JPH10318748A - Method and system for measuring position - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the position at the forward end of a drill pipe quickly and accurately. SOLUTION: A sonde 10 is set at the forward end of a drill pipe 51 being employed in horizontal drilling method and the sonde 10 incorporates a triaxial orthogonal AC magnetic sensor, an angle meter for measuring rotation and inclination of the sonde 10, and means for transmitting the measurement data. A parallel line 31 is laid on the ground surface and fed with an AC current generated from an oscillator 30. An AC field generated by the AC current flowing through the parallel line 31 is detected by the triaxial orthogonal AC magnetic sensor in the sonde 10 and a field data thus detected is transmitted along with a rotation and inclination angle data from the angle meter. The data is received by a computer 41 and processed to determine the relative position of the sonde 10 to the parallel line 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position measuring method and apparatus, and more particularly to a method and apparatus suitable for measuring the position of a bit at the tip of an excavation when constructing a pipeline in the ground or on the sea floor without excavation. It is something.

[0002]

2. Description of the Related Art A horizontal drilling method is known as a method of constructing a pipeline in the ground or on the sea floor without excavation. In this horizontal drilling method, a hole is drilled by pushing a drill pipe having a diameter of about several inches with a drilling device.
FIG. 15 is a diagram showing the shape of the tip of this drill pipe. As shown in this figure, the tip of the drill 100 is cut diagonally, and when the drill 100 is pushed in while being rotated, the drill pipe goes straight and rotates. Stop and push in to turn. Thereby, the direction and route of excavation can be controlled. Normally, shafts are dug on the starting side and the arrival side, and after the tip of the drill pipe reaches the shaft on the arrival side, a pipe called a product pipe is connected to the drill pipe instead of the drill, and from the starting counter side Pull in.
When the diameter of the product pipe is large, a hole is enlarged by inserting a reamer between the drill pipe and the product pipe.

[0003] In such a horizontal drilling method, it is necessary to measure the position of the tip of a drill pipe underground in order to know the path of drilling. The following three methods are known as methods for measuring this position. (1) A method in which an electromagnetic wave is transmitted from a transmitter provided at the tip of a drill pipe, and the electromagnetic wave is detected by a land-based receiver to measure the position of the transmitter. (2) A loop-shaped electric wire is stretched around the land, a DC current is passed through the electric wire, and a DC magnetic field generated by the electric current is measured by a sonde 110 (FIG. 15) attached to a tip of a drill pipe. A method of calculating the position of the sonde by arithmetic processing. (3) A sonde 110 having a magnet compass for measuring the azimuth and a sensor for measuring the inclination of the drill pipe is provided at the tip of the drill, and the drilling length that can be estimated from the azimuth and inclination of the sonde and the length of the drill pipe is provided. Method to measure the position and trajectory of the sound using

[0004]

In the method (1), a measurer usually carries a receiver to a position directly above a transmitter and measures the depth and horizontal position of the transmitter. Therefore, in order to measure the position precisely,
It is necessary for the measurer to change the place where the receiver is placed, and to perform the measurement a plurality of times, so that the measurement cannot be performed quickly and the working time cannot be reduced. In the case of the above method (2), it is necessary to perform two measurements by changing the direction of the direct current in order to remove the influence of the surrounding magnetic material and the geomagnetism. It was difficult to do. Furthermore, in the case of the method (3), since the magnet compass is used for measuring the azimuth, it is difficult to perform accurate measurement in a place where a magnetic material is located around or where geomagnetism is not uniform. Further, since the position of the tip of the drill pipe is calculated by integrating the distance traveled by the tip of the drill pipe, a measurement error is added, and when the drilling length is long, the measurement accuracy is deteriorated.

Accordingly, an object of the present invention is to solve the above-mentioned problems and to provide a position measuring method and apparatus capable of quickly and accurately measuring the position of the tip of a drill pipe.

[0006]

In order to achieve the above object, a position measuring method according to the present invention is a method for measuring the position of an object using a position measuring probe, which is known by an AC magnetic field generating source. step of generating an alternating magnetic field, by the position measuring probe which is attached to the object, located in a plane containing the X ₃ axis and the X ₃ axis and the vertical direction coincides with the long axis direction of the position measurement probe Measuring an alternating magnetic field in each axis direction in the orthogonal coordinate system X ₃ Y ₃ Z ₃ defined by the Z ₃ axis, a rotation angle around the Y ₃ axis, and a rotation angle around the X ₃ axis, and the position measurement Calculating the relative position of the position measurement sonde from the AC magnetic field generation source based on the measurement data from the measurement sonde.

Another position measuring method of the present invention is a position measuring method for measuring a position of a drill in a horizontal drilling method, wherein an AC magnetic field generating source is arranged immediately above the planned drilling position, and step of generating a known AC magnetic field by the source, the position measurement probe which is attached near the tip of the drill, vertical and X ₃ axis and the X ₃ axis coincides with the long axis direction of the position measurement probe direction Coordinate system X ₃ defined by the Z ₃ axis located in the plane including
Measuring an alternating magnetic field in each axis direction in Y ₃ Z _3, a rotation angle around the Y ₃ axis, and a tilt angle that is a rotation angle around the X ₃ axis, and the measurement from the position measuring probe. Calculating a position of the drill based on the data.

