Migration of Ground Penetrating Radar data in heterogeneous and dispersive media

Migration enables us to correctly interpret the GPR data from structurally complex areas and determine the geometry and correct location of reflectors (or scatterers) in the subsurface. The effects produced by heterogeneities, dispersion and attenuation are very important; they may cause mis-positioning of reflectors, degradation of resolution and reduction of the effective depth of observation. To address these issues, we present a modification of the Split Step Fourier migration technique that takes into account, in an efficient and natural way, the dispersion and attenuation effects in the media. A homogeneous wave approximation gives greater numerical stability to the split step operator, allowing the migration of the data through thicknesses equivalent to two or three times the equivalent skin depths of the media (computed at the dominant frequency of the radar signal). The results obtained from real and synthetic data demonstrate that the developed migration technique improves the resolution of the final image and recovers the correct amplitude of the reflections.