EP0733218A1 - Systeme de detection pour detecter, localiser et identifier des objets metalliques - Google Patents

Systeme de detection pour detecter, localiser et identifier des objets metalliques

Info

Publication number
EP0733218A1
EP0733218A1 EP95934044A EP95934044A EP0733218A1 EP 0733218 A1 EP0733218 A1 EP 0733218A1 EP 95934044 A EP95934044 A EP 95934044A EP 95934044 A EP95934044 A EP 95934044A EP 0733218 A1 EP0733218 A1 EP 0733218A1
Authority
EP
European Patent Office
Prior art keywords
sensor system
sensor
objects
data
gradient
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP95934044A
Other languages
German (de)
English (en)
Inventor
Wolfgang Eschner
Ralph Koch
Jürgen Kramer
Bernhard Neumeyer
Rainer Ulbrich
Christian Borgwardt
Wolfgang Schreiner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dornier GmbH
Original Assignee
Dornier GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Dornier GmbH filed Critical Dornier GmbH
Publication of EP0733218A1 publication Critical patent/EP0733218A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
    • G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
    • G01V3/104—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils
    • G01V3/105—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils forming directly coupled primary and secondary coils or loops
    • G01V3/107—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils using several coupled or uncoupled coils forming directly coupled primary and secondary coils or loops using compensating coil or loop arrangements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/15—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for use during transport, e.g. by a person, vehicle or boat

