高分七号卫星激光测高仪无场几何定标法

无场几何定标是未来多波束激光测高卫星面临的一个关键问题。本文针对高分七号（GF-7）线性体制全波形激光测高仪，提出了一种基于地形和波形匹配的无场分步定标方法。在深入分析高分七号卫星激光测高仪特点的基础上，构建了严密几何定位模型，采用公开版的地形参考数据和某地区1∶2000高精度的DOM和LiDAR-DSM基础地理信息成果，开展了在轨无场几何定标试验，显著提高了高分七号卫星激光测高数据精度。在2020年上半年受新冠肺炎影响未进行外场定标期间，有效解决了激光测高数据处理无定标参数的实际困难。本文对无场定标结果与高分七号实际外场定标结果进行对比验证，结果表明，无场定标结果与实际落点位置的平面误差为11.597±3.693 m，最小值为7.115 m，平坦地区高程精度优于0.3 m，虽然略低于外场定标结果，但能满足1∶10 000高程控制点测量需求。

The method of GF-7 satellite laser altimeter on-orbit geometric calibration without field site

On-orbit geometric calibration without field site is a key problem for future multi-beam laser altimetry satellites. In view of the linear system full waveform laser altimeter loaded on the GF-7 satellite, a non-field step by step calibration method based on terrain and waveform matching is proposed. Based on the analysis of the characteristics of the GF-7 satellite laser altimeter, a rigorous geometric positioning model is constructed. The field-free on orbit geometric calibration test is carried out by using the open topographic reference data and the basic geographic information of DOM and LiDAR DSM in a certain area, which has greatly improved the accuracy of the laser altimetry data. With this method, during the first half of 2020, the calibration parameter configuration and data processing of GF-7 satellite laser altimeter was not affected, even the field calibration can't be implemented due to the negative impact of the COVID-19. The accuracy is compared with the field calibration results after the COVID-19, and the results show that the plane error of the non-field calibration is 11.597±3.693 m and the minimum value is 7.115 m. The elevation accuracy of flat area is better than 0.3 m, although it is slightly lower than the results of field calibration, it can basically meet the requirements of 1:10 000 elevation control points.