JP3084550B2 - Underground information collection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a steel rod to be inserted into the ground, and collects signals detected by a sensor provided at the tip of the rod on the ground surface as ground information. It relates to an underground information collection device.

[0002]

2. Description of the Related Art Such an underground information collecting apparatus is provided, for example, in a boring machine having a rotating steel rod. In a boring machine, when trying to obtain information on the rod tip, for example, temperature, in real time, a temperature sensor is attached to the rod tip, and a signal detected by this temperature sensor is collected on the ground side as underground information. It becomes necessary.

[0003] A conventional underground information collecting apparatus includes a steel rod, a sensor embedded near the tip of the rod, and a sensor in the rod, as shown in Japanese Patent Application Laid-Open No. 6-77863. It has a transmitting circuit unit housed in close proximity, a transmitting circuit unit for modulating a carrier wave with underground information detected by this sensor, and a solenoid-shaped transmitting coil. The transmission circuit modulates a carrier with a signal detected by the sensor, that is, underground information, and outputs a modulated carrier to a transmission coil. The transmitting coil generates a magnetic signal that propagates through the steel rod based on the modulated carrier, and the magnetic signal is transmitted to the ground through the rod. In order to receive a magnetic signal from the rod on the ground side, a solenoid-shaped receiving coil is provided on the ground side of the rod. The receiving coil has a central axis, and is wound around the rod as a magnetic core such that the central axis coincides with the axial direction of the rod. Thus, if there is a magnetic signal on the rod, an induction signal is generated on the receiving coil. A receiving circuit unit is connected to the receiving coil,
This receiving circuit receives an induction signal from the receiving coil,
The guidance signal is demodulated to reproduce the underground information.

Incidentally, the receiving coil also generates an induction signal by an external magnetic signal incident from a direction different from the direction of the central axis. Such an induced signal is a noise signal caused by noise coming from an external device other than the underground information collecting device, and should be removed.

[0005]

However, the above-mentioned conventional underground information collecting apparatus does not have a function of removing such a noise signal. On the other hand, the magnetic signal transmitted from the transmission coil underground becomes weaker on the ground surface side as the signal transmission distance, that is, the length of the rod increases. For this reason, the ratio of the guidance signal representing the underground information to the guidance signal due to noise, that is, the signal-to-noise ratio (S / N ratio) decreases as the length of the rod increases. As a result, there is a problem that the signal transmission distance becomes shorter as the noise becomes larger, and the depth at which underground information can be collected becomes shallower.

Accordingly, an object of the present invention is to provide an underground information collecting apparatus capable of extending a signal transmission distance by reducing a magnetic signal mixed as noise into the above-mentioned receiving coil.

[0007]

According to the present invention, there is provided a steel rod inserted into the ground, a sensor provided near the tip of the rod, and a sensor provided near the tip of the rod. A transmitting circuit unit that receives the detected detection signal as an underground information signal, modulates a carrier with the underground information signal and outputs a modulated carrier, and has a central axis coinciding with a central axis of the rod, and the modulated carrier A solenoid-shaped transmitting coil that generates a magnetic signal and transmits the magnetic signal through the rod to the other end opposite to the tip, and is wound around the rod at the other end of the rod. A solenoidal main receiving coil for converting the magnetic signal sent through the rod into an inductive electric signal, and receiving the inductive electric signal as a demodulator input signal to receive the underground information signal In underground information collecting apparatus and a demodulation circuit for demodulating, said apparatus further wound to have a central axis in a direction perpendicular to the center axis of the main receiving coil,
A first solenoidal noise receiving coil that is provided adjacent to the main receiving coil and generates a first induced noise signal having a noise amplitude and a noise phase; a central axis of the main receiving coil; A second induction noise signal having a central axis in a direction orthogonal to the central axis of the first solenoidal noise receiving coil and being provided adjacent to the main receiving coil and having a noise amplitude and a noise phase; A second solenoidal noise receiving coil, and a noise combining circuit for combining the outputs of the first and second noise receiving coils to obtain a combined noise waveform very close to the noise waveform induced in the main receiving coil An amplitude and phase adjustment circuit that adjusts the amplitude and phase of the output of the noise synthesis circuit so as to match the amplitude and phase of the noise component of the output of the main receiving coil; and the adjusted output of the amplitude and phase adjustment circuit, Master Underground information collecting device is obtained, characterized in that it comprises a differential circuit for outputting as said demodulator input signal is taken out a difference signal between the output of the coil.

