GPR DATA ANALYSIS OF AIRFIELD RUNWAY USING MIGRATION VELOCITY SIMULATION ALGORITHM

Ground penetrating radar (GPR) is a geophysical technique based on propagation and reflection of electromagnetic waves in the subsurface. The large amount of data collected takes significant level of experience to interpret. The reflection from a pipe or a cable in the ground is characterized by a hyperbola on the subsurface radar image. The shape of each arc is determined by the shape of the object, its position, dielectric properties, and the structure of the medium and the path of the radar beam. However, in many real applications, the heterogeneities of the media can be important and it becomes necessary to use an algorithm that takes into account the spatial changes of velocity in the media. In this paper, radar image is frequency wavenumber (F-K) migrated for a range of velocities in order to determine the velocity at which the characteristic hyperbola best focuses to a point indicating the propagation velocity in the sample. After migration, depth information can be read from the migrated image. The result of this work on an airfield runway shows that the ground penetrating radar can be used to calculate the depth and position of buried pipes, rebar, cables and to detect voids and cavities under the runway. The simulated results from the algorithm used are compared and verified with the experimental data collected from the airfield runway