JP2014044114A - Differential magnetic probing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a differential magnetic probing system capable of differential magnetic probing by using only one magnetic sensor part.SOLUTION: One magnetic sensor part incorporated in a movable body is used and the strength data of a magnetic field obtained by the magnetic sensor part, while the movable body is moved on a linear probing line is stored in association with the movement distance data of the movable body obtained by a distance sensor part, as position magnetic field data in a storage part. Only the position magnetic field data corresponding to a previously set distance between virtual magnetic sensor parts is extracted from all the position magnetic field data stored in the storage part, during analysis of data, the difference in the strength of the magnetic field between the position magnetic field data having the second largest movement distance is calculated for all the extracted position magnetic field data, and a magnetic object buried in the ground is probed based on the obtained difference in the strength of the magnetic field.

Description

  The present invention relates to a differential magnetic exploration system, and more particularly to a differential magnetic exploration system for exploring a magnetic object buried in the ground from a difference in magnetic field strength at two positions separated on an exploration line.

When conducting magnetic exploration of magnetic exploration objects (magnetic objects) such as unexploded bombs and underground structures during the war, it is common to use a differential magnetic exploration device (differential magnetic exploration system) Has been done.
A differential magnetic exploration device is a two-way magnetic sensing coil (magnetic sensor unit) that detects the magnetism of a magnetic material and holds it in the inner space of the moving body at regular intervals to make a differential connection. The object to be searched is detected from the difference in the strength of the magnetic field obtained by the coil.
In a uniform strong magnetic field such as the earth's magnetic field, even if the differential magnetic exploration device is shaken, the signals cancel each other and no detection signal is generated. However, when a local magnetic field exists, a difference occurs in the magnitude of the magnetic field detected by the two magnetic detection coils. The differential magnetic exploration apparatus is configured to send a magnetic detection signal of a predetermined magnitude to a manager's personal computer using this magnetic field difference. In general differential magnetic exploration devices, in order to detect magnetic anomalies of several m to several tens of m that occur due to unexploded bombs in the ground, the distance between two magnetic sensing coils is 0.5-2. .0m is set.

JP 08-334570 A

  As described above, in the case of the differential magnetic exploration apparatus, the relationship between the distance between the magnetic sensing coils that are differentially connected and the exploration capability is such that if the distance between the magnetic sensing coils is set long (for example, 2.0 m), However, if the distance between the magnetic sensing coils is set short (for example, 0.5 m), the reciprocal relationship cannot be increased. Specifically, if there are objects (such as buildings, vehicles, steel sheet piles, piles, etc.) that are more magnetic than the exploration target in the exploration area, the background noise (magnetism) will In addition, accurate exploration cannot be performed in a region with a radius of several meters to several tens of meters centering on a ferromagnetic object. Therefore, although it is conceivable to shorten the distance between the magnetic detection coils, the exploration range becomes short and the exploration time becomes long.

  Further, in the common sense of differential magnetic exploration so far, it has been an essential requirement to use two magnetic detection coils for differential magnetic exploration. Therefore, for example, when the distance between the two magnetic detection coils is deviated for some reason, such as the movement of the moving body, there is a possibility that accurate magnetic exploration cannot be performed. In addition, the moving body in which the magnetic exploration coil is incorporated, and hence the differential magnetic exploration apparatus, is expensive as much as two magnetic detection coils are used.

  Based on such problems, for example, a magnetic detection coil according to each purpose, that is, a differential magnetic exploration device having a magnetic detection coil distance of 2 m and a differential magnetic exploration device having a magnetic detection coil distance of 0.5 m. It may be possible to employ two differential magnetic exploration devices with different distances between them. In this way, the above-described problem of the reciprocal relationship is improved. However, this method requires two magnetic exploration operations, requires twice as much exploration time, and is limited to two patterns of 0.5 m or 2 m between the magnetic detection coils. In order to conduct high-accuracy exploration (the distance between the magnetic detection coils is less than 0.5 m) or a wider range (the distance between the magnetic detection coils is 2 m or more), the differential type magnetism between the corresponding magnetic detection coils It was necessary to prepare an exploration device.

  Thus, as a result of earnest research, the inventor has obtained only one magnetic sensor unit while the moving body is moving on a linear search line even when only one magnetic sensor unit is built in the moving body. The magnetic field strength data obtained is stored in the storage unit as positional magnetic field data in association with the moving distance data of the moving body obtained by the distance sensor unit, and all the positional magnetic field data stored in the storage unit at the time of data analysis The position magnetic field data is sequentially extracted from the reference position between the measurement points set in advance, and the extracted position magnetic field data and one magnetic sensor unit are equivalent to the reference pitch from the extracted position magnetic field data. Calculate the difference in magnetic field strength (difference in magnetic field strength between virtual magnetic sensor units) with the next position magnetic field data extracted at the moved position, and obtain the difference in magnetic field strength. In the ground If probing the object, the problems discussed above by finding that it is eliminated all completed the present invention.

  In particular, the reference distance between measurement points (distance between a virtual pair of magnetic sensor units) is changed as appropriate, and the reference distance between measurement points for each pattern is selected from all the position magnetic field data stored in the storage unit. If the position magnetic field data is extracted, only one magnetic exploration by one magnetic sensor unit is performed, and the magnetic exploration is performed using a plurality of moving bodies having different distances between the magnetic sensor units. It was found that the resolution of the magnetic object search can be improved by suppressing the influence of the magnetic field of the present invention, and the present invention has been completed.

An object of the present invention is to provide a differential magnetic exploration system capable of performing differential magnetic exploration using only one magnetic sensor unit.
Another object of the present invention is to provide a differential magnetic exploration system that can reduce the influence of a surrounding magnetic field and increase the resolution of exploration of a magnetic object.

  According to the first aspect of the present invention, there is provided a moving body that moves from a measurement start point to a measurement end point on a linear exploration line, a magnetic sensor unit built in the moving body, and the exploration line accompanying the moving body. A distance sensor unit that detects a moving distance from the measurement start point of the magnetic sensor unit that moves above, and the magnetic sensor unit is separated on the search line during the movement of the magnetic sensor unit due to the movement of the moving body A differential magnetic exploration unit for exploring a three-dimensional position of a magnetic object buried in the ground based on a difference in magnetic field strength detected at each of the two positions; a detection signal from the magnetic sensor unit; and A differential magnetic exploration system comprising: an arithmetic processing unit that calculates a three-dimensional position of a magnetic object buried in the ground based on a detection signal from a distance sensor unit, wherein the magnetic sensor unit includes: One, the differential type The air exploration unit includes a plurality of movement distance data obtained based on detection signals from the distance sensor unit, and a plurality of magnetic field strength data obtained based on detection signals from the one magnetic sensor unit. A data creation means for creating a plurality of position magnetic field data in association with each other, a memory for storing the plurality of position magnetic field data, and a reference distance between measurement points set in advance to obtain a difference in strength of the magnetic field And data extraction for extracting corresponding position magnetic field data from the plurality of position magnetic field data stored in the storage unit using the reference distance between the measurement points stored in the storage unit as a reference pitch for extraction And the arithmetic processing means at the position where the one magnetic sensor unit has moved by the reference pitch from the extracted position magnetic field data and the extracted position magnetic field data. The magnetic field strength difference between the extracted position magnetic field data is calculated, and 3 of the magnetic object buried in the ground is calculated based on the magnetic field strength difference obtained by the calculation. This is a differential magnetic exploration system for exploring a dimensional position.

