品字形拼接探测器偏流角补偿研究

Drift Angle Compensation Study of Interleaving Assembly Focal Plane

对遥感卫星TDI-CCD推扫品字形探测器偏流角的补偿进行了研究。根据偏流角产生机理,用轨道要素法推导出一种简单可靠的偏流角计算和补偿方法,将偏流角补偿后重新计算的欧拉角作为控制目标输入闭环进行控制,规避了三轴欧拉角转序的影响。分析了偏流角控制对品字形拼接探测器成像产生的像元错位、调制传递函数(MTF)、通道间配准和幅宽等的影响。结果发现:对偏流角进行控制后穿轨向像元错位可消除,沿轨纵向像元错位不能消除,穿轨和沿轨向MTF均可消除,偏流角可对幅宽无影响;不对偏流角进行控制会严重影响通道间的配准精度。所提方法计算简单,流程清晰,在工程中有一定的应用价值。

The drift angle compensation of interleaving assembly focal plane for TDI-CCD scanning in remote sensing satellite was studied in this paper. A simple and reliable method of computation and compensation of drift angle was given by orbit elements method. The Euler angle calculated after the drift angle had been compensated was used as the control target to input into closed loop for control, which could avoid the influence of the turn order of three Euler angle. The influences of drift angle compensation on pixel malposition, modified transfer function, registration and swath were analyzed. It was found that the pixel malposition in cross-track could be eliminated, the pixel malposition in along-track could not be eliminated？ MTF in cross-track and along-track could both be eliminated, and the drift angle had no influence on swath after the drift angle compensated. And it was also found that the registration accuracy would be affected seriously if the drift angle had not be compensated. The method proposed was simple and clear which was valuable in engineering.