Multilayered Media Parameter Inversion Based on Reflected Trajectory Fitting Method

Media parameter inversion is an important issue in the field of electromagnetic (EM) propagation widely applied to multilayered scenarios in ground penetrating radar (GPR). However, due to unsolvable refraction points in multilayered conditions, computing burden in iterative optimization, and unreachable global optima in multiobjective optimization, the existing inversion methods cannot effectively realize the multilayered inversion. For the problem, demanding for high precision and high efficiency in multilayered applications, a multilayered media parameter inversion based on reflected trajectory fitting is proposed. The method adopts a layer-by-layer inversion mechanism with a novel refraction approximation. At each layer inversion, it utilizes the reflected travel equation of the first A-scan and the reflected trajectory fitting by least square linear regression to draw two relation curves whose intersection position determines layer thickness and permittivity. Finally, through simulations and experiments, the method shows its accuracy and effectiveness in the multilayered structure.