JPS63263485A - Investigating device for underground buried body - Google Patents

Abstract

PURPOSE:To eliminate an error in position detection due to an error in estimation and to perform high-accuracy position detection by providing a display means which displays an echo image of an underground buried body by using the depth direction of the underwater buried body and the moving direction of a moving carriage as parameters. CONSTITUTION:A pseudo echo image 5 of the underwater buried body is displayed on a display part 210 at an optional positions and its peak mark Q and expansion coefficient alpha are varied by pressing switch images of display parts 211 and 212 to put the echo image 4 of the buried body 3 within its interline area. In this case, two echo images 4 and 5 are overlapped with each other to find the coordinates of the peak position P of the echo image 4 of the buried body 3 as the coordinates (x0, t0) of the peak mark Q of the artificial echo image 5. Further, the expansion of the opening part of a hyperbola forming the echo image 5. Further, the expansion of the opening part of the hyperbola forming the echo image 4 is also found from the value alpha of the expansion of the pseudo echo image 5. Consequently, a radio wave propagation speed Vg is found from Vg=2alpha and the need for a measuring instrument which measures the specific dielectric constant of soil is eliminated.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is an underground fg! that detects the position of underground objects such as water pipes, gas pipes, and various cables. This is a deep object exploration device.

(Prior art) In the past, radio waves were emitted from a transmitter mounted on a moving trolley toward the ground, and underground i! 1! A radar-based underground object detection device is known that detects the position and depth of underground objects based on the propagation time of the reflected waves by receiving reflected waves from the objects using a receiver mounted on a moving trolley. It is being

This radar-based underground buried object exploration device calculates the radio wave propagation speed underground as vg1 round trip propagation time Δto, and the depth to the improvised object where the radio wave is reflected as 7. This detects the position of buried objects in the depth direction.

In this case, it is known that the radio wave propagation speed vg changes depending on the relative dielectric constant εre of the soil, and the following relationship is established, where C is the radio wave propagation speed in vacuum.

Therefore, in order to accurately detect the depth 2 of an underground object, it is necessary to confirm the relative dielectric constant ε'e of the soil in advance.

Therefore, the propagation speed ■9 is estimated based on the estimated value of the dielectric constant ε'e for each type of soil such as sandy soil or farmland, and the depth of underground objects is detected based on the estimated propagation speed (KSD manufactured by Charging Manufacturing Co., Ltd.). There is a ``3AM type'' world exploration device). Also,
A method has also been proposed in which soil is actually sampled, the dielectric constant εre is measured, and the depth of underground objects is detected based on the measured value (24th 5ICE Academic Conference 1505r Underground Exploration "Radar Research - Part 2").

(Problem to be Solved by the Invention) However, in the former method of estimating the relative permittivity εre@-, if the change in the radio wave propagation velocity vg with respect to the change Δεre in the relative permittivity εrO is Δvg, then the (2nd ), if the estimation error of the relative permittivity ε'e is ±20%, the error of the radio wave propagation velocity vg will be ±10%, and as a result, the depth detection error will also be ±10%. Therefore, there is a problem that sufficient exploration accuracy cannot be obtained.

On the other hand, the latter method, which actually measures the dielectric constant ε'e, has good accuracy, but requires the preparation of a separate dielectric constant measuring device, which increases the economic burden. Furthermore, if the ground surface is covered with an asphalt shade, it becomes impossible to collect soil, which limits its use.

In addition, propagation speed v9 due to reflected waves from underground objects
The method of estimating the depth Z and detecting the depth Z using the estimated value is described in the journal of the Institute of Electronics and Communication Engineers, "Ground Penetrating Radar System J ('
83/6VOL, J66-B, NO3, P, 713~7
20), but according to this method, it is necessary to perform many complex calculations such as matrix calculations, and the detection result is 1! The problem is that it takes time.

