JP2003156571A - Buried object searching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a buried object searching device, capable of easily measuring a buried object and capable of appropriately searching a buried tube with no experience required for judging the buried tube. SOLUTION: A transmission antenna 2 and reception antennas 4 and 5 whose polarization directions crossing each other are provided on a vehicle 7. The electromagnetic wave is transmitted toward a ground surface from the transmission antenna 2 while moving. The electromagnetic wave reflected on a buried tube 15 existing underground is received with reception antennas 4 and 5. A calculation part 13 calculates an azimuth intensity pattern of the reflection wave based on the reception signal of the reception antennas 4 and 5 and the mutual positional information of the transmission and reception antennas. The position and direction of the buried tube 15 are estimated from the azimuth intensity pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a buried object exploration apparatus for exploring buried objects existing in the ground while moving, and more particularly, to a electromagnetic wave while moving a transmitting antenna installed toward the ground surface. The present invention relates to an embedded object exploration device for exploring an embedded object existing in the ground by transmitting an electromagnetic wave reflected from the embedded object existing in the ground by a receiving antenna.

[0002]

2. Description of the Related Art In a conventional buried object exploration apparatus of this type, as shown in FIG. 6, for example, an antenna section 6 including a transmitting antenna 2 and a receiving antenna 3 is mounted on a vehicle 7 for scanning movement, and is indicated by an arrow 14. While moving the vehicle 7 in the moving direction, a pulse having a time width of several nanoseconds supplied from the transmitting device 1 to the transmitting antenna 2 is emitted from the transmitting antenna 2 to the ground as an electromagnetic wave. The radiated electromagnetic wave propagates in the ground and is reflected by the buried pipe 15 having a different electrical property from the surrounding medium.

This reflected electromagnetic wave is detected by the receiving antenna 3 and supplied from the receiving antenna 3 to the receiving device 8. The receiving device 8 receives the electromagnetic wave and the transmitting antenna 2
The distance to the buried pipe 15 is calculated on the basis of the time relationship with the radiation from, the calculated distance is stored in the memory 11, and the stored data is displayed on the display unit 12.

The above processing is carried out every time the transmitting antenna 2 and the receiving antenna 3 are mounted and the antenna section 6 attached to the vehicle 7 moves a prescribed distance, whereby a plurality of observation signals are collected. ing. Then, the plurality of observation signals are color-converted for each magnitude of the amplitude value and then arranged two-dimensionally to form an observation pattern of the underground section, and the buried pipe 15 is embedded from the observation pattern of the underground section. Judge the position.

Here, as an example, referring to a plan view of a road surface as shown in FIG. 7, a case where the continuous horizontal position of the buried pipe 15 is detected by the conventional buried object searching apparatus shown in FIG. explain.

In this case, the antenna section 6 is normally run in a direction traversing the road for scanning. In this scanning, the measurement range is divided into a plurality of sections at intervals of several meters, and a plurality of antenna scanning lines A, B, and C are set as shown in FIG. 7, and the buried pipe is determined from the underground cross-section observation pattern obtained as a result. The operator determines the position of 15.

For example, when the measurement is performed along the antenna scanning line A, the reflected signal becomes maximum at the position P _A just above the buried pipe 15. Also, when the measurement is performed along the antenna scanning lines B and C, the reflected signal becomes the maximum at the positions P _B and P _C just above the buried pipe 15. As a result, the positions P _A , P
_B, can be estimated that the buried pipe 15 is laid directly below the connecting's path P _C.

[0008]

In the conventional exploration method using the above-mentioned buried object exploration device, it is necessary to perform a number of transverse explorations in order to measure the continuous horizontal position of the buried pipe between two manholes. However, there is a problem that it takes a lot of time for measurement, and since the buried position is determined by using multiple underground cross-section observation patterns obtained as a result of cross-sectional exploration, skill is required for this determination. There is a problem.

Further, depending on the scanning direction, the polarization direction of the antenna and the laying direction of the buried pipe do not coincide with each other, so that the amplitude value of the reflected wave becomes small and the reflected image cannot be clearly observed, and the position of the buried pipe is There is a problem that it becomes difficult to judge.

Specifically, as shown in FIG. 8, the transmitting antenna 2 and the receiving antenna 3 have polarization directions, and when the polarization directions are parallel to the buried pipe 15, the reflected signal is maximum. However, when it is vertical, the reflected signal becomes the minimum, so that the reflected image cannot be clearly observed,
There is a problem that it is difficult to determine the position of the buried pipe.

