Near-surface target position rapid delineation method based on magnetic gradient tensor characteristic value

Abstract

The invention relates to a near-surface target position rapid delineation method based on a magnetic gradient tensor characteristic value, and the method comprises the following steps: 1, carrying out the meshing of a measurement region, and obtaining a magnetic gradient tensor matrix of each grid point; step 2, calculating characteristic values of the magnetic gradient tensor matrix G, and arranging the characteristic values from large to small, and recording the characteristic values as lambda1, lambda2 and lambda3; and step 3, establishing a target position corresponding to the local maximum value of the target position delineation function P. The method provided by the invention has good resolution while effectively overcoming the oblique magnetization influence, and can be applied to rapid delineation of the near-surface target position.

Description

technical field [0001] The invention belongs to the field of geophysical airborne magnetic method detection, in particular to a method for quickly delineating the position of a near-surface target based on the eigenvalue of the magnetic gradient tensor. Background technique [0002] After more than half a century of development, the means of magnetic prospecting have further developed from total field measurement, total field gradient measurement, vector measurement to magnetic field tensor measurement. Foreign countries began to study the magnetic gradient tensor since the 1990s, and it has been commercially applied. Domestic research started relatively late, and the research on theoretical analysis, system integration, data processing and interpretation is not deep enough. Compared with total magnetic field or total field gradient measurement, magnetic gradient tensor measurement has the following advantages: [0003] (1) It can shield the interference of the background ...

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Problems solved by technology

[0009] At present, magnetic gradient tensor eigenvalues ​​have been applied in the fields of geological body boundary detection and structural delineation (CN112749493A; CN 112327383A; Zheng Qiang, Guo Hua, Zhang Guibin, etc. Equilibrium boundary recognition based on magnetic gradient full tensor eigenvalues Method. Petroleum Geophysical Exploration, 2020,55(2):454-464), however, most of the scenarios considered in these applications are large-scale geological body information, and there are few applied researches on the near-surface small magnetic target scenarios

With the continuous development of UAV technology, it is completely feasible to measure the gradient tensor of small magnetic targets near the surface. Jin Huanghuang et al. used a small multi-rotor UAV platform to detect the gradient tensor of near-surface targets. However, Does not take into account the influence of the oblique magnetization of the earth's magnetic field on the target

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