Adaptive finite element GPR frequency domain forward modeling method

A finite element, self-adaptive technology, applied in special data processing applications, complex mathematical operations, instruments, etc., can solve the problems of cumbersome and high calculation costs, achieve good absorption effect, reduce the degree of freedom of nodes, and simplify the parameter optimization process Effect

CN110210129AActive Publication Date: 2019-09-06CENT SOUTH UNIV
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2019-09-06

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Abstract

The invention discloses an adaptive finite element GPR frequency domain forward modeling method. The method comprises the steps of setting parameters of a forward modeling method; calculating a numerical solution and a local error indication value of the current grid; marking a unit set needing to be refined; refining the marked grid; and carrying out numerical solution to obtain a final self-adaptive finite element GPR forward modeling result. The invention provides a self-adaptive finite element GPR forward modeling method. Based on a posteriori error estimation strategy, a posteriori errorestimation strategy is acquired. A self-adaptive finite element method is adopted to carry out GPR frequency domain forward modeling, EPML boundary conditions are introduced into frequency domain forward modeling calculation, the parameter optimization process is simplified, a good absorption effect can be achieved under the condition that the thickness of an absorption layer is small, the degreeof freedom of nodes can be reduced, and the calculation cost is saved to a great extent.
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Description

technical field

[0001] The invention specifically relates to an adaptive finite element GPR frequency domain forward modeling method. Background technique

[0002] Ground Penetrating Radar (GPR) is a non-destructive detection technology that uses high-frequency electromagnetic waves to locate invisible targets inside underground structures or objects (Daniels, 2004; Zeng Zhaofa, 2010). Through GPR forward modeling, the understanding of GPR propagation law and reflection profile can be deepened, and the interpretation level of radar data can be improved (Giannopoulos, 2005; Irving & Knight, 2006). The numerical simulation of GPR can be divided into two categories: time domain and frequency domain. Among them, time domain simulation methods are widely used, including Finite Difference Time Domain (FDTD) (Chen&Huang, 1998; Cassidy&Millington, 2009; Diamanti&Giannopoulos, 2009; Lin et al., 2012; Zhang et al., 2016; Warren et al. al., 2016), Finite Element Time Domain (FETD) (F...

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Embodiment Construction

[0034] Such as figure 1 Shown is the method flow diagram of the inventive method: this adaptive finite element GPR frequency domain forward modeling method provided by the present invention comprises the steps:

[0035] S1. Set the parameters of the forward modeling method, including forward modeling frequency, model parameters and initial grid;

[0036] The initial grid adopts Delaunay triangular grid, and the grid is subdivided to obtain unstructured grid subdivision results;

[0037] S2. Calculate the numerical solution of the current grid according to the parameters set in step S1; specifically, the following steps are used for calculation:

[0038] A. Use the FEFD algorithm to calculate the numerical solution of the grid;

[0039]According to the theory of electromagnetic wave propagation (Taflove & Brodwin, 1975), the propagation of radar waves in a lossy medium follows the Maxwell equations, and the frequency domain representation of the two-dimensional TM wave is:

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