Reverse Time Migration Method of Linear Frequency Modulation Ground Penetrating Radar Based on gprMax

The Reverse Time Migration (RTM) method has been widely applied in the fields of seismic imaging and pulse radar detection because it is not affected by changes in formation structure and lithology, and can realize high-precision imaging of unknown and complex subsurface scenes. In this paper, the reverse time migration imaging technique has been successfully extended to ground penetrating radar (GPR) with linear frequency modulation (LFM) excitation. The forward and backward extrapolation of the electromagnetic wave field is computed using the gprMax tool, which is based on the Finite Difference Time Domain (FDTD) method. The final imaging is realized based on the zero-time imaging condition of the explosive reflector principle. Two-dimensional numerical simulation experiments show that the RTM algorithm can be applied to LFM radar data processing and can accurately restore the characteristics of complex subsurface structures. Three-dimensional RTM experiments confirm that the restoration of three-dimensional information of the target can be achieved based on multidimensional detection data.