Further, the position measuring device of the present invention is a position measuring probe having an AC magnetic field generating source for generating a known AC magnetic field, a three-axis orthogonal type AC magnetic sensor, an inclinometer, and a tachometer. the 3 AC magnetic sensor of the axis orthogonal was consistent with the long axis direction of the position measurement probe X ₃ axis and the X ₃
An AC magnetic field in each axis direction in a rectangular coordinate system X ₃ Y ₃ Z ₃ defined by a Z ₃ axis located in a plane including the axis and the vertical direction is measured, and the tachometer measures a rotation angle around the Y ₃ axis. measured, the inclinometer based position measuring sonde that is adapted to measure a rotation angle about the X ₃ axis and to the said known alternating magnetic field and the measurement data from the position measurement probe Calculating means for calculating the position of the position measuring sonde. Further, the position measuring sonde is mounted near the tip of a drill in the horizontal drilling method.

Further, the position measuring sonde includes a power supply battery, an analog-to-digital converter for converting a measurement output from each of the sensors into digital data, and a modulator to which an output of the analog-to-digital converter is input. A coil for emitting an AC magnetic field modulated based on the output of the modulator, wherein the AC magnetic field emitted from the coil is detected by the second coil and converted into an electric signal, Through the processing means. Further, the position measuring sonde is configured to be supplied with power from a device on the ground via a power supply line, and to convert the measurement data into digital data. A modulator to which the output of the digital converter is input,
Transmitting means for outputting an output of the modulator to the power supply line, wherein the measurement data transmitted via the power supply line is input to the arithmetic means. is there.

Still further, in the other position measuring method and the position measuring device, the AC magnetic field generating source may include an oscillator and a parallel line disposed just above the planned excavation position to which the AC current from the oscillator is supplied. It is said that. Further, the AC magnetic field generating source is a line arranged in an arbitrary polygonal shape so as to include the oscillator and the position immediately above the planned excavation position to which the AC current from the oscillator is supplied. Furthermore, the AC magnetic field generating source is provided with an oscillator and an AC current supplied from the oscillator.
One of the two lines is disposed immediately above the planned excavation position, and the other line is disposed at a position sufficiently farther away than that. . Furthermore, the AC magnetic field generation source is constituted by an oscillator and a single line which is disposed immediately above the excavation scheduled position to which the AC current from the oscillator is supplied and whose tip is grounded. Return routes are those that are considered ground or seawater.

Since a known AC magnetic field is measured using a three-axis orthogonal AC magnetic sensor, high-accuracy measurement can be quickly performed without being affected by surrounding magnetic materials or terrestrial magnetism.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The position measuring method and apparatus of the present invention can be applied in any case within a known alternating magnetic field. An example in which the present invention is applied to measurement will be described. [First Measurement Method] FIG. 1 is a diagram showing the relationship between a ground apparatus, a drill pipe, and a position measurement sonde in a horizontal drilling method to which a first position measurement method of the present invention is applied. In this figure, reference numeral 50 denotes a horizontal drilling device. As shown in the figure, drilling is performed while extending a drill pipe 51 from the horizontal drilling device 50 into the ground. Near the tip of this drill pipe 51 is a position measuring sonde 1
0 is attached, and as described later, inside the position measuring sonde 10, 3 for measuring an AC magnetic field is provided.
An axis orthogonal magnetic sensor, an inclination sensor (inclinometer) and a rotation sensor (rotometer) for measuring the inclination angle and the rotation angle of the position measuring probe 10, and transmission of measurement data from each of the sensors. Means and the like are provided. In this embodiment, means for emitting an AC magnetic field modulated by the measurement data is provided as the means for transmitting.

As shown in the figure, the ground surface immediately above the route to be excavated by the horizontal drilling device 50
Two parallel electric wires (parallel lines) 31 are stretched. An oscillator 30 for supplying an alternating current is connected to the parallel line 31, and an alternating current generated by the oscillator 30 is supplied to the parallel line 31 before excavation. A receiver 40 is placed on the ground near the position measuring probe 10. Although an internal configuration of the receiver 40 is not shown, a coil, a filter, an amplifier, a demodulator, a microprocessor, and a coil for detecting an AC magnetic field modulated by the measurement data from the position measurement probe 10 are provided.
The AC magnetic field received from the coil is input to a demodulator via a filter and an amplifier, and demodulated by the demodulator. The demodulated measurement data is input to a computer 41 serving as arithmetic means via a microprocessor in the receiver 40, and the computer 41 performs arithmetic processing by a method described later to calculate the position of the position measuring probe 10. Then, the position is displayed on the display.

