椭圆轨道TDI CCD相机像移匹配计算与成像验证

Image motion matching calculation and imaging validation of TDI CCD camera on elliptical orbit

针对椭圆轨道卫星地心距和前进速度时刻变化对航天时间延迟积分（TDI） CCD相机成像的影响,提出了一种矢量映射分析方法来计算椭圆轨道时变的像移速度矢量.通过建立不同的坐标系,将椭圆轨道卫星在轨运行速度和地物随地球自转的线速度映射至TDI CCD相机像面坐标系.以某临界回归椭圆轨道为例,计算了影响航天TDI CCD相机成像的像移速度矢量和数据读出频率.最后,利用小卫星姿态控制系统半物理仿真平台和TDI CCD原理样机对提出的像移速度矢量映射分析方法进行了实验验证.结果表明：临界回归椭圆轨道一个周期内,参数按照等比缩放原则配置时,对应的偏流角、像移速度矢量和靶标移动速度分别为-3.76～3.22（°）、0.1673～0.72 mm/s和19.12～ 82.24 pixel/s,获取的图像能够满足1～2 peixl的目标分辨率.实验结果说明,用提出的方法计算像移速度矢量结果准确,可为椭圆轨道航天TDI CCD相机成像匹配提供可靠依据.

In view of the influence of continuous changeable orbit heights and satellite velocities on elliptical orbit on the space TDI CCD camera imaging,a vector map analysis method was proposed to calculate the time varying image motion of the elliptical orbit.Through establishing different coordinates,the satellite velocity and target velocity generated with earth self-rotation were transformed from original coordinate to TDI CCD camera image plane coordinate.By taking a critical regression elliptical orbit as an example,the image motion velocity vectors which affect TDI CCD camera imaging and data readout frequencies were calculated.Finally,a three-axis air flotation turntable attitude simulation system and a TDI CCD camera were used in experiment to verify the vector map analysis method.The results show that during one period of satellite on critical regression elliptical orbit,the values of drift angle,image motion velocity and target movement speed are separately-3.76°-3.22°,0.1673-0.72 mm/s,and 19.12-82.24 pixels/s according to equivalent parameter law.The image collected can satisfy the resolution of the 1-2 pixels,which proves that vector map analysis method is accurate on computing image motion velocity,which is able to provide reliable basis for space TDI CCD camera imaging on the elliptical orbit.