Optical fiber sensing system, optical fiber sensing apparatus, and manhole detection method

Abstract

To detect a manhole buried in the ground.SOLUTION: An optical fiber sensing system includes: a vibration generator (30) that generates vibration on the ground; an optical fiber (10) that is buried in the ground and detects the vibration generated by the vibration generator (30); a communication portion (21) that transmits pulse light to the optical fiber (10) and receives an optical signal from the optical fiber (10); and a detection portion (22) that identifies a vibration pattern of the vibration detected by the optical fiber (10) on the basis of the optical signal received from the optical fiber (10) and detects a manhole (MH) buried in the ground on the basis of the vibration pattern of the vibration detected by the optical fiber (10).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an optical fiber sensing system, an optical fiber sensing device, and a manhole detection method. [Background technology]

[0002] In optical fiber sensing, which uses optical fiber as a sensor, optical fiber can detect vibrations. Therefore, recently, there has been research into using optical fiber sensing for various purposes by taking advantage of these characteristics of optical fiber sensing.

[0003] For example, Patent Document 1 discloses a technique that uses optical fiber sensing to identify the location of a manhole. Specifically, the technique disclosed in Patent Document 1 involves striking a manhole on an optical fiber route, and using optical fiber sensing to determine the vibrations caused by the strike, thereby identifying the strike position on the optical fiber. Then, the strike position on the optical fiber is matched with the position on a map of the struck manhole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-052030 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when paving a road, paving may be done over a manhole, and the manhole may end up being buried underground. In this case, even though the manhole actually exists underground, the existence of the manhole is not recorded as information. Therefore, a technology for detecting manholes buried underground is desired.

[0006] The technology disclosed in the above-mentioned Patent Document 1 is a technology that associates a striking position on an optical fiber with a position on a map of a manhole, assuming the existence of a manhole that can be struck. However, a manhole buried underground cannot be struck because its existence is not recorded as information. Therefore, the technology disclosed in the above-mentioned Patent Document 1 cannot detect a manhole buried underground.

[0007] In view of the above-mentioned problems, an object of the present disclosure is to provide an optical fiber sensing system, an optical fiber sensing device, and a manhole detection method capable of detecting manholes buried underground. [Means for solving the problem]

[0008] According to one aspect, an optical fiber sensing system includes: a vibration generator that generates vibrations on the ground; an optical fiber buried in the ground for detecting the vibration generated by the vibration generator; a communication unit that transmits pulsed light to the optical fiber and receives an optical signal from the optical fiber; The optical fiber is provided with a detection unit that identifies a vibration pattern of the vibration detected by the optical fiber based on an optical signal received from the optical fiber, and detects a manhole buried in the ground based on the vibration pattern of the vibration detected by the optical fiber.

[0009] An optical fiber sensing device according to one aspect includes: a communication unit that transmits pulsed light to an optical fiber buried underground and detects vibrations generated on the ground by a vibration generator, and receives an optical signal from the optical fiber; The optical fiber is provided with a detection unit that identifies a vibration pattern of the vibration detected by the optical fiber based on an optical signal received from the optical fiber, and detects a manhole buried in the ground based on the vibration pattern of the vibration detected by the optical fiber.

[0010] A manhole detection method according to one aspect includes the steps of: A manhole detection method using an optical fiber sensing device, comprising: a communication step of transmitting pulsed light to an optical fiber buried underground, the optical fiber detecting vibrations generated on the ground by a vibration generator, and receiving an optical signal from the optical fiber; The method includes a detection step of identifying a vibration pattern of the vibration detected by the optical fiber based on the optical signal received from the optical fiber, and detecting a manhole buried in the ground based on the vibration pattern of the vibration detected by the optical fiber. Effect of the Invention

[0011] According to the above-mentioned aspects, it is possible to provide an optical fiber sensing system, an optical fiber sensing device, and a manhole detection method capable of detecting a manhole buried underground. [Brief description of the drawings]

