基于水体回波信号仿真的激光雷达水深探测模型研究

Research on the Water Depth Detection Model Based on LiDAR Echo Signal Simulation

Wa-LiD模型是近年来国外学者发展的激光雷达水体回波信号模型,该模型用物理参数仿真了LiDAR激光从水表面穿透水体到水底再返回传感器所形成的波形,水体光学量的表达是该模型重要组成部分,包括水体三要素的吸收和散射,然而涉及到这部分的表达式和参数并未公开。文中借鉴前人在水体吸收、散射光学性质方面的研究成果,构建了物理意义明确的激光雷达水体回波信号仿真模型,提出了基于仿真模型的激光雷达水深探测模型,并分析了模型的水深反演能力。研究结果表明该水深激光雷达探测模型在1~15 m水深段内平均绝对误差15.6 cm、平均相对误差4.58%,在HawkEye系统标称的测深精度范围内;并表现出在大于8 m深水段平均绝对误差普遍大于浅水区域;随水深增大,平均相对误差有递减的趋势。

The Wa-LiD model is a laser radar water echo model developed in recent years by foreign scholars.This model uses the physical parameters to simulate the waveform formed by LiDAR laser, which penetrates the water from water surface to the bottom and then comes back to the sensor. The expression of the optical amount of water is an important part of the model, including the absorption and scattering of the three elements of water.However, the expression and parameters related to this part are not available at present. In this paper, the authors learn from the research results of water absorption and scattering optical nature achieved by previous scholars,and build a laser radar water echo signal simulation model with the explicit physical meaning. Then this paper proposes a laser radar water depth detection model based on the simulation model, and analyzes the ability of the model to invert water depth. The results show that the mean absolute error（MAE） is 15.6 cm, and the mean relative error（MRE） is 4.58% when using the proposed laser radar detection model in the water depth range of 1 to 15 m, with their accuracy according with the nominal precision scope of the Hawk Eye system. The MAE in a depth over 8 m is generally greater than that in a shallow water area. The MRE has a decline tendency with increasing water depth.