JP6813931B2 - Radar ground penetrating device and radar ground penetrating method - Google Patents

Description

The present disclosure relates to a radar ground penetrating radar technique for exploring a hollow non-metal tube buried in the ground.

In order to lay a communication cable such as an optical fiber in the ground, a hollow non-metal tube is buried in the ground, and then a communication cable such as an optical fiber is inserted into the hollow non-metal tube. Here, when concrete is filled in the groove in which the hollow non-metal pipe is laid, or when the surrounding environment of the hollow non-metal pipe buried in the ground changes with time, the burial position of the hollow non-metal pipe And the cross-sectional shape may change. Therefore, when laying a communication cable such as an optical fiber in the ground, a radar ground penetrating radar that sweeps over the road surface is used to search for changes in the buried position of the hollow non-metal pipe, and the inside of the hollow non-metal pipe is explored. A small traveling camera device is used to search for changes in the cross-sectional shape of a hollow non-metal tube. As a disclosure example of the radar ground penetrating radar, Patent Document 1 and the like can be mentioned.

Japanese Unexamined Patent Publication No. 2011-185792

However, the relative dielectric constants of non-metals and air are lower than the relative dielectric constants of metals and soils, and the radar reflectance of hollow non-metal pipes is the radar reflection of metal structures such as gas pipes and water pipes and the change points of soil. Less than the rate, the echo intensity due to the hollow non-metal pipe is lower than the echo intensity due to metal structures such as gas pipes and water pipes, and the change point of the soil. Therefore, only a qualified person for radar ground penetrating radar can search for the buried position of the hollow non-metal pipe, and even a qualified person for radar ground penetrating radar can bury the hollow non-metal pipe. It is difficult to accurately explore the position in a short time.

Therefore, in order to solve the above-mentioned problems, it is an object of the present disclosure to enable accurate exploration of the buried position of the hollow non-metal pipe in a short time even if the person is not a qualified person for radar ground penetrating radar.

Radar exploration data around the hollow non-metal tube in the state where the metal wire is not inserted in the hollow non-metal tube and the state where the metal wire is inserted in the hollow non-metal tube in order to achieve the above object. The difference is calculated for. Then, based on the calculated difference, the insertion position of the metal wire, that is, the hollow non-metal tube, while reducing the influence of the radar reflector located around the hollow non-metal tube and having a radar reflectance larger than that of the hollow non-metal tube. Explore the burial location.

Specifically, the present disclosure is a radar underground exploration device for exploring a hollow non-metal tube buried in the ground, and the hollow non-metal tube in a state where a metal wire is not inserted into the hollow non-metal tube. Radar exploration data around the metal tube (non-insertion state exploration data) and radar exploration data around the hollow non-metal tube when the metal wire is inserted into the hollow non-metal tube (insertion state exploration). Data), a radar exploration data acquisition unit that acquires the difference, a radar exploration data difference unit that calculates a difference between the non-insertion state exploration data and the insertion state exploration data acquired by the radar exploration data acquisition unit, and the radar. Based on the difference calculated by the exploration data difference unit, the hollow non-metal tube is located around the hollow non-metal tube and has a higher radar reflectance than the hollow non-metal tube while reducing the influence of the radar reflector. It is a radar underground exploration device characterized by being provided with a hollow non-metal tube exploration unit for exploring the buried position of the radar.

Further, the present disclosure is a radar underground exploration method for exploring a hollow non-metal tube buried in the ground, wherein the hollow non-metal tube is in a state where a metal wire is not inserted into the hollow non-metal tube. Radar exploration data (non-insertion state exploration data) in the vicinity and radar exploration data (insertion state exploration data) around the hollow non-metal tube when a metal wire is inserted into the hollow non-metal tube. , The radar exploration data difference step for calculating the difference between the non-inserted state exploration data and the inserted state exploration data acquired in the radar exploration data acquisition step, and the radar exploration data difference. Based on the difference calculated in the step, the buried position of the hollow non-metal tube while reducing the influence of the radar reflector located around the hollow non-metal tube and having a radar reflectance higher than that of the hollow non-metal tube. It is a radar underground exploration method characterized in that a hollow non-metal tube exploration step for exploring is provided in order.

According to this configuration, the echo intensity of the metal wire in the inserted state of the metal wire is about the same as the echo intensity of the metal structure such as a gas pipe and a water pipe and the change point of the soil. Then, after calculating the difference between the radar exploration data before and after the insertion of the metal wire, the echo intensity due to the metal wire remains different from the echo intensity due to the change point of the soil and the metal structure such as the gas pipe and the water pipe. Therefore, even if the person is not qualified for radar ground penetrating radar, the buried position of the hollow non-metal pipe can be accurately searched in a short time.