[0012] [Figure 1] 1 is a diagram illustrating a configuration example of an optical fiber sensing system according to a first embodiment. [Diagram 2] 4 is a flowchart showing an example of a schematic operation flow of the optical fiber sensing system according to the first embodiment. FIG. [Diagram 3] FIG. 11 is a diagram illustrating a configuration example of an optical fiber sensing system according to a second embodiment. [Figure 4] FIG. 11 is a diagram showing an example of a correspondence table in which the identification unit according to the second embodiment associates optical fiber distances with GPS position information for manholes buried underground. [Diagram 5] 10 is a flowchart showing an example of a schematic operation flow of the optical fiber sensing system according to the second embodiment. FIG. [Figure 6] FIG. 11 is a diagram illustrating a configuration example of an optical fiber sensing system according to a third embodiment. [Figure 7]FIG. 13 is a diagram showing an example of a GUI screen displayed on a display unit according to the third embodiment, in which the positions of manholes buried underground are superimposed on a map. [Figure 8] FIG. 11 is a flowchart showing an example of a schematic operation flow of the optical fiber sensing system according to the third embodiment. [Figure 9] FIG. 2 is a block diagram showing an example of a hardware configuration of a computer that realizes the optical fiber sensing devices according to the first to third embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. Note that the following description and drawings are omitted and simplified as appropriate for clarity of explanation. In addition, in each of the following drawings, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary.

[0014] <Embodiment 1> First, with reference to FIG. 1, a configuration example of an optical fiber sensing system according to the first embodiment will be described.

[0015] As shown in FIG. 1, the optical fiber sensing system according to the first embodiment includes an optical fiber 10, an optical fiber sensing device 20, and a vibration generator 30.

[0016] The optical fiber 10 is buried in the ground. In the example of Fig. 1, the optical fiber 10 is buried in the ground in such a manner that it is passed through a buried pipeline P buried in the ground G. However, the manner in which the optical fiber 10 is laid is not limited to the manner in which it is passed through the buried pipeline P. Moreover, one end of the optical fiber 10 is connected to an optical fiber sensing device 20 .

[0017] The vibration generator 30 is configured to be movable on the ground by being carried by a user or mounted on a moving body such as a vehicle. The vibration generator 30 generates vibrations at the destination every time the vibration generator 30 moves.

[0018] The optical fiber sensing device 20 is realized by a sensing device such as a Distributed Fiber Optic Sensing (DFOS) device, and includes a communication unit 21 and a detection unit 22.

[0019] The communication unit 21 transmits pulsed light to the optical fiber 10. In addition, the communication unit 21 receives backscattered light generated as the pulsed light is transmitted through the optical fiber 10 from the optical fiber 10 as an optical signal.

[0020] The optical fiber 10 detects the vibration generated by the vibration generator 30. Therefore, the vibration detected by the optical fiber 10 is superimposed on the optical signal received by the communication unit 21 from the optical fiber 10.

[0021] Here, the vibration pattern of the vibration detected by the optical fiber 10 is characterized in that it differs greatly depending on whether or not a manhole MH buried in the ground is present between the vibration generator 30 and the optical fiber 10. Note that Fig. 1 shows a situation in which a manhole MH buried in the ground is present between the vibration generator 30 and the optical fiber 10.

[0022] Therefore, the detection unit 22 identifies the vibration pattern of the vibration detected by the optical fiber 10 based on the optical signal received from the optical fiber 10 by the communication unit 21, and detects the manhole MH buried in the ground based on the vibration pattern of the vibration detected by the optical fiber 10.

[0023] Specifically, when the vibration generator 30 generates vibrations in a situation where a manhole MH buried in the ground is interposed between the vibration generator 30 and the optical fiber 10, the detection unit 22 stores in advance a vibration pattern of the vibration detected by the optical fiber 10 as a reference vibration pattern. When detecting a manhole MH buried in the ground, the detection unit 22 performs pattern matching between the vibration pattern of the vibration detected by the optical fiber 10 and the previously stored reference vibration pattern to detect the manhole MH buried in the ground (in detail, the detection unit 22 detects the manhole MH that is interposed between the vibration generator 30 and the optical fiber 10 and is buried in the ground).

