JPH0136155Y2 - - Google Patents

Description

[Detailed explanation of the idea]

``Technical field of invention'' This invention is an underground system that transmits radio waves underground and receives the reflected waves to detect the existence and direction of underground pipes such as gas pipes, water pipes, and sewer pipes. The present invention relates to a pipe exploration device, and particularly aims to provide an underground pipe exploration device configured to display exploration results in an easy-to-understand manner. "Prior art" As disclosed in Japanese Patent Application Laid-Open No. 158576/1983, radio waves are emitted underground, the reflected waves are received and waveform processed, and the results of the waveform processing are used to detect underground pipes. A method is being considered to detect the presence or absence of buried pipes and the direction in which they are buried. ``Purpose of the invention'' This invention constructs an exploration device using the previously proposed exploration method for underground pipes, and allows for direct visualization of the presence or absence of underground pipes, depth of burial, direction of burial, etc. The object of the present invention is to provide a buried pipe exploration device that allows anyone to easily understand the presence or absence of a buried pipe, its buried depth, and the buried direction from the display. ``Example of the invention'' Figure 1 shows an example of this invention. A portion 1 surrounded by a chain line in the figure corresponds to a portion of the device disclosed in the previously proposed underground pipe exploration method. Part 1 includes a high-frequency oscillator 2, a gate circuit that extracts, for example, one cycle of the high-frequency signal output from the high-frequency oscillator 2, and transmits the high-frequency signal output from the gate circuit 3 into the ground as a radio wave. An antenna 4 that receives reflected waves, a receiver 5 that amplifies the received signal received by the antenna 4 to a predetermined level and extracts it, and a rotation drive device 6 that rotates the plane of polarization of the radio waves emitted from the antenna 4.
and an azimuth determination circuit 7 that detects the rotation angle at which the received signal is obtained and outputs a positive phase detection signal Pa and a negative phase detection signal Pb according to the difference between the positive phase and negative phase of the received signal, which will be described later. Ru. The antenna 4 is composed of at least two sets of dipole antennas arranged orthogonally to each other, and one of the mutually orthogonal dipole antennas is used as a transmitting antenna, and the other is used as a receiving antenna. The transmitting antenna and receiving antenna are rotated while maintaining an orthogonal relationship, thereby rotating the plane of polarization of the transmitted radio waves. At the same time, the reflected wave is received by a receiving antenna arranged orthogonally to the transmitting antenna. Methods for rotating the plane of polarization include mechanically rotating the antenna and rotating the plane of polarization by electronically switching a plurality of antenna elements. In this example, a case will be explained in which the polarization plane of the transmitted radio wave is rotated by electronically switching the antenna element.
In other words, a case will be described in which a switching device 8 is provided and a switching timing signal AN is applied to the switching device 8 from the rotary drive device 6 to switch the antenna elements. As an example of switching, for example, as shown in FIG. 2, eight antenna elements 4A, 4B, 4C, 4D, 4
E, 4F, 4G, and 4H are arranged radially at 45° intervals, and by sequentially switching these eight antenna elements, it is possible to rotate the plane of polarization of the transmitted radio waves by 45°. In Figure 2, the antenna elements are 4A, 4E, 4C, 4G, and 4B, respectively.
