JPH06331313A - Method and device for correcting measured distance of embedded pipe measuring apparatus - Google Patents

Abstract

PURPOSE:To specify the accurate embedded position of a pipeline by correcting the moving distance of an anglular velocity sensor corresponding to the elongation of a cable. CONSTITUTION:An embedded pipe measuring system comprises the angular velocity sensor moved through an embedded pipe 2 and detecting the change quantity in its moving direction and a measuring device 4 measuring the moving distance of the sensor 1 from the sending-out quantity of the power supply/ communication cable 11 connected to the sensor 1 and operates the change quantity in the moving direction of the sensor 1 and the moving distance of the sensor 1 to sepcify the embedded position of the embedded pipe 2. An OTDR device 12 connected to the optical fiber of the cable 11 and detecting the elongation of the cable 11 from the change of the intensity of back scattering light and a computer 13 correcting the moving distance of the sensor on the basis of the elongation of the cable 11 detected by the device 12 are provided. The elongation of the cable 11 is operated by the device 12 and the moving distance of the sensor 1 is corrected on the basis of the elongation of the cable 1. By this constitution, a moving locus can be accurately specified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measurement distance of a buried pipe measuring system for calculating a buried position of a pipeline from a change in angular velocity (change in traveling direction) detected by an angular velocity sensor moving in the pipeline and the moving distance thereof. The present invention relates to a correction method and an apparatus thereof.

[0002]

2. Description of the Related Art A means using an angular velocity sensor (buried pipe measuring system) is widely known for calculating and specifying the buried position of a buried pipe such as a power line. This measuring means is shown in FIG.
It will be described based on.

Reference numeral 1 in the figure denotes an angular velocity sensor, which is passed through an underground buried pipe 2. The angular velocity sensor 1 is connected to a power supply / communication cable 3 for supplying power and transmitting detection data to a computer 5 described later. 4 is a measuring instrument for detecting the amount of power feeding / communication cable 3,
The sending amount of the communication cable 3 is calculated as the moving distance of the angular velocity sensor 1. Reference numeral 5 denotes a computer, which is connected to the angular velocity sensor 1 via the power supply / communication cable 3 to receive the detection data from the angular velocity sensor 1 and also the detection data from the scale 4, and calculate these data. The movement locus of the angular velocity sensor 1 is specified as the buried position of the buried pipe 2.

A wire 6 is passed through the buried pipe 2 to pull the angular velocity sensor 1. The wire 6 is wound around a winch 7.

With the above structure, the angular velocity sensor 1 is connected to the wire 6 passed through the other pipe opening of the buried pipe 2, inserted from one pipe opening, and pulled by the winch 7. At this time, the output amount of the power feeding / communication cable 3 is determined by the angular velocity sensor 1.
Is measured by the scale 4, and the change in the traveling direction is detected as a change in the angular velocity by the angular velocity sensor 1 itself. These data are taken into the computer 5, and the computer 5 calculates the moving distance of the angular velocity sensor 1 from the detection data of the scale 4, and the traveling direction from the detection data of the angular velocity sensor 1. Then, the movement locus is calculated from the movement distance and the traveling direction, and the buried position of the buried pipe 2 is specified.

[0006]

By the way, when the buried pipe 2 becomes longer, the length of the measuring pipe becomes longer, and accordingly, the power supply
The communication cable 3 must also be extended, and the weight of the fed power supply / communication cable 3 and the lateral pressure thereof increase. When this self-weight increases, the power feeding / communication cable 3
The tension acting on the cable also increases, and as a result, the cable 3 is stretched. Although the relationship between the tension and the elongation varies depending on the tension member used, it usually has the relationship shown by lines a and b in FIG.

Further, in the buried pipe measuring system, the position at which the feed amount of the power feeding / communication cable 3 is measured by the measuring instrument 4 is the pipe opening of the buried pipe 2. The elongation of 3 cannot be measured.

For this reason, the expansion of the power supply / communication cable 3 remains an error, and the length of the buried pipe 2 in which the delivery amount of the cable 3 is long and the buried pipe 2 in which the lateral pressure is large and having many bends are high. There is a problem that it is difficult to measure accuracy.

The present invention has been made in view of the above problems, and provides a measuring distance correction method and apparatus for a buried pipe measuring system capable of accurately detecting the moving distance of an angular velocity sensor and improving the measuring accuracy. The purpose is to do.