[0024] Next, with reference to FIG. 2, an example of a schematic operation flow of the optical fiber sensing system according to the first embodiment will be described.

[0025] 2, the communication unit 21 transmits pulsed light to the optical fiber 10 and receives backscattered light as an optical signal from the optical fiber 10 (step S11). The process of step S11 is continuously performed thereafter.

[0026] Meanwhile, the vibration generator 30 generates vibrations on the ground (step S12). The processing of steps S11 and S12 can be started in any order, but they must be performed simultaneously while the manhole MH is being detected.

[0027] Next, the detection unit 22 identifies the vibration pattern of the vibration detected by the optical fiber 10 based on the optical signal received by the communication unit 21 in step S11 (step S13). Thereafter, the detection unit 22 detects a manhole MH buried underground based on the vibration pattern of the vibration detected by the optical fiber 10, which was specified in step S12 (step S14).

[0028] As described above, according to the first embodiment, the communication unit 21 transmits pulsed light to the optical fiber 10 and receives an optical signal from the optical fiber 10. The detection unit 22 identifies the vibration pattern of the vibration detected by the optical fiber 10 based on the optical signal, and detects the manhole MH buried in the ground based on the identified vibration pattern. This makes it possible to detect the manhole MH buried in the ground.

[0029] <Embodiment 2> First, with reference to FIG. 3, a configuration example of an optical fiber sensing system according to the second embodiment will be described.

[0030] As shown in Figure 3, the optical fiber sensing system of this embodiment 2 differs from the configuration of the optical fiber sensing system of the above-mentioned embodiment 1 in Figure 1 in that the optical fiber sensing device 20 is replaced with an optical fiber sensing device 20A, and the vibration generator 30 is replaced with a vibration generator 30A.

[0031] Vibration generator 30A differs from vibration generator 30 according to the above-described first embodiment in that a GPS (Global Positioning System) function and a communication function are additionally provided. That is, the vibration generator 30A calculates GPS position information indicating the latitude / longitude of the vibration generator 30A when vibration is generated based on a satellite signal from a GPS satellite, and transmits the calculated GPS position information to the optical fiber sensing device 20A. Note that the transmission of the GPS position information to the optical fiber sensing device 20A may be performed by wireless communication of any wireless communication method.

[0032] The optical fiber sensing device 20A differs from the optical fiber sensing device 20 according to the above-described first embodiment in that a specifying unit 23 is added. The determination unit 23 is capable of determining the distance of the optical fiber 10 from the location of the optical fiber sensing device 20A (communication unit 21) to the location where the optical fiber 10 detects vibration based on the time difference between the time when the communication unit 21 transmits pulsed light to the optical fiber 10 and the time when the communication unit 21 receives an optical signal with vibration superimposed thereon from the optical fiber 10.

[0033] Therefore, when the detection unit 22 detects a manhole MH buried in the ground, the identification unit 23 identifies the distance of the optical fiber 10 from the location of the optical fiber sensing device 20A (communication unit 21) to the location where the optical fiber 10 detected the vibration, i.e., the distance of the optical fiber 10 to the location where the manhole MH buried in the ground was detected.

[0034] In addition, when the detection unit 22 detects a manhole MH buried in the ground, the identification unit 23 acquires the GPS position information of the vibration generator 30A when vibration was generated, transmitted from the vibration generator 30A, as the GPS position information of the manhole MH buried in the ground.

