Accounting for the Different Propagation Velocities for the Focusing and Time–Depth Conversion in a Layered Medium

This contribution deals with the focusing and time–depth conversion of GPR data in a two-layer scenario. In a layered scenario, the different propagation velocities of the electromagnetic waves in different layers can induce distortion in the reconstruction. In particular, it is not possible, with common data processing, to achieve the focusing of both the targets embedded in the upper and deeper layers at the same time. We will present a strategy for mitigating this problem. The strength points of this strategy are its simplicity and the fact that it only requires a commercial code for the GPR data processing plus some steps easily implementable through a homemade code. This work extends a contribution of the same authors at the 20th International GPR conference held in Chanchung, China, in June 2024, and the conclusions are updated with three-dimensional numerical results, including depth slices determined directly in the spatial domain. Both numerical and experimental data will be shown.