A Modified Plane Wave Model for Fast and Accurate Characterization of Layered Media

The accuracy and computational speed of ground penetrating radar (GPR) largely rely on the inverse model implemented. In most cases, both accuracy and processing speed cannot be achieved together because of the inherent limitation of modeling GPR signal in complex media. Full wave models (FWMs) are most promising approaches to characterize multilayered media. However, they are inefficient due to the requirement of significant time for integration over singularity. In this paper, a modified plane wave model (MPWM) is proposed to achieve accuracy and better computational speed. The model is derived based on the analytical solution of an FWM. It is versatile for finding response due to multilayered media. The rigorous analysis has shown the similarity between the proposed model and FWMs with cross-correlation value close to unity across a broad frequency spectrum and large ranges of media parameters. Model inversion is achieved by a novel layer stripping technique followed by a gradient-based method. Testing of layered media in laboratory environment demonstrates that the proposed MPWM has significant advantage over FWMs.