资源三号02星对地激光测高系统几何检校及验证

Geometric Calibration and Validation of ZY3-02 Satellite Laser Altimeter System

星载激光测高仪安装误差、激光指向和激光测距误差等导致最终激光测高精度不高,对激光器进行在轨几何检校可以有效提升激光测高精度。针对资源三号02星(ZY3-02)激光测高仪的工作模式,以裸露地表的航天飞机雷达地形测绘任务(shuttle radar topography mission,SRTM)数字高程模型(digital elevation model,DEM)数据约束同轨激光测距值,通过逼近地形起伏趋势线实现了卫星激光器出射方向的初始检校,实验证明不同轨激光指向的相对检校精度在20m以内。利用地面铺设激光靶标的方法对星载激光测高系统进行几何精检校,并通过外业测量验证了ZY3-02激光器在平坦区域的测高精度优于0.5m。

The location accuracy of space-borne laser altimeters suffers from installation errors.Calibration could improve the positioning and height accuracy effectively based on the operation data of satellite in orbit.A novel calibration method is put forward for ZiYuan-3（02）satellite（ZY3-02）laser altimeter that without waveform.In this approach,the error in the laser distance and positioning calibration is indicated by the terrain matching method.A test area with an exposed surface constrains the orbit laser ranging using SRTM-DEM data,and the initial calibration of the direction of the starter is obtained by approximating the terrain fluctuation trend line.The test results were verified;the relative pointing precision of different orbits data was 20 meters.A series of laser reflectors operated on the ground determine the surface radiometric intensity of the laser footprint.The calibration parameters compensate the laser positioning model;the height accuracy of the ZY3-02 satellite laser altimeter was 0.5 meter on a flat surface.