  In the second aspect of the present invention, the storage unit stores a plurality of reference distances between the measurement points, and the data extraction unit extracts the plurality of reference distances between the measurement points stored in the storage unit. As the reference pitch, the corresponding position magnetic field data is extracted from the plurality of position magnetic field data stored in the storage unit, and the arithmetic processing means extracts each reference distance between the plurality of measurement points. Of the magnetic field strength between the extracted position magnetic field data and the extracted position magnetic field data at a position where the one magnetic sensor unit has moved by the reference pitch from the extracted position magnetic field data. The difference is calculated, and the three-dimensional position of the magnetic object buried in the ground is respectively searched based on a calculation result for each reference distance between the plurality of measurement points by the calculation processing unit. A differential type magnetic survey system.

  According to a third aspect of the present invention, the one magnetic sensor unit includes three magnetic sensors having high sensitivity only in one specific axial direction, and the X direction, the Y direction, and the Z direction so that the respective axes are orthogonal to each other. The three-axis magnetic sensor individually arranged on the movable body is a sway that detects the X-axis tilt, Y-axis tilt, and Z-axis tilt of the three-axis magnetic sensor moving on the search line. A sensor is provided, and the differential magnetic exploration unit includes X-axis tilt data, Y-axis tilt data, and Z-axis tilt data of the three-axis magnetic sensor obtained by a detection signal from the motion sensor. 3. The differential magnetic exploration system according to claim 1, further comprising an angle correction unit that corrects an X-axis tilt, a Y-axis tilt, and a Z-axis tilt of the three-axis magnetic sensor. is there.

The differential magnetic exploration system here refers to the difference in magnetic field strength between the magnetic sensor units by differentially connecting two magnetic sensor units separated on the exploration line, which was the common general technical knowledge until then. Unlike searching for magnetic objects in the ground, only one magnetic sensor unit is moved from the measurement start point to the measurement end point on the search line, and the movement distance data from the measurement start point of one magnetic sensor unit , Measuring the magnetic field strength data at the measurement position of each moving distance data, and then associating the corresponding moving distance data with the magnetic field strength data to create a plurality of position magnetic field data, In the software (application), two corresponding position magnetic field data are extracted from a plurality of position magnetic field data using a preset reference distance between measurement points as a reference pitch for extraction. From the difference in the intensity of al of the magnetic field it is intended to probe the magnetic object in three dimensions.
The direction of the exploration line is arbitrary as long as it is linear. For example, it may be a vertical direction (vertical exploration) toward the ground or a horizontal direction (horizontal exploration) parallel to the ground. The horizontal exploration here refers to the case where the moving body moves horizontally in a horizontal excavation hole formed by excavating parallel to the ground (horizontal), and the case of a non-magnetic tube supported in parallel to the ground. This includes a case where the moving body moves horizontally inside and a case where an operator carries the moving body along a ground search line.

The material of the moving body is not limited as long as it is a non-magnetic material. For example, aluminum may be used. Moreover, as a shape of a moving body, a cylindrical body can be employ | adopted, for example. The diameter and length of the moving body are not limited. When the exploration line exists in the ground, the excavation hole through which the moving body moves may be a vertical hole. Alternatively, an inclined hole may be used. Furthermore, a horizontal hole may be sufficient. The diameter and depth of the borehole are not limited.
The moving means of the moving body is not limited. For example, a guide source may be provided and the guide roller may roll and move in the guide groove. Moreover, you may move by the automatic raising / lowering using a winch. Furthermore, the worker may move it by holding it in his hand.
Examples of magnetic objects subjected to magnetic exploration include unexploded shells and underground structures during the war. The material of the magnetic object is not limited. For example, any metal having magnetism such as iron or nickel may be used. The shape and size of the magnetic object are also arbitrary.

As used herein, “one magnetic sensor unit” refers to, for example, one magnetic sensor having high sensitivity only in a specific one-axis direction, and uniaxial magnetism in which the high-sensitivity direction is directed in a direction orthogonal to the moving direction. A sensor can be employed. In addition, a three-axis magnetic sensor in which three magnetic sensors having high sensitivity only in a specific one-axis direction are individually arranged in the X, Y, and Z directions so that the respective axes are orthogonal to each other may be employed. When a three-axis magnetic sensor is used, since the three-dimensional (three-dimensional) magnetic exploration can be performed with higher sensitivity than in the case of the uniaxial magnetic exploration, the exploration accuracy can be increased. The three magnetic sensors can be arranged close to each other.
When one magnetic sensor unit is a three-axis sensor, the difference in magnetic field strength (detection data value) is the difference in the X direction component between the two magnetic sensor units. Only the difference in the components or the difference in the components in the Z direction of the two magnetic sensor units may be used. Further, only the X-direction component and the Y-direction component of both magnetic sensor units may be used, or only the X-direction component and the Z-direction component of both magnetic sensor units may be used. Alternatively, only the Y-direction component and the Z-direction component of both magnetic sensor units may be used. Furthermore, all components of both magnetic sensor units may be used.

The kind of magnetic sensor is not limited. For example, a magnetic oscillation type magnetic sensor can be employed. In addition, a flux gate type magnetic sensor may be used. A fluxgate type magnetic sensor is a magnetic sensor that utilizes the fact that the BH characteristic of a high permeability magnetic core is shifted by an input magnetic field.
As the distance sensor unit, for example, a unit that detects the moving distance of the moving body based on the number of rotations of the drum of the electric winch that moves the moving body on the search line by winding the wire can be adopted. In addition, a distance meter or a cable with a mark may be used.
Examples of the arithmetic processing means include a CPU of a personal computer.

The differential magnetic exploration unit includes a data creation unit, a data extraction unit, and a storage unit in order to perform the pseudo differential magnetic exploration on software.
In the data creation means, “a plurality of movement distance data obtained based on the detection signal from the distance sensor unit and a plurality of magnetic field strength data obtained based on the detection signal of one magnetic sensor unit are obtained. “Create a plurality of positional magnetic field data in association with each other” means that, for example, when the moving object reaches a point P on the search line, the moving distance data (search line) to the point P of the moving object obtained by the distance sensor unit. (Position data after movement above) and magnetic field strength data detected by one magnetic sensor unit at point P are correlated in a one-to-one relationship to create position magnetic field data at point P on the search line. That means.
Explaining this in detail with examples, the reference distance between measurement points (ΔD) is 0.2 m, and the moving object is 1 m (measurement end point, measurement start point, measurement start point) When moving 1 meter to the end of survey line (end point of exploration) (conditions for creating position magnetic field data), the distance sensor unit continuously detects the movement distance data and one magnetic sensor unit is at the detection position of the movement distance data. Continuously detecting the magnetic field strength data, and then associating the moving distance data with the magnetic field strength data by the data creation means in the one-to-one relationship to obtain a plurality of position magnetic field data. Say.

The “reference distance between measurement points” here corresponds to the “distance between two magnetic sensor units built in a single moving body apart from each other” in the conventional differential magnetic exploration system. In order to perform dynamic magnetic exploration using one magnetic sensor unit, the distance between the magnetic sensor units from among a plurality of positional magnetic field data stored in advance as data in the storage unit and stored in the storage unit Is a distance (extraction pitch) that serves as an extraction reference when the data extraction means extracts the position magnetic field data corresponding to. The reference distance between measurement points may be one or plural (two or three or more).
Magnetic field of several to tens of meters generated from unexploded shells that are a kind of magnetic objects buried in the ground based on the difference between magnetic field data of two different points on the survey line acquired according to the reference distance between measurement points When detecting an abnormality, the reference distance between measurement points is preferably set to 0.5 to 2.0 m.

