Integrateci modeling of near-field ground-penetrating radar and electromagnetic induction data for reconstructing multilayered media

We used a new integrated modeling procedure for analyzing near-field ground-penetrating radar (GPR) and electromagnetic induction (EMI) data for reconstructing the electrical properties of multilayered media. Both GPR and EMI systems are set up using vector network analyzer technology and operate with the antennas on the ground or in near-field conditions. The antennas are modeled using a set of infinitesimal dipoles and characteristic, frequency-dependent, global reflection and transmission coefficients. Wave propagation and diffusion in the medium are described using a set of three-dimensional multilayered media Green´s functions. GPR and EMI antennas were calibrated using measurements collected at different heights over water of know electrical conductivity. The GPR and EMI models were then validated for measurements collected over water subject to different salinity levels. The models showed a high degree of accuracy for reproducing the observed data and model inversion provided good estimates of the medium electrical properties, though discrepancies between measured and estimated water electrical conductivity values were observed in some cases due to a lack of sensitivity. The proposed approach is in particular promising for joint analysis of GPR and EMI data in an inverse data fusion framework, especially as the calibration and modeling procedures are identical for both instruments.