Definitions

  • the invention relates to a sensor system for the electronic detection of metallic objects which are located below the surface of the earth.
  • Metallic objects beneath the earth's surface can be, for example, military and industrial contaminated sites that pose a high risk to people and the environment.
  • the object of the invention is therefore to create a sensor system with which the lateral and vertical resolution of conventional metal detectors and magnetic field probes is considerably improved.
  • the sensor system according to the invention comprises at least one sensor module with at least one active gradient metal detector.
  • the active gradient metal detector comprises at least one gradient coil and one excitation coil.
  • the gradient coil and excitation coil are preferably in a rigid configuration.
  • a gradient metal detector comprises two gradient coils orthogonal to one another. Such a metal detector is referred to below as a double gradient metal detector.
  • the sensor system according to the invention achieves a significantly higher resolution than the known sensor systems. In order to make full use of the improvement in resolution, the sensor signals are advantageously evaluated with a higher dynamic range of 22 bits, corresponding to 130 dB.
  • a signal analysis or a model calculation for the reconstruction of the measurement signals is additionally carried out.
  • the model calculation the three-dimensional position of objects, their shape and size, but also their electrical and magnetic material parameters are determined. From these calculated data of depth, size, shape and material of the metallic objects, the sensor system according to the invention carries out a classification of the objects found, which enables the essential decision to be made as to which objects can remain in the ground as harmless or uninteresting.
  • FIG. 1 shows a schematic representation of an active metal detector belonging to the prior art
  • FIG. 2 shows a schematic representation of an active gradient metal detector as used in the sensor system according to the invention
  • Fig. 3 typical waveform of a prior art
  • FIG. 4 typical waveform of an active gradient metal detector with the Diameter D when passing over a metal ball
  • FIG. 5 shows a schematic illustration of an active double-gradient metal detector as used in the invention
  • FIG. 6 shows a sensor module in a linear two-dimensional array arrangement with double-gradient metal detectors and three-axis detectors Fluxgate magnetometers
  • FIG. 7 circular arrangement of the sensors from FIG. 6,
  • FIG. 8 an embodiment of the sensor system according to the invention
  • FIG. 9 an embodiment of a sensor module according to the invention.
  • 10 shows a hand-carried version of the sensor system according to the invention. 11 to 13 examples for the evaluation of the sensor data.
  • active sensors metal detectors or induction coil sensors
  • passive sensors magnetic field probes
  • Gradient metal detectors are used as metal detectors. They differ from conventional metal detectors (FIG. 1) in that the pickup coil is divided into two coils (pair of coils) connected to one another (FIG. 2) and thus a field gradient component is measured. Such a pair of coils is referred to in this application as a gradient coil.
  • the measurement signals of a conventional metal detector and a gradient metal detector for a metal ball are compared in FIGS. 3 and 4.
  • the signal swing differs for the two variants not, but the half-width of the signals and thus the lateral resolution in the gradient metal detector is halved to the size of half the diameter of the excitation coil.
  • the advantage of the resolution improvement is only fully exploited if the field gradient is measured in both horizontal directions.
  • a second pair of pickup coils which is oriented in the measuring plane perpendicular to the first pair of coils, must be present and is also measured (FIG. 5).
  • the two pairs of pickup coils are arranged in the manner of a cloverleaf.
  • This double gradient metal detector is operated by a common excitation coil. This arrangement is referred to below as a hardware gradiometer.
  • the same gradient components are calculated which a double-gradient metal detector also measures.
  • the difference between this "software gradiometer” and the “hardware gradiometer” is that in the hardware gradiometer, coherent interference signals are immediately eliminated by the simultaneous formation of differences and not in the software gradiometer. The signal noise is therefore higher in the latter.
  • the measurement grid for the software gradio meter must be made finer. So it has to be measured longer.
  • the hardware gradiometer used in the sensor system according to the invention therefore allows a greater search performance. To eliminate faults, e.g. caused by paramagnetic or moist earth soils, a multi-frequency method is used.
  • a sensor module can additionally comprise passive magnetic field probes.
  • absolute field measuring devices such as proton resonance magnetometers are mostly used in geophysical measurements.
  • the measurement results of these magnetometers are independent of the spatial position of the measuring instruments, and the measurement values are therefore independent of twists and turns.
  • they have the disadvantage that their measuring frequency range is limited to a maximum of 1 Hz.
  • 3-axis fluxgate magnetometers are therefore used. They allow measuring frequencies up to 1 kHz. The individual sensitivities of the 3 magnetometers are determined in a calibration process. With their help, the absolute value of the magnetic field is calculated from the individual measured values.
  • This part of the sensor system according to the invention represents a fast absolute value measuring device. Dynamic range and linearity of the fluxgate magnetometer still allow field resolutions of less than 1 nT.
  • Natural and human-generated magnetic noise is in the frequency band up to 100 Hz, depending on the environment, at some 100 nT.
  • a further reference magnetometer must be installed in addition to the magnetometers already mentioned.
  • the magnitude of the magnetic field is also formed for the reference magnetometer. The difference between see the squares and the measurement results of the measuring magnetometer and the reference magnetometer are then:
  • a signal is therefore obtained which is proportional to the magnetic field to be measured, the noise is thus eliminated.
  • FIG. 5 To increase the search performance, that is, the area searched per hour, several double-gradient metal detectors (FIG. 5) and magnetic field probes can be integrated into the device.
  • the sensors can be arranged in a two-dimensional linear arrangement (FIG. 6) or on a disk (FIG. 7) rigidly and / or movably with respect to one another.
  • the passive magnetic field sensor 1 4 is calibrated by a reference magnetometer 1 6 (FIG. 8) such that the earth field noise is removed from its measurement signal.
  • the measured data from the sensors are processed together with data from a rotary encoder 10 and a displacement encoder 8 (the displacement encoder 8 measures the position of the system relative to a reference point) from a measured value acquisition 6 and via a transmission link 12 to a central control and processing unit , for example to a central computer 1 8, transmitted to or in a vehicle 20.
  • the data of the various sensor modules are stored, processed, evaluated and shown on a display.
  • the search with the sensor system according to the invention takes place in such a way that an operator observes the high-resolution two-dimensional magnetic image of the floor on the monitor of the central computer. He thus receives a supervision of the magnetic image of the objects located below the earth's surface.
  • the objects can be recognized interactively by the operator himself or automatically by an image processing program. When an object has been recognized, the measured data are evaluated mathematically to determine depth, shape and material and then the object is classified. 1C
  • the location of the objects found is indicated on the map created in real time and by a marking device on the site.
  • the system has a modular structure and consists of one or more modules (FIG. 9), the modules being connected to one another in a fixed manner, but individually movable or else completely rigidly.
  • the sensor module as well as the devices for evaluating and displaying the sensor signals are integrated into a compact unit and mounted on wheels or a sliding trough. They are either manually operated by an operator (pushed) or pushed or pulled (externally moved) by a vehicle.