SUMMARY OF THE INVENTION An object of the present invention is to provide an underground object exploration device capable of detecting the position of an underground object in a short time with a high degree of vi and a simple configuration.

(Means for Solving the Problems) The present invention provides a display means for displaying an echo image of an underground object using the depth direction of the underground object and the moving direction of a mobile cart as parameters, and a display means for displaying an echo image of an underground object using the depth direction of the underground object and the moving direction of a mobile cart, and a radio wave from a transmitter. a first means for forming the hyperbolic echo acid based on the propagation time W1 of the reflected wave obtained when the mobile cart is moved a certain distance while emitting light, and displaying the echo acid on the display means; a second means for displaying on the display means a pseudo echo consisting of two hyperbolas spaced apart from each other at a predetermined distance while maintaining an equal distance; and a second means for displaying the pseudo echo image on the display means; a third means for inputting information into the second means for matching the position and the extent of the opening with the echo image of the underground object; and a fourth means for deceiving the propagation speed of underground radio waves using information indicating the apex position and the spread of the aperture of the pseudo echo image when it is displayed within the area between the lines. The system is configured to detect the position of an underground object at an arbitrary point based on the value of the propagation velocity detected by the means.

(Effect) When radio waves are emitted at multiple points on the ground surface above an underground object, echo O is generated based on the information on the transmission time of the reflected waves at each point. It becomes hyperbolic.

Therefore, an operation is performed to superimpose a pseudo echo image consisting of the above two hyperbolas on this echo image.

As a result, if the two echo images overlap (the echo image falls within the area between the two hyperbolic lines of the pseudo echo image), the apex position of the echo image and the width of the aperture can be determined based on the information of the pseudo echo image. Therefore, the underground radio wave propagation velocity vg can be determined by the information indicating the apex position and the width of the opening.
can be easily calculated. If vg can be used equally, it is possible to easily determine the location of underground objects based on the relationship with the propagation time information at any location.

(Embodiment) FIG. 1 is a block diagram showing an embodiment of the present invention, which is roughly divided into a moving trolley 1 and a main body 2. The mobile trolley 1 is a transmission IF that emits radio waves toward the underground object 3! ! 10 and antenna 11, and reception JR 12 and reception antenna 1 that receive reflected waves from buried object 3.
3, and a distance sensor 14 that generates one pulse every time the mobile cart 1 moves a unit distance. The main body 2 also receives pulse signals from the distance sensor 14 and receives d
12, and a display section e121 that displays the formed echo image.

FIG. 2 is a plan view showing the details of the display surface of the display device 21. On the display surface, there is an echo 04 of the buried object 3 and a simulated image 1@5 (5a, 5b) (Q indicates this apex mark). ), a second display section 211 that displays an image of a position movement switch that moves the display position of the pseudo echo image 5 in the horizontal and vertical directions by a pressing operation; A third display section 212 is provided for displaying an image of a spread information input switch for varying the spread of both hyperbolic openings No. 5 by a suppression operation, and a transparent touch panel for detecting the suppression operation position is provided on the entire display surface. (not shown) is attached, and the touch panel is configured to detect operations of the position movement switch and the spread information input switch.゛In the above configuration, when radio waves are emitted from the transmission IF 110 while moving the mobile table IT1 on the ground surface, the buried object 3
The echo flJ4 has a hyperbolic shape as shown in FIG. That is, as shown in FIG. 3(a), the coordinate axis of the distance when the mobile cart 1 moves on the ground surface is x1, and the coordinate axis showing the distance in the depth direction toward the ground is 7, and J ! ! ! Equipment 3
Assuming that the thick material 3 exists at the V coordinates (Xo, ZC), the transmitting/receiving antenna 11.13 is located at point B of n1 of point C.
If the buried object 3 is located at the distance 1ii between points 8.0
It can be observed as an echo image at a depth Zo corresponding to IIBC.

