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基于线阵时间延迟积分(TDI)CCD推扫成像原理,分析了敏捷卫星在三轴姿态机动过程中动态成像的像移问题。由于姿态对地指向不断改变会导致像面空间方位不断改变,从而造成像移速度的改变,本文通过坐标变换法推导出了动态成像方式下的像移速度数学解析表达式,仿真得到了不同姿态机动角速度情况下的TDICCD积分时间数量级。数值仿真分析表明:当前50μs级的航天相机在700km的轨道高度可以实现以0.5(°)/s角速度上限进行动态推扫成像;当姿态机动角速度大于0.5(°)/s时,曝光时间越来越短,需要设计更高水平的相机。以上结论表明,对于不同角速度的动态成像任务,需要量化TDICCD积分时间数量级,实现在三轴姿态机动过程中开启光学有效载荷来完成推扫成像的动态成像。
Based on the principle of linear time-delay integration (TDI) CCD push-broom imaging, the image shift problem of agile satellite in dynamic imaging during three-axis attitude maneuver is analyzed. Because the orientation of the ground to the ground keeps changing, the orientation of the image space will change constantly, resulting in the change of the image moving speed. In this paper, the mathematical expression of the image moving speed under the dynamic imaging mode is deduced by coordinate transformation method. TDICCD Integration time in the case of maneuvering angular velocity. The results of numerical simulation show that the current 50μs space camera can perform dynamic push-scan imaging with an upper limit of angular velocity of 0.5 (°) / s at a track altitude of 700 km. When the attitude maneuver angular velocity is greater than 0.5 (°) / s, the exposure time is more and more The shorter, the need to design a higher level of camera. The above conclusion shows that for the dynamic imaging tasks with different angular velocities, it is necessary to quantify the order of the TDICCD integral time and to realize the dynamic imaging of the push-and-scan imaging by turning on the optical payload during the three-axis attitude maneuvering.