资源三号02星激光测高误差分析与指向角粗标定

Error Analysis and Preliminary Pointing Angle Calibration of Laser Altimeter on Ziyuan-3 02 Satellite

2016年5月30日,中国成功发射了民用三线阵立体测图卫星资源三号02星,该卫星搭载了中国第一个用于对地观测的激光测高试验性载荷。资源三号02星在轨运行以来获取了多轨测高数据,为保证其测高数据的有效应用,需分析影响测高精度的各项误差来源,并通过一定的方法予以消除或减弱。首先根据卫星激光测高严密几何模型分析资源三号02星激光测高的各项误差来源,分析表明激光指向角对激光测高精度的影响相对较大;构建通过已有大范围地形数据进行激光指向角粗标定的数学模型,并利用已有公开地形数据（AW3D30DSM）对激光指向角进行粗标定,从而提高激光足印定位精度。实验结果表明,利用已有地形数据对指向角进行粗标定后,能将激光测高精度从几十米提高到3m以内,验证了卫星激光测高误差分析的合理性和利用已有地形数据修正激光指向角的数学模型的有效性,为消除卫星激光测高粗差提供了参考,能为星载激光测高外场在轨检校工作提供支撑。

The Ziyuan-3 02 satellite（ZY-3 02）,which is the second domestic stereo mapping satellite in China,was launched at May 30,2016.Apart from optical cameras,the ZY-3 02 satellite carries the first Chinese satellite laser altimeter for Earth observation.During orbiting,the ZY-3 02 has obtained a certain amount of laser altimeter data.Based on this data,we analyze the error sources and conducts preliminary pointing angle calibration.In this paper,comprehensive analysis of the error sources is presented according to the rigorous geometric model of satellite laser altimeter,which shows that the bias of laser pointing contributes most to the height error of laser footprints.Then,a novel method for preliminary laser pointing calibration method without field surveying is proposed and its mathematical model is presented.After that the open source topographic data（AW3 D30 DSM）is used to rectify the laser pointing angle.Experimental results indicate that the rectified pointing angle based on exist topographic data can improve the height accuracy from more than ten meters to less than 3 meters.Thus the error analysis is proved to be right and the preliminary laser pointing calibration method to be useful.The proposed method gives a way to eliminate the coarse errors of laser footprint location and strongly supports the ground calibration of satellite laser altimeter which will farther improves the positioning accuracy of laser footprints.