[0035] Then, the identifying unit 23 associates the distance of the optical fiber 10 identified above with the GPS position information acquired from the vibration generator 30A for the manhole MH buried in the ground. An example of a correspondence table resulting from this association is shown in FIG. 4. In the example of FIG. 4, for example, as the position of manhole A among the manholes MH buried in the ground, the distance a of the optical fiber 10 from the location of the optical fiber sensing device 20A (communication unit 21) is associated with the latitude / longitude: Xa / Ya indicated by the GPS position information. Note that, in the example of FIG. 4, names such as manhole A, B, etc. are given to the manholes MH buried in the ground, but the names may be given arbitrarily. In addition, the correspondence table shown in FIG. 4 may be held by the identifying unit 23, or may be held by any component inside or outside the optical fiber sensing device 20A.

[0036] Next, with reference to FIG. 5, an example of a schematic operation flow of the optical fiber sensing system according to the second embodiment will be described.

[0037] As shown in FIG. 5, first, the processes of steps S21 to S24 similar to steps S11 to S14 in FIG. 2 of the above-mentioned first embodiment are performed.

[0038] If the manhole MH buried in the ground is detected by the detection unit 22 in step S24 (Yes in step S24), the identification unit 23 identifies the distance of the optical fiber 10 from the location of the optical fiber sensing device 20A (communication unit 21) to the location where the manhole MH buried in the ground is detected, based on the pulsed light and optical signal transmitted and received by the communication unit 21 in step S21 (step S25). In addition, the identification unit 23 acquires, from the vibration generator 30A, GPS position information of the vibration generator 30A when vibration is generated as GPS position information of the manhole MH buried in the ground, and associates the acquired GPS position information with the distance of the optical fiber 10 identified in step S25 (step S26). On the other hand, if the manhole MH buried in the ground is not detected by the detection unit 22 in step S24 (No in step S24), the process ends.

[0039] As described above, according to the second embodiment, when the detection unit 22 detects a manhole MH buried in the ground, the identification unit 23 identifies the distance of the optical fiber 10 from the location of the optical fiber sensing device 20A (communication unit 21) to the location where the manhole MH buried in the ground is detected, based on the pulsed light and the optical signal. In addition, the identification unit 23 acquires, from the vibration generator 30A, GPS position information of the vibration generator 30A when vibration is generated as GPS position information of the manhole MH buried in the ground, and associates the acquired GPS position information with the distance of the optical fiber 10 identified above. As a result, the location of the manhole MH buried in the ground can be identified as the distance of the optical fiber 10 and the GPS position information, and the distance of the optical fiber 10 can be associated with the GPS position information. The other effects are the same as those of the first embodiment described above.

[0040] <Embodiment 3> First, with reference to FIG. 6, a configuration example of an optical fiber sensing system according to the third embodiment will be described.

[0041] As shown in Figure 6, the optical fiber sensing system of this embodiment 3 differs from the configuration of the optical fiber sensing system of the above-mentioned embodiment 2 in Figure 3 in that the optical fiber sensing device 20A is replaced by optical fiber sensing device 20B and a display unit 40 is added.

[0042] The display unit 40 is realized by a display, a monitor, etc. In the example of Fig. 6, the display unit 40 is provided outside the optical fiber sensing device 20B, but is not limited to this and may be provided inside the optical fiber sensing device 20B.

[0043] The optical fiber sensing device 20B differs from the optical fiber sensing device 20A according to the above-described second embodiment in that a display control unit 24 is added. The display control unit 24 causes various GUI (Graphical User Interface) screens to be displayed on the display unit 40. In the third embodiment, when a manhole MH buried in the ground is detected by the detection unit 22, the display control unit 24 causes the display unit 40 to display the position indicated by the GPS position information acquired from the vibration generator 30A as the position of the manhole MH buried in the ground, superimposed on a map. An example of the GUI screen is shown in Fig. 7.

[0044] Next, with reference to FIG. 8, an example of a schematic operation flow of the optical fiber sensing system according to the third embodiment will be described.

[0045] As shown in FIG. 8, first, the processes of steps S31 to S36 similar to steps S21 to S26 in FIG. 5 of the above-mentioned second embodiment are performed.

