On the feasibility of using GPR technology for the UXO detection and discrimination in the volcanic soil of Hawaii

In this paper we describe the recent results from an ongoing project at the University of Hawaii to use advanced GPR technology for the detection and discrimination of UXO in the high iron content volcanic soil of Hawaii. To help determine a suitable frequency range for detecting targets at two feet depth from the surface, a soil characterization effort has been implemented. Both the dielectric and magnetic properties of the earth soil are being measured using a unique shunt capacitance terminating a transmission line method and a recently fabricated TEM cell. Both the reflection and transmission S-parameters are being measured to determine both the complex permittivity and permeability of the soil. Furthermore, a TLS-Prony method together with FDTD 3D simulations of typical detection environments are being used to extract the complex natural resonance frequencies (CNR) of targets from the late arrival signals associated with the scattering mechanisms from these targets. A UXO testbed has been development to help experimentally validate simulation results and provide data to check and improve the accuracy of the detection/discrimination algorithm. Results from this study including dielectric and magnetic characterization of the volcanic soils, and CNR of typical UXO targets encountered in Hawaii will be presented.