, 4F, 4D and 4H each constitute one dipole antenna. A switch 8 selects a relationship in which these four sets of dipole antennas intersect each other by 90 degrees, and connects the transmitting terminals T ₁ and T ₂ and the receiving terminals R ₁ and R ₂ to perform transmission and reception. A concrete example of the switching device 8 is shown in FIG. The high frequency signal for one cycle taken out from the gate circuit 3 is converted into a balanced signal by the unbalanced-balanced converter 11 and sent to the transmission terminals T ₁ and T ₂ . Further, the signals received at the receiving terminals R ₁ and R ₂ are converted into unbalanced signals by the balanced-unbalanced converter 12 and supplied to the receiving means 5 . Transmitting terminals T ₁ , T ₂ , receiving terminals R ₁ , R ₂ and each antenna element 4A, 4B, 4C, 4D, 4E, 4F.4
48 relay contacts S ₁₁ to S ₄₈ are connected between each of _G and 4H, and _the antenna When elements 4A and 4E operate as transmitting antennas, antenna elements 4C and 4G operate as receiving antennas. When antenna elements 4B and 4F operate as transmitting antennas, antenna elements 4D and 4H operate as receiving antennas. When antenna elements 4C and 4G operate as transmitting antennas, antenna elements 4A and 4E operate as receiving antennas. When antenna elements 4D and 4H operate as transmitting antennas, antenna elements 4B and 4F operate as receiving antennas. When antenna elements 4A and 4E operate as transmitting antennas (from which the excitation polarity of the antenna elements is reversed), antenna elements 4C and 4G operate as receiving antennas. When antenna elements 4F and 4B operate as transmitting antennas, antenna elements 4A and 4D operate as receiving antennas. When antenna elements 4G and 4C operate as transmitting antennas, antenna elements 4E and 4A operate as receiving antennas. When antenna elements 4H and 4D operate as transmitting antennas, antenna elements 4F and 4B operate as receiving antennas. Each of these timings is expressed as ~. It is assumed that each of these timings is switched and scanned at intervals of, for example, 40 milliseconds. In addition, when exploring a buried pipe, antenna element 4A is set to the north, antenna element 4E is set to the south,
It is assumed that 4C is set to match the east direction and 4G is set to match the west direction. Here, the relationship between the buried direction of the buried pipe and the received signal will be explained. When the buried pipe 13 is buried in the east-west direction as shown in FIGS. 5A to 5E, for example, FIGS. 5A, B,
Received signals 15a, 15b, 15c, 15d are obtained only when the transmitting and receiving antennas intersect the buried pipe 13 at an angle of 45 degrees, as shown in FIGS.
This phenomenon occurs only when radio waves are emitted from a dipole antenna toward a long and narrow object such as a tube, and the reflected waves are received by a receiving antenna placed perpendicular to the transmitting antenna. This phenomenon does not occur if the buried object has a large area. This point is published in Japanese Patent Publication No. 58-158576.
As disclosed in the publication No. In FIG. 5, signal waveform 14 represents a transmitted signal. At the timing shown in Figure 5A, the receiving terminal
A positive-phase received signal 15a that is in phase with the transmitted signal 14 is obtained at R ₁ and R ₂ . Further, at the timing shown in B, an anti-phase reception signal 15b having an anti-phase relationship with the transmission signal 14 is obtained at the reception terminals R ₁ and R ₂ . At the timing shown in C in the figure, a normal phase received signal 15c is obtained at the receiving terminals R ₁ and R ₂ . At the timing shown in D in the figure, an opposite phase received signal 15d is obtained at the receiving terminals R ₁ and R ₂ . timing,,
, no received signal can be obtained as shown in FIG. Furthermore, if the buried pipe body 13 is buried in the north-south direction as shown in FIG. 6A to D, the reverse phase reception signal 16a is received between the reception terminals _R1 and _R2 at the timing shown in FIG. Ru. Further, at the timing shown in FIG. 2B, a normal phase received signal 16b is obtained between the receiving terminals _R1 and _R2 . At the timing shown in C in the same figure, an anti-phase received signal 16c is obtained. Figure D
At the timing shown in , the positive phase received signal 16d
is obtained. The following three rules can be derived from these results. (a) When a positive-phase received signal is obtained, the buried pipe 13 exists in the direction of +45° (clockwise rotation is +) from the position of the antenna element to which the transmitting terminal _T1 is connected. (b) When a reverse phase received signal is obtained, the buried pipe 13 is located at a -45° direction from the position of the antenna element to which the transmitting terminal _T1 is connected. (c) The direction of the buried pipe defined in (a) and (b) is the direction of the two sides sandwiching the antenna element connected to the transmitting terminal T ₁ with the intersection point of the antenna as the origin. Based on this rule, the direction from the origin of the buried pipe (with the intersection point of the antenna as the origin) can be determined as shown in the table below by checking whether the phase of the received signal is in phase or in reverse at each timing. I can do it.

[Table] The direction determination circuit 7 determines the polarity of the rising edge of the received signal output from the receiving device 5, and outputs a positive phase detection signal Pa when the rising edge is positive polarity, and outputs a negative phase detection signal Pa when the rising edge is negative polarity. Pb, and gives the positive phase detection signal Pa, negative phase detection signal Pb, and switching timing signal AN to the azimuth address generator 17,
Direction address signal from direction address generator 17
Output A ₁ to A ₈ . The orientation address generator 17 can be configured as shown in FIG. 7, for example. 17A and 17B indicate octal counters. These two octal counters 1
A switching timing signal AN for switching the antenna 4 is given to 7A and 17B, and the switching timing signal
Count AN and detect timing ~ condition. The counter 17A operates as a means for generating an azimuth address signal when it detects a positive phase reception signal, and the counter 17B generates an azimuth address signal when it detects a negative phase reception signal. counter 17A
and 17B have three output terminals A, B, and C, and these three output terminals A, B, and C are connected to the latch circuit 17.