Further, the present disclosure has been acquired by the radar exploration data acquisition unit based on a known radar reflector located at a known location around the hollow non-metal tube and having a radar reflectance higher than that of the hollow non-metal tube. The non-inserted state exploration data and the inserted state exploration data are further provided with an exploration data alignment unit for aligning in a direction horizontal to the ground, and the radar exploration data difference unit is positioned with the exploration data alignment unit. It is a radar underground exploration apparatus characterized by calculating the difference between the non-inserted state exploration data and the inserted state exploration data that have been combined.

The present disclosure is also acquired in the radar exploration data acquisition step based on a known radar reflector located at a known location around the hollow non-metal tube and having a radar reflectance greater than that of the hollow non-metal tube. An exploration data alignment step for aligning the non-inserted state exploration data and the inserted state exploration data in a direction horizontal to the ground is further provided between the radar exploration data acquisition step and the radar exploration data difference step. In the radar exploration data difference step, a radar underground exploration method is characterized in that the difference is calculated for the non-insertion state exploration data and the insertion state exploration data aligned in the exploration data alignment step. Is.

According to this configuration, the difference between the radar exploration data before and after the insertion of the metal wire is more accurate even when the radar exploration range on the same radar exploration line is different in the non-inserted state and the inserted state of the metal wire. Can be calculated. Therefore, even if the person is not a qualified radar ground penetrating radar, the buried position of the hollow non-metal pipe can be searched more accurately.

Further, the present disclosure further includes a peripheral relative permittivity estimation unit that estimates the relative permittivity around the hollow non-metal tube based on the difference calculated by the radar exploration data difference unit, and further comprises the hollow non-metal. The pipe exploration unit is a radar ground penetrating radar device that searches for a buried position of the hollow non-metal pipe in a direction perpendicular to the ground based on the relative permittivity estimated by the peripheral relative permittivity estimation unit. Is.

Further, in the present disclosure, the peripheral relative permittivity estimation step for estimating the relative permittivity around the hollow non-metal tube based on the difference calculated in the radar exploration data difference step is referred to as the radar exploration data difference step. Further provided between the hollow non-metal tube exploration step, in the hollow non-metal tube exploration step, the hollow non in the direction perpendicular to the ground based on the relative permittivity estimated in the peripheral relative permittivity estimation step. This is a radar ground penetrating method characterized by exploring the buried position of a metal pipe.

According to this configuration, the relative permittivity around the hollow non-metal tube is more accurate after the difference calculation of the radar exploration data before and after the insertion of the metal wire, not before the difference calculation of the radar exploration data before and after the insertion of the metal wire. Can be estimated to. Therefore, even if the person is not qualified for radar ground penetrating radar, the buried position of the hollow non-metal pipe in the depth direction can be searched more accurately.

As described above, the present disclosure enables accurate exploration of the buried position of the hollow non-metal pipe in a short time even if the person is not a qualified radar ground penetrating radar.

It is a figure which shows the structure of the radar ground penetrating radar of this disclosure. It is a figure which shows the procedure of the radar ground penetrating radar of this disclosure. It is a figure which shows the processing of the radar exploration data difference part of this disclosure. It is a figure which shows the process of the exploration data alignment part of this disclosure. It is a figure which shows the processing of the peripheral relative permittivity estimation part of this disclosure.

Embodiments of the present disclosure will be described with reference to the accompanying drawings. The embodiments described below are examples of the embodiments of the present disclosure, and the present disclosure is not limited to the following embodiments.

(Configuration of radar ground penetrating radar of the present disclosure)
The configuration of the radar ground penetrating radar of the present disclosure is shown in FIG. The procedure of the radar ground penetrating radar of the present disclosure is shown in FIG. The radar ground penetrating radar P includes a radar transmitting unit 1, a radar receiving unit 2, a radar exploration data acquisition unit 3, an exploration data alignment unit 4, a radar exploration data difference unit 5, a peripheral relative dielectric constant estimation unit 6, and a hollow non-metal. It is composed of a tube exploration unit 7, and steps S1 to S6 are executed.