[0046] After the processing of step S36, the display control unit 24 causes the display unit 40 to display the position indicated by the GPS position information acquired from the vibration generator 30A as the position of the manhole MH buried in the ground, superimposed on the map (step S37).

[0047] As described above, according to the third embodiment, when the detection unit 22 detects a manhole MH buried in the ground, the display control unit 24 causes the position indicated by the GPS position information acquired from the vibration generator 30A to be displayed as the position of the manhole MH buried in the ground, superimposed on a map, on the display unit 40. This allows the user to visually recognize the position of the manhole MH buried in the ground. The other effects are the same as those of the second embodiment described above.

[0048] <Other embodiments> In the above-mentioned first to third embodiments, the communication unit 21, the detection unit 22, the identification unit 23, and the display control unit 24 are provided in the same optical fiber sensing device 20, 20A, 20B, but this is not limited thereto and they may be arranged separately from each other. For example, the communication unit 21, the detection unit 22, the identification unit 23, and the display control unit 24 may be arranged in separate devices. Furthermore, the detection unit 22, the identification unit 23, and the display control unit 24 may be arranged on the cloud.

[0049] <Hardware configuration of the optical fiber sensing device according to the embodiment> Next, with reference to FIG. 9, an example of the hardware configuration of a computer that realizes the optical fiber sensing devices 20, 20A, and 20B according to the above-mentioned first to third embodiments will be described.

[0050] 9, a computer 90 includes a processor 91, a memory 92, a storage 93, an input / output interface (input / output I / F) 94, and a communication interface (communication I / F) 95. The processor 91, the memory 92, the storage 93, the input / output interface 94, and the communication interface 95 are connected by a data transmission path for transmitting and receiving data to and from each other.

[0051] The processor 91 is, for example, an arithmetic processing device such as a central processing unit (CPU) or a graphics processing unit (GPU). The memory 92 is, for example, a random access memory (RAM) or a read only memory (ROM). The storage 93 is, for example, a storage device such as a hard disk drive (HDD), a solid state drive (SSD), or a memory card. The storage 93 may also be a memory such as a RAM or a ROM.

[0052] The storage 93 stores programs that realize the functions of the components of the optical fiber sensing devices 20, 20A, and 20B. The processor 91 executes each of these programs to realize the functions of the components of the optical fiber sensing devices 20, 20A, and 20B. When executing each of the above programs, the processor 91 may read these programs onto the memory 92 before executing them, or may execute them without reading them onto the memory 92. The memory 92 and the storage 93 also serve to store information and data held by the components of the optical fiber sensing devices 20, 20A, and 20B.

[0053] The above-mentioned program can be stored using various types of non-transitory computer readable media and can be provided to a computer (including the computer 90). The non-transitory computer readable medium includes various types of tangible storage media. Examples of the non-transitory computer readable medium include magnetic recording media (e.g., flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (e.g., magneto-optical disks), compact disc-ROMs (CD-ROMs), CD-recordables (CD-Rs), CD-rewritables (CD-R / Ws), and semiconductor memories (e.g., mask ROMs, programmable ROMs (PROMs), erasable PROMs (EPROMs), flash ROMs, and RAMs). The program can also be provided to a computer by various types of transitory computer readable media. Examples of the transitory computer readable medium include electric signals, optical signals, and electromagnetic waves. The transitory computer readable medium can provide the program to a computer via a wired communication path such as an electric wire and an optical fiber, or via a wireless communication path.

[0054] The input / output interface 94 is connected to a display device 941, an input device 942, a sound output device 943, and the like. The display device 941 is a device that displays a screen corresponding to drawing data processed by the processor 91, such as an LCD (Liquid Crystal Display), a CRT (Cathode Ray Tube) display, or a monitor. The input device 942 is a device that accepts an operation input by an operator, and is, for example, a keyboard, a mouse, or a touch sensor. The display device 941 and the input device 942 may be integrated and realized as a touch panel. The sound output device 943 is a device that acoustically outputs a sound corresponding to the sound data processed by the processor 91, such as a speaker.