Connect to C, 17D. The latch circuit 17C is supplied with the positive phase detection signal Pa output from the azimuth determination circuit 7 when a positive phase reception signal is detected, and latches the count value of the counter 17A at that time. Further, the latch circuit 17D is supplied with a negative phase detection signal Pb outputted from the direction determination circuit 7 when a negative phase reception signal is detected.
The count value of B is latched in the latch circuit 17D. The relationship between the count values of the counters 17A and 17B and the azimuth address signals A ₁ to An can be defined as shown in FIG. 8, for example. Taking the positive phase received signal side as a reference, the count value of the counter 17A changes to all zeros at the timing as shown in Figure 8A.
0,0'', and this address signal of ``0,0,0'' is defined as address signal <sub>A1</sub> representing northeast.
At the timing, the count value of counter 17A becomes “0,
0,1”. This address signal of "0, 0, 1" is defined as address signal <sub>A2</sub> representing east. At this timing, the count value of the counter 17A becomes "0, 1, 0". This address signal of "0, 1, 0" is defined as address signal <sub>A3</sub> representing southeast. In this way, the count value of the counter 17A is a switching timing signal representing the rotation angle of the antenna 4.
The count value is incremented one by one by AN, goes around from the address "0, 0, 0" representing the northeast to the address "1, 1, 1" representing the north, and then the count value is determined by the next switching timing signal AN. Return to "0,0,0" and return to the northeast address. Therefore, each timing~
Address signals A <sub>1</sub> to <sub>A 8</sub> ranging from "0, 0, 0" to "1, 1, 1" are output from the counter 17A, and when a positive phase reception signal is detected between these timings, the counter is activated at that timing. 17A
The latch circuit 17C latches the count value and outputs the address signal to the address selector 23. On the other hand, the counter 17B is a counter that generates an azimuth address signal when an opposite phase received signal is detected. As is clear from the table shown above, the azimuth address signal generated from this counter 17B is delayed by 3 timings, or 90 degrees, with respect to the azimuth specified by the positive phase received signal (clockwise direction is assumed to be leading).
ing. For this reason, the counter 17B uses a presettable counter, and the counter 17A is set to "0,"
The setting device 17E is configured to preset "1, 1, 0" each time the state becomes "0, 0" and start counting with "1, 1, 0" as the initial value. With this configuration, the counter 17A
The relationship between the address signal output from the counter 17B and the azimuth and the relationship between the address signal output from the counter 17B and the azimuth can be matched. Therefore, the azimuth address output from these two latch circuits 17C and 17D is shared and the address selector 23
give to In this example, the latch circuits 17C and 17D have 5
Advance counters 17F and 17G are attached, and the latch circuits 17C and 17D are activated after five timings have elapsed from the timing when the count value of the counter 17A or 17B is latched by the positive phase detection signal Pa and the negative phase detection signal Pb themselves. Advance counter 17F and 1
A case is shown in which the latch is relatched by a carry output of 7G, and two azimuth address signals are generated from the latch circuit 17C or 17D, respectively. In other words, these two azimuth address signals are mutually
Address signals corresponding to azimuths different by 180° and opposite to each other are applied to the address selector 23. On the other hand, the received signal output from the receiver 5 is AD
The amplitude value is given to the converter 18, the amplitude value is AD converted, and the AD conversion output is sent to the converter 18 through the buffer 19, for example.
It is given as amplitude data M to a memory 21 such as a RAM. This amplitude data M represents the thickness of the buried pipe, and it can be seen that the larger the amplitude is, the thicker the buried pipe is. The AD converter 18 adjusts the amplitude of the received signal by ±1, for example.