[0008]

In the underground information collecting apparatus according to the present invention, when the transmitting coil is located in the direction of the center axis of the main receiving coil, the magnetic signal having an angle different from the axial direction may be transmitted from another device or an unspecified noise source. This is the generated noise signal.

Since the first and second solenoidal noise receiving coils have extremely low detection sensitivity to magnetic signal components in the direction of the central axis of the main receiving coil, only noise incident from directions other than the central axis of the main receiving coil is used. And the noise signal obtained from the first and second noise receiving coils is combined to obtain a noise signal having the same phase or opposite phase that is very close to the noise signal mixed into the main receiving coil. .

If the output signals obtained from the first and second noise receiving coils are subtracted from the output signal obtained from the main receiving coil, a noise reduction effect can be obtained, so that the detection level of a signal transmitted from underground is improved. Will do.

The signals detected by the first and second noise receiving coils have different signal output intensities and phases depending on the incident directions of the signals to the first and second noise receiving coils.
By adjusting the amplification factor and phase, the noise reduction effect can be enhanced by matching the amplitude and phase of the noise mixed into the main receiving coil.

The amplitude and phase adjustment circuit can obtain an optimum noise reduction effect by automatic adjustment using an adaptive filter.

[0013]

FIG. 1 is a diagram schematically showing the entire configuration of an underground information collecting apparatus according to one embodiment of the present invention.

The underground information collecting apparatus of this embodiment also has a steel rod 11 inserted into the ground and a temperature sensor 12 provided near the tip of the steel rod 11, similarly to the conventional underground information collecting apparatus. A transmission circuit unit 26 provided near the tip of the steel rod 11 and receiving a detection signal detected by the temperature sensor 12 as an underground information signal, modulating a carrier with the underground information signal and outputting a modulated carrier. And a steel rod 11
A solenoidal transmission coil 18 having a central axis coinciding with the central axis of the above, generating a magnetic signal by the modulated carrier wave, and transmitting the magnetic signal through the steel rod 11 to the other end side opposite to the distal end; The other end of the steel rod 11 is wound around the steel rod 11 so as to go therearound, and a solenoid-shaped main receiving coil 19 for converting a magnetic signal sent through the steel rod 11 into an inductive electric signal; A demodulation circuit 25 that receives the induction electric signal as a demodulator input signal and demodulates the underground information signal described above.

Thus, the underground information collecting apparatus of the present embodiment is further wound so as to have a central axis in a direction orthogonal to the central axis of the main receiving coil 19 and is provided adjacent to the main receiving coil 19. A first solenoidal noise receiving coil 20 for generating a first induction noise signal having a noise amplitude and a noise phase, and a central axis of the main receiving coil 19 and the first solenoidal noise receiving coil 20. A second solenoidal noise receiving coil having a central axis perpendicular to the central axis and provided adjacent to the main receiving coil 19 for generating a second induced noise signal having a noise amplitude and a noise phase; 21
And a noise combining circuit 22 that combines the outputs of the first and second noise receiving coils 20 and 21 to obtain a combined noise waveform very close to the noise waveform induced in the main receiving coil 19.
An amplitude / phase adjusting circuit 23 for adjusting the amplitude and phase of the output of the noise synthesizing circuit 22 to match the amplitude and phase of the noise component of the output of the main receiving coil 19;
3. A differential circuit 2 that extracts a difference signal between the adjusted output of 3 and the output of the main receiving coil 19 and outputs it as a demodulator input signal
And 4. In the drawing, reference numeral 27 denotes a receiving circuit unit.

The transmission circuit section 26 converts the DC voltage output from the temperature sensor 12 into a signal having a digital value corresponding to the input voltage, and outputs an A / D conversion signal from the A / D conversion circuit 13. A transmission code generation circuit 14 that receives and outputs a serial code for performing communication, an oscillation circuit 15 that outputs a signal of a constant frequency as a carrier wave, and receives a serial code from the transmission code generation circuit 14, and A modulation circuit 16 that modulates the carrier obtained from 15; and a power amplification of the carrier band output obtained from the modulation circuit 16;
And an amplifier circuit 17 that outputs the amplified electric signal to a transmission coil 18 in order to convert the electric signal into magnetism.

As described above, the temperature sensor 12 is incorporated at the tip of the steel rod 11, and this temperature sensor 12 outputs a DC voltage corresponding to the underground temperature. This DC voltage is applied to an A / D conversion circuit 13, where it is converted into a signal having a digital value corresponding to the input voltage, input to a transmission code generation circuit 14, and
4 outputs a serial code for performing communication. Oscillation circuit 1
Reference numeral 5 outputs a signal of, for example, 1 kHz as a carrier, and the output is supplied to a modulation circuit 16. The modulation circuit 16 receives the serial code from the transmission code generation circuit 14 and thereby modulates the carrier obtained from the oscillation circuit 15. Modulation circuit 1
The output of the carrier band obtained from 6 is power-amplified by an amplifier circuit 17 and then applied to a transmission coil 18 to convert an electric signal into magnetism.

