王洪华^1,2,,
龚俊波¹,
梁值欢¹,
张智¹,
徐涛^2,3
1. 桂林理工大学, 地球科学学院, 广西 桂林 541004
2. 中国科学院地质与地球物理研究所, 岩石圈演化国家重点实验室, 北京 100029
3. 中国科学院地球科学研究院, 北京 100029

基金项目: 国家自然科学基金项目（41604102）和广西自然科学基金项（2020GXNSFAA159121）联合资助


详细信息

作者简介: 王洪华, 男, 1986年生, 博士, 副教授, 主要从事探地雷达正反演理论及应用研究.E-mail: wanghonghua5@glut.edu.cn

中图分类号: P631

收稿日期:2020-09-01
修回日期:2021-04-19
上线日期:2021-06-10

Three-dimensional reverse time migration of ground penetrating radar data based on electromagnetic wave attenuated compensation

WANG HongHua^1,2,,
GONG JunBo¹,
LIANG ZhiHuan¹,
ZHANG Zhi¹,
XU Tao^2,3
1. College of Earth Sciences, Guilin University of Technology, Guangxi Guilin 541004, China
2. State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
3. Innovation Academy for Earth Science, Chinese Academy of Sciences, Beijing 100029, China


MSC: P631

--> Received Date: 01 September 2020
Revised Date: 19 April 2021
Available Online: 10 June 2021


摘要
摘要:常规探地雷达（GPR）逆时偏移大都未考虑高频电磁波在地下高电导率介质中传播的强衰减特性，致使高衰减区域的成像质量低；实际地下结构呈三维空间分布，二维GPR逆时偏移难以将反射波准确归位和绕射波完全收敛于真实位置.为此，本文构建了一种基于电磁波衰减补偿的三维GPR逆时偏移算法.该算法采用三维时域有限差分法计算正传和反传电磁波场，并通过改变反传电磁波方程中包含电导率的衰减项的正负号，人为保持反传时的时间对称性和反转不变性，以补偿正传时衰减的能量；零时刻成像条件用于获取地下三维结构的成像结果.数值试验结果表明：相比于常规GPR逆时偏移算法，基于电磁波衰减补偿的三维GPR逆时偏移可精确补偿电磁波在地下高电导率介质中正传衰减的能量，高电导率区域的成像精度更高，分辨率更好，抗干扰能力更强，其结果更有利于指导后续雷达剖面的解译.
关键词: 探地雷达/
电磁波衰减补偿/
三维逆时偏移/
零时刻成像条件

Abstract:The strong attenuation characteristic of high-frequency electromagnetic wave propagation in underground media with high conductivity is not considered in conventional Reverse-Time Migration (RTM) of Ground Penetrating Radar (GPR) data, resulting in low image quality in high attenuation areas. In addition, actual underground media are present in a three-dimensional (3D) space, thus the 2D RTM of GPR data is difficult to achieve the exact homing and complete convergence of diffracted waves. To solve this problem, a 3D GPR RTM algorithm based on electromagnetic wave attenuated compensation is proposed in this paper. In this approach, a 3D finite difference time domain method is used to calculate the forward and reverse time extrapolation of the electromagnetic field and compensation of attenuated electromagnetic waves is conducted by changing the sign before the attenuation term of the electromagnetic wave equation which contains conductivity. The zero-time imaging condition is employed to obtain the imaging results of underground 3D space. Then, the simulated 3D GPR data of two typical models is processed by using this program, and compared with conventional RTM results. The comparison demonstrates that the 3D GPR RTM algorithm based on attenuated electromagnetic wave compensation can effectively compensate the electromagnetic wave propagation in the underground attenuated media, and imaging accuracy and resolution of the high-conductivity area can be greatly improved and has better anti-interference ability, which is more helpful to the subsequent interpretation of GPR profiles.
Key words:Ground Penetrating Radar (GPR)/
Attenuated electromagnetic wave compensation/
Three-dimensional reverse time migration/
Zero time imaging condition



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