Further, even if a point object such as a rock or a cavity exists below the scanning line, a reflection signal similar to that of the buried pipe can be obtained, so that when a large object such as the buried pipe is crossed. There is a problem that it is difficult to distinguish it from the reflection of.

The present invention has been made in view of the above,
It is an object of the present invention to provide a buried object exploration apparatus which can easily measure a buried object exploration, does not require skill to judge the buried pipe, and can accurately probe the buried pipe.

[0013]

In order to achieve the above object, the present invention according to claim 1 is a buried object exploration apparatus for exploring an buried object existing in the ground while moving it, which is directed toward the ground surface. A transmitting antenna installed so as to transmit the electromagnetic wave while moving, and a receiving antenna installed so as to receive a reflected wave from an embedded object existing in the ground of the electromagnetic wave transmitted from the transmitting antenna, And a calculation means for calculating the azimuth intensity pattern of the reflected wave based on the mutual arrangement information of the transmission antenna and the reception antenna and the reception signal from the reception antenna, and at least one of the transmission antenna and the reception antenna is plural. The gist is that the polarization directions of the transmitting and receiving antennas are arranged so as to intersect with each other.

According to the first aspect of the present invention, a plurality of sets of transmitting antennas and receiving antennas whose polarization directions cross each other are arranged, and the electromagnetic waves are transmitted from the transmitting antennas toward the ground surface while transmitting. In order to receive the reflected wave from the buried object existing in the ground of the electromagnetic wave with the receiving antenna and calculate the azimuth intensity pattern of the reflected wave based on the mutual arrangement information of the receiving signal of the receiving antenna and the transmitting / receiving antenna, The position and direction in which the buried pipe is laid can be accurately determined from the azimuth intensity pattern.

Further, the present invention according to claim 2 is based on claim 1.
In the invention described above, the calculating means transmits the number of the transmitting antennas and the number of the receiving antennas, respectively, n, m, the received signal by the combination of the i-th transmitting antenna and the j-th receiving antenna, S _ij (t), and When the polarization directions of the antenna and the receiving antenna are θ _i and ψ _j , respectively, and the coefficient representing the influence of the polarization of the transmitting antenna and the receiving antenna is f _ij , the azimuth intensity pattern is

[Equation 2] The gist is to have a means for calculating the azimuth intensity pattern defined by.

Further, the present invention according to claim 3 provides the invention according to claim 1.
In the invention described above, the gist is that the azimuth intensity pattern is represented by a pie chart in which a time axis is a radial direction and an angle axis is a circumferential direction.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an embedded object exploration apparatus according to an embodiment of the present invention. The buried object exploration apparatus shown in FIG. 1 has an antenna unit 6 which is mounted on a vehicle 7 for scanning movement and which includes one transmitting antenna 2 and two receiving antennas 4 and 5, and the transmitting antenna 2 is the transmitting apparatus 1. , And the two receiving antennas 4 and 5 are connected to two receiving devices 9 and 10, respectively.

The receiving antennas 4 and 5 radiate into the ground a pulse having a time width of, for example, several nanoseconds supplied from the transmitting device 1 by the transmitting antenna 2 as an electromagnetic wave, and the radiated electromagnetic wave propagates in the ground. , So as to receive the reflected wave of the electromagnetic wave from the buried pipe 15 having a different electrical property from the surrounding medium buried in the ground and supply the received voltage signals of the received reflected wave to the receiving devices 9 and 10, respectively. Has become.

The receiving devices 9 and 10 measure the time from the emission of electromagnetic waves from the transmitting antenna 2 to the reception of reflected waves at the receiving antennas 4 and 5, and calculate the distance to the buried pipe 15 based on this time. At the same time, the measured time and the received voltage signals from the receiving antennas 4 and 5 are stored in the memory 11.

Further, the calculating unit 13 will be described later based on the time until the reception of the reflected wave stored in the memory 11, each received voltage signal, and the mutual arrangement relationship between the transmitting antenna 2 and the receiving antennas 4 and 5. In addition, the azimuth intensity pattern of the reflected wave is calculated and displayed on a display means (not shown in FIG. 1).

