线阵CCD倾斜布置敏捷卫星辐射定标的姿态计算方法

Attitude Computation of Radiometric Calibration for Agile Satellite with Tilted Linear CCD

针对搭载倾斜布置的多片线阵CCD相机的敏捷卫星上所有探测器对同一区域成像的相对辐射定标,提出了基于地面成像轨迹重合的偏航角速度计算模型与方法,充分利用敏捷卫星对偏航角速度的控制潜力。建立了地面物点到相机焦平面的空间坐标变换关系;推导了斜视成像时地心角的计算公式;给出了对同一区域成像的敏捷卫星偏航角速度计算方法。以5片线阵CCD共30 000个探测器、相邻两片倾斜0.3°的敏捷卫星作为仿真对象,给出了所有探测器在约30s的定标成像过程中的地面轨迹间隔宽度,结果表明:为了实现所有探测器对同一区域成像,需要间隔一定周期调整偏航角速度,当调整周期为0.36s时,对应的地面轨迹宽度在赤道附近优于1个像元、在纬度50°附近优于6个像元。文章对敏捷卫星基于同一区域成像的相对辐射定标可提供一定的参考价值。

In the light of the agile satellite relative radiometric calibration method with all detectors of tilted linear CCD viewing the same scene,this paper provides the modeling and computation of satellite yaw angular velocity（YAV）based on the same trajectories of all detectors,which makes full use of the ability of yaw angle control.The space coordinate transform process from an object point on the earth to the image point in the focal plane is found.The formulas of geocentric angles are derived to be used for squint imaging mode.Furthermore,the calculation method of YAV for satellite CCD camera imaging the same scene is given.Taking an agile satellite equipped with 30,000 detectors in five CCD arrays and 0.3°tilted angle each other as an example,Simulation experiments are carried out,and the ground trajectory interval width is given during calibration process more than 30 simaging.Computation results indicate that YAV should be adjusted with certain interval period for all the detectors imaging the same scene.With YAV adjusting period of 0.36 s,the ground trajectory interval width is less than one pixel near the equator,and about six pixels at 50°latitude.This paper has important reference value for relative radiometriccalibration of the agile satellite based on all detectors imaging the same scene.