On the other hand, since the transmitted radio wave has a spread in its propagation direction, when the transmitting/receiving antenna 11.13 moves from directly above point C to point A shifted to the left, an echo image of buried object 3 can be observed. be able to. The echo image in this case is point AC
It can be observed at a point at a depth corresponding to the distance between ((X-Xo) +Zo2) 1/2. Therefore, the locus of point D (X, Z) when the moving table tIi1 is moved, that is, the echo image 4 of the buried object 3 is Z = AD = (x-xo) + Zo2)"2 = AC... (4) It becomes a hyperbolic shape represented by .

On the other hand, the echo proximal time t until the radio waves emitted from the transmitting antenna 11 are received by the receiving antenna 13, the radio wave propagation velocity vg, and 1! There is a relationship between L' and the depth Z of the facility 3.

Therefore, by equations (4) and (5), ((x-x
. )2+(Vg゛1°>2)1/2 holds true. However, toGj is the echo delay time at point B, and tQ, V (l is an unknown quantity.

On the other hand, in the echo tgA4 of the buried object 3 displayed on the display unit 210 of the display device 21, the horizontal axis is the distance axis of the trolley 1 x 1 and the vertical axis is the time axis t, as shown in FIG. be.

That is, the echo image of the buried object 3 is displayed with the distance axis Z in the depth direction converted to the time axis t.

Therefore, as shown in FIG. 4(a), a pseudo echo image 5 consisting of two hyperbolas 5a and 5b that are spaced apart from each other at a predetermined distance while maintaining the same distance between the lines is displayed at an arbitrary position on the display section 210. At the same time, the echo image 4 of the buried object 3 is displayed in the area between the lines by changing the position of the vertex mark Q and the spread coefficient α by suppressing the switch images on the display sections 211 and 212 (that is, the echo image 4 of the buried object 3 is displayed in the area between the lines). sandwiched at hyperbolic 158°5b). At this time, the standard hyperbolic of the pseudo echo 5! 15a is x- in the coordinate system as follows ((x-xo
)2+ (α・to)2)1/2=α・t
... (7), then the following relationship is established by comparing the coefficients of the above equation (6) and this equation (7).

Vg=2α...(8) Here, (
Xo, to) is the apex point of the hyperbola 5a (coordinates of the apex mark Q), and its increase or decrease is instructed and determined by the switch image on the display section 211. Nita, α is hyperbolic 1!5
The factor for the spread of the aperture of the Ken-like echo image 5 consisting of a and 5b is displayed on the display unit 212 so that when the spread is increased, α becomes larger, and when it is reduced, α becomes smaller. Variable by suppressing the switch color.

Therefore, as shown in FIG. 4(b), two echo colors 4
, 5 (sandwiching the echo image 4 with the pseudo echo image 5), the coordinates of the apex position P (Fig. 2) of the echo color 4 of the temporary object 3 are set to the apex mark Q of the pseudo echo image 5.
can be determined as the coordinates (x o * t o >). Further, the spread of the hyperbolic aperture forming the echo @4 can also be determined by the value α of the spread of the pseudo echo image 5.

As a result, ■ri (radio wave propagation speed) is found by equation (8), and this vg and to (point B directly above buried object 3)
By substituting the echo "duration time" in Equation (5) for calculation, the apex position coordinates of the B! installed animal 3 echo team 4, that is, the depth 2 can be easily obtained.

Based on the above principles, jI! The depth 2 of the buried object 3 is detected, but in order to do so, it is first necessary to display the echo image 4 of the buried object 3. Therefore, in this embodiment, the echo image 4 is displayed in the following manner.

Now, if we radiate the radio wave pulse optically oscillated by the transmission n10 through the transmitting antenna 11, this radio wave pulse propagates through the soil, reflects on the surface of the ypa object 3 in the soil, and propagates through the soil again. The signal reaches the receiving antenna 13 and is received by the receiver 12. Therefore, in this embodiment, the radio pulse is transmitted through the transmitter 10 and the transmitting antenna 11 at fixed time intervals T, and the signal observed by the receiver JR 12 during this time T is further transmitted at another fixed time interval Tα. Each time (every hour) nα data strings are obtained by sampling (where T ==, Tα·nα).

