Frequency Domain Gpr Signal Forward and Inverse Modelling for Identifying the Subsurface Dielectric Properties
نویسندگان
چکیده
Research has focused on the development of a new integrated approach including ground penetrating radar (GPR) design, GPR signal forward modelling, and GPR signal inversion to estimate the dielectric permittivity and electric conductivity of the shallow subsurface. We propose to use an ultrawide band (UWB) stepped frequency continuous wave (SFCW) radar combined with an offground monostatic transverse electromagnetic (TEM) horn antenna. Forward modelling is based on linear system response functions for describing the antenna, and on the exact solution of Maxwell’s equations for wave propagation in a horizontally multilayered medium representing the subsurface. Model inversion, formulated by the classical least-squares problem, is carried out iteratively using advanced global optimisation techniques. The proposed approach is validated under laboratory conditions on a homogeneous sand subject to different water contents. The frequency dependence of the electric conductivity is characterized and the effect of soil roughness is analysed. The approach offers great promise in bridging the gap between airborne/spaceborne measurements of surface soil moisture and ground truth measurements.
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