FIG. 2 shows an example of the configuration of the position measuring probe 10. As shown in FIG. The position measuring sonde 10 has a cylindrical watertight container made of a non-magnetic material, and is built in a tip portion of the drill pipe 51. In this position measuring sonde 10, as shown in the figure, a rectangular coordinate system X ₃ Y ₃
Z ₃ is determined such that the X ₃ axis coincides with the long axis direction of the position measuring probe 10 and the Z ₃ axis is located in a plane including the X ₃ axis and the vertical direction. Incidentally, X ₃ axis coincides with the direction in which the tip of the drill advances.

Inside the probe for position measurement 10, a three-axis orthogonal type AC magnetic sensor (hereinafter referred to as “three-axis magnetic sensor”) 11 measures the rotation angle of the probe for position measurement 10 around the Y ₃ axis. inclinometer 12, the angle meter 13, the power supply battery 14, electronic circuitry and a control circuit 15 and the signal modulator 16 for measuring the rotation angle around the X ₃ axis position measurement sonde 10, and the coil 17 is built .

Although not shown, the three-axis magnetic sensor 11 is composed of three one-axis magnetic sensors arranged orthogonally to each other. Has sensitivity only to the magnetic field of. A fluxgate magnetic sensor can be used as the one-axis magnetic sensor, and a commercially available three-axis orthogonal fluxgate magnetic sensor having a frequency band from DC to about 1 kHz can be used. Incidentally, the three-axis magnetic sensor 11, the direction of sensitivity of each of the one-axis magnetic sensor is arranged so as to coincide with each of the X ₃ axis, Y ₃ axis and Z ₃ axes.

Next, referring to FIG.
The angle measured by the goniometer 13 will be described. This
In the figure, the coordinate system X_ThreeY_ThreeZ_ThreeIs for the position measurement described above
The coordinate system is fixed to the sonde 10. Also, X₁Y₁Z
₁Is a coordinate system fixed to the ground, and Z₁The axis is vertical
And X₁Axis is Z₁Axis and X_ThreeIt will be placed in the plane containing the axis
Is defined as Further, the coordinate system X_TwoY_TwoZ_TwoIs X_Two
Axis is X_ThreeY axis_TwoAxis is Y ₁Defined to match the axis
ing. Θ and Φ represent Euler angles.
12 is Y of the position measuring sonde 10_ThreeTilt angle Θ around the axis
The goniometer 13 measures the X of the position measuring probe 10._Three
The rotation angle Φ around the axis is measured. What
The inclinometer 12 and the angle meter 13 are small weights.
It is possible to use a servo accelerometer, which is a force accelerometer, etc.
it can.

FIG. 4 is a diagram showing the electrical configuration of the position measuring probe 10. As shown in FIG. As shown in the figure, inside the control circuit 15, filters and amplifiers 21 to 23 connected so that outputs from the three-axis magnetic sensor 11, the inclinometer 12 and the goniometer 13 are respectively inputted, A multiplexer 24 for selecting and outputting the output from each of the filters and the amplifiers 21 to 23;
An analog-to-digital converter (A / D converter) 25 for converting the signal selected by 4 into digital data, and
A microprocessor 26 to which the output of the A / D converter 25 is input is provided. The output of the microprocessor 26 is connected to the signal modulator 16, and the output of the signal modulator 16 is connected to the coil 17.

The position measuring probe 1 constructed as described above.
At 0, the measurement signals from the sensors 11 to 13 are respectively input to the filters and the amplifiers 21 to 23, and after necessary signals are extracted by the filters,
It is amplified and applied to the multiplexer 24. The multiplexer 24 selects the output of the filter and the amplifiers 21 to 23 under the control of the microprocessor 26 and outputs the selected output to the A / D converter 25. A / D converter 2
5 converts the analog measurement signal output from the multiplexer 24 into digital data. The microprocessor 26 takes in the measurement data converted into a digital signal by the A / D converter 25 and
Output to The output from the microprocessor 26 is converted into a modulation signal such as frequency shift keying (FSK) in the signal modulator 16 and then applied to both ends of the coil 17 as an electric signal. The generated alternating magnetic field is emitted.
Thus, the three-axis magnetic sensor 1
The measurement signal including the amplitude and the relative phase relationship of the three-directional components of the AC magnetic field detected by 1 and the measurement signals by the inclinometer 12 and the angle meter 13 are transmitted.

In the above-described embodiment, the transmission of the measurement signal by the position measuring sonde 10 is performed by a modulated AC magnetic field, but the signal measuring signal is transmitted between the position measuring sonde 10 and the computer 41 on the ground. If an electric wire can be drawn, it is also possible to transmit a signal by a wired method. FIG. 5 is a diagram showing a relationship between the ground apparatus, the drill pipe, and the position measurement sonde in the embodiment in which a signal is transmitted between the position measurement sonde 10 and the computer 41 on the ground in a wired manner. is there. In this figure, FIG.
The same components as those described above are assigned the same reference numerals to avoid duplication of description. 60 is the position measuring sonde 10
This is a position measuring sonde having a three-axis magnetic sensor, a rotation angle sensor, and a tilt sensor as in the case of the first embodiment. In this embodiment, the position measuring probe 60 is supplied with power for operation from the horizontal drilling device 50 via a power supply line, and the sensors are connected via the power supply line. It is adapted to transmit measurement data. Therefore, the measurement data from the position measuring sonde 60 is transmitted to the horizontal drilling device 50 via the power supply line, where the measurement data is separated and the data is separated via the signal line 42. The data is input to the computer 41. According to this embodiment, it is not necessary to install the above-described receiver 40, and the measurement can be easily performed.

