UAV-based GPR and microwave tomography: 2D and 3D results

The integration of UAV and GPR enables non-invasive subsurface imaging across various fields, enhancing data collection efficiency, while enhancing safety and acquisition time. However, the effective use of UAV-based GPR systems involves several challenges, as the need of data processing strategies able to account for the irregular spatial distribution of the measurement points and the presence of the air-soil interface. This work proposes a linear microwave tomography approach for 2D or 3D subsurface imaging. In both cases, the approach treats the imaging as an inverse scattering problem formulated according to the Born approximation. Specifically, the equivalent permittivity model is adopted to describe the signal propagation in a half-space scenario, where the upper medium is air and the lower one has the electromagnetic characteristics of the inspected soil. In addition, the shift-and-zoom strategy is exploited to reduce the computational burden. The main contribution of this work is an experimental validation referred to data collected along a single or multiple irregular flight trajectories at Altopiano di Verteglia, Avellino, Italy. Specifically, the 2D modeling of the scattering phenomenon is used to process single line data, while the 3D model is considered in the case of multiple measurement lines.