The transmitting antenna 2 and the receiving antennas 4 and 5 are
As shown in the top view of FIG. 2, the polarization directions are arranged so as to intersect with each other. In the present embodiment, it is necessary that at least one of the transmitting antenna and the receiving antenna is provided in plural so that a plurality of sets of the transmitting antenna and the receiving antenna are configured. In the present embodiment shown in FIG. 1, two sets of a first transmitting / receiving antenna group consisting of a transmitting antenna 2 and a receiving antenna 4 and a second transmitting / receiving antenna group consisting of a transmitting antenna 2 and a receiving antenna 5 are provided. 2 cross each other as shown in FIG. As mentioned above,
It is only necessary to provide a plurality of sets of transmitting antennas and receiving antennas, and for that purpose, at least one of the transmitting antennas and the receiving antennas may be provided in a plurality. In this case, a plurality of sets are provided. It is only necessary that the polarization directions of the transmitting antenna and the receiving antenna cross each other.

Next, with reference to the plan view of the road surface shown in FIG. 3, the operation of the buried object exploration apparatus of the present embodiment configured as described above, particularly the processing for estimating the position and extension direction of the buried pipe will be described. explain.

As shown in FIG. 3, the buried object exploring apparatus of this embodiment is moved from the transmitting antenna 2 to the ground surface while moving the buried object exploring apparatus of the present embodiment along the illustrated antenna scanning line with respect to the buried pipe 15 buried in the ground. When an electromagnetic wave is radiated toward the electromagnetic wave, the reflected wave from the ground of the electromagnetic wave is received by the receiving antennas 4 and 5, and the received voltage is measured as the intensity of the reflected wave, the buried pipe 15 is located at a position P immediately below the maximum intensity. It can be presumed to exist.

However, there is a possibility that non-long-sized objects such as cavities and rocks may exist in the ground, and the strength of the reflected wave from such cavities and rocks may be wrong and the buried pipe 15
Since it may be measured as the intensity of the reflected wave from
In this embodiment, in order to eliminate such a mistake,
As described below, the azimuth intensity pattern of the reflected wave is calculated, and the position and extension direction of the buried pipe 15 are estimated from this azimuth intensity pattern.

That is, assuming that the signals of the reflected waves received by the receiving antennas 4 and 5 at the positions of maximum intensity measured as described above, that is, the received signals are S ₁₁ and S ₁₂ , respectively, the received signals S ₁₁ and S _{12 are obtained.} Is illustrated as the graph shown in the right part of FIG.

Specifically, FIG. 4 shows the actual measurement data. The left side of the figure shows the depth on the vertical axis, the scanning distance on the horizontal axis, and the circled position in the figure. A reflection image from the buried pipe 15 is displayed. The right part of FIG. 4 is a graph showing the reflection signal at a certain point of the buried pipe 15.
The vertical axis represents time, the horizontal axis represents the reception voltage of the reception antennas 4 and 5, the upper side represents the reception signal S ₁₁ from the reception antenna 4, and the lower side represents the reception signal S ₁₂ from the reception antenna 5. The time on the vertical axis is between the depth and the relationship of time = depth / radio wave propagation velocity, that is, depth = time × radio wave propagation velocity.

FIG. 5 is a circle graph showing the azimuth characteristics of the reflected signal using the graph of the reflected signal shown on the right side of FIG. 4, and the polarization direction of the receiving antenna 4 is used as a reference in the circumferential direction. And the azimuth angle φ, and the depth (dept
h) is shown.

Here, the transmitting antenna 2 and the receiving antenna
The polarization directions of 4 and 5 are θ₁ And ψ ₁ , Ψ₂ , Send
Coefficient representing the effect of polarization of antenna 2 and receiving antennas 4 and 5
F₁₁, F₁₂, Ie transmit antenna 2 and receive antenna
The coefficient representing the influence of the polarization of 4 is f ₁₁, Transmitting antenna 2 and receiving
The coefficient representing the influence of the polarized wave of the reception antenna 5 is f₁₂Then,
They are f₁₁(θ₁ , Ψ₁) = Cos φ f₁₂(θ₁ , Ψ₂) = Cos (φ−π / 2) , The combined signal strength for azimuth φ
The degree is calculated by the following formula.

