Buried target signature extraction from ground penetrating radar signal based on the equivalence principle

Ground penetrating radar is poised to be a very valuable tool in the field of humanitarian demining. Recently a monostatic stepped-frequency continuous wave (SFCW) ground penetrating radar (GPR) has been developed for the characterization of the soil electromagnetic (EM) parameters ϵ (dielectric permittivity), μ (magnetic permeability) and σ (electric conductivity). The approach is extended here for the GPR signal extraction of buried targets. The equivalence principle is used to decompose the GPR signal in its soil and target-in-soil contributions. It permits the subtraction of the soil contribution from the total GPR signal, which provides the signature of the buried target. We have extracted clean frequency and time-domain signatures of a metallic sphere and a PMN-2 plastic mine embedded in a multilayered medium at various moisture levels. The GPR signal of the metallic sphere has been simulated using the Method of Moments and shows good agreement with its measured counterpart.