  • Sensor module as well as the devices for evaluating and displaying the sensor signals (e.g. front-end computer, central computer, monitor, etc.) are arranged on a driven carrier vehicle.
  • the carrier vehicle can be a land vehicle, but also an aircraft, e.g. be a zeppelin. A hovercraft is also possible.
  • the sensor system can be designed as a hand-held device that is carried by an operator over the surface of the earth to be examined. Any movements of the hand-held device are possible. For example, the operator can perform pendulum movements transversely to his direction of movement when running forward, so that the terrain to be examined can be covered as quickly and seamlessly as possible.
  • the fact that the device has no mechanical contact with the earth's surface places special demands on the position determination.
  • the following means for positional adjustment are advantageously suitable for this hand-held device:
  • Satellite-supported GPS sensors in conjunction with directional gyros and acceleration sensors and / or speed sensors, a two-dimensional ultrasound system that interacts with a correlation computer, a laser tracking system, a two-dimensional laser Doppler sensor system, and a two-dimensional cable pull system.
  • the determined coordinates can be corrected by a calibration measurement by measuring the location points with respect to a reference point.
  • FIG. 10 An example of such a hand-held device is shown in FIG. 10. It comprises a sensor module 22 with at least one gradient metal detector, advantageously a double gradient metal detector.
  • the sensor module 22 is preferably immovably connected to the frame 32 of the device.
  • a position sensor 26 is also arranged on the frame 32 of the device. be coupled.
  • the same aids as in (1.e) can be used for this purpose.
  • the arrangement of the sensors in the system can be selected in such a way that the distances between the sensors and objects which negatively influence the sensor function (for example other sensors, metallic components in the overall system) remain constant over time. In the case of rotating sensors, this can be achieved, for example, by synchronizing the movement of the sensors.
  • the speed of movement of the system is reduced. Due to the lower speed, measured values can be taken in higher density, so that the measurement resolution increases. With the higher measuring point density in the two-dimensional grid, the fine resolution of the magnetic signals can be increased by the subsequent data processing. This improves the spatial separation of small and large objects.
  • the measured values of the double-gradient metal detectors are preprocessed and color-coded in a two-dimensional image of the area searched. Additional representations, e.g. Isolines are possible.
  • the measurement data of the magnetic field probes can be reproduced in the same image with a different color coding. In this way, objects with and without their own magnetic field can be distinguished from one another in the image.
  • the color coding can be adapted to the measurement situation by the operator.
  • the measured values are fed to an evaluation computer. Detected objects are shown.
  • an eddy current distribution can be calculated. From this, the shape, size and depth as well as the position of the object can be determined. The conductivity of non-magnetic objects is calculated, and the magnetic moment is determined for magnetic objects.
  • the identified objects can be identified with the aid of the determined object parameters shape, volume and electrical conductivity.
  • the characteristic data of the objects to be expected are stored in a database.
  • a corresponding computer program offers the operator of the device suggestions for identification.
  • the data are evaluated using the following methods:
  • An active double-gradient metal detector (FIG. 5) supplies a magnitude signal when driving over a metallic object, the phase position of which depends on the excitation voltage on the material of the metal and on the frequency of the excitation voltage.
  • metals such as brass, iron, copper or aluminum can be distinguished regardless of their shape and size.
  • a background signal from the ground often prevents material detection.
  • a double gradient metal detector which is excited at one frequency, but particularly advantageously at several frequencies.
  • the measuring Values of such a double gradient metal detector are linked as punctual data records with frequency-dependent magnitude and phase values with the associated location coordinates of the metal detector from a computer to a (in terms of excitation frequencies) a multidimensional data field which can be differentiated according to the location coordinates.
  • a data set at a spatial point P (x, y) within the area to be examined contains 1?
  • the excitation coil of the metal detector is operating at two frequencies .
  • v 2 the following components:
  • the specified 2-dimensional measurement data set expands accordingly to an N-dimensional data set.
  • the individual components of the measurement data set can also be linked to one another.
  • results of the difference formation can advantageously be assigned to a gray scale or color scale and (advantageously in real time) can be displayed as a two-dimensional representation on the display unit of a computer.
  • the areas between the individual calculated points of the two-dimensional representation can advantageously be filled by interpolated gray or color values.
  • a grid of individual location points is shown at the top left, each of these location points being assigned a measurement data record measured at these points.
  • FIG. 12 shows some examples of the alignment of the gradient vectors for certain materials and shapes of the detected objects.
  • the sketch at the top left shows the gradient vectors for a punctiform and ferromagnetic object.
  • the vectors all point to a point, which is thereby recognized as the center of the object.
  • the determined gradient vectors for a point-like, paramagnetic object are shown at the top right. The vectors in this case point away from the object.
  • the middle column shows the unit vector field of the gradients at a fixed excitation frequency, as already described in FIGS. 11 and 12.
  • the first column shows the scalar field of the amounts of the associated measurement data sets at the same excitation frequency.
  • the values between the measuring points are interpolated.
  • the magnitude values are assigned to a color scale, so that different magnitude values or intervals correspond to different color values.
  • the third column shows the final result of the evaluation.
  • the top line shows the evaluation for a simple object (point-shaped).
  • the vectors here all point towards a single point. In this color coding, the absolute values are represented as concentric circles around this point. This central point can thus be recognized and marked as the position of the object.
  • the middle line shows the evaluation for a compound object (several point objects).
  • the gradient vectors point to several points here.
  • the color coding of the absolute values has a corresponding symmetry.
  • the components of the data field can be processed and evaluated for each individual excitation frequency in the manner described.
  • a material detection eg copper, brass, aluminum, iron, nickel, precious metals
  • the physical basis for this is the fact that the signal received by an object changes in a typical manner depending on the type of material with the excitation frequency.
  • information about the material properties of the objects hidden in the ground is obtained which uniquely characterize and distinguish them.
  • a database can be present in which a characteristic frequency dependency for a large number of materials and objects is stored. Identification can be obtained by comparing the measured values with the content of the database.
  • the invention achieves a high-resolution magnetic measurement of the upper layer of the earth, the real-time representation of the measured values obtained on a map, the real-time marking of the found object positions on the ground, and the classification of the found objects.
  • the classification enables a significant reduction in the number of objects to be excavated. Time and costs for soil remediation as well as dangers for cleaning staff are considerably reduced. List of reference numerals used in Figures 8, 9 and 10:

