机载LiDAR测深中海底地形坡度的影响及改正  

Analysis and correction in the airborne LiDAR bathymetric error caused by the effect of seafloor topography slope

作　　者：亓超[1,2] 宿殿鹏 阳凡林 马跃[1,3] 王贤昆 杨安秀[1,2,4] QI Chao;SU Dianpeng;YANG Fanlin;MA Yue;WANG Xiankun;YANG Anxiu(College of Geodesy and Geomatics,Shandong University of Science and Technology,Qingdao 266590,China;Key Laboratory of Ocean Geomatics,Ministry of Natural Resources of China,Qingdao 266590,China;School of Electronic Information,Wuhan University,Wuhan 430072,China;Key Laboratory of Submarine Geoscience,Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China)

机构地区：[1]山东科技大学测绘与空间信息学院,青岛266590 [2]自然资源部海洋测绘重点实验室,青岛266590 [3]武汉大学电子信息学院,武汉430072 [4]自然资源部第二海洋研究所,杭州310012

出　　处：《遥感学报》2022年第12期2642-2654,共13页NATIONAL REMOTE SENSING BULLETIN

基　　金：国家自然科学基金(编号:41930535,41830540,52001189);国家重点研发计划(编号:2018YFF0212203,2017YFC1405006,2018YFC1405900);山东科技大学科研创新团队支持计划(编号:2019TDJH103)。

摘　　要：机载LiDAR测深ALB(Airborne LiDAR Bathymetry)是测量沿海地区地形图和水深图的最有效的技术之一,其通常是利用ALB海面和海底反射回波的峰值位置来计算水深值。然而,当绿色(532 nm)激光光束到达海底时,光斑范围内的具有坡度的海底地形会导致海底反射回波波形展宽、峰值位置偏移等现象,从而产生海底位置的不确定性,进而直接影响海底地形测量的准确性。为了减小这种影响,本文提出了一种机载LiDAR测深的海底地形坡度影响改正方法。通过考虑ALB激光光斑内海底地形的连续性,基于ALB激光光斑范围内局部地形参数模型FTPM(Footprint-scale Topography Parameters Model)构建ALB海底反射回波模型,通过定量分析不同水深、不同海底地形坡度所引起的海底反射回波峰值位置变化,以确定海底地形坡度对ALB测深的影响规律,进而构建ALB测深误差方程针对性地改正海底地形坡度引起的测深误差。本文采用中国南海甘泉岛附近海域所测ALB和多波束测深数据对所提方法进行了验证。结果表明,海底地形坡度影响改正后,平均绝对误差MAE(Mean Absolute Error)和中误差RMSE(Root Mean Square Error)分别减小到9.4 cm和12.3 cm,较改正前分别降低了35.6%和33.5%,对ALB测深数据处理具有参考意义。The airborne LiDAR bathymetry(ALB) is one of the most effective technologies to retrieve the topographic and bathymetric maps of coastal zones.The water depth is typically calculated from the sea surface and seafloor peak positions of the ALB waveforms.However,the seafloor topography slope within the footprint scale causes the seafloor waveform stretching and peak shifting when the bluegreen laser beam reaches the seafloor,which induces the timing uncertainly to influence the accuracy of the measured seafloor topography.In this work,a correction method in the airborne LiDAR bathymetric error caused by the effect of seafloor topography slope at the footprint scale is proposed to reduce the influence.In this method,the ALB seafloor waveform simulation model is achieved based on the footprint-scale topography parameters model,taking into account the effect of seafloor topography.The ALB error correction equation is obtained based on the quantitative relationship between seafloor topography slope and peak timing of echo waveforms.The developed method is used to correct the ALB data collected near Ganquan Island in the South China Sea and verified by the topography data captured by a ship-borne multi-beam echo sounder.Results show that the mean absolute error and root mean square error are reduced to 9.4 and 12.3 cm after the correction,respectively.Specifically,MAE and RMSE decreased by 35.6% and 33.5%,respectively.

关 键 词：遥感 机载LiDAR测深 海底地形 海底坡度 水深改正 海底光斑 

分 类 号：P2[天文地球—测绘科学与技术]