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The agile satellite is widely used in optical remote sensing for earth observation. Due to the property of agility, the agile satellite has the ability to operate the optical sensor with big yawing angle, rolling angle and pitching angle. These three attitude angles represent the viewing angle of the optical sensor carried on the agile satellite. The big viewing angle of agile satellite brought the results of degradation for image quality, thus made the varying of image property with different viewing angle. This work analyzed the internal and external influences on imaging quality with big viewing angle for agile satellite. The analyses of internality were working on the impacts from the satellite of the micro-vibration. The analysis of externality was working on the impacts from the atmospheric effect of path radiance. Image modulation transferring function was an image quality parameter involved in this work. The mechanism of internal impacts was causing pixel shifting of the optical sensor and degrading the modulation transferring function. The mechanism of external impacts was degrading the contrast of target from background and reducing the modulation transferring function. The impact of micro-vibration was analyzed by computing the pixel shifting and evaluating the modulation transferring function degradation of specified micro-vibration of different viewing angle. The impact of integration time matching is analyzed by computing the pixel shifting and evaluating the modulation transferring function degradation of the matching accuracy of different viewing angle. The impact of atmospheric effect is analyzed by simulating the contrast of target from background and evaluating the modulation transferring function degradation with different viewing angle. Two experiments were conducted by maneuvering agile satellite on orbit. One experiment recorded the micro vibration parameters to analyze the pixel-shifting effect. Another experiment recorded the viewing angles to dissect the atmosphere path influences. The results showed that: 1) For micro-vibration, the degrading on modulation transferring function is strengthened as vibration frequency and integration level being higher in agile imaging mode. In the same maneuvering condition, the MTF of 100Hz micro-vibration decreased 6.20% and 3.84% than 60Hz with integration level of 48 and 72 separately. 2) For atmospheric effect, the influences on image contrast and modulation transferring function were increasing as viewing path becoming bigger for a specified atmosphere model. The length of viewing path had negative effects on MTF. The degradation of MTF were 6.15%, 12.72% and 27.35% with viewing angle of 24.95 ̊, 32.75 ̊ and 43.49 ̊ comparing with nadir viewing.
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