[0055] The communication interface 95 transmits and receives data to and from an external device. For example, the communication interface 95 communicates with the external device via a wired communication path or a wireless communication path.

[0056] Although the present disclosure has been described above with reference to the embodiments, the present disclosure is not limited to the above-described embodiments. Various modifications that can be understood by a person skilled in the art can be made to the configuration and details of the present disclosure within the scope of the present disclosure. For example, the above-described embodiments may be used in combination with one another in whole or in part.

[0057] Furthermore, some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes. (Appendix 1) a vibration generator that generates vibrations on the ground; an optical fiber buried in the ground for detecting the vibration generated by the vibration generator; a communication unit that transmits pulsed light to the optical fiber and receives an optical signal from the optical fiber; a detection unit that identifies a vibration pattern of the vibration detected by the optical fiber based on an optical signal received from the optical fiber, and detects a manhole buried underground based on the vibration pattern of the vibration detected by the optical fiber. Fiber optic sensing system. (Appendix 2) The detection unit is storing in advance a reference vibration pattern, which is a vibration pattern of the vibration generated by the vibration generator in a situation where a manhole buried underground is interposed between the vibration generator and the optical fiber; detecting a manhole that is interposed between the vibration generator and the optical fiber and that is buried underground, based on a vibration pattern of the vibration detected by the optical fiber and the reference vibration pattern; 2. The optical fiber sensing system of claim 1. (Appendix 3) and a determination unit that, when a manhole buried underground is detected by the detection unit, determines a distance of the optical fiber from a location of the communication unit to a location of the manhole buried underground based on the pulsed light and the optical signal. 2. The optical fiber sensing system of claim 1. (Appendix 4) The vibration generator has a GPS (Global Positioning System) function, When a manhole buried in the ground is detected by the detection unit, the identification unit acquires, from the vibration generator, GPS location information of the vibration generator at the time when the vibration generator generated vibration, and associates the identified distance of the optical fiber with the acquired GPS location information. 4. The optical fiber sensing system of claim 3. (Appendix 5) A display control unit is further provided that causes the display unit to display the position indicated by the acquired GPS position information as the position of a manhole buried underground by superimposing the position on a map. 5. The optical fiber sensing system of claim 4. (Appendix 6) The vibration generator is configured to be movable on the ground and generates vibrations at a destination each time the vibration generator moves. 2. The optical fiber sensing system of claim 1. (Appendix 7) a communication unit that transmits pulsed light to an optical fiber buried underground and detects vibrations generated on the ground by a vibration generator, and receives an optical signal from the optical fiber; a detection unit that identifies a vibration pattern of the vibration detected by the optical fiber based on an optical signal received from the optical fiber, and detects a manhole buried underground based on the vibration pattern of the vibration detected by the optical fiber. Optical fiber sensing device. (Appendix 8) The detection unit is storing in advance a reference vibration pattern, which is a vibration pattern of the vibration generated by the vibration generator in a situation where a manhole buried underground is interposed between the vibration generator and the optical fiber; detecting a manhole that is interposed between the vibration generator and the optical fiber and that is buried underground, based on a vibration pattern of the vibration detected by the optical fiber and the reference vibration pattern; 8. The optical fiber sensing device of claim 7. (Appendix 9) and a determination unit that, when a manhole buried underground is detected by the detection unit, determines a distance of the optical fiber from a location of the communication unit to a location of the manhole buried underground based on the pulsed light and the optical signal. 8. The optical fiber sensing device of claim 7. (Appendix 10) The vibration generator has a GPS (Global Positioning System) function, When a manhole buried in the ground is detected by the detection unit, the identification unit acquires, from the vibration generator, GPS location information of the vibration generator at the time when the vibration generator generated vibration, and associates the identified distance of the optical fiber with the acquired GPS location information. 10. The optical fiber sensing device of claim 9. (Appendix 11) A display control unit is further provided that causes the display unit to display the position indicated by the acquired GPS position information as the position of a manhole buried underground by superimposing the position on a map. 11. The optical fiber sensing device of claim 10. (Appendix 12) The vibration generator is configured to be movable on the ground and generates vibrations at a destination each time the vibration generator moves. 8. The optical fiber sensing device of claim 7. (Appendix 13) A manhole detection method using an optical fiber sensing device, comprising: a communication step of transmitting pulsed light to an optical fiber buried underground, the optical fiber detecting vibrations generated on the ground by a vibration generator, and receiving an optical signal from the optical fiber; A detection step of identifying a vibration pattern of the vibration detected by the optical fiber based on the optical signal received from the optical fiber, and detecting a manhole buried underground based on the vibration pattern of the vibration detected by the optical fiber. Manhole detection method. (Appendix 14) The method further includes a holding step of holding in advance a reference vibration pattern, which is a vibration pattern of vibration generated by the vibration generator in a situation where a manhole buried underground is interposed between the vibration generator and the optical fiber, In the detection step, detecting a manhole that is interposed between the vibration generator and the optical fiber and that is buried underground, based on a vibration pattern of the vibration detected by the optical fiber and the reference vibration pattern; 14. The manhole detection method according to claim 13. (Appendix 15) and a step of determining a distance of the optical fiber from a location of the optical fiber sensing device to a location of the manhole buried underground based on the pulsed light and the optical signal when the manhole buried underground is detected by the detection step. 14. The manhole detection method according to claim 13. (Appendix 16) The vibration generator has a GPS (Global Positioning System) function, In the identifying step, when a manhole buried underground is detected in the detecting step, GPS location information of the vibration generator at the time when the vibration generator generates vibration is acquired from the vibration generator, and the identified distance of the optical fiber is associated with the acquired GPS location information. 16. The manhole detection method according to claim 15. (Appendix 17) A display control step of displaying the position indicated by the acquired GPS position information as the position of a manhole buried in the ground on a display unit by superimposing the position on a map, 17. The manhole detection method according to claim 16. (Appendix 18) The vibration generator is configured to be movable on the ground and generates vibrations at a destination each time the vibration generator moves. 14. The manhole detection method according to claim 13. [Explanation of symbols]