The transmission coil 18 is wound around a rod portion near the tip of the steel rod 11 as a magnetic core, and generates a magnetic flux change of the steel rod 11 by the excitation power from the amplifier circuit 17.

The transmission coil 18 is actually located inside the surface of the steel rod 11, and the outside is protected from being damaged. The magnetic flux thus formed reaches the other end of the steel rod 11, that is, the ground surface side. On the ground surface side, a main receiving coil 19 having the central axis of the steel rod 11 as an axis.
A first noise receiving coil 20 and a second noise receiving coil 21 are provided in a direction close to and orthogonal to the main receiving coil 19. Before describing the operation of these three receiving coils, a general description will be given when a plurality of coils are arranged with reference to FIGS.

FIG. 2 shows the main receiving coil 19 as a reference.
The first noise receiving coil 20 (see FIG. 1) orthogonal to the main receiving coil 19 or the first and second noise receiving coils 2
It is a figure explaining the sensitivity directionality and signal phase relation of a coil when 0 and 21 are arranged.

Referring also to FIG. 1, in a state where the vertical component of the magnetic signal from the transmission coil 18 is incident immediately below the center axis of the main reception coil 19, the magnetic signal mixed as noise is applied to the main reception coil 19. When the light is incident at a certain angle, the vertical component NV of the magnetic signal is received as noise, but the horizontal component NH does not become noise because the main receiving coil 19 has no detection sensitivity. From the above, the horizontal component NH of the magnetic signal mixed as noise is detected in the first or second noise receiving coil 20 or 21 having the central axis orthogonal to the main receiving coil 19 in FIG. Does not have the detection sensitivity, so that it cannot be detected including the magnetic signal from the transmission coil 18. Therefore, signals detected by the first or second noise receiving coil 20 or 21 are Sin and Cos of the horizontal component NH, respectively.
The magnetic signal is mixed as component noise. Since the noise source in the actual environment is a composite signal of a number of noise wave sources, the scalar of both signals received by the first and second noise receiving coils 20 and 21 is obtained and multiplied by a code determined from the polarities of both signals. As a result, a waveform very close to the noise component incident on the main receiving coil 19 can be obtained from the synthesized noise signal obtained in this way. By adjusting the signal amplitude and the phase of the synthesized noise signal obtained in this way, a signal having the same amplitude and phase as the noise magnetic signal component incident on the main receiving coil 19 is reproduced. Can be. This signal is sent to the main receiving coil 19
Is subtracted from the signal obtained in
The noise magnetic signal component can be removed from the signal obtained in step (1).

Returning to FIG. 1, the main receiving coil 19 is mounted so that the steel rod 11 passes through the central axis thereof, and the first and second noise receiving coils 20 and 21 have the central axes thereof mainly. The receiving coil 19 is attached in a direction orthogonal to the central axis. Therefore, for the magnetic signal in the direction of the steel rod 11, the first and second noise receiving coils 2
0 and 21 have no detection sensitivity. Here, induced noise is detected from the main receiving coil 19 and the first and second noise receiving coils 20 and 21, amplified by an amplifier (not shown), and amplified by the first noise receiving coil 20 and the second noise receiving coil 20. The output of the noise receiving coil 21 is scalar-converted by the noise synthesizing circuit 22 and the sign is added as described above, and the amplitude and phase are adjusted by the amplitude / phase adjusting circuit 23 and input to the differential circuit 24. The amplified output of the main receiving coil 19 is directly input to the differential circuit 24, where a difference signal between the two outputs is obtained, and demodulated by the demodulation circuit 25 to obtain underground information with little influence of noise components. .

FIG. 3 shows the main receiving coil 19, first and second coils.
FIG. 3 is a diagram showing an arrangement of noise receiving coils 20 and 21 of FIG.
The second noise receiving coil 21 has a center axis 21a which is located between the center axis 19a of the main receiving coil 19 and the first noise receiving coil 20.
Are mounted so as to be orthogonal to both the center axis 20a of the first noise receiving coil 20 and have no receiving sensitivity to the magnetic signal in the direction of the steel rod 11 like the first noise receiving coil 20.

