Application of Coupled-Wave Wentzel-Kramers-Brillouin Approximation to Ground Penetrating Radar

Abstract

This paper deals with bistatic subsurface probing of a horizontally layered dielectric half-space by means of ultra-wideband electromagnetic waves. In particular, the main objective of this work is to present a new method for the solution of the two-dimensional back-scattering problem arising when a pulsed electromagnetic signal impinges on a non-uniform dielectric half-space; this scenario is of interest for ground penetrating radar (GPR) applications. For the analytical description of the signal generated by the interaction of the emitted pulse with the environment, we developed and implemented a novel time-domain version of the coupled-wave Wentzel-Kramers-Brillouin approximation. We compared our solution with finite-difference time-domain (FDTD) results, achieving a very good agreement. We then applied the proposed technique to two case studies: in particular, our method was employed for the post-processing of experimental radargrams collected on Lake Chebarkul, in Russia, and for the simulation of GPR probing of the Moon surface, to detect smooth gradients of the dielectric permittivity in lunar regolith. The main conclusions resulting from our study are that our semi-analytical method is accurate, radically accelerates calculations compared to simpler mathematical formulations with a mostly numerical nature (such as the FDTD technique), and can be effectively used to aid the interpretation of GPR data. The method is capable to correctly predict the protracted return signals originated by smooth transition layers of the subsurface dielectric medium. The accuracy and numerical efficiency of our computational approach make promising its further development.

A Compressive Sensing-Based Approach to Reconstructing Regolith Structure from Lunar Penetrating Radar Data at the Chang’E-3 Landing Site

“…It is possible that there is a smooth variation in the permittivity on the interface. The overall reflection generated by a gradual interface has a different shape than the transmitted pulse [38], whereas a sudden permittivity change generates a reflection having a different amplitude, but the same shape as the transmitted pulse. This is a challenge for the CS algorithm.…”

TU1208 Open Database of Radargrams: The Dataset of the IFSTTAR Geophysical Test Site

“…WG 3 studied electromagnetic forward [21][22][23][24] and inverse [25,26] methods for the solution of near-field scattering problems by buried structures, imaging techniques [27][28][29][30] and data processing algorithms [31][32][33]. The Members of this WG contributed to the Action by developing and releasing free software, including a new and open-source version of the well-known finite-difference time-domain (FDTD) simulator gprMax [34] and further tools for GPR modeling and data analysis [35][36][37][38].…”

On the Introduction of Canny Operator in an Advanced Imaging Algorithm for Real-Time Detection of Hyperbolas in Ground-Penetrating Radar Data

“…Sparse reconstruction algorithms find application in the imaging of targets embedded in stratified dielectric media [38,39]. Moreover, fast and accurate forward solvers [40][41][42][43][44] are of high interest in this area of research, too, because they can be combined with imaging algorithms and full-wave inversion techniques [45,46].…”