JPS59231466A - Positional detection of underground article - Google Patents

Abstract

PURPOSE:To perform positional detection with high accuracy, by an inexpensive apparatus having such simple constitution that radio waves are transmitted from a plurality of transmission antennas and the phases of these radio waves are brought to the same phase to each other in a detecting region. CONSTITUTION:The trigger signal from a trigger circuit 13 is supplied to transmission circuit 16, 17 to respectively form transmission signals and detecting radio waves 18, 19 are sent into a ground from transmission antennas 10, 11. The radio waves 18, 19 sent out at this time are mutually coincided in the phases thereof in an underground detecting region by the delay manipulation of a delay circuit 15. Therefore, the amplitude of the synthesized wave of the radio waves 18, 19 comes to the sum of the amplitudes thereof and the intensity thereof becomes large. On the other hand, the reflected wave 20 from an underground article of the synthesized wave is propagated through the ground and received by a receiving antenna 12 to be converted to a receiving signal which is, in turn, introduced into a control circuit 22 through a receiving circuit 21 and, after predetermined signal processing is applied herein, the processed signal is displayed by a monitor TV23 or recorded in a recording apparatus 24.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the position of an underground object, such as a nof brine, for detecting the position of the object buried underground from the ground.

Conventionally, as this type of underground object position detection method, the first
As shown in the figure, a transmitting antenna 2 is provided facing the ground surface 1, and a receiving antenna 3 is provided at a distance from the transmitting antenna 2. A method is known in which a pulse signal of several nanoseconds is emitted at a repeating frequency of several tens of kilohertz, and the reflected wave from the underground object 4 is received by the receiving antenna 3. FIG. 2 is a diagram showing the state of reflected waves from the underground object 4. As shown in FIG. In this case, for example, as shown in FIG.
When moving from point 1 to point 22, at point 21, PI at depth
The distance at the 22 points is P2X, and the receiving antenna 3 apparently detects that there is an underground object 4 in the confectionery, so the depth at the 22 points is Y. In other words, due to the movement of the receiving antenna 3, the locus of the detection depth of the underground object 4 draws a dotted line curve (■) passing through the X and Y points.

Therefore, by moving the receiving antenna 3 using this method and displaying the A scope in shading according to the ear width, the reflected image shown in FIG. 4 can be obtained, and the position directly above the underground object 4 can be obtained. The buried position of the underground object 4 can be detected.

By the way, in this type of detection method, radio waves radiated underground are attenuated when propagating underground because the earth is conductive. The appearance of this attenuation is as follows. That is, when the electrical constants of the earth are ε and μ, and the angular frequency of the radio wave is ω, the radio wave intensity Ex is expressed as Ex ``” E6 e−fx. However, E. is the intensity at distance O, which is still 1 -α+jβ. The electrical constants ε and μ of the earth vary with the angular frequency ω, and the higher the frequency, the greater the attenuation. FIG. 5 shows an example of its characteristics.

Therefore, in general, a relatively low frequency of about 100 M) (z) is selected, and this is used to detect the position of underground objects.According to this detection, Detection can be performed.

However, when such a low frequency is used, highly accurate detection cannot be performed because the horizontal and vertical resolution and parallel tube separation ability are low. For this reason, in the past, for example, the frequency was
-00 MHz is set to a high frequency, and the reduction in detectable depth due to the use of this high frequency is compensated for by increasing the output voltage of the transmitted radio wave.This makes it possible to detect buried objects in deep areas. It is possible. However, such a method requires a high-frequency, high-power switching element, but such a switching element does not currently exist, and even if it did exist, it would be extremely large and expensive, and the transmitter circuit system would be required. Coupled with the need for a high-voltage structure, this leads to larger and more expensive equipment.
Not suitable for practical use.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to sufficiently detect the position of V-structures even in deep areas without increasing the transmission power even when using high-frequency transmission radio waves. It is an object of the present invention to provide a method for detecting the position of underground objects, which can detect the position of objects buried underground by using a simple and inexpensive device.

In order to achieve the above-mentioned goal, the present invention arranges a transmitting antenna and one receiving antenna facing the ground surface, and aligns the phases of each of the transmitting antennas 14 times. By transmitting each radio wave and combining them M): By receiving the reflected waves from underground objects with a receiving antenna,
It is designed to detect the position of buried objects.

An embodiment of the present invention will be described below with reference to FIGS. 6 and 7. FIG. 6 is a schematic diagram of a position detecting device for carrying out the IF1' detection method of this embodiment. In the figure, 1 indicates the ground surface and 4 indicates an underground object.

The detection device has two transmitting antennas 1θ, 1 and one receiving antenna 12 arranged opposite to the ground surface l. The trigger signal generated in the circuit 13 is then guided through the signal cable 14 to the transmission circuit 16, 17 through the signal cable 21 on one side and the delay circuit 15 on the other side. Here, the delay circuit 15 is
This is to delay the trigger signal supplied to the transmitting circuit 17 by a predetermined amount so that the phases of the radio waves transmitted from each transmitting antenna 10.11 match.

