Linear GPR inversion for lossy soil and a planar air-soil interface

A three-dimensional (3-D) inversion scheme for fixedoffset ground penetrating radar (GPR) is derived that takes into account the loss in the soil and the planar air–soil interface. The forward model of this inversion scheme is based upon the first Born approximation and the dyadic Green function for a two-layer medium. The forward model is inverted using the Tikhonov-regularized pseudo-inverse operator. This involves two steps: filtering and backpropagation. The filtering is carried out by numerically solving Fredholm integral equations of the first kind and the backpropagation is performed using fast Fourier transforms (FFTs). Numerical results are provided to illustrate the performance of the inversion scheme.