Inversion scheme for ground penetrating radar that takes into account the planar air-soil interface

A three-dimensional (3D) diffraction-tomography inversion scheme that takes into account the planar air-soil interface is derived for fixed-offset ground penetrating radar (GPR). The inversion scheme is based on a plane-wave expansion of the dyadic Green's function for the interface problem and the first Born approximation. It can be implemented efficiently with fast Fourier transforms. Numerical examples demonstrate the importance of taking into account the air-soil interface and the ability of the inversion scheme to locate strong scatterers such as metal pipes.