根据宽覆盖相机的特性, 分析了其侧摆成像的几何关系。建立了地面物点到相机像面的空间坐标变换关系, 在此基础上, 推导了基于圆地球模型的相机侧摆像移速度计算公式, 并以像移失配传递函数MTFmismatch作为评价方法分析了相对像移匹配残差对像质的影响。以某宽覆盖型相机为例, 计算了不同侧摆角和不同地心角条件下的像面像移速度。计算结果表明: 像面各点的侧摆像移速度均不相同, 且变化趋势也不相同, 远地点处像移速度相对变化量最大。在侧摆角为25°且积分级数为48的条件下, 像移失配传递函数的最大值为0.681。外场成像试验结果表明, 积分级数控制在16级以内时的相机成像质量良好。

According to the feature of a wide coverage space camera, the geometrical relation of scroll imaging was analyzed .The space coordinate transform process from an object point on the earth to the image point in the focal plane was found. Furthermore, the calculation formulas of scroll image motion velocity were deduced based on a round earth model by using the transform of space coordinate system. The effect of relative image motion match error on the image quality was analyzed by the image motion mismatch modulation transfer function(MTFmismatch). By taking a wide coverage space camera for an example, image motion velocities at different scroll angles and different centrifugal angles were researched. Computation results indicate that the image motion velocities and their variation trends with the scroll angle are different in the different positions of image plane. The MTFmismatch caused by mismatch image motion velocity reaches 0.681 at the perigee if the scroll angle is 25° and the TDI stage is 48. The actual field experimental results show that it is necessary to keep the TDI stages within 16 to ensure good image quality.