Large-Scale 3D Forward Modeling Method for Ground Penetrating Radar Based on FDTD

Abstract

The invention discloses a ground penetrating radar large-scale three-dimensional forward modeling method based on the FDTD. According to the method, data exchange of nodes is carried out through a network, and communication and synchronization of the nodes are achieved; a measured point in any node is selected to be subjected to forward modeling parallel calculation on the basis of the FDTD, firstly, an electric field value is calculated, magnetic field calculation is carried out by adding an excitation source after electric field calculation is finished, iteration is continuously carried out through communication, electric field calculation and magnetic field calculation, and when calculation of the set time total step length is finished, calculation is stopped, output data are stored, the data serve as a radar reflected signal of the measured point; initialization updating is carried out on all field values, a whole computational domain recovers to the state before calculation, and then a transmitting antenna and a receiving antenna are moved to a next measured point to start forward modeling calculation again; if calculation of all the measured points is finished, data of all the nodes are collected to carry out imaging and image postprocessing. The ground penetrating radar large-scale three-dimensional forward modeling method based on the FDTD is applicable to calculation of dielectrics and models with complex scales, has the advantage of being high in universality, and is especially applicable to large-scale and high-precision forward modeling.

Description

technical field [0001] The invention relates to a ground-penetrating radar forward modeling simulation method used as a ground-penetrating radar theoretical research means. Background technique [0002] Ground Penetrating Radar (Ground Penetrating Radar, GPR) method is a spectral (1MHz-1GHz) electromagnetic wave technology used to determine the distribution of underground media. Ground-penetrating radar is a relatively new geophysical method that has gradually matured in the past 10 years. The development of ground penetrating radar is not only accompanied by various military and civilian needs, but also promoted by the development of high technology [0003] At present, most of the GPR detection and interpretation technologies are based on the two-dimensional basis. Two-dimensional radar detection is based on the assumption that the geological body is uniform in the direction of the vertical detection section, that is, the geological body is infinitely extended, but in eng...

AI Technical Summary

Problems solved by technology

When the calculation space is three-dimensional and the scale is much larger than the wavelength (that is, the electric large scale), the required storage space is completely beyond the limit of the current stand-alone computer, making the calculation impossible; secondly, to obtain a stable numerical solution for the FDTD method, the time step must satisfy , that is, the Courant stability condition, which leads to a very long calculation time for a single survey point of GPR in 3D; Calculate the complete radar wave process of each measuring point in turn. When the measuring points are densely distributed and the number is large, the calculation time required is extremely long, or even impossible to calculate

Therefore, at present, only small-scale simulations can be carried out, and there is nothing that can be done for large-scale and large-scale forward simulations.

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