Contactless Full 3-D GPR Imaging via Circular Surveys: Achievable Performance

This paper addresses the full 3-D subsurface imaging by a contactless ground penetrating radar survey carried out along a circular observation trajectory. The imaging problem is formulated as a linear inverse scattering one and accounts for the electromagnetic wave propagation through the air-soil interface thanks to a ray-based propagation model. The inverse problem is ill-posed and solved in a regularized way by resorting to the Truncated Singular Value Decomposition inversion scheme. The resolution performance achievable with the circular synthetic aperture is investigated in detail. Specifically, the focus is to examine how the filtering properties of the scattering operator are influenced by the geometrical and electromagnetic parameters of the scenario. Reconstruction results confirm the effectiveness of the imaging approach and support the validity of the theoretical resolution analysis.