Numerical and Field Investigations of GPR: Toward an Airborne GPR

Abstract

The main objective of our work is to explore the feasibility of designing an airborne RADAR system much like the University of Texas Institute for Geophysics airborne ice-penetrating radar systems for use in the detection of underground structures. Here we summarize our initial efforts toward achieving this goal. The studies conducted so far include two major tasks: (1) development of hybrid numerical-analytical techniques for simulating the radar response of underground targets, and (2) a ground penetrating radar field experiment conducted at a known site that has underground tunnels. In our numerical simulation, we used analytic solutions to propagate the EM wave field from an airplane to the ground surface and then used a finite difference scheme to compute the response of complex geology including some underground structure. During the field investigation, we collected several surface GPR profiles with varying source-receiving antenna separations and configurations. The data were processed using algorithms similar to those used in seismic data processing. Despite the high moisture content in the field area during data collection, we were able to identify features in the data that can be modeled as diffractions from underground targets. The results are encouraging. Our future work will include revisiting the site during the summer months since we expect to be able to image the underground facilities better when the ground is dry. Based on the success of the ground based GPR field surveys, we will investigate the possibilities of designing and testing an airborne system.