星载微脉冲光子计数激光雷达的探测性能仿真分析

Analysis of the detection performance of spaceborne micropulse photon-counting lidar

星载微脉冲光子计数激光雷达能够实现对地面目标的高重频、多波束探测,有效提高了激光雷达在轨测量的采样密度和覆盖宽度,满足全球高效高精度测绘的需求。依据微脉冲光子计数激光雷达的工作原理,建立了基于多像元光电倍增管(PMT)的星载微脉冲光子计数激光雷达的探测仿真分析模型,并对典型探测过程进行了仿真分析。结果表明,多像元PMT像元数的增加能够明显降低激光雷达的首光子效应,提高测距精度;激光雷达的测距标准差随地形坡度增大而明显增大;对于复杂地形,增加像元数和回波光子数,光子计数点云能够更准确描述地形轮廓的分布特征。同时,机载飞行试验验证了在复杂地形条件下,多像元PMT能够显著增加有效回波光子计数点,准确有效地反映了被测地形的轮廓特征,实现复杂地形下的高精度光子计数测距,验证了仿真分析结果的正确性。

The spaceborne micropulse photon-counting lidar can realize high repeat frequency and multi-beam detection for the ground targets,improve the sampling density and coverage width of lidar in-orbit measurement effectively,meet the high-efficiency and high-precision surveying and mapping requirement.The simulation model was established based on the multi-pixel photomultiplier tube(PMT) considering the working principle of micropulse photon-counting lidar.Then the typical detection process of the micropulse photon-counting lidar was analyzed.The results show that the increase of pixel of PMT can obviously decrease the first photon effect of the lidar,improve the ranging accuracy.The ranging standard deviation of lidar would increase obviously with the increase of terrain slop.In addition,the distribution characteristics of the terrain profile can be described more accurately by the photon-counting point cloud with the increased number of pixel and arriving photons.Meanwhile,the airborne flight test verifies that the numbers of effective echo photons points increase obviously with the increasing pixel of PMT,which can reflect the contour features of tested terrain more accurately and efficiently.It can realize the high-precision photon-counting ranging under the complicated terrain,verify the correction of the simulation analysis result.