FIG. 4 shows the three receiving coils 19 and 20 described above.
And 21 are used for the receiving circuit 27 (see also FIG. 1) of the ground portion including a circuit for adjusting the amplitude and phase of the output signals of the first and second noise receiving coils 20 and 21. It is a figure which shows a structure concretely.

The signals output from the main receiving coil 19, the first noise receiving coil 20, and the second noise receiving coil 21 are supplied to the first amplifier circuit 32, the second amplifier circuit 33, and the third amplifier circuit 33, respectively.
, Respectively. The outputs of the second and third amplifying circuits 33 and 34 are squared by a first squaring circuit 35 and a second squaring circuit 36, respectively.
And both are added. The output of the adding circuit 37 is input to a square root circuit 38, and the added signal is squared to obtain a scalar of synthetic noise. The outputs of the second and third amplifying circuits 33 and 34 are input to a quadrant discriminating circuit 39, which performs quadrant discrimination based on a combination of the signs of the input signal voltages. If it is the third quadrant, -1 is output, and the multiplication circuit 40 multiplies the output of the square root circuit 38 to obtain a synthesized noise signal waveform output, which is input to the amplitude / phase adjustment circuit 41 and appears at the output of the differential circuit 42. The amplitude and phase are adjusted so that the noise signal component is minimized.
In the differential circuit 42, the adjusted synthesized noise is subtracted from the signal obtained from the main receiving coil 19 and amplified by the first amplifier circuit 32, and the noise incident on the main receiving coil 19 is removed. .

As described above, the outputs of the first and second noise receiving coils 20 and 21 are combined using two or more receiving coils having different sensitivity directions to obtain a combined noise signal. The amplitude and phase of the signal output are
By adjusting the signal so as to match the noise signal incident on the main receiving coil 19 and subtracting it from the signal obtained from the main receiving coil 19, the noise of the receiving coil can be removed, and the signal-to-noise ratio is greatly improved.

In the above description, it has been described that the two or three receiving coils are all arranged at right angles to each other.
Although it is explained geometrically even to some extent away from a right angle, the reduction in the effect is small and practically acceptable.

Further, in the above-described embodiment, the temperature sensor 12 has been described as an example of the sensor, but it goes without saying that the temperature sensor 12 is appropriately selected according to the type of information to be detected, such as torque and water pressure.

In addition to the above-described amplitude and phase adjustment methods, a method of manually adjusting the amplitude and phase while monitoring the output of the differential circuit 42 with an oscilloscope or the like,
There is also a method of automatically adjusting the amplitude and the phase so that the mean square error of the output of the output becomes zero.

[0030]

As is apparent from the above description, according to the present invention, the signal-to-noise ratio is greatly improved by arranging the receiving coils other than the first receiving coil so as to have different central axis directions. Therefore, the reach (depth) of the signal by magnetism is remarkably improved, so that the reliability and economy of the underground information collecting device are improved.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an overall configuration of an underground information collecting apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a first receiving coil orthogonal to the main receiving coil based on the main receiving coil in the underground information collecting apparatus illustrated in FIG. 1;
FIG. 7 is a diagram for explaining the sensitivity directionality and signal phase relationship of the coil when the noise receiving coil or the first and second noise receiving coils are arranged.

FIG. 3 is a diagram showing an arrangement of a main receiving coil and first and second noise receiving coils in the underground information collecting apparatus shown in FIG. 1;

FIG. 4 is a diagram illustrating the synthesis and amplitude of the output signals of the first and second noise receiving coils when the main receiving coil and the first and second noise receiving coils are used in the underground information collecting apparatus shown in FIG. 1; FIG. 3 is a diagram specifically showing a configuration of a receiving circuit unit in a ground portion including a circuit for adjusting a phase.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Steel rod 12 Temperature sensor 13 A / D conversion circuit 14 Transmission code generation circuit 15 Oscillation circuit 16 Modulation circuit 17 Amplification circuit 18 Transmission coil 19 Main reception coil 19a Central axis of main reception coil 20 First noise reception coil 20a First Central axis of 1 noise receiving coil 21 Second noise receiving coil 21a Central axis of second noise receiving coil 22 Noise synthesis circuit 23 Amplitude / phase adjustment circuit 24 Differential circuit 25 Demodulation circuit 26 Transmission circuit section 27 Receiving circuit section 32 1st amplifier circuit 33 2nd amplifier circuit 34 3rd amplifier circuit 35 1st square circuit 36 2nd square circuit 37 Addition circuit 38 Square root circuit 39 Quadrant discrimination circuit 40 Multiplication circuit 41 Amplitude phase adjustment circuit 42 Differential circuit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-77863 (JP, A) JP-A-63-160430 (JP, A) JP-A-63-74328 (JP, A) (58) Survey Field (Int.Cl. ⁷ , DB name) H04B 13/00 E21B 47/12 E21B 47/14 E21B 47/16 E21B 47/18