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  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Geophysics (AREA)
  • Electromagnetism (AREA)
  • Geophysics And Detection Of Objects (AREA)

Abstract

L'invention concerne un système de détection à haute résolution qui permet de détecter, de localiser et d'identifier des objets métalliques, situés sous la surface de la terre. Ce système comprend au moins un détecteur actif de métaux à gradient.
EP95934044A 1994-10-10 1995-10-09 Systeme de detection pour detecter, localiser et identifier des objets metalliques Withdrawn EP0733218A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE19944436078 DE4436078A1 (de) 1994-10-10 1994-10-10 Bildgebendes hochauflösendes Sensorsystem zu Detektion, Ortung und Identifizierung von metallischen Objekten
DE4436078 1994-10-10
PCT/DE1995/001375 WO1996011414A1 (fr) 1994-10-10 1995-10-09 Systeme de detection pour detecter, localiser et identifier des objets metalliques

Publications (1)

Publication Number Publication Date
EP0733218A1 true EP0733218A1 (fr) 1996-09-25

Family

ID=6530329

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95934044A Withdrawn EP0733218A1 (fr) 1994-10-10 1995-10-09 Systeme de detection pour detecter, localiser et identifier des objets metalliques

Country Status (4)

Country Link
EP (1) EP0733218A1 (fr)
CA (1) CA2178332A1 (fr)
DE (1) DE4436078A1 (fr)
WO (1) WO1996011414A1 (fr)

