Precise infrastructure mapping using full-waveform inversion of ground penetrating radar signals
First Claim
1. A method for determining physical properties of a subsurface object disposed in a surrounding media, comprising:
- acquiring measured ground penetrating data from a ground penetrating radar device, wherein the measured ground penetrating data includes at least one measured diffraction hyperbola;
estimating a plurality of parameters of an initial model of the subsurface object and the surrounding media, such that the initial model produces a simulated diffraction hyperbola that is offset less than one-half a wavelength from the measured diffraction hyperbola, wherein the plurality of parameters includes at least one of the following;
a velocity of electromagnetic waves through media in which the subsurface object is located;
a depth of the subsurface object in the surrounding media;
a horizontal location of the subsurface object;
a size of the subsurface object;
a conductivity of the surrounding media;
a permittivity of the surrounding media;
a permittivity of any material or fluid within an outer surface of the subsurface object;
acquiring a measured source wavelet and deconvolving the initial model from the measured ground penetrating data to produce a corrected source wavelet;
simulating ground penetrating data for the initial model with the corrected source wavelet; and
determining a cost function and adjusting at least one of the plurality of parameters to minimize the cost function.
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Accused Products
Abstract
A new method for FWI of common-offset GPR data, particularly targeting the dimensions and infilling material of buried pipes. The method is useful in situation where clear isolated diffraction hyperbolas indicate the presence of a pipe, but pipe dimensions and filling may be unknown. The invention is a method of taking GPR data and applying advanced numerical methods to get the depth and size of an underground pipe in a very accurate manner. An embodiment of the method consists of five main steps: GPR data processing, ray-based analysis to set a good initial model, 3D to 2D transformation of data, effective SW estimation, and FWI.
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Citations
20 Claims
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1. A method for determining physical properties of a subsurface object disposed in a surrounding media, comprising:
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acquiring measured ground penetrating data from a ground penetrating radar device, wherein the measured ground penetrating data includes at least one measured diffraction hyperbola; estimating a plurality of parameters of an initial model of the subsurface object and the surrounding media, such that the initial model produces a simulated diffraction hyperbola that is offset less than one-half a wavelength from the measured diffraction hyperbola, wherein the plurality of parameters includes at least one of the following; a velocity of electromagnetic waves through media in which the subsurface object is located; a depth of the subsurface object in the surrounding media; a horizontal location of the subsurface object; a size of the subsurface object; a conductivity of the surrounding media; a permittivity of the surrounding media; a permittivity of any material or fluid within an outer surface of the subsurface object; acquiring a measured source wavelet and deconvolving the initial model from the measured ground penetrating data to produce a corrected source wavelet; simulating ground penetrating data for the initial model with the corrected source wavelet; and determining a cost function and adjusting at least one of the plurality of parameters to minimize the cost function. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for determining the cross-sectional size of an underground pipe, comprising:
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operating a ground penetrating radar device with at least one antenna in a broadside orientation with respect to the underground pipe, wherein the ground penetrating radar device discharges and receives electromagnetic waves; acquiring measured ground penetrating data from the ground penetrating radar device, wherein the measured ground penetrating data includes at least one measured diffraction hyperbola; estimating a plurality of parameters of an initial model of the underground pipe and the surrounding media, such that the initial model produces a simulated diffraction hyperbola that is offset less than one-half a wavelength from the measured diffraction hyperbola, wherein the plurality of parameters includes; a velocity of electromagnetic waves through media in which the underground pipe is located; a depth of the underground pipe in the surrounding media; a horizontal location of the underground pipe; a size of the underground pipe; a conductivity of the surrounding media; a permittivity of the surrounding media; a permittivity of any material or fluid within an outer surface of the underground pipe; producing a corrected source wavelet by acquiring a measured source wavelet and deconvolving the initial model from the measured ground penetrating data; simulating ground penetrating data for the initial model with the corrected source wavelet; and determining a cost function by running a forward model and optimizing each of the plurality of parameters using full waveform inversion to minimize the cost function, exception for the conductivity of the surrounding media. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A method for determining the cross-sectional size of an underground pipe, comprising:
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operating a ground penetrating radar device with at least one antenna in a broadside orientation with respect to the underground pipe, wherein the ground penetrating radar device discharges and receives electromagnetic waves; acquiring measured ground penetrating data from the ground penetrating radar device, wherein the measured ground penetrating data includes at least one measured diffraction hyperbola; estimating a plurality of parameters of an initial model of the underground pipe and the surrounding media, such that the initial model produces a simulated diffraction hyperbola that is offset less than one-half a wavelength from the measured diffraction hyperbola, wherein the plurality of parameters includes; a velocity of electromagnetic waves through media in which the underground pipe is located; a depth of the underground pipe in the surrounding media; a horizontal location of the underground pipe; a size of the underground pipe; a conductivity of the surrounding media; a permittivity of the surrounding media; a permittivity of any material or fluid within an outer surface of the underground pipe; transforming the initial model from three-dimensional data to two-dimensional data; producing a corrected source wavelet by acquiring a measured source wavelet and deconvolving the initial model from the measured ground penetrating data; simulating ground penetrating data for the initial model with the corrected source wavelet; and determining a cost function and optimizing each of the plurality of parameters to minimize the cost function, exception for the conductivity of the surrounding media.
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Specification