~2V, ±2~3V, ±4~5V, ±6~7V, ±7~
It is assumed that the voltage is quantized into six levels of 8V, ±9 to 10V, and each quantization level is converted into, for example, a 4-bit digital code. This 4-bit digital code is applied to the storage means 21 as amplitude data M via the buffer 19. The depth of the buried pipe can be determined by determining the time difference between the transmitted signal and the received signal. For this purpose, the transmission signal output from the gate circuit 3 and the reception signal obtained from the reception device 5 are applied to a depth address generator 22 having a time difference measurement function, and the depth address generator 22 calculates the time difference between the transmission signal and the reception signal. The time difference is digitally encoded and output, and this digital code is applied to the address selector 23 as a depth address signal. In other words, the depth address is associated with the depth from the ground surface. For example, the area from 0 to 10 cm is D <sub>1</sub> and 10 to 20
The area of cm is D <sub>2</sub> , the area of 20 to 30 cm is D <sub>3</sub> , etc., with a resolution of 10 cm, and it is determined which area D <sub>1</sub> to <sub>Do</sub> corresponds from the time difference between the transmitted signal and the received signal, The digital codes assigned to the corresponding areas D <sub>1</sub> to D <sub>o</sub> are output as depth addresses AD <sub>1</sub> to <sub>AD o</sub> . As shown in FIG. 9, the memory device 21 is oriented northeast
It has eight storage areas corresponding to east, southeast, south, southwest, west, and northwest, and these eight storage areas are accessed and selected by azimuth address signals <sub>A1</sub> to <sub>A8</sub> .
Inside these eight storage areas are further memory blocks.
The memory block is subdivided into memory blocks <sub>B1</sub> to <sub>B0</sub> , and the subdivided memory blocks <sub>B1</sub> to <sub>B0</sub> are accessed by depth addresses <sub>AD1</sub> to <sub>AD0</sub> . Therefore, the azimuth address A <sub>1</sub> to A <sub>8</sub> and the depth address
AD <sub>1</sub> ~ Memory block determined by AD <sub>o</sub> B <sub>1</sub> ~
Store amplitude data M in B <sub>o</sub> . Here, since the azimuth address generator 17 outputs two address signals indicating mutually opposite directions, the storage device 21
means that two memory blocks are accessed at once,
Amplitude data M is stored in two memory blocks. To illustrate this storage example, if a pipe is buried at a position corresponding to depth area D <sub>2</sub> in the east-west direction, azimuth addresses A <sub>7</sub> and A <sub>6</sub> and depth address AD are stored as shown by hatching in FIG. Amplitude data M is stored in two memory blocks <sub>B2</sub> accessed by <sub>B2</sub> . The address selector 23 controls the memory 2 by the write/read command signal WR output from the controller 24.
Switch the address signal given to 1. In other words, during writing, the azimuth address signals A <sub>1</sub> to A <sub>8</sub> output from the azimuth address generator 17 and the depth address generator 22
and depth address signals AD <sub>1</sub> to AD <sub>o</sub> are applied to the memory 21, and at the time of reading, a read address signal outputted from the read address generator 25 is applied to the memory 21. The read address generator 25 first outputs the depth address <sub>AD1</sub> for reading the memory block <sub>B1</sub> , and in this state advances the first address signal corresponding to the azimuth address to read the memory block <sub>B1</sub> of each storage area.
Read about. Then depth address AD <sub>2</sub>
A second address signal corresponding to the memory block <sub>B2</sub> of each storage area is read out.
Furthermore, reading is performed for memory block <sub>B3</sub> of each storage area. In this way, memory blocks at the same depth in each storage area are read. The data read from the storage means 21 is temporarily stored in the data transfer means 26 and given to the DA converter 27. The DA converter 27 converts the amplitude data M read from the storage means 21 into an analog signal and supplies it to the video signal generator 28. Video signal generator 28
converts the amplitude value into a color signal. That is ±1~2V
For example, the area is light blue, the area of ±2 to 3V is cyan,
±4~5V area is green, ±6~7V area is yellow, ±7
A video signal having color information is generated so that the range of ~8V is orange and the range of ±8 to 10V is red, and this video signal is applied to the color cathode ray tube 29. On the other hand, a read address signal is taken out from the address selector 23, and this read address signal is applied to a synchronization signal generator 31 to generate a synchronization signal. A synchronizing signal is given to the deflection circuit 32, and the color cathode ray tube 29
gives a deflection signal to the As shown in FIG. 10, the color cathode ray tube 29 scans with the center of the display screen as the origin P, and scans in a circular pattern around the origin P. This scanning method is called a helical scan and is used in radars and the like. When scanning one circle, the memory 21 sequentially reads memory blocks corresponding to the same depth in each memory area. Each storage area is associated with a direction as described above. Therefore, by projecting the amplitude data read from the storage means 21 onto the positions on the cathode ray tube corresponding to the azimuth addresses <sub>A1</sub> to <sub>A8</sub> , the color cathode ray tube 29 displays X,
The Y-axis, XY-axis, and axes are virtual. Therefore, for example, when a buried pipe is buried in the east-west direction as shown in FIG. 5, spots Q <sub>1</sub> and Q <sub>2</sub> are projected on the horizontal axis X as shown in FIG. The distance from the origin P to the spots Q <sub>1</sub> and Q <sub>2</sub> represents the depth, and the color of the spots Q <sub>1</sub> and Q <sub>2</sub> indicates the thickness of the buried pipe. The buried pipes are antenna elements 4C and 4D, for example.