The storage unit stores at least a plurality of position magnetic field data and a reference distance between measurement points. As the storage unit, for example, a storage unit (memory) of a terminal such as a personal computer can be employed.
Here, “extracting corresponding position magnetic field data from a plurality of position magnetic field data stored in the storage unit using the reference distance between measurement points stored in the storage unit as a reference pitch for extraction” refers to the following Means that. For example, the position magnetic field data when the reference distance between measurement points (ΔD) is 0.2 m and the moving body moves on the search line from 0 m point (measurement line start point) to 1 m point (measurement line end point) by 1 m is stored in the storage unit. Remember. Here, since the reference distance between measurement points is 0.2 m, (1) position magnetic field data including movement distance data of 0.2 m from the plurality of position magnetic field data stored in the storage unit, (2) Positional magnetic field data including moving distance data of 0.4 m, (3) positional magnetic field data including moving distance data of 0.6 m, (4) positional magnetic field data including moving distance data of 0.8 m, (5) This means that position magnetic field data including moving distance data of 0 m is extracted.

Here, “the strength of the magnetic field between the extracted position magnetic field data and the extracted position magnetic field data at the position where one magnetic sensor unit has moved by the reference pitch from the extracted position magnetic field data. ”Means the following. For example, in the case where the reference distance (ΔD) between the measurement points is 0.2 m and the moving body moves from the 0 m point to the 1 m point on the search line in accordance with the above-described conditions for generating the position magnetic field data, the position magnetic field Difference in magnetic field strength (A) between data (1)-(2) (between position magnetic field data (1) and position magnetic field data (2)), magnetic field between position magnetic field data (2)-(3) Intensity difference (B), magnetic field strength difference (C) between position magnetic field data (3)-(4), and magnetic field strength between position magnetic field data (4)-(5) It means that the difference (D) is calculated by the calculation processing means.
Therefore, the arithmetic processing means can use only one magnetic sensor part so that differential magnetic exploration can be performed in the same way as when two conventional magnetic sensor parts are used. For the position magnetic field data, the magnetic field strength difference between the extracted position magnetic field data and the position magnetic field data having the next largest moving distance data value is calculated.

Moreover, the reference distance between measurement points may be plural. In this case, the data extraction means uses the reference distance between the measurement points as a reference pitch for extraction, and selects the corresponding position magnetic field data from the plurality of position magnetic field data stored in the storage unit. Separate and extract by distance. For example, when two reference distances between measurement points (ΔD) of 0.2 m and 0.3 m are set, (ΔD = 0.2 m) as the group, the position magnetic field data (1) to ( 5) is extracted. In addition, (6) positional magnetic field data including moving distance data of 0.3 m from the positional magnetic field data stored in the storage unit as the (ΔD = 0.3 m) group, (7) moving distance of 0.6 m Position magnetic field data including data and (8) position magnetic field data including moving distance data of 0.9 m are extracted.
In that case, in the arithmetic processing means, for each reference distance between a plurality of measurement points, the extracted position magnetic field data and the position at which one magnetic sensor unit has moved by the reference pitch from the extracted position magnetic field data. The difference in magnetic field strength between the extracted position magnetic field data is calculated. Specifically, in the case of the (ΔD = 0.2 m) group, the magnetic field strength differences (A) to (D) are calculated by the arithmetic processing means, and in the case of the (ΔD = 0.3 m) group. The difference in magnetic field strength (E) between the position magnetic field data (6)-(7) and the difference in magnetic field strength (F) between the position magnetic field data (7)-(8) Are each calculated by an arithmetic processing means.

The motion sensor is a detector that detects rotation or inclination (roll, pitch, yaw) in the three-axis direction of a three-axis magnetic sensor that is one magnetic sensor unit. Here, the roll means rotation or inclination in the left-right direction around the Z-axis that faces the movement (advance) direction of the three-axis sensor. The pitch means rotation or inclination in the front-rear direction around the X axis facing the left-right direction of the three-axis sensor. Furthermore, yaw refers to rotation or tilting about the Y axis that faces the vertical direction of the three-axis sensor.
As the motion sensor, for example, DMS2-05 can be adopted for the roll and pitch, and the yaw can be calculated using the magnetic sensor as the compass for the yaw.

The angle correction means is a means that corrects, for example, the rotation matrix of the roll, pitch, and yaw of the three-axis magnetic sensor detected by the vibration sensor.
For example, first, the difference transformation matrix R is obtained by the following formula 1.

(Equation 1)
R = RxRyRz

  Here, Rx is an X-axis rotation matrix (pitch, Formula 2), Ry is a Y-axis rotation matrix (Yaw, Formula 3), and Rz is a Z-axis rotation matrix (Roll, Formula 4).

  Next, each axis component matrix T of the measurement data is obtained by Equation 5.

(Equation 5)
T = X (i) Y (i) Z (i)

  Further, a corrected matrix T ′ of each axis component is obtained by Expression 6.

(Equation 6)
T '= RT

Thereafter, each component of T ′ is input to X (i) Y (i) Z (i), and the roll, pitch, and yaw of the three-axis magnetic sensor are corrected.

  According to the first aspect of the present invention, while the moving body is moving from the measurement start point to the measurement end point on the linear search line, the magnetic field strength data is acquired by one magnetic sensor unit, and the distance sensor unit The movement distance data of the moving body is acquired by the above, the data is created by associating these data as the magnetic field strength at a predetermined position on the search line, and the data creation means creates a plurality of position magnetic field data. The magnetic field data is stored in the storage unit. Then, using the data extraction means using the reference distance between measurement points stored in advance in the storage unit as the extraction reference pitch, the corresponding position magnetic field data is extracted from the plurality of position magnetic field data stored in the storage unit. The difference in magnetic field strength between the extracted position magnetic field data and the extracted position magnetic field data at a position where one magnetic sensor unit has moved by a reference pitch from the extracted position magnetic field data. Are calculated by the calculation processing means, and the position of the magnetic object buried in the ground is searched based on the calculation result.

  In this way, the magnetic field strength detected by one magnetic sensor unit moving on the search line is stored in the storage unit as a plurality of position magnetic field data in association with the position (movement distance) on the search line. At the time of analysis, on the basis of the “reference distance between measurement points” corresponding to the distance between two magnetic sensor units built in the conventional mobile body, the calculation data of the difference in the magnetic field strength is acquired on the software. Since the position of the magnetic object in the ground is searched from the calculation result, one magnetic sensor can be used without using the two magnetic sensor portions that have been common sense in differential magnetic exploration. Differential magnetic exploration can be performed using only the sensor unit.

  In particular, according to the second aspect of the present invention, when the corresponding position magnetic field data is extracted from the position magnetic field data stored in the storage unit by the data extraction means, the reference distance between the measurement points which becomes the extraction reference pitch. A plurality of As a result, the effect of the surrounding magnetic field can be reduced in the same manner as when magnetic exploration is performed using a plurality of moving bodies with different distances between the magnetic sensor portions by only one magnetic exploration by one magnetic sensor portion. It can be suppressed and the resolution of magnetic object search can be increased.

