激光测高卫星大气散射延迟改正现状及展望

激光测高卫星可以在大范围内获得亚米甚至厘米级的地表高程信息，但不可避免受云、气溶胶等粒子引起的散射影响，其中前向散射引起的激光测距和最终测高误差不容忽视。文中系统梳理激光测高卫星大气散射误差改正技术，介绍了国内外卫星激光测高系统参数、大气探测及散射改正算法，有别于已有的蒙特卡洛模拟改正方法，提出了一种基于指数函数模型的大气散射改正算法，选择青海湖等区域的ICESat/GLAS开展试验，结果表明，光学厚度小于2时能有效提升受大气散射影响的数据精度，同时提升数据可利用率约9%，该算法更易于实现业务化应用。最后针对大气参数同步探测的必要性，结合星载大气参数探测设备对后续国产激光测高卫星大气散射改正提出了若干建议。

Progress and prospect of atmospheric scattering correction for laser altimetry satellite

Laser altimetry satellite can obtain the surface elevation information of sub-meter or even centimeter-level in a wide range, but it is inevitably affected by the scattering caused by particles such as clouds and aerosols. The laser ranging and final height measurement errors caused by forward scattering of the cloud or fog can not be ignored. In this paper, the atmospheric scattering error correction technology of laser altimetry satellite was systematically reviewed, and the satellite laser altimeter system parameters, atmospheric detection and scattering correction algorithm at home and abroad were introduced. Different from the Monte Carlo simulation correction method theory, an atmospheric scattering correction algorithm based on exponential function model was proposed. The data of GLAS (Geo-science Laser Altimeter System) on the ICESat (Ice, Cloud and land Elevation Satellite) in Qinghai Lake and other regions was selected for the experiment, and the experimental results show that the algorithm can effectively improve the accuracy of the altimetry data affected by atmospheric scattering when the optical thickness is less than 2, and the data availability rate can be improved by about 9%. The algorithm is easier to realize operation application. Finally, according to the necessity of synchronous detection of atmospheric parameters, some suggestions for atmospheric scattering correction of domestic laser altimetry satellites were put forward in combination with onboard atmospheric parameter detection equipment.