FIG. 6 is a view showing the internal configuration of the position measuring probe 60. As shown in FIG. As shown in this figure, a watertight container is also used in the position measuring sonde 60,
A three-axis magnetic sensor 11, an inclinometer 12, an angle meter 13, a control circuit, a signal modulator 61, and a power separation circuit 70 are sealed in the watertight container. The power separation circuit 70 has a power supply line 71 connected to the horizontal drilling device 50.
The power separation circuit 70 separates the power supply voltage from the signal modulated by the measurement data output from the signal modulator.

FIG. 7 is a block diagram showing an electrical configuration of the position measuring probe 60. As shown in FIG. In this figure, the same components as those in FIG. 4 are denoted by the same reference numerals, and description thereof will be omitted. As is apparent from a comparison between FIG. 7 and FIG. 4 described above, the position measuring probe 6 in this embodiment is shown.
0, the output of the signal modulator 16 is connected to a power separation circuit 70, and the output of the signal modulator 16 is connected to the horizontal drilling device via a power supply line 71 via the power separation circuit 70. The data is supplied to the computer 41 via the signal line 42 as described above. The signal modulator 16
As a modulation method in FSK, as in the case described above, FSK
A method or the like can be used.

Next, in the first position measuring method of the present invention in which the parallel line 31 is disposed immediately above the planned excavation route as described above, the calculation executed for position measurement in the computer 41 will be described in detail. I do. First, the resolution of measurement by this position measurement method will be examined. (Measurement Resolution) As described above, a flux gate type magnetic sensor having a frequency band of about 1 kHz from DC is commercially available.
The frequency of the alternating current to be supplied can be from DC to about 1 kHz. Assuming that the interval between the parallel lines 31 is 20 cm, the excavation depth is 1.5 m, and the current value of the alternating current is 1 A, the magnitude of the magnetic field is calculated using an approximate expression described later. The magnetic field in the direction is Bz = 18 [nT (nano Tesla)], and the magnetic field in the lateral direction is Bz
y = 24y [nT] (where y is the center of the parallel wire and 3
It represents the distance in the horizontal plane between the axial magnetic sensors). The unit uses the MKS unit system. what if,
When the position measuring probe 10 moves 1 cm in the lateral direction, the magnetic field changes by 24/100 = 0.24 [nT]. Since the typical noise level of a commercially available fluxgate magnetic sensor is 0.03 [nT / √Hz], it is easy to achieve a resolution of about 1 cm by using a filter having a band of about 1 Hz. It is. Also, by increasing the current value or increasing the distance between parallel wires,
It is also possible to further increase the resolution.

(Principle of Measurement by First Method) The principle of measurement in the present embodiment will be described below. a. Coordinate system transformation. FIG. 8 is a diagram showing a coordinate system used for this calculation. In this figure, P (y, z) indicates the position of the three-axis magnetic sensor 11. Further, XYZ coordinate system fixed to the parallel line 31, X ₀ Y ₀ Z ₀ is the 3 position of the axis magnetic sensor 11 as an origin parallel coordinate system XYZ, X ₃ Y ₃ Z ₃ is the 3-axis magnetic Coordinate system fixed to sensor 11, Ψ, Θ, Φ
Is the Euler angle. These Euler angles Ψ, Θ and Φ
Are the directions of the three-axis magnetic sensor 11 in the horizontal plane, respectively.
Corresponds to pitching and rotation angle.

The magnetic field vector Bhat ⁽³⁾ detected by the three-axis magnetic sensor 11 is

(Equation 1) And Here, the superscript (3) indicates that the superscript is represented by the X ₃ Y ₃ Z ₃ coordinate system. In addition, in a formula, a character in which a chevron symbol is added to an alphabet is expressed by adding a character "hat" to the alphabet, such as "Bhat", in the sentence.

As described above, the three-axis magnetic sensor 11
Pitch Θ and rotation angle Φ are inclinometer 12 and goniometer 1
3 measured. When the pitching Θ and the rotation angle Φ are known as described above, the magnetic field vector Bhat ⁽³⁾ of the above equation (1) is expressed in the X ₁ Y ₁ Z ₁ coordinate system using the following equation (2). Can be.

(Equation 2) here,

(Equation 3)

(Equation 4) It is.

Further, the magnetic field vector Bhat ⁽¹⁾ expressed in the X ₁ Y ₁ Z ₁ coordinate system of the above equation (2) is converted into the X ₀ Y ₀ Z ₀ coordinate system by using the following equation (5). Can be represented.

