MIMO Ground-Penetrating Radar for Layered Soil Permittivity

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Solution Overview

Problem

Existing ground-penetrating radar methods for estimating the relative permittivities and thicknesses of soil layers are inaccurate due to the use of average values and fail to account for multi-layered soil structures, leading to uncertainties in target detection.

Innovation Solution

A method using a ground-penetrating radar with multiple transmitting and receiving antennas to estimate the most probable pairs of delay and relative permittivity for each soil layer, employing a specific algorithm to calculate correlation coefficients and filter results based on predetermined thresholds, allowing for precise estimation of permittivities and thicknesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If average relative permittivity values are used for the entire soil structure, then the measurement process is simplified, but the measurement precision deteriorates

Engineering Contradiction:
Improvesimplicity of measurement processVSAvoidaccuracy of relative permittivity estimation
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The soil structure is divided into multiple layers, each with its own relative permittivity value. The GPR signal is analyzed to identify reflections from interfaces between layers, allowing separate estimation of permittivity for each layer rather than using a single average value for the entire soil structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The problem is transformed from a one-dimensional average value estimation to a multi-dimensional analysis considering multiple soil layers at different depths. By analyzing the vertical stratification of soil layers and their respective electromagnetic properties, the method achieves more precise characterization of the subsurface structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If hyperbola curve fitting is used to estimate average dielectric properties, then the calibration process is simplified, but the reliability deteriorates when multiple soil layers are present

Engineering Contradiction:
Improvesimplicity of calibration processVSAvoidaccuracy of permittivity estimation in multi-layered soil
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Instead of fitting a single hyperbola to represent the entire soil structure, the method segments the analysis by identifying multiple hyperbolic patterns corresponding to reflections from different soil layer interfaces. Each interface reflection is analyzed separately to determine the permittivity of adjacent layers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method uses an iterative approach where initial permittivity estimates are refined by comparing predicted hyperbolic patterns with actual GPR data. The correlation coefficient calculation provides feedback to adjust and optimize the permittivity values for each layer, improving the reliability of the estimation.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If migration is used to reduce hyperbolas to points for accurate target positioning, then the position definition is improved, but the device complexity increases

Engineering Contradiction:
Improveaccuracy of target position and depth definitionVSAvoidcomplexity of mathematical processing
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The method performs preliminary estimation of relative permittivity values for each soil layer before conducting migration processing. This preliminary characterization of the subsurface electromagnetic properties provides accurate velocity models that simplify the subsequent migration process and improve target positioning accuracy.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The method changes the approach from using a single average permittivity value to using layer-specific permittivity values in the migration process. This parameter refinement allows for more accurate velocity calculations and improved depth focusing without requiring overly complex processing algorithms.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method provides accurate determination of soil layer permittivities and thicknesses, enhancing the precision of radar detection algorithms for underground targets.

Implementation Method 1

ground penetrating radar

Methodology Applied
Scientific EffectRadar: Radar

Implementation Method 2

the penetrating wave encounters buried targets or interfaces between different soil layers

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

determining the relative permittivity of a material

Methodology Applied
Scientific EffectDielectric Permittivity: Dielectric Permittivity

Data Source

PatentEP4375663B1Method and apparatus for determining the relative permittivity of a material using a ground penetrating radar
Publication Date: 2025.08.27 COMMISSARIAT A LENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES
  • EP4375663B1 patent drawingFigure 1
  • EP4375663B1 patent drawingFigure 2a~2b
  • EP4375663B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a new method for accurately estimating the relative permittivities and thicknesses of each layer of a material such as soil. The method is based on measurements acquired by a ground-penetrating radar equipped with multiple transmitting and receiving antennas (MIMO radar, "Multiple Input Multiple Output"). The proposed method relies on a specific algorithm that estimates the most probable pairs (delay, relative permittivity) corresponding to the different layers composing the soil structure.