Claims (2)

(57) [Claims] 1. A steel rod inserted into the ground, a sensor provided near a tip of the rod, and a detection signal provided near the tip of the rod and detected by the sensor is an underground information signal. And a transmission circuit unit that modulates a carrier with the underground information signal to output a modulated carrier, and has a center axis that coincides with the center axis of the rod, and generates a magnetic signal with the modulated carrier, Through the rod to the other end side opposite to the tip, a solenoid-shaped transmission coil, and the other end side of the rod is wound around the rod so as to circulate around the rod, and the magnetic force is sent through the rod. An underground including a solenoid-shaped main receiving coil that converts a signal into an inductive electric signal, and a demodulation circuit that receives the inductive electric signal as a demodulator input signal and demodulates the underground information signal In the information collecting device, the device is further wound so as to have a center axis in a direction orthogonal to a center axis of the main receiving coil, and is provided adjacent to the main receiving coil, and is configured to reduce noise amplitude and noise phase. First
A first solenoidal noise receiving coil that generates an induced noise signal of the following, having a central axis in a direction orthogonal to the central axis of the main receiving coil and the central axis of the first solenoidal noise receiving coil; A second solenoidal noise receiving coil that is provided adjacent to the main receiving coil and generates a second induced noise signal having a noise amplitude and a noise phase; A noise synthesizing circuit for synthesizing the respective outputs to obtain a synthesized noise waveform very close to the noise waveform induced in the main receiving coil; and a noise component of the output of the main receiving coil for the amplitude and phase of the output of the noise synthesizing circuit. An amplitude / phase adjustment circuit for adjusting the amplitude and phase of the signal to match the amplitude and phase of the signal, and a difference signal for extracting a difference signal between the adjusted output of the amplitude / phase adjustment circuit and the output of the main receiving coil and outputting the signal as the demodulator input signal. Underground information collecting apparatus, comprising a circuit. 2. A steel rod inserted into the ground, a sensor provided near the tip of the rod, and a detection signal provided near the tip of the rod and detected by the sensor is an underground information signal. And a transmission circuit unit that modulates a carrier with the underground information signal to output a modulated carrier, and has a center axis that coincides with the center axis of the rod, and generates a magnetic signal with the modulated carrier, Through the rod to the other end opposite to the tip, a solenoidal transmission coil, and the other end of the rod wound around the rod so as to go around the rod, and the magnetic sent through the rod An underground including a solenoid-shaped main receiving coil that converts a signal into an inductive electric signal, and a demodulation circuit that receives the inductive electric signal as a demodulator input signal and demodulates the underground information signal In the information collecting device, the device is further wound so as to have a center axis in a direction orthogonal to a center axis of the main receiving coil, and is provided adjacent to the main receiving coil, and is configured to reduce noise amplitude and noise phase. First
A first solenoidal noise receiving coil that generates an induced noise signal of the following, having a central axis in a direction orthogonal to the central axis of the main receiving coil and the central axis of the first solenoidal noise receiving coil; A second solenoidal noise receiving coil provided adjacent to the main receiving coil for generating a second induced noise signal having a noise amplitude and a noise phase; the main receiving coil; the first solenoidal noise receiving coil; , Second and third amplifying the signals output from the noise receiving coil of FIG. 1 and the second solenoidal noise receiving coil, respectively.
, A first and second squaring circuit for squaring the outputs of the second and third amplifying circuits, respectively, and an adding circuit for receiving the outputs of the first and second squaring circuits and adding them And a square root circuit that receives the output of the addition circuit, squares the addition signal to obtain a scalar of synthesized noise, and the second and third circuits.
And a quadrant discriminator that outputs +1 for the first or fourth quadrant and -1 for the second or third quadrant by receiving the output of the amplifier circuit of A multiplying circuit for multiplying the output of the quadrant discriminating circuit with the output of the square root circuit to obtain a synthesized noise signal waveform output, and receiving the output of the multiplying circuit to minimize a noise signal component appearing at the output of the differential circuit. And a demodulation circuit that extracts a difference signal between a signal obtained from the main receiving coil and amplified by the first amplifier circuit and an output signal of the amplitude and phase adjustment circuit. And a differential circuit for outputting as a device input signal.