(Equation 5) Therefore, X ₀ Y ₀ Z ₀ magnetic field represented by the coordinate system vector Bhat ⁽⁰⁾ is represented by the formula (6).

(Equation 6)

Since the direction of the magnetic vector is orthogonal to the parallel line 31, the x component B of the vector in the above equation (6)
⁽¹⁾ _x = 0. Therefore, the following equation (7) can be derived.

(Equation 7) From this equation (7), the direction of the three-axis magnetic sensor in the horizontal plane Ψ
Can be requested.

As described above, the Euler angles Θ, Φ, and Ψ are all known, and the magnetic field detected by the three-axis magnetic sensor 11 is represented by the X ₀ Y ₀ Z ₀ coordinate system by the equations (2) and (5). It became possible. Also, the X ₀ Y ₀ Z ₀ coordinate system and the X
Since the YZ coordinate system is parallel, vector B ⁽⁰⁾ = vector B
It is. After all, the AC magnetic field detected by the three-axis magnetic sensor 11 can be represented by an XYZ coordinate system. Therefore, in the following description, description will be made using the XYZ coordinate system shown in FIG.

B. Description of the magnetic field. In FIG. 9, the magnetic field at an arbitrary point P (x, y) is represented by the following equations (8) and (9).

(Equation 8)

(Equation 9)

C. Approximate solution. First, an approximate solution is obtained. If the condition of the following equation (10) is assumed to be established, established the approximation of formula (11), B _y of the equation (8) is modified as equation (12).

(Equation 10)

[Equation 11]

(Equation 12)

Similarly, when the approximation of the equation (11) is used, B _{z in the} equation (9) is transformed into the following equation (13).

(Equation 13) Further, if it is assumed that the following equation (14) is approximated, equation (15) is obtained.

[Equation 14]

(Equation 15)

Therefore, the above equations (12) and (15)
Equations (16) and (17) below can be obtained from

(Equation 16)

[Equation 17] By using the above procedure as vector B = vector Bhat, the point P where the three-axis magnetic sensor 11 is placed
The approximate position of (x, y) can be known. That is, the relative position of the position measuring sonde 10 or 60 from the parallel line 31 can be calculated.

D. Numerical calculation procedure by Newton method. Next, a procedure for calculating a more accurate position using the Newton method will be described. Vector t, f (t), matrix J (t)
Is defined as in the following equations (18) to (22). Also,
B _y and B _z is represented the formula (8) in equation (9). In addition,
It is assumed that Δy and Δz adopt sufficiently small values.

(Equation 18)

[Equation 19]

(Equation 20)

(Equation 21)

(Equation 22)

First, using the equations (16) and (17), the initial value vector t ⁽¹⁾ = (y ⁽¹⁾ ,
z ⁽¹⁾ ) ^{Find t} . Next, using equation (23),
t ⁽²⁾ , t ⁽³⁾ , t ⁽⁴⁾ ,... are sequentially calculated.

(Equation 23) Assuming that ε is a sufficiently small positive number, the calculation of Expression (23) is repeated until | t ^{(v + 1)} −t ^(v) | <ε, and a solution for obtaining the vector t ^{(v + 1)} is obtained. In this way, a more accurate position P (x, y) of the three-axis magnetic sensor 11 can be obtained.

[Second Measurement Method] In the first measurement method described above, an alternating current is supplied to the parallel line 31 and an alternating magnetic field generated by the alternating current is measured. In the method, an AC current is applied to an electric wire stretched in an arbitrary polygonal shape, and an AC magnetic field generated from the AC current is measured using the position measuring sonde to measure a relative position of the position measuring sonde.

FIG. 10 shows an embodiment of the relationship between the ground equipment, the drill pipe, and the probe for the position measuring device when the second position measuring method is applied. In this embodiment, prior to excavation, a line (wire) 32 is formed in an arbitrary shape directly above a planned route, and an alternating current generated by the oscillator 30 is allowed to flow. The configuration and arrangement of the position measuring sonde, receiver, computer, etc., and the method of transmitting signals to and from the ground computer are the same as those in the first embodiment shown in FIG.

In the case where a position measuring sonde for transmitting a measurement signal by wire is used as in the second embodiment shown in FIG. 5, the relationship between the ground equipment, the drill pipe and the position measuring sonde is described. Is shown in FIG. As shown in this figure, this case differs from the case of FIG. 10 in that the position measuring probe 60 shown in FIGS. 6 and 7 is used.