[0010]

In order to solve the above-mentioned problems, the method of the present invention is to move an angular velocity sensor to which a power feeding / communication cable is connected in a pipe, and at the time of moving the angular velocity sensor, use a bending part or a connecting part. When measuring the moving direction of the angular velocity sensor from the change in the generated angular velocity while measuring the moving distance from the output amount of the power supply / communication cable, when specifying the moving path of the angular velocity sensor to specify the buried position of the pipeline, Using a cable in which an optical fiber is twisted as a power supply / communication cable, the extension of the cable is calculated from the intensity change of the backscattered light generated by the incidence of pulsed light on the optical fiber, and the extension of this cable causes the angular velocity sensor The feature is that the moving distance is corrected.

Further, the device of the present invention moves in a pipe line,
An angular velocity sensor that detects the amount of change in the moving direction at the bending portion or the connection portion, and a measuring instrument that measures the moving distance of the angular velocity sensor from the output amount of the power supply / communication cable connected to the angular velocity sensor, In an embedded pipe measuring system for calculating an amount of change in a moving direction by an angular velocity sensor and a moving distance by a measuring instrument to specify a buried position of a pipeline, an optical fiber twisted into the power feeding / communication cable, and the optical fiber. And an optical pulse test device connected to the optical pulse test device for detecting the extension of the cable from the intensity change of the backscattered light, and an arithmetic processing unit for correcting the moving distance of the angular velocity sensor by the extension of the cable detected by the optical pulse test device. Is characterized by.

[0012]

According to the method of the present invention, the movement distance of the angular velocity sensor can be accurately measured by calculating the extension of the cable using the backscattered light and correcting the movement distance of the angular velocity sensor. Can be accurately specified. As a result, it is possible to specify the exact buried position of the pipeline.

With the above-mentioned device of the present invention, the backscattered light generated in the optical fiber is measured by an optical pulse tester, the extension of the cable is detected from the intensity change of the backscattered light, and the data of the extension of the cable is taken in by the arithmetic processing section. Correct the moving distance of the angular velocity sensor with. Then, the buried position of the pipeline is specified from the corrected moving distance and the amount of change in the moving direction detected by the angular velocity sensor.

[0014]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing a buried pipe measuring system according to this embodiment. Since the entire structure of the buried pipe measuring system according to the present embodiment is almost the same as that of the conventional system, the same members are designated by the same reference numerals and the description thereof will be omitted.

Reference numeral 11 in FIG. 1 denotes a power supply / communication cable according to this embodiment, in which an optical fiber for communication is twisted.
Reference numeral 12 is an optical pulse test device (hereinafter referred to as “OTDR device”) connected to the optical fiber of the power supply / communication cable 11.
Then, the extension of the cable 11 is detected from the change in the intensity of the backscattered light. Reference numeral 13 denotes a computer as an arithmetic processing unit, which is connected to the angular velocity sensor 1, the scale 4 and the OTDR device 12 through the optical fiber of the power supply / communication cable 11, and detects from the angular velocity sensor 1 and the scale 4. The data is calculated, and the movement distance of the angular velocity sensor 1 is corrected by the extension of the power feeding / communication cable 11 detected by the OTDR device 12. The computer 5 and the OTDR device 12 connected to the computer 5 by the optical fiber constitute a measurement distance correction device.

Next, a method of correcting the measured distance by the buried pipe measuring system having the above structure will be described.

As for the measurement of the buried pipe, the angular velocity sensor 1 is connected to the wire 6 passed through the other pipe mouth of the buried pipe 2, inserted from one pipe mouth and pulled by the winch 7, as in the prior art. . As a result, the power supply / communication cable 11 is fed into the buried pipe 2, but the cable 11 stretches due to its own weight or the like. This elongation is small at the mouth of the buried pipe 2 and increases as it approaches the angular velocity sensor 1. Due to this extension, the optical fiber of the cable 11 is distorted, and the received light intensity of the backscattered light detected by the OTDR device 12 changes.

An example of this is shown in FIG. In this graph, the vertical line indicates the received light intensity, and the horizontal line indicates the light scattering from OTD.
It is the distance to the R device 12. Power supply / communication cable 11
In the state where no tension is applied and no extension occurs, the received light intensity linearly decreases as the distance increases, as indicated by the dotted line.
However, in the state where the cable 11 is stretched by applying tension, the received light intensity sharply decreases as shown by the solid line.