If it is located in the middle of , thin spots will be displayed on both the X axis and
It is displayed that there is a buried pipe between the X axis and the axis. ``Effect of the invention'' As explained above, according to this invention, the direction of burial, the depth and thickness of the buried pipe, etc. can be determined from the positions of the spots Q ₁ and Q ₂ projected on the color cathode ray tube 29. . Furthermore, since the display is easy to see, anyone can distinguish the direction, depth, and thickness of the buried pipe, and it is possible to provide a buried pipe exploration device that is easy to handle. "Modification of the invention" In the above, a structure was described in which the eight antenna elements 4A to 4H are switched to distinguish and display the four directions of the buried pipe without moving the position of the antenna 4. The number of elements is not limited to 8, but may be at least 4 or more.
A storage area may be prepared in the storage device 21 corresponding to the number of each antenna element. In addition, in the above description, for convenience of explanation, the antenna element 4 is
It has been explained that A is aligned with the north direction, 4E with the south direction, 4C with the east direction, and _4G with the west direction, respectively _. Install the antenna so that it is located on the line, and the antenna element 4 at that time
It is also possible to know the direction of the buried pipe from the directions A to 4H.

[Brief explanation of the drawing]

Figure 1 is a system diagram for explaining an embodiment of this invention, Figure 2 is a plan view for explaining an example of an antenna used in this invention, and Figure 3 is an example of an antenna switching device used in this invention. Figure 4 is a diagram to explain the operation of the antenna switching device, Figures 5 and 6 are diagrams to explain the method of exploring the buried direction of the buried pipe used in this invention. Figure 7 is a system diagram to explain the structure of the main part of this invention, Figure 8 is a waveform diagram to explain the operation of Figure 7, and Figure 9 is the inside of the memory device used in this invention. FIG. 10, which is a diagram for explaining the structure, is a front view showing an example of the display of the device according to this invention. 2: High frequency oscillator, 3: Gate circuit, 4: Antenna, 5: Receiving device, 6: Rotation drive device, 7: Direction determination circuit, 8: Antenna switching device, 13: Buried pipe, 14: Transmission signal, 15a to 15d , 16a~
16d: Received signal, 17: Direction address generator,
18: AD converter, 19: buffer, 21: memory, 22: depth address generator, 23: address selector, 24: controller, 25: read address generator, 26: transfer means, 27: DA converter, 2
8: Video signal generator, 29: Color cathode ray tube, 3
1: Synchronization signal generator.

Claims (1)

[Claims for Utility Model Registration] A. Rotating the plane of polarization of transmitted radio waves and transmitting pulsed radio waves as transmission signals at each predetermined angle of rotation,
In a device that receives the reflected wave as a received signal and detects an underground pipe and its direction based on the polarity of the received signal and a timing signal representing the rotation angle of the plane of polarization, B converts the amplitude value of the received signal into an AD converter. an AD converter that obtains amplitude data; C; an azimuth address signal that indicates the direction of the underground pipe based on the positive phase and negative phase detection signals that indicate the polarity of the rising edge of the received signal; and a timing signal that indicates the angular position of the polarization plane; D. a depth address generator that generates a depth address representing the depth of the underground pipe from the time difference between the transmission time of the transmission signal and the reception time of the reception signal; E. the orientation address. a memory device that stores the amplitude data in a memory block determined by the azimuth address signal output from the generator and the depth address output from the depth address generator; a readout address generator for reading out the emitted radio waves; Scanning is performed in a concentric circle with a point corresponding to the rotation axis as the origin, the radiation direction of the display point is defined by the first address from which the amplitude data is read out, and the second address is scanned so that the amplitude data is read out. an indicator that specifies the distance between the display points and displays the direction and depth of the underground pipe from the radial direction of the display points and the distance between the display points; Pipe exploration device.