S ₁₁ cosφ + S ₁₂ sinφ Therefore, the received signals S ₁₁ and S ₁₂ measured by the receivers 9 and 10 of the buried object exploration apparatus of FIG. 1 are calculated as shown in the right side of FIG. 4 with respect to this equation. When the azimuth intensity pattern is calculated by applying it in the unit 13, the azimuth intensity pattern as shown in FIG. 5 is obtained. In the example of the azimuth intensity pattern shown in FIG. 5,
A strong reflection image shown by white stripes appears in the direction centered at the angle of 55 °, and it can be estimated that the buried pipe 15 is buried in this direction.

The above-mentioned calculation formula is generalized and transmitted.
The number of antennas and the number of receiving antennas are
Combination of i-th transmitting antenna and j-th receiving antenna
Received signal by S_ij(t), transmitting antenna and receiving antenna
The polarization direction of the tenor is θ _i And θ_j , With transmit antenna
Coefficient f representing the influence of the polarization of the receiving antenna_ijThen, one
The position intensity pattern is

[Equation 3] Is defined by

Therefore, by applying the received signal measured by the buried object exploration apparatus of FIG. 1 to this equation in the arithmetic unit 13 to calculate the azimuth intensity pattern, the azimuth intensity pattern as shown in FIG. 5 is obtained. Therefore, by observing this azimuth intensity pattern and detecting a portion where a strong reflection image displayed as a white stripe appears, the buried direction of the buried pipe 15 can be easily and accurately estimated. You can

[0032]

As described above, according to the present invention,
A plurality of sets of transmitting antennas and receiving antennas that cross each other in the polarization direction are arranged, and the electromagnetic waves are transmitted from the transmitting antennas to the ground surface while transmitting, and the reflected waves from the buried object existing in the ground of the electromagnetic waves. Is received by the receiving antenna, and the azimuth intensity pattern of the reflected wave is calculated based on the mutual arrangement information of the reception signal of this receiving antenna and the transmitting / receiving antenna. It is possible to make a simple and appropriate determination without requiring skill as in the past.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embedded object exploration apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing an arrangement relationship between a transmitting antenna and a receiving antenna in the embodiment shown in FIG.

FIG. 3 is a plan view of a road surface in which a buried pipe used for explaining the operation of the buried object exploration apparatus of the embodiment shown in FIG. 1 is buried.

FIG. 4 is a diagram showing actual measurement data measured by the buried object exploration apparatus of the embodiment shown in FIG. 1.

5 is a diagram showing the reflection image for each angle in FIG. 4, specifically, FIG.
6 is a circle graph displaying the azimuth characteristics of the reflected signal using the graph of the reflected signal shown on the right side of FIG.

FIG. 6 is a diagram showing a configuration of a conventional buried object exploration apparatus.

FIG. 7 is an explanatory diagram showing an example of scanning in which the position of the buried pipe is searched by the conventional buried object research apparatus shown in FIG.

FIG. 8 is an explanatory diagram showing a relationship between a buried pipe and a transmitting / receiving antenna in polarization directions.

[Explanation of symbols]

1 transmitter 2 transmitting antenna 4,5 receiving antenna 6 Antenna section 7 Scanning vehicle 9,10 Receiver 11 memory 13 Operation part 15 buried pipe

Claims (3)

[Claims] 1. A buried object exploration device for exploring an embedded object existing in the ground while moving, the transmitting antenna being installed so as to transmit electromagnetic waves toward the ground surface, and the transmitting antenna. A receiving antenna installed so as to receive a reflected wave from an embedded object existing in the ground of the electromagnetic wave transmitted from, based on mutual arrangement information of the transmitting antenna and the receiving antenna and a received signal from the receiving antenna. A transmitting means and a receiving antenna, wherein at least one of the transmitting antenna and the receiving antenna is provided in plural, and the polarization directions of the transmitting and receiving antennas are arranged so as to intersect with each other. A buried object exploration device characterized by being present. 2. The calculating means transmits the number of the transmitting antennas and the number of the receiving antennas, respectively, n, m, the reception signal by the combination of the i-th transmitting antenna and the j-th receiving antenna, S _ij (t), and the transmission signal. The polarization directions of the antenna and the receiving antenna are θ _i and ψ _j , respectively, and the coefficient representing the influence of the polarization of the transmitting antenna and the receiving antenna is f _ij.
Then, as the azimuth intensity pattern, 2. The buried object exploration apparatus according to claim 1, further comprising means for calculating an azimuth intensity pattern defined by. 3. The buried object exploration device according to claim 1, wherein the azimuth intensity pattern is represented by a circle graph in which a time axis is a radial direction and an angle axis is a circumferential direction.