The radar ground penetrating radar P executes radar exploration along the radar exploration line L on the ground G in order to explore the hollow non-metal pipe N buried in the underground U. The radar transmission unit 1 transmits a radar irradiation wave to the underground U. The radar receiving unit 2 receives the radar reflected wave from the underground U. The distance between the transmitting antenna of the radar transmitting unit 1 and the receiving antenna of the radar receiving unit 2 may be constant as shown in FIG. 1 or may be changed as a modification.

(Processing of radar exploration data difference part of the present disclosure)
Next, the radar exploration data acquisition unit 3, the radar exploration data difference unit 5, and the hollow non-metal tube exploration unit 7 will be described. The processing of the radar exploration data difference part of the present disclosure is shown in FIG. The exploration data alignment unit 4 and the peripheral relative permittivity estimation unit 6 will be described in detail later.

The radar exploration data acquisition unit 3 acquires radar exploration data (non-insertion state exploration data) around the hollow non-metal tube N in a state where the metal wire M is not inserted into the hollow non-metal tube N (step S1). ). The radar exploration data acquisition unit 3 acquires radar exploration data (insertion state exploration data) around the hollow non-metal tube N in a state where the metal wire M is inserted into the hollow non-metal tube N (step S2). .. As for the order of steps S1 and S2, step S1 may be the first as shown in FIG. 2, and step S2 may be the first as a modification.

The upper and middle stages of FIG. 3 show the buried positions of the hollow non-metal tube N and the radar reflectors R1, R2, and R4 when the ground G is viewed from above. A hollow non-metal pipe N such as a vinyl chloride pipe and a radar reflector R2 such as a gas pipe and a water pipe are buried in the ground U so as to extend substantially in parallel. A radar reflector R1 such as a metal structure is buried in the ground U immediately below the radar exploration line L1 which is substantially perpendicular to the extending direction of the hollow non-metal tube N and the radar reflector R2. A radar reflector R4 such as a metal structure is buried in the ground U directly below the radar exploration line L2 which is substantially perpendicular to the extending direction of the hollow non-metal tube N and the radar reflector R2. The metal wire M is inserted into the hollow non-metal tube N after opening a manhole on the ground G.

The upper part of FIG. 3 shows the non-insertion state exploration data in the non-insertion state of the metal wire M. In the non-insertion state exploration data DN (L1) on the radar exploration line L1, the bicurve echoes EH (R1) and EH (R2) by the radar reflectors R1 and R2 are observed, and the bicurve echoes by the hollow non-metal tube N are observed. Almost no echo is observed. In the non-insertion state exploration data DN (L2) on the radar exploration line L2, hyperbolic echoes EH (R2) and EH (R4) by the radar reflectors R2 and R4 are observed, and the hyperbolic echoes by the hollow non-metal tube N are observed. Almost no echo is observed.

The middle part of FIG. 3 shows the insertion state search data in the insertion state of the metal wire M. In the insertion state exploration data DI (L1) on the radar exploration line L1, hyperbolic echoes EH (R1) and EH (R2) by the radar reflectors R1 and R2 are observed, and the hyperbolic echo EH by the metal wire M ( M) is also observed. In the insertion state exploration data DI (L2) on the radar exploration line L2, hyperbolic echoes EH (R2) and EH (R4) by radar reflectors R2 and R4 are observed, and hyperbolic echo EH by metal wire M ( M) is also observed.

The radar exploration data difference unit 5 calculates the difference between the non-insertion state exploration data and the insertion state exploration data acquired by the radar exploration data acquisition unit 3 (step S4). The hollow non-metal tube exploration unit 7 is located around the hollow non-metal tube N based on the above difference calculated by the radar exploration data difference unit 5, and has a radar reflectance higher than that of the hollow non-metal tube N. , R2, and R4 are reduced, and the insertion position of the metal wire M, that is, the burial position of the hollow non-metal tube N is explored (step S6). In addition, steps S3 and S5 will be described in detail later.

The lower part of FIG. 3 shows the exploration data after the difference calculation after the difference calculation of the radar exploration data. In the exploration data DS (L1) after calculating the difference on the radar exploration line L1, the hyperbolic echoes EH (R1) and EH (R2) by the radar reflectors R1 and R2 hardly remain, but the hyperbolic echoes by the metal wire M are formed. Echo EH (M) remains. In the exploration data DS (L2) after calculating the difference on the radar exploration line L2, the hyperbolic echoes EH (R2) and EH (R4) by the radar reflectors R2 and R4 hardly remain, but the hyperbolic echoes by the metal wire M are formed. Echo EH (M) remains. The hyperbolic echo EH (M) by the metal wire M reflects the insertion position of the metal wire M, that is, the burial position of the hollow non-metal tube N.