Families Citing this family (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5842986A (en) * 1995-08-16 1998-12-01 Proton Sciences Corp. Ferromagnetic foreign body screening method and apparatus
US6965792B2 (en) 1996-06-25 2005-11-15 Mednovus, Inc. Susceptometers for foreign body detection
US7047059B2 (en) 1998-08-18 2006-05-16 Quantum Magnetics, Inc Simplified water-bag technique for magnetic susceptibility measurements on the human body and other specimens
US6496713B2 (en) 1996-06-25 2002-12-17 Mednovus, Inc. Ferromagnetic foreign body detection with background canceling
DE19648834A1 (de) * 1996-11-26 1998-05-28 Foerster Inst Dr Friedrich Verfahren zum Betrieb und zur Auswertung von Signalen einer Wirbelstromsonde und Vorrichtung zur Ausübung des Verfahrens
DE19648833A1 (de) * 1996-11-26 1998-05-28 Foerster Inst Dr Friedrich Verfahren und Vorrichtung zur Lokalisierung und Identifizierung von im Boden versteckten Suchobjekten, insbesondere Plastikminen
DE19652977C1 (de) * 1996-12-19 1998-04-30 Vallon Gmbh Ortungseinrichtung für im Erdbereich befindliche Objekte
DE29717370U1 (de) * 1997-09-29 1998-01-08 Ebinger, Klaus, 51149 Köln Sondenanordnung
GB9813889D0 (en) 1998-06-27 1998-08-26 Secr Defence Apparatus for detecting metals
SE511951C2 (sv) * 1998-09-29 1999-12-20 Saab Ab Minröjningsrobot
DE10104924B4 (de) * 2001-01-30 2004-09-30 Mit Gmbh Magnetic Imaging Tools Mobile Messvorrichtung und Verfahren zur ortsaufgelösten Bestimmung magnetischer und/oder elektrischer Parameter von in Flüssigkeiten oder festen Stoffen eingebetteten Körpern
US6525539B2 (en) * 2001-03-15 2003-02-25 Witten Technologies Inc. Apparatus and method for locating subsurface objects in conductive soils by measurements of magnetic fields by induced currents with an array of multiple receivers
GB0124887D0 (en) 2001-10-17 2001-12-05 Qinetiq Ltd Metal detection apparatus
EP1828811A2 (fr) * 2004-12-20 2007-09-05 Andrä, Wilfried Dispositif et procede pour reperer des objets magnetiques ou magnetisables
DE102009042616A1 (de) 2009-09-23 2011-03-24 Christoph Rohe Handführbare Vorrichtung zum Detektieren von in einem Untergrund, insbesondere einer Wand oder dergleichen, befindlichen metallischen Objekten
DE102011077068A1 (de) * 2011-06-07 2012-12-13 Hilti Aktiengesellschaft Verfahren und Vorrichtung zum Detektieren eines leitfähigen Objektes
US9638824B2 (en) * 2011-11-14 2017-05-02 SeeScan, Inc. Quad-gradient coils for use in locating systems
US9927545B2 (en) * 2011-11-14 2018-03-27 SeeScan, Inc. Multi-frequency locating system and methods
US9488747B2 (en) 2012-03-23 2016-11-08 Seesoon, Inc. Gradient antenna coils and arrays for use in locating systems
DE102012218174A1 (de) * 2012-10-05 2014-04-10 Robert Bosch Gmbh Ortungsvorrichtung zur Bestimmung einer Objekttiefe
DE102015206275A1 (de) * 2015-03-18 2016-09-22 Gerd Reime System, Verfahren und Computerprogramm zur mobilen Bereitstellung von Daten verborgener Objekte
US10274630B2 (en) * 2015-06-02 2019-04-30 Syncrude Canada Ltd. In Trust For The Owners Of The Syncrude Project As Such Owners Exist Now And In The Future Tramp metal detection
DE102016108988B4 (de) * 2016-05-13 2019-05-29 Heinrich Hirdes Gmbh Verfahren und Vorrichtung zum Auffinden elektrisch leitfähiger Gegenstände unter einer Bodenoberfläche
DE102017210672A1 (de) * 2017-06-23 2018-12-27 Heinrich Hirdes Gmbh Verfahren zur Messung einer Überdeckung einer Leitung und Vorrichtung
US20220291412A1 (en) * 2021-03-12 2022-09-15 Christopher Frank Eckman Metal detecting sensor array for discriminating between different objects
DE102024110381A1 (de) * 2024-04-12 2025-10-16 Endress+Hauser SE+Co. KG Metalldetektor zur Positionsbestimmung von leitfähigen Gegenständen, Verfahren zur Positionsbestimmung von leitfähigen Gegenständen mit einem Metalldetektor, Messstelle zum Entdecken von leitfähigen Gegenständen in einem Medium

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3826973A (en) * 1973-01-10 1974-07-30 Benson R Electromagnetic gradiometer
US3875497A (en) * 1973-12-26 1975-04-01 Seatrek Ltd Waterborne magnetic anomaly detection system and apparatus
US4021725A (en) * 1976-03-05 1977-05-03 The United States Of America As Represented By The Secretary Of The Navy Mobile mine detection system having plural color display
US4727329A (en) * 1986-02-19 1988-02-23 Atlantic Richfield Company Method and system for measuring displacement of buried fluid transmission pipelines
DE3619308C1 (de) * 1986-06-07 1991-08-29 Klaus Ebinger Sonde fuer ein Metallsuchgeraet
DE4242541C2 (de) * 1992-12-16 1996-03-28 Tzn Forschung & Entwicklung Vorrichtung zum Orten von unterhalb der Erdoberfläche befindlicher Munition

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9611414A1 *

Also Published As

Publication number Publication date
CA2178332A1 (fr) 1996-04-18
WO1996011414A1 (fr) 1996-04-18
DE4436078A1 (de) 1996-04-11

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