In this case, the relationship between the extension amount Δl of the cable 11 due to the tension and the change amount ΔI of the received light intensity has a unique proportional relationship as shown in FIG. Therefore, the extension amount Δl of the cable 11 can be known from the change amount ΔI of the received light intensity that can be detected by the OTDR device 12. This elongation Δl
The moving distance of the angular velocity sensor 1 is corrected by.

Specifically, the amount of the power feeding / communication cable 11 sent out is measured by the scale 4, the angular velocity sensor 1 detects the change in the angular velocity, and the OTDR device 12 changes the intensity of the backscattered light. Is measured. Then, these data are transmitted to the computer 5.

In the computer 5, the moving distance of the angular velocity sensor 1 is calculated based on the detection data of the scale 4. Furthermore, the moving distance of the angular velocity sensor 1 is OTDR.
It is corrected by the expansion amount Δl of the cable 11 calculated from the data from the device 12. Also, the angular velocity sensor 1
The moving direction is calculated by the detection data from. Then, from the corrected moving distance and moving direction, the angular velocity sensor 1
Is calculated, and the buried position of the buried pipe 2 is specified.

Further, in the OTDR device 12, the extension of the power supply / communication cable 11 (directly the extension of the optical fiber) is constantly monitored while the angular velocity sensor 1 is being pulled by the winch 7. When the monitor detects an abnormal elongation, that is, when a large tension is applied to the power feeding / communication cable 11, the winch 7 is temporarily stopped to prevent the optical fiber from being broken.

As described above, power is supplied by the OTDR device 12.
Since the extension of the communication cable 11 is detected to correct the moving distance of the angular velocity sensor 1, the accurate moving distance of the angular velocity sensor 1 can be known, and the accurate position of the angular velocity sensor 1, that is, the buried pipe 2 You will be able to know the exact position of.

Further, since the expansion of the power supply / communication cable 11 is constantly monitored, it is possible to prevent accidents such as disconnection of the optical fiber.

[0026]

As described in detail above, the present invention has the following effects.

(1) Since the optical pulse test device detects the extension of the power feeding / communication cable to correct the moving distance of the angular velocity sensor, the accurate moving distance of the angular velocity sensor can be known. You can know the exact movement trajectory of. Thereby, it is possible to know the exact position of the buried pipe in which the angular velocity sensor has moved inside.

(2) Since the expansion of the power supply / communication cable is constantly monitored, accidents such as disconnection of the optical fiber can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a buried pipe measuring system according to the present invention.

FIG. 2 is a graph showing the relationship between the received light intensity of backscattered light in an optical fiber and its distance.

FIG. 3 is a graph showing the relationship between the amount of change in received light intensity and the length of a power supply / communication cable.

FIG. 4 is a schematic configuration diagram showing a conventional buried pipe measuring system.

FIG. 5 is a graph showing a relationship between elongation and tension of a power supply / communication cable.

[Explanation of symbols]

 1 Angular velocity sensor 2 Buried pipe 4 Measuring instrument 11 Power supply / communication cable 12 OTDR device 13 Computer

Claims (2)

[Claims] 1. An electric power feeding / communication cable connected to an angular velocity sensor is moved in a pipe, and the electric power is fed while the moving direction of the angular velocity sensor is measured from a change in the angular velocity generated at a bending portion or a connecting portion during the movement. -When the moving distance is measured from the sending amount of the communication cable and the moving path of the angular velocity sensor is specified and the buried position of the pipeline is specified, a cable in which an optical fiber is twisted is used as the power supply / communication cable. Measurement of the buried pipe measuring system characterized in that the extension of the cable is calculated from the intensity change of the backscattered light generated by the incidence of the pulsed light on the optical fiber, and the movement distance of the angular velocity sensor is corrected by the extension of the cable. Distance correction method. 2. An angular velocity sensor that moves in a pipe line to detect the amount of change in the moving direction at a bending portion or a connecting portion, and the movement of the angular velocity sensor based on the output amount of a power supply / communication cable connected to the angular velocity sensor. In a buried pipe measuring system, which comprises a measuring instrument for measuring a distance, and calculates the amount of change in the moving direction by the angular velocity sensor and the moving distance by the measuring instrument to identify the buried position of the pipeline, An optical fiber twisted into the cable, an optical pulse tester connected to the optical fiber to detect the extension of the cable from the change in the intensity of the backscattered light, and the movement of the angular velocity sensor due to the extension of the cable detected by the optical pulse tester. A measuring distance correcting device for a buried pipe measuring system, comprising: an arithmetic processing unit for correcting the distance.