高分七号卫星激光测高仪分系统关键技术设计与实现

Design and Implementation of Key Technology of GF-7 Satellite Laser Altimeter Subsystem

针对1∶10000比例尺立体测绘对高程控制点的需求,高分七号激光测高仪分系统在传统激光脉冲式距离测量技术的基础上,通过可见光光学被动成像与激光接收光学复合设计方案,同时获取激光足印在地物影像上的二维方位信息和大足印内的多回波波形,并对激光指向在轨监测关键技术进行了设计实现。关键技术仿真及试验结果表明:激光足印平面定位精度可达到5μrad,对强度变化33 dB内的回波测距均值最大变化3.3 cm。在轨监测数据表明:激光发射光轴稳定性优于0.5μrad,无云区域回波探测概率达到100%。测量获取的具备5μrad平面精度、1 m高程精度的激光落点可为1∶10000比例尺测绘提供高质量的控制点信息。

In response to the demand for elevation control points of 1∶10000 scale stereo mapping,based on the traditional laser pulse distance measurement technology,the GF-7 satellite laser altimeter subsystem is designed through combination of visible light optical imaging and laser receiving optics.The two-dimensional azimuth information of the laser footprint on the ground image and the multi-echo waveform in the big footprint are obtained and the laser pointing on-orbit monitoring key technology is designed and implemented.Simulation and laboratory tests show that the positioning accuracy of the laser foot print plane can reach 5μrad,and the maximum change in the average value of the echo ranging within 33dB of the intensity change is 3.3cm.The on-orbit monitoring data shows that the stability of the laser emission optical axis is better than 0.5 urad,and the probability of echo detection in the cloudless area reaches 100%.The measured laser spot with 5urad plane accuracy and 1m elevation accuracy can provide high-quality control point information for 1∶10000 scale mapping.