According to the invention described in claim 3, since the three-axis magnetic sensor individually arranged in the X direction, the Y direction, and the Z direction so that the respective axes are orthogonal to each other is adopted as the magnetic sensor unit, the planar exploration is performed. Unlike the case of using a single-axis sensor that is a search close to (three-dimensional search with low accuracy), high-precision three-dimensional search of a magnetic object in the ground can be performed.
In addition, the tilt sensor detects the X-axis tilt, the Y-axis tilt, and the Z-axis tilt (hereinafter referred to as three-axis tilt) of the axial magnetic sensor, and the angle correction means corrects these tilts on software. Thereby, even if the moving body tilts three-dimensionally during the search for the magnetic object, the tilt can be automatically corrected.

(A) is a schematic plan view which shows the acquisition operation state of the movement distance data in the differential magnetic exploration system which concerns on Example 1 of this invention, and magnetic field strength data. (B) is a schematic top view which shows the relationship of the reference distance between the measurement points on the several search line in the differential magnetic survey system which concerns on Example 1 of this invention. It is a perspective view which shows the vertical exploration work state of the unexploded bomb using the differential magnetic exploration system which concerns on Example 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a moving body incorporating a single axis sensor in a differential magnetic exploration system according to Embodiment 1 of the present invention. It is a block diagram of the control part of the differential magnetic exploration system concerning Example 1 of this invention. It is a front view which shows the excavation work state of a vertical shaft in the differential magnetic exploration system which concerns on Example 1 of this invention. It is a flow sheet which shows the vertical exploration method of the unexploded bomb using the differential magnetic exploration system concerning Example 1 of this invention. It is a graph which shows the exploration result of the unexploded shell by the differential magnetic exploration system which has the uniaxial magnetic sensor which concerns on Example 1 of this invention. It is a perspective view which shows the horizontal exploration work state by the differential magnetic exploration system which concerns on Example 2 of this invention. It is a front view of the mobile body which incorporated the 3-axis sensor and the fluctuation sensor in the differential magnetic exploration system based on Example 2 of this invention. It is a block diagram of the control part of the differential magnetic exploration system which concerns on Example 2 of this invention. It is a flow sheet which shows the horizontal exploration method of the unexploded bomb using the differential magnetic exploration system concerning Example 2 of this invention. It is a continuation of the flow sheet of FIG. It is a graph which shows the search result of the X-axis component of the 3-axis magnetic sensor by the differential magnetic search system which concerns on Example 2 of this invention. It is a graph which shows the search result of the Y-axis component of the 3-axis magnetic sensor by the differential magnetic search system which concerns on Example 2 of this invention. It is a graph which shows the search result of the Z-axis component of the 3-axis magnetic sensor by the differential magnetic search system which concerns on Example 2 of this invention. It is a graph which shows the search result of the 3 axis component total of the 3 axis magnetic sensor by the differential magnetic search system which concerns on Example 2 of this invention.

  Examples of the present invention will be specifically described below. Here, a differential magnetic exploration system for magnetic exploration of unexploded bullets (magnetic objects) buried in the ground is taken as an example.

  2 to 4, reference numeral 10 denotes a differential magnetic exploration system (hereinafter, exploration system) according to Embodiment 1 of the present invention. The exploration system 10 moves on a vertical and linear exploration line a. Body 11, magnetic sensor unit 12 built in mobile body 11, distance sensor unit 13 that detects the travel distance of magnetic sensor unit 12 that has moved along exploration line a along with mobile body 11, and mobile body 11 During the movement of the magnetic sensor unit 12 due to the movement, the unexploded bullets buried in the ground (from the difference in the strength of the magnetic field respectively detected by the magnetic sensor unit 12 at two positions apart on the preset search line a) The position of the unexploded bomb 14 buried in the ground is determined based on the differential magnetic exploration unit 15 for exploring the position of the magnetic object 14, the detection signal from the magnetic sensor unit 12, and the detection signal from the distance sensor unit 13. Operate Calculation processing means 16 and a computer 17 which is mounted.

Hereinafter, these components will be specifically described.
As shown in FIGS. 1 and 3, the moving body 11 has a columnar body 18 made of titanium. One magnetic sensor portion 12 is housed in a fixed state at a tip portion (end portion in the advancing direction) 18 a having a large diameter of the main body portion 18, and a moving wire is placed on an end surface 18 b on the original side of the main body portion 18. 19 and the cable 20 for electrical connection are connected.
The movable body 11 is movable in the axial direction of the PVC pipe 22 into a 6-m long PVC pipe 22 made of non-magnetic vinyl chloride and inserted into a drilling hole 21 formed by excavating the ground. Inserted. Accordingly, the total length of the search line a here is 6 m.

A device that moves the moving body 11 within the PVC pipe 22 is a tripod 24 equipped with an electric winch (moving means) 23 that is disposed immediately above the exploration point. The electric winch 23 is provided on the shaft support portion 24a of the three legs of the tripod 24, and the wire 19 connected to the upper end surface of the movable body 11 is wound around the drum so that each guide roller is placed in each guide groove. The moving body 11 moves in the PVC pipe 22 while rolling.
The distance sensor unit 13 is provided in the electric winch 23 and detects the distance that the moving body 11 continuously moves in the PVC pipe 22 by detecting the rotation speed of the servo motor for drum rotation. The detection signal is input to the personal computer 17 through the connection box, the uniaxial magnetic field measuring device for the uniaxial magnetic sensor, and the A / D converter. Thereafter, arithmetic processing is performed by the arithmetic processing means 16 via the interface circuit (I / O) and the bus in a time-sharing manner in the personal computer 17 and converted into data.

  One magnetic sensor unit 12 includes one single-axis magnetic sensor (Z-axis sensor) S having high sensitivity only in the vertical direction (Z-axis direction). Here, as the uniaxial magnetic sensor S, a product name HM-3510 manufactured by MIT Corporation is adopted. The uniaxial magnetic sensor S detects the strength (magnetism) of the magnetic field in the vertical direction during vertical movement in the PVC pipe 22 along with the moving body 11. The uniaxial magnetic field measuring device is a dedicated sensor for uniaxial magnetic measurement manufactured by MIT Corporation. This has a minimum resolution of 10 nT and full scale ± 0.5%.

Hereinafter, the differential magnetic exploration unit 15 will be described in detail with reference to the block diagram of FIG.
The differential magnetic exploration unit 15 is obtained based on a plurality of movement distance data obtained based on the detection signal from one distance sensor unit 13 and the detection signal during movement of one magnetic sensor unit 12. A plurality of magnetic field strength data obtained by associating the plurality of magnetic field strength data as the magnetic field strength at the position on the search line a, and a plurality of positional magnetic fields. A storage unit 26 for storing data and a reference distance between measurement points set in advance to obtain a difference in magnetic field strength, and a reference distance between measurement points stored in the storage unit 26 as a reference pitch for extraction. Data extraction means 27 for extracting corresponding position magnetic field data from the plurality of position magnetic field data stored in the storage unit 26, and difference data of the plurality of magnetic field strengths obtained for each reference distance between the measurement points. Graph Having a rough means 32, a display 33 for image display of the graph obtained based distance-between measured points by graphing means 32.