Here, before and after the insertion of the metal wire M, the presence or absence of the hyperbolic echo EH (M) by the metal wire M changes, and the hyperbolic echoes EH (R1) and EH (R1) by the radar reflectors R1, R2, and R4 ( The intensities of R2) and EH (R4) may also change. However, before and after the insertion of the metal wire M, the hyperbolic echoes EH (R1), EH (R2), and EH (R4) due to the radar reflectors R1, R2, and R4 are the hyperbolic echoes due to the metal wire M. It can be considered to be much smaller than the change in the intensity of EH (M). Therefore, in the exploration data DS (L1) and DS (L2) after the difference calculation, the hyperbolic echoes EH (R1), EH (R2), and EH (R4) by the radar reflectors R1, R2, and R4 hardly remain. , The hyperbolic echo EH (M) by the metal wire M may be considered to remain.

As described above, in the inserted state of the metal wire M, the echo intensity of the metal wire M is about the same as the echo intensity of the metal structure such as the gas pipe and the water pipe and the change point of the soil. Then, after calculating the difference between the radar exploration data before and after the insertion of the metal wire M, the echo intensity due to the metal wire M remains different from the echo intensity due to the metal structures such as gas pipes and water pipes and the change point of the soil. Therefore, even if the person is not qualified for radar ground penetrating radar, the buried position of the hollow non-metal pipe N can be accurately searched in a short time.

(Processing of the exploration data alignment unit of the present disclosure)
Next, the exploration data alignment unit 4 will be described. The processing of the exploration data alignment unit of the present disclosure is shown in FIG. Although the radar exploration range in the non-inserted state of the metal wire M and the radar exploration range in the inserted state of the metal wire M are on the same radar exploration line L, the user can measure the radar ground penetrating radar P. It may be different for convenience of operation.

Then, when the non-insertion state exploration data and the insertion state exploration data are not aligned on the same radar exploration line L, the difference between the radar exploration data before and after the insertion of the metal wire M cannot be calculated accurately. .. Therefore, it is desirable to have a mechanism that enables alignment of the non-inserted state exploration data and the inserted state exploration data on the same radar exploration line L.

Therefore, the exploration data alignment unit 4 acquires radar exploration data based on the known radar reflector R3, which is located at a known location around the hollow non-metal tube N and has a radar reflectance higher than that of the hollow non-metal tube N. The non-insertion state exploration data and the insertion state exploration data acquired by the part 3 are aligned in the horizontal direction with respect to the ground G (step S3).

The upper and middle stages of FIG. 3 show the installation positions of the radar reflector R3 when the ground G is viewed from above. A radar reflector R3 such as a metal tape is installed on the ground G along a direction substantially parallel to the extending direction of the hollow non-metal tube N and the radar reflector R2. The radar reflector R3 may be a metal tape or the like installed on the ground G as shown in FIG. 3, or may be a metal structure or the like buried in the underground U as a modification. ..

The upper part of FIG. 4 shows the non-insertion state exploration data in the non-insertion state of the metal wire M. In the non-insertion state exploration data DN (L1) on the radar exploration line L1, the bicurve echoes EH (R1), EH (R2) by the radar reflectors R1 and R2 and the echo EP (R3) by the radar reflector R3 are observed. Therefore, the bicurve echo by the hollow non-metal tube N is hardly observed. Then, the echo EP (R3) by the radar reflector R3 is observed at the origin of the non-insertion state search data DN (L1) on the radar search line L1.

The middle part of FIG. 4 shows the insertion state exploration data before the alignment on the radar exploration line L in the insertion state of the metal wire M. In the insertion state exploration data DI (L1) before alignment on the radar exploration line L1, the bicurve echoes EH (R1), EH (R2) by the radar reflectors R1 and R2 and the echo EP (R3) by the radar reflector R3. ) Is observed, and a double-curved echo EH (M) by the metal wire M is also observed. Then, the echo EP (R3) by the radar reflector R3 is observed at a point deviated from the origin of the insertion state search data DI (L1) before the alignment on the radar search line L1.

Here, the exploration data alignment unit 4 includes the reflection phase by the radar reflector R3 in the non-insertion state exploration data DN (L1) and the reflection phase by the radar reflector R3 in the insertion state exploration data DI (L1). The non-inserted state exploration data DN (L1) and the inserted state exploration data DI (L1) are aligned in the horizontal direction with respect to the ground G so that they are in the same phase.

