面向森林植被的星载大光斑激光雷达回波仿真

Simulation of Forest Vegetation Return Waveform for Satellite Large-Footprint LiDAR

利用星载激光雷达的大光斑全波形数据估测植被结构参数、监测森林生态已受到广泛关注。为了更准确地理解森林植被的结构参数和光学特性对激光雷达回波波形的影响,利用实测森林植被数据提取植被空间分布的统计规律,考虑地形坡度变化和植被冠层反射特性的影响,生成参数化的森林植被空间轮廓反射模型,结合星载激光雷达的回波理论,建立了面向植被的星载激光雷达波形仿真器。由大兴安岭地区的实测植被数据提取的统计规律生成的森林目标仿真波形与地球科学激光测高仪系统（Geoscience Laser Altimeter System,GLAS）真实回波波形具有较好的一致性,平均相关系数R-2达到0.91。通过波形仿真分析发现,光斑尺寸减小有利于大坡度地形的森林信息反演,研究成果对中国未来研制星载激光雷达载荷的系统参数设计具有参考意义。

Vegetation structure parameters retrieval and forest ecological monitoring based on satellite large-footprint and full-waveform lidar（light detection and ranging）data is a hotspot in recent years.Since vegetation structure parameters and the optical properties have effects on lidar return waveforms,a waveform simulator specified to vegetations for a satellite lidar is established to investigate the influence in detail.The statisticlaw of the spatial vegetation distribution is extracted from field measurements;the parameterized vegetation reflection model is generated by considering the surface roughness and slope,and vegetation canopy reflection characteristics;then,the waveform simulator is developed based on the echo theory for satellite lidars.The simulated waveforms based on the field measurement data in Greater Khingan Mountains and the GLAS echo waveforms have good consistency with R-2 equal to 0.91.The smaller footprint diameter is beneficial to retrievethe vegetation information that locates at the terrain with a large slope.This research is of reference to the lidar system design for the developingsatellite lidar system of our country.