In the data creation means 25, when one magnetic sensor unit 12 moves on the search line a, a plurality of data acquired based on detection signals from the distance sensor unit 13 that measures the rotation of the drum of the electric winch 23 is obtained. The movement distance data and a plurality of magnetic field strength data acquired by one magnetic sensor section 12 every time one magnetic sensor section 12 moves 0.1 m in accordance with the detection of each movement distance data, In a one-to-one relationship, the mobile body 11 creates a plurality of positional magnetic field data in association with the strength of the magnetic field at the position on the search line a.
The storage unit 26 is a ROM or a RAM built in the personal computer 17. The storage unit 26 stores a plurality of position magnetic field data created by the data creation unit 25 and data of a reference distance (ΔD) set in advance (ΔD = 0.2 m, 0.5 m, 1 m). , 1.5m, 4) and the like are stored.
The data extraction unit 27 uses 4 reference distances between measurement points as extraction reference pitches, and stores 4 stored in the storage unit 26 from a plurality of positional magnetic field data acquired every time the moving body 11 moves 0.1 m. Using the reference distance between two measurement points as a reference pitch for extraction, the corresponding position magnetic field data is grouped and extracted for each reference distance between the measurement points.

The arithmetic processing means 16 is a CPU which is a central processing unit of the personal computer 17 and is extracted at the position where one magnetic sensor unit 12 is moved by a reference pitch from the extracted position magnetic field data and the extracted position magnetic field data. (B) Calculate the difference in magnetic field strength from the extracted position magnetic field data. For example, in the case where the total length of the exploration line (exploration distance) a is 6 m and the reference distance between measurement points ΔD is 0.2 m, the moving body 11 from the survey line (exploration) start point (0 m position) on the exploration line a will be described. Of the magnetic field between the first position magnetic field data at a position moved by 0.2 m and the second position magnetic field data at a 0.4 m movement position having the next moving distance data next to the first position magnetic field data. Calculate the difference in strength. Similarly, between the position magnetic field data at the position immediately before the last (5.8 m position) and the position magnetic field data at the last position (6 m position which is the end point of the survey line (exploration)). Calculate up to the difference in magnetic field strength. In addition, when the reference distance between measurement points ΔD is 0.5 m, ΔD is 1 m, and ΔD is 1.5 m, similar calculation processing is performed. The obtained calculation results are grouped according to the reference distance between the four measurement points and stored in the storage unit 26.
The graphing means 32 performs a process of graphing the difference data of the magnetic field strength with a line graph, and graphs the difference data of the magnetic field strengths obtained for each reference distance between the measurement points.
As the display 33, a liquid crystal display is adopted.

Next, with reference to the flow sheets of FIGS. 1 to 5 and FIG. 6, a method for magnetic exploration of the unexploded shell 14 buried in the ground using the differential magnetic exploration system 10 according to the first embodiment will be described. To do.
First, as shown in FIG. 5, a boring machine is installed at an exploration point, and an excavation hole 21 having a predetermined depth is formed vertically. Specifically, a tower 28 is assembled on a ground exploration point, and a boring machine 29 is installed. The boring machine 29 includes a motor 30 as a driving source, a swivel head equipped with a rotation and a feeding device, a hoist, a transmission, and the like.

At the time of excavation, the boring machine 29 excavates the ground vertically for a predetermined exploration length while sequentially adding short tubular partial casings (made of iron) through insertion guide pipes suspended at the exploration point. Thereby, the long casing 31 is assembled after excavation. The inner diameter of the casing 31 is, for example, 140 mm. Next, the short vinyl chloride resin-made PVC pipes 22 are inserted into the casing 31 in succession. The inner diameter of the PVC pipe 22 is, for example, 110 mm.
Thereafter, the boring machine 29 is removed from the vicinity of the exploration point, and as shown in FIG. 2, the tripod 24 on which the electric winch 23 is mounted is disposed immediately above the exploration point. The electric winch 23 is provided on the shaft support 24 a of the three legs of the tripod 24, and the wire 19 connected to the upper end surface of the movable body 11 is wound around the drum. Thereafter, the operator inserts the moving body 11 into the PVC pipe 22 and operates the electric winch 23 toward the feeding side of the wire 19 so that the moving body 11 is gradually inserted into the PVC pipe 22.

  At that time, the distance of the servo motor that rotates the drum is detected by the distance sensor unit 13 so that the moving distance of one magnetic sensor unit 12 associated with the suspension of the moving body 11 is detected at intervals of 1 cm. The detection signal from the distance sensor unit 13 is sequentially input to the personal computer 17 through the connection box, the distance measuring device, and the A / D converter. Then, computation processing is performed by the computation processing means 16 via the interface circuit (I / O) and the bus in a time-sharing manner in the personal computer 17 to obtain a plurality of movement distance data.

At this time, one magnetic sensor unit 12 (one-axis magnetic sensor) 12 reaches from the survey line start point (0 m position) on the survey line a having a total length of 6 m to the survey line end point (6 m position). Thus, the strength of the magnetic field in the soil is continuously searched (FIG. 1 (a)). Detection signals from the magnetic sensor unit 12 are sequentially input to the personal computer 17 via the connection box, the single-axis magnetic field measuring device, and the A / D converter. Then, calculation processing is performed by the calculation processing means 16 through the interface circuit (I / O) and the bus in a time-sharing manner in the personal computer 17 to obtain a plurality of magnetic field strength data.
The obtained plurality of movement distance data and the plurality of magnetic field strength data are respectively stored in the storage unit 26, and the data creation means 25 sets 1 as the magnetic field strength at a predetermined position on the search line a. A plurality of positional magnetic field data are created in a one-to-one relationship (Table 1). Although not shown, a line graph of distance and magnetic flux density is created from each data of Table 1, and distance data and magnetic flux density data not displayed in Table 1 are acquired from the graph.

The generated plurality of position magnetic field data includes the movement distance (i = 0 to 6 m) of one magnetic sensor unit (moving body 11) 12 on the survey line (measurement line) a inputted in advance and the reference between measurement points. The distances (ΔD = 0.2 m, 0.5 m, 1 m, 1.5 m) are stored in the storage unit 26 of the personal computer 17 in the descending order of the moving distance data.
Thereafter, the corresponding position magnetic field data is extracted from the plurality of position magnetic field data stored in the storage unit 26 by using the four reference distances between the measurement points stored in the storage unit 26 as reference pitches for extraction (see FIG. 1 (b)). Specifically, among the plurality of position magnetic field data stored in the storage unit 26, a group of position magnetic field data having a reference distance (ΔD) between measurement points of 0.2 m and a group of position magnetic field data of 0.5 m. And 1 m position magnetic field data group and 1.5 m position magnetic field data group.

  The obtained four position magnetic field data groups (groups) for each reference distance between the measurement points are then extracted in order from the position magnetic field data group of ΔD = 0.2 m from the line start point to the line end point on the search line a. The arithmetic processing means 16 calculates the difference in magnetic field strength between the extracted position magnetic field data and the extracted position magnetic field data at the position where the magnetic sensor unit 12 has moved by the reference pitch from the extracted position magnetic field data. Calculate. In other words, the difference in magnetic field strength between the extracted position magnetic field data and the position magnetic field data having the next moving distance data value next to the extracted position magnetic field data is calculated for each reference distance between measurement points. Calculate each.

  In other words, when the reference distance between measurement points ΔD is 0.2 m, the first (i = 0.2 m) position magnetic field data at a position moved 0.2 m from the measurement start point on the search line a of the mobile object 11. And the difference in magnetic field strength between the first position magnetic field data and the second (i = 0.4 m) position magnetic field data at the 0.4 m movement position where the movement distance data is the next largest. Similarly, the difference in magnetic field strength between the 2-3 (i = 0.6 m) th position magnetic field data and the magnetic field difference between the 3-4 (i = 0.8 m) th position magnetic field data. Difference in strength: The difference in magnetic field strength between the position magnetic field data of the last one before (i = 5.8 m) and the last (i = 6 m) is calculated. Further, when the reference distance between measurement points ΔD is 0.5 m, the first (i = 0.5 m) position magnetic field data at a position moved 0.5 m from the measurement start point on the search line a of the mobile object 11. Difference in magnetic field strength between the first position magnetic field data and the second (i = 1 m) position magnetic field data at the 1 m movement position where the movement distance data is next to the first position magnetic field data. (I = 5.5 m) −The difference in magnetic field strength between the final (i = 6 m) position magnetic field data is calculated.