Moreover, in the device of this embodiment, colors are determined for each of these individual data according to their signal levels, and the display device 21
The time axis of the first display section 210 in the direction (11
direction), these nα pieces of data are displayed in different colors in levels, each with a different color corresponding to each signal level. Note that the timing of displaying the time axis in the direction is determined by the distance resolution of the distance sensor 14, which generates one pulse when the mobile cart 1 moves a certain distance by β, that is, the value of Lβ. Yes, distance sensor 1
4 generates a pulse, the first radio wave pulse emitted from the transmitter 10 is displayed along the time axis in a direction-column manner, and then, as the mobile cart 8 moves by a distance Lβ, such a The time axis is displayed in the direction of the distance axis
The data (echo data) for nB columns are displayed in a manner that is sequentially scanned in the direction.

Once the echo image 4 is displayed in this way, the pseudo echo image 5 (5a, 5b) is formed by the stop device 20 and displayed at an appropriate position on the display section 210. Images of the movement switch and the spread information input switch are also displayed on the display sections 211 and 212, respectively.

In this state, echo image 4 is converted into pseudo echo image 5 as described above.
When the position movement switch is operated so as to be sandwiched between the two hyperbolas 5a and 5b, the arithmetic unit 20
”, “↓”, “→”, and “←” each time the switches are operated, a constant value j is subtracted from the initial appropriate display position coordinates (xs, ts) of the apex mark Q in the pseudo echo acid 5. and update this. Similarly, in response to the operation of the spread information input switch, the appropriate spread coefficient αS of the pseudo echo image 5 in the initial display state is increased or decreased by a constant value and updated. Then, each time the update is performed, new values Xs', ts',
A pseudo echo image 5 corresponding to αS' is formed in accordance with the equation (7) (these xs').

The values of ts' and αS' are substituted into Xo, t'o, and α in equation (7), respectively).

As a result, as shown in FIG. 4(b), the echo image 4 of the object becomes two hyperbolas 85a of the pseudo echo image 5.

5b, the propagation velocity v can be calculated by substituting αS' at this time for α in the above equation (8).
Calculate g. After this, v9 obtained as above
and the echo delay time t at the exploration position corresponding to the apex mark Q of the pseudo echo image
) and calculate the depth 2.

In addition, since the increase/decrease value when updating αS is multiplied by the square, as seen from equation (7), αS' changes suddenly,
It is conceivable that the update operation will be incorrect. Therefore, in this case, if the value is updated using the square root increase/decrease value as shown in the following equation, the magnitude of the change will be reduced and the operation will be easier.

as' = as +KvC or <Las' = as
- to -ya (K: constant) By the way, in the above embodiment, the echo image 4 is displayed in color according to the received intensity of the same echo, but it is displayed in monochrome of white/black, and at the maximum reception sensitivity. It is also possible to display only the echo image of .

In either case, as a pseudo echo image, two lines are spaced apart at a predetermined distance while maintaining the same distance from each other as described above.
By using two hyperbolas, it is possible to improve the visibility when capturing echo images of the existing object, making it very easy to fine-tune and match these echo images. Can be done. Specifically, J! I! M1 confirms that the echo image of the fixture has settled.

■ Match the parallelism of the curves of the two hyperbolas (pseudo echo images) and the buried object echo image.

Anybody should do the work.

In addition, by operating the touch panel, you can create a pseudo echo fii5.
Although the position and width of the input terminal are variable, they can be replaced with various input means such as mechanical contact switches, keyboards, joysticks, etc. as appropriate.

