A Novel Forward Model of Ground Penetrating Radar In The Far Field

Ground Penetrating Radar (GPR) is a widely used Non-Destructive Testing (NDT) tool. It is crucial to construct an appropriate GPR forward model for accurately estimating the electric properties of the subsurface layered media. In this paper, we developed a novel forward model for quasi mono-static configuration GPR based on a recently developed modeling approach for zero-offset mono-static configuration. When GPR operates on the quasi mono-static configuration, it can obtain higher signal to Noise ratio (SNR) and better inversion performance. In the new model, the effects of antennas and their interaction with media are modeled by a linear transfer function system, and the response due to multilayered media is modeled by 3-D Green's functions. Considering that part of the electromagnetic wave directly propagating from the transmitting antenna to the receiving antenna will be reflected outside as a new emission signal, this effect is also included in the new model. The new model is validated in laboratory conditions above a plasterboard and wood block with known thicknesses. Results showed remarkable agreement between the measured and modeled waveform. A comparison between the new quasi monostatic model and the zero-offset mono-static model was conducted by theoretical and experiment data, and the results suggested that the new model has a better inversion performance.