目前在轨和在研的光学遥感卫星大都搭载的是离轴遥感相机,为了保证视轴正对星下点成像,相机需要整体俯仰一定角度补偿离轴角,这样就导致相机的焦平面无法平行于星下点水平面进行推扫成像,相机的积分时间计算不准确.针对以上问题,提出一种基于等效焦面的高精度积分时间计算方法,该方法构建与星下点水平面平行的等效焦面,通过建立严密的几何关系,求出真正电荷转移时间对应的像元尺寸,从而得到准确的积分时间.仿真试验表明,该方法可以将积分时间计算精度提高1. 2%,为卫星在轨提高成像质量提供有效手段.%At present ,most of the in-orbit and in-producing optical remote sensing satellites are equipped with off-axis remote sensing cameras .In order to ensure the view axis imaging at the nadir ,the camera needs to pitch a certain angle to compensate for the off-axis angle .As a result , there will be an angle between the focal plane and the horizontal plane of nadir when imaging by push broom and it will lead to an inaccurate integral time . An accurate method of calculating integral time based on equivalent focal plane was proposed . This method constructed an equivalent focal plane parallel to the horizontal plane of nadir .By establishing a strict geometric model ,the pixel size corresponding to the real time of electric charge moving was calculated and thus the accurate integral time was obtained .Simulation experiments show that this method can increase the calculation accuracy of the integral time by 1 .2%, and it will improve the image quality in orbit .
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