[0058] 10 Optical Fiber 20, 20A, 20B Optical fiber sensing device 21 Communications Department 22 Detection unit 23 Specific section 24 Display control section 30,30A Vibration Generator 40 Display section 90 Computer 91 Processor 92 Memory 93 Storage 94 Input / Output Interface 941 Display device 942 Input Device 943 Sound output device 95 Communication Interface MH Manhole P Buried pipe

Claims

1. a vibration generator that generates vibrations on the ground; an optical fiber buried in the ground for detecting the vibration generated by the vibration generator; a communication unit that transmits pulsed light to the optical fiber and receives an optical signal from the optical fiber; a detection unit that identifies a vibration pattern of the vibration detected by the optical fiber based on an optical signal received from the optical fiber, and detects a manhole buried underground based on the vibration pattern of the vibration detected by the optical fiber. Fiber optic sensing system.

2. The detection unit is storing in advance a reference vibration pattern, which is a vibration pattern of the vibration generated by the vibration generator in a situation where a manhole buried underground is interposed between the vibration generator and the optical fiber; detecting a manhole that is interposed between the vibration generator and the optical fiber and that is buried underground, based on a vibration pattern of the vibration detected by the optical fiber and the reference vibration pattern; The optical fiber sensing system of claim 1 .

3. and a determination unit that, when a manhole buried underground is detected by the detection unit, determines a distance of the optical fiber from a location of the communication unit to a location of the manhole buried underground based on the pulsed light and the optical signal. The optical fiber sensing system of claim 1 .

4. The vibration generator has a GPS (Global Positioning System) function, When a manhole buried in the ground is detected by the detection unit, the identification unit acquires, from the vibration generator, GPS location information of the vibration generator at the time when the vibration generator generated vibration, and associates the identified distance of the optical fiber with the acquired GPS location information. The optical fiber sensing system of claim 3 .