  When the reference distance ΔD between the measurement points is 1 m, the first (i = 1 m) position magnetic field data and the first position magnetic field data at a position moved by 1 m from the measurement start point on the search line a of the moving body 11. Difference in magnetic field strength from the second (i = 2m) position magnetic field data at the 2m movement position where the movement distance data is the next largest, ..., the last one before (i = 5m)-the last The difference in magnetic field strength between the position magnetic field data of (i = 6 m) is calculated. When the reference distance ΔD between the measurement points is 1.5 m, the first (i = 1.5 m) position magnetic field data at the position moved 1.5 m from the movement start position on the search line a of the mobile object 11 and Difference in magnetic field strength from the second (i = 3 m) position magnetic field data at the 3 m movement position where the movement distance data is next to the first position magnetic field data, and the final position (i = 4. 5m) —Calculates the difference in magnetic field strength between the final position magnetic field data (i = 6 m). These calculation results are grouped according to the reference distance between measurement points, and stored in the storage unit 26, respectively.

  The difference in magnetic field strength between the four types of position magnetic field data obtained in this way is graphed according to the reference distance between measurement points, and the undulation status of each graph is the same as in the case of general differential magnetic exploration. The inspector visually examines (magnetic anomaly) and examines the presence or absence of the unexploded shell 14 buried in the ground and its buried position. That is, it is presumed that a magnetic object that seems to be a non-explosive bullet 14 is buried in an elliptical area in the graph of FIG. As is apparent from the graph of FIG. 7, when the uniaxial sensor S is employed as one magnetic sensor unit 12, the four graphs are accompanied by similar undulations. Therefore, when only one uniaxial sensor S is used, the graph may be only for ΔD = 1 m, for example.

  As described above, in the first embodiment, a plurality of magnetic field strength data detected by one magnetic sensor unit 12 moving on the search line a and a plurality of movement distance data detected by the distance sensor unit 13 are obtained. A plurality of positional magnetic field data associated as the magnetic field strength at the position on the search line a is stored in the storage unit 26, and between the measurement points corresponding to the distance between the two conventional magnetic sensor units 12 at the time of data analysis Based on the reference distance, a plurality of corresponding position magnetic field data are extracted, and based on these position magnetic field data, the calculation of the magnetic field strength difference is performed by the arithmetic processing means 16 on the software, and the calculation result is obtained. Because the position of the unexploded shell 14 buried in the ground is searched from the ground, one magnetic sensor can be used without using the two magnetic sensor units 12 that are the conventional common knowledge of differential magnetic exploration. Part 12 It is possible to perform differential type magnetic survey in only.

Here, the magnetic exploration method of the unexploded shell 14 by the differential magnetic exploration system 10 according to the first embodiment will be specifically described with reference to the flow sheet of FIG. Here, the strength of the magnetic field is expressed as magnetic flux density.
First, in S101 of the flow sheet of FIG. 6, the total length of the moving distance of one magnetic sensor unit 12 (moving body 11) on the survey line a (measurement line) 6 m, and the survey line end point on the survey line a Up to the measurement point (i), the magnetic flux density (magnetic field strength) M detected by one magnetic sensor unit 12 (uniaxial magnetic sensor) at each measurement point, and the reference distance (ΔD = 0. 2m, 0.5m, 1m, 1.5m) is stored in the storage unit 26 of the personal computer 17.
Next, in S102, a minimum value of 0.2 m is selected from among ΔD stored in the storage unit.
Thereafter, in S103, i = 0 m (measurement point), which is the minimum line start point, is selected from the movement distance data of the ΔD = 0.2 m group stored in the storage unit 26.
Next, in S104, using the arithmetic processing means 16, i = 0 m position extracted at ΔD = 0.2 m, and i = 0.2 m position from which one magnetic sensor unit 12 has moved by the reference pitch. The difference in the magnetic field strength between the two is calculated by the following equations.

(Equation 7)
MΔD (i) = M (i−ΔD / 2) −M (i + ΔD / 2)

The obtained calculation result is stored in the storage unit 26 (S105).
Thereafter, in S106, it is determined whether i has reached the survey line end point (6 m). If the line end point has been reached, the process proceeds to S107, and if the line end point has not been reached, the process proceeds to S108. In S108, the second i = 0.2m moving distance data is selected from the moving distance data of the ΔD = 0.2m group with reference to the survey line start point. Thereafter, the process returns to S104, and thereafter, each operation of S104 to S108 (excluding S107) is sequentially repeated until i reaches the line end point in Step 106.

If i has reached the end point of the survey line, the routine proceeds to step 107 where it is determined whether or not ΔD has reached 1.5 m. If ΔD = 1.5 m, the process proceeds to S109, and if not, the process proceeds to S110. In S110, among the four ΔD = 0.2m, 0.5m, 1m, and 1.5m, ΔD = 0.5m having the next largest value after 0.2m is selected. After that, the process returns to S104, and the movement position data at the 0m point that is the line start point of the ΔD = 0.5m group and the movement position data at the second (i) = 1m point with reference to the line start point. Find the difference in magnetic field strength. Thereafter, in S106, the above-described steps are repeated until i reaches the line end point. Thereafter, the steps from S103 to S110 (except S109) except S107 are sequentially repeated until ΔD reaches 1.5 m.
Next, the difference data of all the magnetic field strengths are mounted on the control unit of the personal computer 17 for each of ΔD = 0.2 m group, ΔD = 0.5 m group, ΔD = 1 m group and ΔD = 1.5 m group. Each graph is converted into a line graph using the graphing means 32 (S109, the graph of FIG. 7), and this is displayed on the display 33, and each graph is displayed in the same manner as in the general differential magnetic exploration described above. The position of the unexploded bomb 14 buried in the ground is searched by visual judgment based on the experience of the inspector from the undulation state of the ground.

Next, a differential magnetic exploration system according to Embodiment 2 of the present invention will be described with reference to FIGS.
As shown in FIGS. 8 to 12, the feature of the differential magnetic exploration system 10 </ b> A according to the second embodiment of the present invention is that the data of the reference distance between measurement points is ΔD = 0.1 m, 0.2 m, 0.5 m, The three-axis magnetic sensor S1 is adopted as one magnetic sensor unit 12 instead of the one-axis magnetic sensor S of the first embodiment, and the movable body 11A is a hand-held movable body 11A. The moving body 11A is provided with a fluctuation sensor unit 40 for detecting the X-axis tilt, the Y-axis tilt, and the Z-axis tilt of the three-axis magnetic sensor S1 moving on the exploration line a. The point is that angle correction means 41 for correcting the X-axis tilt, Y-axis tilt, and Z-axis tilt of the triaxial magnetic sensor S1 is provided in the magnetic exploration unit 15A.