(Measurement Principle of the Second Method) As shown in FIGS. 10 and 11, the position of the position measuring sonde in the case where the line 32 is provided in an arbitrary polygonal shape at a part immediately above the planned excavation route. The calculation method of will be described. a. Definition of Coordinate System An orthogonal coordinate system XYZ fixed to the ground and a spherical coordinate system rαβ are determined as shown in FIG. The origin O of the two coordinate systems is defined so as to substantially coincide with the center of gravity of the current loop 33. Also,
The X axis and the Y axis define a horizontal plane, and the Z axis defines a vertical direction.
It is assumed that the three-axis magnetic sensor 11 is at the point P. Although not shown, the coordinate systems X ₁ Y ₁ Z ₁ , X ₂ Y ₂ Z ₂ and X
₃ Y ₃ and Z ₃ are defined as in the first embodiment described above. The origin of these coordinate systems is fixed at point P. X
₃ Y ₃ Z ₃ is a coordinate system fixed to the 3-axis magnetic sensor 11, each of the axis coincides with the direction having a sensitivity of each single-axis magnetic sensor. X ₁ Y ₁ Z ₁ is a coordinate system parallel to XYZ.

As in the case of the first embodiment, the inclinometer 12 and the goniometer 13 are built in,
Since the pitching Θ and the rotation angle Φ of the position measuring sonde 10 or 60 can be measured, the output vector Bhat of the three-axis magnetic sensor 11 expressed in the X ₃ Y ₃ Z ₃ coordinate system can be measured.
⁽³⁾ can be transformed into an X ₁ Y ₁ Z ₁ coordinate system to obtain a vector Bhat ⁽¹⁾ . Further, since X ₁ Y ₁ Z ₁ and XYZ are parallel coordinate systems, the vector Bhat ⁽¹⁾ = the vector Bhat. Therefore, the output vector Bhat ⁽³⁾ of the three-axis magnetic sensor 11 expressed in the X ₃ Y ₃ Z ₃ coordinate system can be converted into the vector Bhat, and in the following analysis, the point P
The measured value of the magnetic field at (x, y) is represented by a vector Bhat.

B. Approximate solution First, an approximate solution is obtained and used as an initial value for numerical calculation by the following Newton method. The current loop is replaced by a minute current loop 33 existing at the origin O, and its magnetic moment is set to m. Assuming that the area of the current loop is S,

(Equation 24) Holds. Note that the direction of m coincides with the Z axis.

The magnetic field due to the magnetic moment m is expressed as follows in the XYZ coordinate system.

(Equation 25)

(Equation 26)

[Equation 27] From the above equations (25) and (26), β is expressed as follows.

[Equation 28]

B _XY is defined as in equation (29).

(Equation 29) Therefore, according to the sign of B _XY / B _Z , α is given by equation (3)
0) or Equation (31).

[Equation 30]

(Equation 31)

By substituting α and β obtained in this way into the above equation (25) or (26) or (27), r can be calculated. By using the above procedure as vector B = vector Bhat, 3
The approximate position of the point P where the axial magnetic sensor 11 is placed can be known.

C. Numerical calculation procedure by Newton method. Next, a more accurate calculation method using the Newton method will be described. According to Biot-Savart's law, the point P (xp,
magnetic field vector B of yp) (B _x, B _y, B _z) is expressed by the following equation (32) to (34).

(Equation 32)

[Equation 33]

(Equation 34) Here, the integration is performed along the current loop 33.

The vectors t, f (t) and matrix J (t) are
Each is defined as in the following equations (35) to (40).
Here, Δy and Δz adopt sufficiently small values. Also,
B _x, B _y, the B _z is the magnetic field which is calculated by the equation (32) to (34).

(Equation 35)

[Equation 36]

(37)

(38)

[Equation 39]

(Equation 40)

First, using the approximate solution calculated in the previous section, an initial value vector t ⁽¹⁾ of the vector t is obtained. Next, according to equation (41), t ⁽²⁾ , t ⁽³⁾ , t ⁽⁴⁾ ,.
Are sequentially calculated.

[Equation 41] Assuming that ε is a sufficiently small positive number, the calculation of the above equation (41) is repeated until | vector t ^{(v + 1)} −vector t ^(v) | <ε, and a solution for obtaining the vector t ^{(v + 1)} is obtained. And Thus, the accurate position of the three-axis magnetic sensor 11 can be calculated.

[Third Measurement Method] Next, still another measurement method of the present invention will be described. FIG. 13 is a diagram showing the relationship between the above-mentioned equipment on the ground, a drill pipe and a sonde for position measurement in this measurement method. In this figure, a position measuring sonde 60 of a type for transmitting the measurement data described with reference to FIGS.
Although FIG. 2 is used as an example, FIG.
Alternatively, a position measuring sonde 10 incorporating a battery shown in FIG. 4 may be used.

As shown in FIG. 13, in this embodiment, one of the two lines to which the AC signal is supplied from the oscillator 30 is located just above the path to be excavated, that is, the position measuring sonde 60. The line 34 is arranged almost straight on the straight line, and the other electric wires are located at a sufficiently distant position. Other configurations are the same as those in the above-described embodiment.

(Principle of Measurement by Third Method) In the case where the tracks 34 are arranged in this way, as shown in FIG.
The XYZ coordinate system on the ground is determined so that the axis is the axis and the vertical direction is the Z axis. If the position of the sonde 60 is (X, Y),
The AC magnetic field at the position of the sonde can be approximated by the following equations (42) and (43).

(Equation 42)

[Equation 43]

From the above equations (42) and (43),
(X, Y) is represented by the following equations (44) and (45).

