卫星后摆补偿地速研究及成像仿真分析

分析了卫星在对地观测时降低轨道高度提高成像分辨率的过程。针对卫星相机的数据读出频率会随轨道的降低明显升高而产生高频干扰这一问题,提出拍照过程的同时后摆补偿地速方案,即轨道降低后,在保证相机数据的读出频率一定的条件下,在小角度范围内,利用卫星的俯仰角速度补偿引起过高读出频率的地速。依据轨道下降高度和俯仰角速度变化引起的偏流角变化,TDI CCD的速率失配,成像畸变等误差,利用TDI CCD相机像点与物点的对应模型的仿真系统进行试验仿真,分析了图像的MTF函数和互相关相似性测度。在拍照时间要求不太长,俯仰角为小角度时,方案仿真成像能较好地满足要求。

Satellite Swaying to Compensate Earth Speed Research and Imaging Simulation Analysis

The process of reducing orbit altitude to improve satellites imaging resolution while taking earth observation was analyzed. The frequency of satellites' data read out from camera would significantly increase with orbit altitude reducing. It would produce high-frequency interference. Then, the proposal that the satellite swung to compensate earth speed was put forward. Namely, under the condition that read out frequency of data was certain, use satellite pitch angular velocity to compensate earth speed which resulted in higher read-out frequency within small angle. According to errors of the change of deviant angle which caused by declination in orbit altitude and change in pitch angular velocity, TDI CCD rate mismatch and image distortion, TDI CCD camera simulation system with the material point corresponding to imaging point model was used to analyze the imaging MTF and mutual correlation similarity measure. It certified that the simulation imaging of this proposal can better meet the requirements when imaging in a shorter time and pitch angle was at small range.