Also, xs', ts' of poems that superimpose pseudo-echo images
, the increase/decrease value of αS' has been explained as a constant value, but if the distance from the echo image 4 is large, the increase/decrease value is increased, and when the distance from the echo image 4 approaches to a certain range, the increase/decrease value is decreased from lc. , further improving operability.

On the other hand, a pseudo echo image is also formed using equation (7), and in equation (7), as to changes, the spread of the hyperbola also changes. However, by using the following method, it is possible to perform parallel translation only in the vertical direction (time axis direction) without changing the spread of the hyperbola.

For simplicity, both sides of equation (7) are shown here as squared. In other words, (x-XO)2+(α・to)2=(α・t)2...(9) is the (7th
) is an expression equivalent to the expression.

Here, if this is transformed by setting α·to=D and t1=O, it becomes (X−Xo)2+[)2=α2·(t−tl)2 (10).

Therefore, for the operation of the position movement switch, if [↑] is operated...t1←t1-M
↓" is operated...t1←t1+M"←
” is operated...Xo 4-XO-N "
→” is operated... tl, Xo is increased/decreased IM, N is updated as Xo+Xo+N, and when the spread information input switch is operated, when "←→" is operated, If D←α·to is set and the pseudo echo image 5 is formed as “→←” is operated, only vertical translation can be performed without changing the spread. Note that F(α) is α
This is the function value determined between .

〔Effect of the invention〕

As explained above, in the present invention, the position of the echo image of an underground object and the spread of the hyperbolic opening are detected by sandwiching them between pseudo echo images consisting of two hyperbolas separated from each other, and the detected value is Since the position of underground objects is detected by calculating the radio wave propagation velocity in the soil based on the radio wave propagation speed, there is no need for a measuring device to measure the relative dielectric constant of the soil, making it possible to have an inexpensive configuration. The position of underground objects under asphalt can also be detected with high accuracy.

Furthermore, since the estimated value of the dielectric constant of the soil is not used, there is no position detection error due to estimation error, and highly accurate position detection can be performed. Furthermore, since complex operations such as matrix calculations are not performed, position detection results can be obtained in a short time.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a plan view showing details of the display screen of the display device, and Fig. 3 is an explanatory diagram for explaining that the echo image becomes hyperbolic. , Figure 4 is fg! FIG. 7 is an explanatory diagram for explaining the operation of sandwiching the installation animal-0 between pseudo-echo colors consisting of two hyperbolas. 1... Moving trolley, 2... Main body, 3... Buried object,
4... U animal echo image, 5 (5a, 5b)... pseudo echo image, 10... transmitter, 12... receiver, 2
0... Performance device, 21... Display device, Q... Apex mark. 1st drawing 1 AB Fig. 3 (Q) Fig. 3 (b) Fig. 4 (b)

Claims (1)

[Claims] A radio wave emitted underground from a transmitter mounted on a movable trolley and reflected by an underground object is received by a receiver mounted on the movable trolley, and A radar-based underground object detection device for detecting the position of an underground object, comprising: a display means for displaying an echo image of the underground object using a depth direction of the underground object and a moving direction of a mobile cart as parameters; a first means for forming the hyperbolic echo image on the display means based on the propagation time of the reflected wave obtained when the mobile cart is moved a certain distance while emitting radio waves from the transmitter, and displaying the echo image on the display means; a second means for forming and displaying on the display means a pseudo echo image consisting of two hyperbolas spaced apart at a predetermined distance while maintaining an equal distance between the lines; and a second means for moving the display position of the pseudo echo image. a third means for inputting information to the second means for matching the apex position and the width of the opening with an echo image of the underground object; and a second means for causing the echo image to form the pseudo echo image. and a fourth means for calculating the propagation speed of underground radio waves based on the information indicating the apex position and the spread of the aperture of the pseudo echo image when displayed within the area between the lines of the two hyperbolas; An underground object exploration device, characterized in that the position of the underground object is detected at any point based on the value of the propagation velocity calculated by the fourth means.