The lower part of FIG. 4 shows the insertion state search data after alignment on the radar search line L in the insertion state of the metal wire M. In the insertion state exploration data DI'(L1) after alignment on the radar exploration line L1, the bicurve echoes EH (R1), EH (R2) by the radar reflectors R1 and R2 and the echo EP by the radar reflector R3 ( R3) is observed, and a double-curved echo EH (M) by the metal wire M is also observed. Then, the echo EP (R3) by the radar reflector R3 is observed at the origin of the insertion state search data DI'(L1) after the alignment on the radar search line L1.

Then, the radar exploration data difference unit 5 calculates the difference between the non-insertion state exploration data DN (L1) and the insertion state exploration data DI'(L1) that the exploration data alignment unit 4 has aligned (step S4). ). Here, in FIG. 4, the origin of the inserted state exploration data DI (L1) is aligned with the origin of the non-inserted state exploration data DN (L1). That is, in FIG. 4, the reflection phase by the radar reflector R3 in the insertion state search data DI (L1) is matched with the reflection phase by the radar reflector R3 in the non-insertion state search data DN (L1). However, as a modification, the origin of the non-insertion state exploration data DN (L1) may be aligned with the origin of the insertion state exploration data DI (L1). That is, as a modification, the reflection phase by the radar reflector R3 in the non-insertion state search data DN (L1) may be matched with the reflection phase by the radar reflector R3 in the insertion state search data DI (L1).

In this way, even when the radar exploration range on the same radar exploration line L is different in the non-inserted state and the inserted state of the metal wire M, the difference between the radar exploration data before and after the insertion of the metal wire M can be obtained. It can be calculated accurately. Therefore, even if the person is not qualified for radar ground penetrating radar, the buried position of the hollow non-metal pipe N can be searched more accurately.

(Processing of Permittivity Permittivity Estimator of the Present Disclosure)
Next, the peripheral relative permittivity estimation unit 6 will be described. The processing of the peripheral relative permittivity estimation unit of the present disclosure is shown in FIG. The peripheral relative permittivity estimation unit 6 estimates the relative permittivity around the hollow non-metal tube N based on the above difference calculated by the radar exploration data difference unit 5 (step S5). For the peripheral relative permittivity estimation unit 6, for example, a synthetic aperture technique, a hyperbolic method technique, or the like can be used. The hollow non-metal tube exploration unit 7 searches for the buried position of the hollow non-metal tube N in the direction perpendicular to the ground G based on the relative permittivity estimated by the peripheral relative permittivity estimation unit 6 (step S6).

The upper part of FIG. 5 shows the insertion state search data in the insertion state of the metal wire M. In the insertion state exploration data DI (L1) on the radar exploration line L1, hyperbolic echoes EH (R1) and EH (R2) by the radar reflectors R1 and R2 are observed, and the hyperbolic echo EH by the metal wire M ( M) is also observed. Therefore, when estimating the relative permittivity around the hollow non-metal tube N based on the shape of the echo EH (M) by the metal wire M, the echoes EH (R1) and EH (R2) by the radar reflectors R1 and R2. Will be affected by.

The middle part of FIG. 5 shows the exploration data after the difference calculation after the difference calculation of the radar exploration data. In the exploration data DS (L1) after calculating the difference on the radar exploration line L1, the hyperbolic echoes EH (R1) and EH (R2) by the radar reflectors R1 and R2 hardly remain, but the hyperbolic echoes by the metal wire M are formed. Echo EH (M) remains. Therefore, when estimating the relative permittivity around the hollow non-metal tube N based on the shape of the echo EH (M) by the metal wire M, the echoes EH (R1) and EH (R2) by the radar reflectors R1 and R2. Almost unaffected by.

The lower part of FIG. 5 shows the exploration data after the relative permittivity estimation after the relative permittivity estimation around the hollow non-metal tube N. In the exploration data DP (L1) after estimating the relative permittivity on the radar exploration line L1, a substantially circular echo EP (M) by the metal wire M is extracted.

In this way, the relative permittivity around the hollow non-metal tube N is calculated not before the difference calculation of the radar exploration data before and after the insertion of the metal wire M, but after the difference calculation of the radar exploration data before and after the insertion of the metal wire M. It can be estimated accurately. Therefore, even if the person is not a qualified radar ground penetrating radar, the buried position of the hollow non-metal pipe N in the depth direction can be searched more accurately.