5. A display control unit that displays the position indicated by the acquired GPS position information as the position of the manhole buried in the ground on a display unit by superimposing the position on a map. The optical fiber sensing system of claim 4 .

6. The vibration generator is configured to be movable on the ground and generates vibrations at a destination each time the vibration generator moves. The optical fiber sensing system of claim 1 .

7. a communication unit that transmits pulsed light to an optical fiber buried underground and detects vibrations generated on the ground by a vibration generator, and receives an optical signal from the optical fiber; a detection unit that identifies a vibration pattern of the vibration detected by the optical fiber based on an optical signal received from the optical fiber, and detects a manhole buried underground based on the vibration pattern of the vibration detected by the optical fiber. Optical fiber sensing device.

8. The detection unit is storing in advance a reference vibration pattern, which is a vibration pattern of the vibration generated by the vibration generator in a situation where a manhole buried underground is interposed between the vibration generator and the optical fiber; detecting a manhole that is interposed between the vibration generator and the optical fiber and that is buried underground, based on a vibration pattern of the vibration detected by the optical fiber and the reference vibration pattern; 8. The optical fiber sensing device according to claim 7.

9. and a determination unit that, when a manhole buried in the ground is detected by the detection unit, determines a distance of the optical fiber from a location of the communication unit to a location of the manhole buried in the ground based on the pulsed light and the optical signal.

8. The optical fiber sensing device according to claim 7.

10. The vibration generator has a GPS (Global Positioning System) function, When a manhole buried in the ground is detected by the detection unit, the identification unit acquires, from the vibration generator, GPS location information of the vibration generator at the time when the vibration generator generated vibration, and associates the identified distance of the optical fiber with the acquired GPS location information.

10. The optical fiber sensing device according to claim 9.

11. A display control unit that displays the position indicated by the acquired GPS position information as the position of the manhole buried in the ground on a display unit by superimposing the position on a map. The optical fiber sensing device according to claim 10.

12. The vibration generator is configured to be movable on the ground and generates vibrations at a destination each time the vibration generator moves.

8. The optical fiber sensing device according to claim 7.

13. A manhole detection method using an optical fiber sensing device, comprising: a communication step of transmitting pulsed light to an optical fiber buried underground, the optical fiber detecting vibrations generated on the ground by a vibration generator, and receiving an optical signal from the optical fiber; A detection step of identifying a vibration pattern of the vibration detected by the optical fiber based on the optical signal received from the optical fiber, and detecting a manhole buried underground based on the vibration pattern of the vibration detected by the optical fiber. Manhole detection method.

14. The method further includes a holding step of holding in advance a reference vibration pattern, which is a vibration pattern of vibration generated by the vibration generator in a situation where a manhole buried underground is interposed between the vibration generator and the optical fiber, In the detection step, detecting a manhole that is interposed between the vibration generator and the optical fiber and that is buried underground, based on a vibration pattern of the vibration detected by the optical fiber and the reference vibration pattern; The manhole detection method according to claim 13.

15. and a step of determining a distance of the optical fiber from a location of the optical fiber sensing device to a location of the manhole buried underground based on the pulsed light and the optical signal when a manhole buried underground is detected by the detection step. The manhole detection method according to claim 13.

16. The vibration generator has a GPS (Global Positioning System) function, In the identifying step, when a manhole buried underground is detected in the detecting step, GPS location information of the vibration generator at the time when the vibration generator generates vibration is acquired from the vibration generator, and the identified distance of the optical fiber is associated with the acquired GPS location information. The manhole detection method according to claim 15.

17. A display control step of displaying the position indicated by the acquired GPS position information as the position of the manhole buried in the ground on a display unit by superimposing the position on a map. The manhole detection method according to claim 16.

18. The vibration generator is configured to be movable on the ground and generates vibrations at a destination each time the vibration generator moves. The manhole detection method according to claim 13.

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