Reverse Time Migration for Ground Penetrating Radar Using Finite Difference Time Domain Method

Abstract

The finite difference time domain (FDTD) method is calculated by stepping finite approximation scheme for two Maxwell's curl equations. Since it allows arbitrary electrical conductivity and permittivity variations within a model, the FDTD method has become one of the powerful forward modeling methods for electromagnetic (EM) phenomena. The reverse time migration, which is performed by inserting the recorded data as a boundary conditions at each recorder position in reverse time order, is one of the imaging algorithms. In this paper, the reverse time migration for the ground penetrating radar (GPR) data is formulated using FDTD scheme. In a lossless media case, the method is successfully demonstrated to synthetic data for two models: steeply dipping structure and point diffractors model. In a lossy media case, the forward scheme includes diffusion term, while the reverse time scheme includes divergence term. In such a case, when the EM wave velocity is regarded as constant, this methodology is applicable successively. We discussed the reverse time migration under the lossless media condition for the lossy media after the amplitude recovery.