The three-axis magnetic sensor S1 is a sensor in which three magnetic sensors (X sensor Sx, Y sensor Sy, Z sensor Sz) having high sensitivity only in one specific axial direction are arranged close to each other so that their axes are orthogonal to each other. . Here, as each magnetic sensor Sx, Sy, Sz, the same magnetic sensor (product name HM-3510, manufactured by MTI Corporation) of the same magnetic oscillation system is adopted. A detection signal from the triaxial magnetic sensor S1 is input to the personal computer 17 through a connection box, a triaxial magnetic field measuring device, and an A / D converter. Then, in the personal computer 17, the arithmetic processing means 16 performs arithmetic processing through the interface circuit (I / O) and the bus in a time-sharing manner, and the data is converted into data (magnetic field strength data). A triaxial magnetic field measuring device is a product name HM-3510, manufactured by MIT Corporation. This can measure the X, Y, and Z axis components of the DC magnetic field simultaneously, and the minimum resolution is 0.1 microtesla.
The obtained plurality of movement distance data and the plurality of magnetic field strength data in the X, Y, and Z axis components are respectively stored in the storage unit 26, and at a predetermined position on the search line a by the data creation means 25. A plurality of positional magnetic field data are created by associating the magnetic field strengths of the X, Y, and Z axis components with a one-to-one relationship (Table 2). In addition, the strength data value of each magnetic field of the X-axis component, the strength data value of each magnetic field of the Y-axis component, and the strength data value of each magnetic field of the Z-axis component in Table 2 are obtained by angle correction means 41 described later. The angle is a numerical value after correction. Although not shown, line graphs of the relationship between the distance and the magnetic flux density are created for each of the X-axis, Y-axis, Z-axis, and their total from each data in Table 1, and these graphs are displayed in Table 2. It is assumed that distance data and magnetic flux density data that are not used are respectively acquired.

Further, a U-shaped gripping arm 42 is fixed to both ends of the moving body 11A in a side view, and the operator holds the gripping arm 42 so that the height of the moving body 11A from the ground is fixed. And the length direction (axial direction) of the moving body 11A is always coincident with the search line a, and the unexploded shell 14 is searched while carrying the moving body 11A. In addition, two exploration lines a are drawn at intervals of 1 m so as to divide this area into three equal parts in the lateral direction in the exploration area defined by the survey line 43 stretched in a rectangular shape in plan view. Yes.
The motion sensor unit 40 is built in a fixed state in the middle part of the moving body 11A in the axial direction (length direction) and is a triaxial rotation angle (1) a rolling angle centered on the Z axis in the traveling direction ( 2) A pitching angle centered on the X axis and (3) a yawing angle centered on the Y axis are detected. The DMS2-05 type manufactured by TSS is used as the fluctuation sensor unit 40 for measuring the roll and pitch. However, yaw is calculated using a magnetic sensor as an azimuth meter.
The angle correction means 41 uses the rotation matrix method based on the X-axis tilt data, Y-axis tilt data, and Z-axis tilt data of the three-axis magnetic sensor S1 obtained from the detection signal from the motion sensor unit 40. The X-axis tilt, Y-axis tilt, and Z-axis tilt of the three-axis magnetic sensor S1 are respectively corrected.

Hereinafter, a specific correction method by the angle correction unit 41 will be described with reference to the flowcharts of FIGS. 11 and 12.
First, in S201 of the flow sheet in FIG. 11, the total length of the moving distance of one magnetic sensor unit 12 (moving body 11A) on the survey line a (measurement line) 6m and the measurement start point on the search line a (measurement line) From the measurement point (i) to the end point of the survey line, the magnetic flux density value (magnetic field strength) of the X component detected by the X-axis magnetic sensor Sx at each measurement point (i) on the X-axis, The magnetic flux density value (magnetic field strength) of the Y component detected by the Y axis magnetic sensor Sy at the measurement point (i) and the Z component detected by the Z axis magnetic sensor Sz at each measurement point (i) on the Z axis line. Magnetic flux density value (magnetic field strength), total magnetic flux density value at each measurement point (i) obtained by combining these three-axis components (X component, Y component and Z component), and each measurement point (i) The tilt angle (φ of the three-axis magnetic sensor S1 around the roll axis detected by the fluctuation sensor unit 40 in FIG. And the tilt angle (θ) of the triaxial magnetic sensor S1 centered on the pitch axis detected by the motion sensor unit 40 at each measurement point (i) and the motion sensor unit 40 detected at each measurement point (i). The inclination angle (ψ) of the three-axis magnetic sensor S1 around the yaw axis and the reference distance between measurement points (ΔD = 0.1 m, 0.2 m, 0.5 m, 1 m, 1.5 m) Is stored in the storage unit 26.

Next, in S <b> 202, (i) = 0.1 m (measurement point), which is the line survey starting point that is the minimum value among the movement distance data stored in the storage unit 26, is selected. At this time, φ initial value = φ (measurement line start point), θ initial value = θ (measurement line start point), and ψ initial value = ψ (measurement line start point).
Next, in S203, a difference conversion matrix R is obtained. The X-axis rotation matrix (pitch) is Rx (rotation angle), the Y-axis rotation matrix (yaw) is Ry (rotation angle), and the Z-axis rotation matrix (roll) is Rz (rotation angle).
Specifically, in S204, a difference conversion matrix R is obtained from the following equation.

(Equation 8)
R = RzRxRy

Here, Rx; (θ initial value−θ (measurement start point)), Ry; (ψ initial value−ψ (measurement start point)), Rz; (φ initial value− (φ measurement start point)).
Next, in S205, a matrix T of each axis component of measurement data and a corrected matrix T ′ of angular axis components are obtained by the following two equations.

(Equation 9)
T = X (i) Y (i) Z (i)

(Equation 10)
T '= RT

Thereafter, each component of T ′ obtained is input to X (i) Y (i) Z (i).
Next, in S206, it is determined whether i has reached the line end point. If the line end point has been reached, the process proceeds to S207 (flow sheet in FIG. 7), and if the line end point has not been reached, the process proceeds to S208. In S208, the second (i) = 0.2 m moving distance data is selected with reference to the survey line start point. After this selection, the process returns to S203 and S204 in order, and similarly, a difference conversion matrix R is obtained, and a matrix T of each axis component of measurement data and a corrected matrix T ′ of angular axis components are obtained (S205). Based on the obtained calculation results, the X-axis tilt, Y-axis tilt, and Z-axis tilt of the three-axis magnetic sensor S1 are corrected, and the corrected magnetic field strength data of each X-axis component and its position magnetic field are corrected. Data, corrected Y-axis component magnetic field strength data and its position magnetic field data, corrected Z-axis component magnetic field strength data and its position magnetic field data are stored in the storage unit 26 (S211).

Thereafter, if i reaches the line end point in S206, the process proceeds to S207, and the minimum value of 0.1 m is selected from among ΔD stored in the storage unit 26.
Next, in S209, (i) = 0.1 m (measurement point), which is the minimum line start point among the movement distance data of ΔD = 0.1 m group stored in the storage unit 26, is selected.
Next, in S210, the arithmetic processing means 16 is used to extract (i) = 0.1 m position at ΔD = 0.1 m in the X component, Y component and Z component, and one magnetic sensor unit 12 therefrom. Is moved by the reference pitch (i) = the difference in magnetic field strength from the position of 0.2 m is calculated by the following three formulas. The obtained calculation result is stored in the storage unit 26 (S211).

(Equation 11)
XΔD (i) = X (i−ΔD / 2) −X (i + ΔD / 2)

(Equation 12)
YΔD (i) = Y (i−ΔD / 2) −Y (i + ΔD / 2)

(Equation 13)
ZΔD (i) = Z (i−ΔD / 2) −Z (i + ΔD / 2)

  Thereafter, in S212, it is determined whether i has reached the line end point. If the line end point has been reached, the process proceeds to S213, and if the line end point has not been reached, the process proceeds to S214. In this S214, the second (i) = 0.2m moving distance data is selected from the moving distance data of ΔD = 0.1m group with reference to the survey line start point. Thereafter, the process returns to S210, and the above-described steps are repeated between the movement distance data at (i) = 0.1 m point on the search line a and the movement distance data at (i) = 0.2 m point. .