Then, the position detection device generates a monocycle wave or a pulse wave having a pulse width of several nanoseconds as shown in FIG. Detection radio waves 18 and 19 are applied to the antennas 1θ and 11, respectively, and sent underground.

On the other hand, the position detecting device receives a reflected wave 20 from the underground object 4 of the composite wave of the above-mentioned respective transmitted radio waves 18 and 19 through the receiving antenna 1.
2, and the received signal is received by the receiving circuit 21 and then introduced into the control circuit 22. This control circuit 22 performs signal processing such as waveform shaping on the received signal to create a received image signal, which is guided to a monitor television 23 for display, and is also recorded in a recording device 24 such as a Teso recorder. I try to do that.

Now, in order to detect the position of the buried object 4 using such a device, first, the transmitting antenna 10° 11 and the receiving antenna 12 are set to face the ground surface 1, and in this state, the trigger circuit 13 is driven. . Then, trigger circuit 1
3 outputs a trigger signal and supplies it to the transmitting circuits 16 and 17, and as a result, each of the transmitting circuits 16 and 17 generates a transmission signal, and a detection radio wave 18 and 19 is sent underground from the transmitting antenna 10 and 11. Sent out.

By the way, due to the delay operation of the delay circuit 15, the radio waves 18 and 19 sent out at this time have the same phase in the underground detection area. Therefore, the amplitude of the composite wave of 1 wave 18.19 for each city is the sum of the amplitudes of each radio wave, and the intensity is large.

On the other hand, the reflected wave 20 of the synthetic wave by the underground striking object 4 is as follows:
After propagating underground, the signal is received by the receiving antenna 12, where it is converted into a received signal, and then introduced into the control circuit 22 via the receiving circuit 21. Then, after predetermined signal processing is performed in the control circuit 22, the monitor television 23
and recorded on the recording device 24.

In this embodiment, two transmitting antennas 10
．． 11 were prepared, and radio waves 18 and 19 were transmitted from these antennas 10 and 11, respectively, and the phases of the respective transmitted radio waves were made to be in phase with each other in the underground detection area by delay operation of the delay circuit 15. Therefore, the amplitude of the composite wave of the respective transmitted radio waves 18.19 in this detection area corresponds to the sum of the amplitudes of the respective radio waves 18.19, and as a result, even if the attenuation of each transmitted radio wave 18.19 is large, each of the transmitted radio waves 18.19 Even if the amplitude becomes small, radio waves with sufficiently large amplitude can be obtained. Therefore, high-resolution detection can be performed deep into the body without increasing the output of the transmitting circuit.

Note that the present invention is not limited to the above embodiments,
For example, the number of transmitting antennas is not limited to two, but three or more may be provided. In addition, +14 formation of position detection device and l'+43
``6' type 74H etc. also deviate from the gist of the present invention1.
It can be implemented with some modification within a range of 7.

As described in detail below, according to the present invention, radio waves are transmitted from a plurality of transmitting antennas so that the orders 11 of these radio waves are mutually in phase in the detection area.
Even when transmitting radio waves with a frequency of A method for detecting the location of underground objects that can be detected can be provided.

[Brief explanation of the drawing]

Figures 1 to 5 are for explaining the conventional method; Figure 1 is a schematic diagram of a device to which the method is applied; Figure 2 is a diagram showing reflected waves from underground objects; Figure 3 is a diagram to explain the distance to underground objects when the receiving antenna is moved, Figure 4 is a diagram showing the reflected image when the receiving antenna is moved, and Figure 5 is a diagram showing the transmission radio frequency and Characteristic diagrams 6 and 7 showing the relationship with the propagation attenuation positioning needle are used to explain the buried position detection method in one embodiment of the present invention, and FIG. 6 shows the method for implementing the method. FIG. 7 is a schematic configuration diagram of the useless position detection device, and is a waveform diagram showing the transmitted wave signals. 1... Ground surface, 4... Underground object, 10.11... Transmitting antenna, 12... Receiving antenna, 13... Tori circuit, 14... Transmitting cable, 15... Delay circuit, 1
6.17... Transmission circuit, 18.19... Transmission radio wave,
20... Reflected wave, 21... Receiving circuit, 22... Control circuit, 23... Monitor television, 24... Recording device. Applicant's representative Patent attorney Takehiko Suzue Procedural amendment 6ゎ罎8. ';(,29B Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Request for indication of the case No. 106180/1983, Relationship with the person making the amendment '4-1 Applicant (412) Nippon Steel Co., Ltd. 4. Agent 6, Statement of the subject matter of the amendment 7. Statement of contents of the amendment, page 3, line 10, amend the statement as follows.

Claims (1)

[Claims] A plurality of transmitting antennas and one receiving antenna are placed facing the ground surface and spaced apart from each other, and each of the transmitting antennas emits radio waves whose phases are controlled so that they are in phase with each other in a detection area underground. A method for detecting the position of an underground object, characterized in that the reflected wave of the synthesized radio wave by the underground object is received by the receiving antenna, and the position of the underground object is detected from the received information.