In the radar underground exploration device and the radar underground exploration method of the present disclosure, in order to lay a communication cable such as an optical fiber in the ground, after burying a hollow non-metal pipe in the ground, a communication cable such as an optical fiber is used. It can be applied when inserting into a hollow non-metal tube.

P: Radar ground penetrating radar 1: Radar transmitting unit 2: Radar receiving unit 3: Radar exploration data acquisition unit 4: Exploration data alignment unit 5: Radar exploration data difference unit 6: Peripheral specific dielectric constant estimation unit 7: Hollow non Metal tube exploration unit G: Ground U: Ground L, L1, L2: Radar exploration line N: Hollow non-metal tube M: Metal wire R1, R2, R3, R4: Radar reflector

Claims (6)

A radar ground penetrating radar for exploring hollow non-metal pipes buried in the ground.
Radar exploration data (non-insertion state exploration data) around the hollow non-metal tube in a state where the metal wire is not inserted into the hollow non-metal tube, and metal wire is inserted into the hollow non-metal tube. A radar exploration data acquisition unit that acquires radar exploration data (insertion state exploration data) around the hollow non-metal tube in the state, and
A radar exploration data difference unit that calculates a difference between the non-insertion state exploration data and the insertion state exploration data acquired by the radar exploration data acquisition unit.
Based on the difference calculated by the radar exploration data difference unit, the effect of the radar reflector located around the hollow non-metal tube and having a radar reflectance larger than that of the hollow non-metal tube is reduced, and the hollow non-metal tube is used. Hollow non-metal pipe exploration unit for exploring the buried position of metal pipe,
A radar ground penetrating radar characterized by being equipped with. The non-insertion state exploration data acquired by the radar exploration data acquisition unit based on a known radar reflector located at a known location around the hollow nonmetal tube and having a radar reflectance higher than that of the hollow nonmetal tube. Further, the insertion state exploration data is further provided with an exploration data alignment unit for aligning in a horizontal direction with the ground.
The radar exploration data difference unit according to claim 1, wherein the radar exploration data difference unit calculates the difference between the non-insertion state exploration data and the insertion state exploration data aligned by the exploration data alignment unit. Radar ground penetrating radar. A peripheral relative permittivity estimation unit that estimates the relative permittivity around the hollow non-metal tube based on the difference calculated by the radar exploration data difference unit is further provided.
The hollow non-metal tube exploration unit is characterized in that it searches for a buried position of the hollow non-metal tube in a direction perpendicular to the ground based on the relative permittivity estimated by the peripheral relative permittivity estimation unit. The radar ground penetrating radar according to claim 1 or 2. A radar ground penetrating method for exploring hollow non-metal pipes buried in the ground.
Radar exploration data (non-insertion state exploration data) around the hollow non-metal tube in a state where the metal wire is not inserted into the hollow non-metal tube, and metal wire is inserted into the hollow non-metal tube. In the state, the radar exploration data acquisition step for acquiring the radar exploration data (insertion state exploration data) around the hollow non-metal tube, and the radar exploration data acquisition step.
The radar exploration data difference step for calculating the difference between the non-insertion state exploration data and the insertion state exploration data acquired in the radar exploration data acquisition step, and the radar exploration data difference step.
Based on the difference calculated in the radar exploration data difference step, the hollow non-metal tube is located around the hollow non-metal tube and has a radar reflectance larger than that of the hollow non-metal tube while reducing the influence of the radar reflector. Hollow non-metal tube exploration step to explore the buried position of metal tube,
Radar ground penetrating method characterized by providing in order. The non-insertion state exploration data acquired in the radar exploration data acquisition step based on a known radar reflector located at a known location around the hollow non-metal tube and having a radar reflectance greater than that of the hollow non-metal tube. Further, an exploration data alignment step for aligning the inserted state exploration data in the horizontal direction with respect to the ground is further provided between the radar exploration data acquisition step and the radar exploration data difference step.
The fourth aspect of claim 4, wherein the radar exploration data difference step calculates the difference between the non-insertion state exploration data and the insertion state exploration data aligned in the exploration data alignment step. Radar ground penetrating method. Based on the difference calculated in the radar exploration data difference step, the peripheral relative permittivity estimation step for estimating the relative permittivity around the hollow non-metal tube is performed with the radar exploration data difference step and the hollow non-metal tube exploration. Further prepare between steps
The hollow non-metal tube exploration step is characterized in that the buried position of the hollow non-metal tube in the direction perpendicular to the ground is searched based on the relative permittivity estimated in the peripheral relative permittivity estimation step. The radar ground penetrating method according to claim 4 or 5.

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