[Equation 44]

[Equation 45]

As described above, by using the inclinometer 12 and the goniometer 13, the magnetic field (X ₃ Y ₃ Z ₃ coordinate system) detected by the three-axis magnetic sensor 11 can be converted into an XYZ coordinate system. Can be. That is, it is possible to obtain the B _y and B _z, the equation (44) and the position of the sonde by the equation (45) based on this (X, Y) can be determined. Thus, also in this embodiment, the position of the probe can be calculated from the measurement data of the three-axis magnetic sensor 11, the inclinometer 12, and the goniometer 13.

[Fourth Measurement Method] Still another position measurement method of the present invention will be described with reference to FIG. According to this method, one of the outputs of the oscillator 30 is connected to the ground, and a wire (line) 35 connected to the other output terminal of the oscillator 30 is placed straight above the expected excavation position, that is, almost directly above the sonde 60. It is placed on the top and its tip is connected to ground. In this case, the return path of the alternating current is ground. Such an arrangement is particularly effective when excavating below the sea floor. At this time, the return path of the alternating current is seawater.

In FIG. 14, the XYZ coordinate system is shown in FIG.
3 and the position of the sound is (X, Y), the AC magnetic field at the position of the sound can be approximated by the above formulas (42) and (43) in this embodiment as well. it can. Therefore, the position (X, Y) of the sound can be calculated in the same manner as in the embodiment shown in FIG. It should be noted that also in this embodiment, the position measuring sonde incorporating the battery shown in FIGS. 2 and 3 can be employed.

In the above description, the case of measuring the position of the excavation tip in the horizontal drilling method has been described as an example. However, the position measuring device of the present invention is not limited to this, and the position in the known AC magnetic field is not limited to this. The measurement can be applied in the same manner.

[0056]

As described above, according to the position measuring method and apparatus of the present invention, extremely accurate position measurement can be performed. In addition, since an AC magnetic field is used, there is no influence from surrounding magnetic materials or terrestrial magnetism, and since it is not necessary to change the place where the receiver is placed and repeat the measurement, the measurement can be performed quickly. . Further, according to the present invention, in which the measurement data is transmitted to the receiver using the AC magnetic field modulated by the measurement data, it is possible to reduce the connection pipe connection work time. Therefore, the efficiency of the excavation work is improved, and the time required for the work can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a relationship between respective devices in an embodiment in which a first position measuring method of the present invention is applied to a horizontal drilling method.

FIG. 2 is a diagram showing a configuration of a position measuring probe used in the position measuring method and device of the present invention.

FIG. 3 is a diagram for explaining angles measured by an inclinometer 12 and a goniometer 13 mounted on a position measuring sonde used in the present invention.

FIG. 4 is a block diagram showing an electrical configuration of a configuration example of a position measuring probe used in the present invention.

FIG. 5 is a diagram for explaining a relationship among devices in another embodiment when the first position measuring method of the present invention is applied to a horizontal drilling method.

6 is a diagram showing a configuration example of a position measuring sonde used in the position measuring method and device shown in FIG. 5;

FIG. 7 is a diagram showing an electrical configuration of the position measuring sonde shown in FIG. 6;

FIG. 8 is a diagram for explaining a coordinate system in the first position measurement method of the present invention.

FIG. 9 shows XYZ in the first position measuring method of the present invention.
It is a figure for explaining a coordinate system.

FIG. 10 is a diagram for explaining the relationship between the respective devices when the second position measuring method of the present invention is applied to the horizontal drilling method.

FIG. 11 is a diagram for explaining the relationship among devices in another embodiment when the second position measuring method of the present invention is applied to a horizontal drilling method.

FIG. 12 is a diagram for explaining a coordinate system in a second position measurement method of the present invention.

FIG. 13 is a diagram for explaining the relationship between the respective devices when the third position measuring method of the present invention is applied to the horizontal drilling method.

FIG. 14 is a diagram for explaining the relationship among the devices when the fourth position measuring method of the present invention is applied to the horizontal drilling method.

FIG. 15 is a view for explaining a configuration of a drill used in the horizontal drilling method.

[Explanation of symbols]

 10, 60, 110 Position measuring sonde 11 3-axis magnetic sensor 12 Inclinometer 13 Angle meter 14 Battery 15 Control circuit 16 Signal modulator 17 Coil 21-23 Filter and amplifier 24 Multiplexer 25 A / D converter 26 Microprocessor 30 Oscillator DESCRIPTION OF SYMBOLS 31 Parallel line 32, 34, 35 Line 33 Current loop 40 Receiver 41 Computer 42 Signal line 50 Horizontal drilling device 51 Drill pipe 61 Control circuit and signal modulator 70 Power separation circuit 71 Power supply line 100 Drill

Claims (14)

