Electromagnetic inversion and interface tracking: system calibration and application

An integrated approach to monostatic GPR processing for pavement profiling is presented. Several aspects are considered. The antenna/ground interaction is characterized by modelling the antenna with equivalent sources placed on the aperture section. Then, a calibration procedure is used to obtain the approximate source distribution. The accurate forward EM modelling within the inversion loop automatically accounts for the contribution of near-field effects. In order to reduce the computational complexity, the detection/tracking (D/T) algorithm is introduced. It permits to estimate the number of interfaces (detection) and, for each interface, the amplitude and delay of echoes by exploiting the continuity across neighbouring surveys (tracking). The D/T approach seems to be the only feasible solution for processing large amount of data in real time (i.e., during acquisition) while EM inversion can be limited to selected dataset for more accurate analysis. Some experimental results on the antenna modelling procedure and on a pavement profile estimation are discussed.