Device and method for precisely measuring transient electromagnetic characteristic responses of unexploded ordnance

A characteristic response, accurate measurement technology, applied in measurement devices, electrical/magnetic exploration, geophysical measurement, etc., can solve the problems of characteristic response measurement error, large characteristic response, reducing the accuracy of target recognition, etc., to improve the accuracy Effect

Inactive Publication Date: 2017-11-21
JILIN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This equivalence has the following disadvantages: firstly, the actual target body has a certain volume, and the primary fields received by each position are not the same, which will lead to measurement errors of the characteristic response; secondly, the ground and other background responses are not deducted during the measurement, resulting The characteristic response is too large; finally, due to the influence of signal saturation and noise, the measured characteristic response of the target body is seriously distorted, which will reduce the accuracy of target recognition

Method used

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  • Device and method for precisely measuring transient electromagnetic characteristic responses of unexploded ordnance
  • Device and method for precisely measuring transient electromagnetic characteristic responses of unexploded ordnance
  • Device and method for precisely measuring transient electromagnetic characteristic responses of unexploded ordnance

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Experimental program
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Effect test

Embodiment 1

[0030] The measuring device of embodiment 1 unexploded bomb characteristic response

[0031] The characteristic response of the unexploded bomb needs to be obtained under the excitation of a uniform magnetic field along the main axis or perpendicular to the main axis. Generally, the transmitting coil cannot generate a uniform primary field in a large range. Long straight solenoid coils and rectangular coil groups to generate a uniform primary field, such as figure 1 Shown:

[0032] figure 1 In (a), n with length l and diameter D 0 The long-turn straight solenoid produces a pulsed magnetic field uniformly distributed along the axial direction, which is used to excite the characteristic response of the target along the main axis, ensuring that all parts of the target are excited by the same primary field, and greatly improving the measurement accuracy of the characteristic response of the target along the main axis. precision. Assuming that the current intensity in the long ...

Embodiment 2

[0036] Embodiment 2 Measuring method of the present invention is further analyzed as follows:

[0037] 1. Definition of Unexploded Bomb Characteristic Response

[0038] Such as figure 2 As shown, the unexploded bomb in the pulsed magnetic field H P The eddy current is induced under the excitation of the (primary field), and the magnetic field (secondary field) generated by the eddy current in space can be equivalent to a group of dipoles with coincident centers and orthogonal directions m=(m x , m y , m z ) the magnetic field generated in space, the secondary field H at point P in space can be calculated as:

[0039]

[0040] (1) In the formula, r is the position vector of point P, r is the modulus value of r, e r is a unit vector parallel to r.

[0041] When the main axis of the unexploded bomb is parallel to the z-axis, the dipole m is calculated as:

[0042]

[0043] β of axisymmetric target body xx = β yy , collectively referred to as the magnetic polarizat...

Embodiment 3

[0081] Embodiment 3 measurement length is 27cm, and diameter is the characteristic response of 82mm mortar shell

[0082] 1. Establish a measurement device for the characteristic response of a finite conductor

[0083] established as image 3 A pair of characteristic response measuring devices shown: a long straight solenoid with a length l of 120 cm and a diameter of 22 cm, n 0 Equal to 30, evenly distributed, as a measurement device for the characteristic response of the vertical axis. The rectangular coil group consists of two identical rectangular coils, the length a of each rectangular coil is equal to 100cm, the width b is equal to 60cm, and the number of turns is n 1 Equal to 12, two rectangular coils are placed parallel and coaxially, the distance d is equal to 36cm, and the two coils are connected in series in the same direction to form a horizontal axis characteristic response measurement device.

[0084] 2. Measure the characteristic response in the direction of ...

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Abstract

The invention discloses a device and a method for precisely measuring transient electromagnetic characteristic responses of unexploded ordnance and belongs to the technical field of target detection and recognition. The device and the method are used for measuring characteristic responses of the all types of unexploded ordnance in a libratory, so an unexploded ordnance characteristic response database is established and used as the basis for recognizing a target in the actual detection. The device comprises a long straight solenoid, a rectangular coil group and a receiving coil. The method comprises steps of measuring secondary fields generated in the longitudinal axis direction and the transverse axis direction of the unexploded ordnance under the excitation of uniform pulsed magnetic fields HP; and calculating the measured secondary fields to obtain the characteristic responses lp(t), lv(t) of a target. Based on a problem of low measurement precision of the traditional method, the invention provides a special device for measuring the characteristic responses of the unexploded ordnance, and also provides a background field deduction method and a measurement distance method in order to improve the measurement precision of the characteristic responses, so an effective means is provided for precise acquisition of the characteristic responses of a target.

Description

technical field [0001] The invention belongs to the technical field of target detection and identification, and specifically relates to the theory and method of using a specially designed device to accurately measure the characteristic responses of various unexploded bombs in a laboratory. These characteristic responses can be used to establish a characteristic response database. As the basis for the system to identify various targets during actual detection. Background technique [0002] Unexploded ordnance mainly refers to landmines, artillery shells, aerial bombs, etc. that have not yet been detonated after war or other military activities. These munitions are scattered on the surface or extremely shallow underground, seriously threatening people's lives and affecting local social and economic development. The transient electromagnetic method is widely used in the detection of unexploded bombs due to its high detection efficiency and strong ability to identify targets. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01V3/11
CPCG01V3/104
Inventor 张爽陈曙东王昊丰郭欣
Owner JILIN UNIV
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