[Claims] 1. A method for measuring the position of an object using a position measuring sonde, the method comprising: generating a known AC magnetic field by an AC magnetic field generating source; Each of the directions of the respective axes in an orthogonal coordinate system X ₃ Y ₃ Z ₃ defined by an X ₃ axis coincident with the major axis direction of the position measuring sonde and a Z ₃ axis located in a plane including the X ₃ axis and the vertical direction. AC magnetic field, the step of measuring the rotation angle of the rotation angle and the X ₃ about the axis around the Y ₃ axis, and, on the basis of the respective measured data from the position measuring probe, the alternating of the position measurement probe A position measuring method comprising calculating a relative position from a magnetic field source. 2. A position measuring method for measuring a position of a drill in a horizontal drilling method, wherein an AC magnetic field generating source is disposed immediately above a planned drilling position, and a known AC magnetic field is generated by the AC magnetic field generating source. Step: The position measuring sonde attached near the tip of the drill has an X that matches the longitudinal direction of the position measuring sound.
₃ axis and the X ₃ axis and located in a plane containing the vertical direction Z ₃ orthogonal coordinate defined by the axis system X ₃ Y ₃ AC magnetic fields in the respective axial direction of Z _3, rotation angle and the around the Y ₃ axis measuring a rotational angle around X ₃ axis, and, on the basis of the respective measured data from the position measuring probe position measuring method characterized by comprising the step of calculating the position of the drill. 3. The AC magnetic field generating source according to claim 2, wherein the AC magnetic field generating source is an oscillator and a parallel line disposed just above the planned excavation position to which the AC current from the oscillator is supplied. Position measurement method. 4. The method according to claim 1, wherein the AC magnetic field generating source is a line arranged in an arbitrary polygonal shape so as to include an oscillator and a position directly above the planned excavation position to which the AC current from the oscillator is supplied. The position measuring method according to claim 2, wherein the position measuring method is characterized in that: 5. The AC magnetic field generating source has an oscillator and two lines to which AC current from the oscillator is supplied, and one of the two lines is located at the position to be excavated. 3. The position measuring method according to claim 2, wherein the line is disposed immediately above, and the other lines are disposed at positions farther away from the line. 6. The AC magnetic field generating source is constituted by an oscillator and a single line which is disposed immediately above the planned excavation position to which an AC current from the oscillator is supplied and whose tip is grounded. 3. The position measuring method according to claim 2, wherein the return path of the alternating current is ground or seawater. 7. A position measuring probe having an AC magnetic field generating source for generating a known AC magnetic field, a three-axis orthogonal type AC magnetic sensor, an inclinometer and a tachometer, wherein the three-axis orthogonal type AC magnetic field is provided. sensor Z ₃ located in the plane containing the major axis X ₃ axis and the X ₃ axis and the vertical direction coincides with the direction of the position measurement probe
An alternating magnetic field in each axis direction in a rectangular coordinate system X ₃ Y ₃ Z ₃ defined by the axes is measured, the tachometer measures a rotation angle around the Y3 axis, and the inclinometer measures a rotation around the X ₃ axis. And a calculating means for calculating the position of the position measuring sonde based on the measurement data from the position measuring sonde and the known AC magnetic field. A position measuring device characterized by the above-mentioned. 8. The position measuring apparatus according to claim 7, wherein the position measuring sonde is mounted near a tip of a drill in a horizontal drilling method. 9. The position measuring probe includes a power supply battery, an analog-to-digital converter that converts the measurement data into digital data, a modulator to which an output of the analog-to-digital converter is input, and the modulator. And a coil that emits an AC magnetic field modulated based on the output of the AC coil. The AC magnetic field emitted from the coil is detected by a second coil, converted into an electric signal, and the electric signal is output through a demodulator. 9. The position measuring device according to claim 7, wherein the position measuring device is adapted to be taken into a calculating means. 10. An analog-to-digital converter configured to receive power from a device on the ground via a power supply line, and to convert each of the measurement data into digital data. A modulator to which an output of the analog-to-digital converter is input, and a transmission unit that outputs an output of the modulator to the power supply line, wherein the measurement data transmitted through the power supply line 9. The position measuring apparatus according to claim 7, wherein the position information is input to the calculating means. 11. The AC magnetic field generating source according to claim 8, wherein the AC magnetic field generating source is an oscillator and a parallel line disposed immediately above the planned excavation position to which the AC current from the oscillator is supplied. Position measuring device. 12. The AC magnetic field generating source may be a line arranged in an arbitrary polygonal shape so as to include an oscillator and a position directly above the planned excavation position to which an AC current from the oscillator is supplied. 9. The position measuring device according to claim 8, wherein the position measuring device is characterized in that: 13. The AC magnetic field generating source has an oscillator and two lines to which AC current from the oscillator is supplied,
9. The method according to claim 8, wherein one of the two tracks is disposed immediately above the planned excavation position, and the other track is disposed at a position sufficiently farther than the one. Position measuring device. 14. The AC magnetic field generating source is constituted by an oscillator and a single line that is disposed immediately above the planned excavation position to which an AC current from the oscillator is supplied and whose tip is grounded. 9. The position measuring device according to claim 8, wherein the return path of the alternating current is ground or seawater.