  Thereafter, when i = the end point of the survey line is reached, it is determined in S213 whether ΔD has reached 1.5 m. If ΔD = 1.5 m, the process proceeds to S215, and if not, the process proceeds to S216. In S216, among the five ΔD = 0.1m, 0.2m, 0.5m, 1m, and 1.5m, ΔD = 0.2m having the next largest value after 0.1m is selected. Thereafter, the process returns to S209, and the movement position data of the 0.2m point that is the line start point of the ΔD = 0.2m group, and the movement position data at the second (i) = 0.4m point with respect to the line start point Find the difference in magnetic field strength between the two. Thereafter, the above-described steps are repeated until i reaches the line end point. Thereafter, the steps from S209 to S216 except S215 are sequentially repeated until ΔD reaches 1.5 m.

  Next, in step S215, all the magnetic field strengths are classified for each of ΔD = 0.1 m group, ΔD = 0.2 m group, ΔD = 0.5 m group, ΔD = 1 m group, and ΔD = 1.5 m group. The difference data are converted into line graphs using the graphing means 32 mounted on the control unit of the personal computer 17 (graphs of FIGS. 13 to 16), and the same as in the case of the general differential magnetic exploration described above. Next, the position of the unexploded shell 14 buried in the ground is searched from the undulation state of each graph. Specifically, a small unexploded shell 14 is embedded in the vicinity of the 2.4 m position from the starting point of the survey line, a large unexploded shell 14 is embedded in the vicinity of 3 m from the starting point of the survey line, and the steel is disposed in an area of 4 to 5 m from the starting point of the measuring line. It is presumed that the sheet pile is buried. Note that the size of the unexploded shell 14 buried in the soil can be searched from the graph of the total magnetic flux density of the three-axis component in FIG.

  As described above, when the corresponding position magnetic field data is extracted from the position magnetic field data stored in the storage unit 26 by the data extraction means 27, a plurality of reference distances between the measurement points serving as the extraction reference pitch are set. As a result, the effect of the surrounding magnetic field is the same as in the case where the magnetic exploration is performed by using only one magnetic exploration by one magnetic sensor unit 12 and using a plurality of moving bodies with different distances between the magnetic sensor portions. And the resolution of exploration of the unexploded shell 14 can be increased.

In addition, as the magnetic sensor unit 12, the three-axis magnetic sensor S1 that is individually arranged in the X direction, the Y direction, and the Z direction so that the respective axes are orthogonal to each other is adopted, and therefore, the uniaxial magnetic sensor S that is a planar search is used. Unlike the case, the unexploded shell 14 in the ground can be searched three-dimensionally, and the search accuracy can be improved.
In addition, the tilt sensor section 40 detects the X-axis tilt, the Y-axis tilt, and the Z-axis tilt of the triaxial magnetic sensor S1, and the angle correction means 41 corrects these tilts on software. Thereby, even if the moving body 11A tilts three-dimensionally during the exploration of the unexploded shell 14, the tilt can be automatically corrected. As a result, there is no need for a guide structure that moves the moving body linearly on the exploration line a while preventing inclination including rotation.
Other configurations, operations, and effects are in a range that can be inferred from the first embodiment, and thus description thereof is omitted.

  The present invention is useful for exploration of unexploded bombs, exploration in the vicinity of ferromagnetic materials, and the like. It is also useful as a technology that can expand the exploration range of magnetic exploration and save labor in magnetic exploration.

10, 10A differential magnetic exploration system,
11, 11A mobile body,
12 Magnetic sensor part,
13 Distance sensor part,
14 Unexploded shell (magnetic object),
15, 15A differential magnetic exploration part,
16 arithmetic processing means,
25 data creation means,
26 storage unit,
27 data extraction means,
40 Fluctuation sensor,
41 angle correction means,
S single-axis magnetic sensor,
S1 3-axis magnetic sensor,
a Exploration line.

Claims (3)

A moving body that moves from the measurement start point to the measurement end point on a linear exploration line;
A magnetic sensor unit built in the moving body;
A distance sensor unit that detects a moving distance from the measurement start point of the magnetic sensor unit that moves on the search line with the moving body;
During the movement of the magnetic sensor unit accompanying the movement of the moving body, the magnetic sensor unit detects the magnetic object buried in the ground from the difference in the magnetic field strength detected at two positions spaced apart on the search line. A differential magnetic exploration unit for exploring a three-dimensional position;
A differential magnetic exploration comprising arithmetic processing means for calculating a three-dimensional position of a magnetic object buried in the ground based on a detection signal from the magnetic sensor unit and a detection signal from the distance sensor unit A system,
The magnetic sensor unit is one piece.
The differential magnetic exploration part is
A plurality of movement distance data obtained based on detection signals from the distance sensor unit and a plurality of magnetic field strength data obtained based on detection signals from the one magnetic sensor unit are associated with each other. Data creation means for creating position magnetic field data of
A storage unit that stores the plurality of position magnetic field data and a reference distance between measurement points that is set in advance to obtain a difference in strength of the magnetic field;
Data extraction means for extracting corresponding position magnetic field data from the plurality of position magnetic field data stored in the storage unit using the reference distance between the measurement points stored in the storage unit as a reference pitch for extraction. Have
The arithmetic processing means is configured to extract between the extracted position magnetic field data and the extracted position magnetic field data at a position where the one magnetic sensor unit has moved by the reference pitch from the extracted position magnetic field data. Calculate the difference in magnetic field strength at
A differential magnetic exploration system for exploring a three-dimensional position of a magnetic object buried in the ground based on a difference in strength of the magnetic fields obtained by this calculation. The storage unit stores a plurality of reference distances between the measurement points,
The data extraction means uses the reference distances between the plurality of measurement points stored in the storage unit as reference pitches for extraction, and the corresponding position magnetic field from among the plurality of position magnetic field data stored in the storage unit. Extract the data,
The arithmetic processing unit is configured to extract the position magnetic field data extracted for each reference distance between the plurality of measurement points, and a position where the one magnetic sensor unit has moved by the reference pitch from the extracted position magnetic field data. Calculating the difference in magnetic field strength between the extracted position magnetic field data at
2. The differential magnetic exploration system according to claim 1, wherein each of the three-dimensional positions of the magnetic object buried in the ground is searched based on a calculation result for each reference distance between the plurality of measurement points by the calculation processing unit. . The one magnetic sensor unit is a three-axis magnetic sensor in which three magnetic sensors having high sensitivity only in a specific one-axis direction are individually arranged in the X, Y, and Z directions so that the respective axes are orthogonal to each other. so,
The moving body is provided with a sway sensor that detects the X-axis tilt, the Y-axis tilt, and the Z-axis tilt of the three-axis magnetic sensor moving on the search line,
The differential magnetic exploration unit includes the three axes based on X-axis tilt data, Y-axis tilt data, and Z-axis tilt data of the three-axis magnetic sensor obtained by a detection signal from the motion sensor. The differential magnetic exploration system according to claim 1 or 2, further comprising angle correction means for correcting the X-axis tilt, the Y-axis tilt, and the Z-axis tilt of the magnetic sensor.

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