMTF can be measured by software、hardware in the lab, which is the important indicator of imaging quality of imaging system. But the measurement of MTF on-orbit restricts such methods because of the environment of spatial imaging. We use the special surface features with a huge contrast to do inversion of MTF on-orbit.5、NIIRS image quality assessmentImage quality assessment can be as quality evaluation index of remote sensing images. And it also reflects the imaging quality of satellite imaging system. By contrast of subjective or objective image quality evaluation system, the image quality assessment based on NIIRS can evaluate the entire imaging link quantitatively and qualitatively. So the image quality evaluation based on NIIRS can be as the effective evaluation of satellite flutter image quality. The experiments validate feasibility of NIIRS evaluation system.6、Restoration of satellite flutter imagesSatellite flutter on-orbit can cause the decline in image quality. But the MIF model based on MTF can recover and compensate the satellite flutter image effectively. We use the MIF filter model based on MTF, which is calculated by images, to restorate the satellite flutter images.Firstly, calculation2-dimensions of MTF with the images. Secondly, do the restoration of flutter images with MIF filter and Wiener filter. Experiments indicate that MIF filter based on MTF can restorate the flutter images effectively.