WO2020059640A1 - Manhole position specification method and manhole position specification system - Google Patents

Manhole position specification method and manhole position specification system Download PDF

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Publication number
WO2020059640A1
WO2020059640A1 PCT/JP2019/035986 JP2019035986W WO2020059640A1 WO 2020059640 A1 WO2020059640 A1 WO 2020059640A1 JP 2019035986 W JP2019035986 W JP 2019035986W WO 2020059640 A1 WO2020059640 A1 WO 2020059640A1
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Prior art keywords
manhole
optical fiber
vibration
scattered light
impact
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PCT/JP2019/035986
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French (fr)
Japanese (ja)
Inventor
岡本　達也
飯田　大輔
博之 押田
真鍋　哲也
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日本電信電話株式会社
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Priority claimed from JP2019058575A external-priority patent/JP6974747B2/en
Application filed by 日本電信電話株式会社 filed Critical 日本電信電話株式会社
Priority to US17/275,327 priority Critical patent/US11644347B2/en
Publication of WO2020059640A1 publication Critical patent/WO2020059640A1/en

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    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
    • E02D29/00—Independent underground or underwater structures; Retaining walls
    • E02D29/12—Manhole shafts; Other inspection or access chambers; Accessories therefor
    • E02D29/14—Covers for manholes or the like; Frames for covers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for

Definitions

  • the present invention is a technology for specifying the position of a manhole through which an optical fiber communication line passes by expressing the position of the manhole by an optical fiber length from a communication aggregation building.
  • Non-Patent Document 2 for detecting whether an optical closure containing an optical fiber is submerged by a remote light test using OTDR (Optical Time Domain Reflectometry: Optical Time Domain Backscattering Measurement Method).
  • the location is specified by the distance of the optical fiber from the OTDR in the optical fiber communication path. For example, when the inside of a manhole is submerged and the optical closure is submerged, the OTDR detects the distance from the communication building. At this time, the manhole to be operated is specified with reference to a database in which the route and the position of the manhole are described.
  • Non-patent Document 1 As a technology for remotely measuring a state on an optical fiber, there is a vibration sensor to which the OTDR is applied (Non-patent Document 1). With this vibration sensor, when the optical fiber moves, it is possible to measure the vibration of the optical fiber and the position represented by the fiber length by detecting the time change in which the length changes minutely. It is a distributed sensor. As a distributed sensor for detecting vibration due to a minute change in the length of an optical fiber, there is a sensor using an interferometer other than the sensor using OTDR (Non-Patent Document 3).
  • the location is specified only by the distance on the tested optical fiber.
  • the optical fiber length differs greatly from the distance on the map due to the length of the pre-length at the connection part, and may be changed as necessary by adding a branch or connection with a cable on the route. You. For this reason, the optical fiber length as an index indicating the position of the manhole is not a reliable index.
  • the optical fiber length is associated with the manhole position, the position of the manhole to be worked is specified, and the position is specified by the manhole optical fiber length.
  • the purpose of the present invention is to clarify the above route and to enable the management of manhole positions by the length of optical fibers on a database.
  • Another object of the present invention is to provide a vibration position specifying technique using optical fiber vibration sensing and vibration imparting, in which signal processing is performed on a measurement result to facilitate specifying a vibration position.
  • a first aspect of the manhole position specifying method is a method for detecting the time of scattered light from the optical fiber when a hit is applied to the manhole cover on the optical fiber path.
  • a second step of specifying a hitting position on the optical fiber by determining based on a time change, and a position on the map of the manhole that has hit the hitting position and the lid on the optical fiber; And a third step of specifying a position represented by an optical fiber length from the end of the manhole.
  • a predetermined vibration is applied to the lid as the blow, at a designated frequency, temporal timing, or pulsing,
  • the vibration due to the impact is detected by performing a filtering process for extracting the predetermined vibration component on the signal of the time change at each position of the scattered light intensity distribution.
  • a predetermined vibration at a specified frequency is applied to the lid as the impact
  • the signal of the time change at each position of the scattered light intensity distribution is calculated by calculating a spectrum of an envelope and performing a filtering process for extracting a peak of the specified frequency in the spectrum, thereby detecting the vibration due to the impact.
  • the impact and the measurement of the time change of the scattered light are measured using a communication interface. To synchronize.
  • a backward pulse generated by applying a light pulse to the measurement of the time change of the scattered light is provided.
  • An optical time domain backscatter measurement method for measuring scattered light is used, and the frequency of the impact is set to a frequency having a period longer than the time when the light pulse reciprocates in the optical fiber.
  • the scattering of the optical fiber may be performed by using an optical interferometer from both ends of the optical fiber. A method of measuring a time change of light is used.
  • a seventh aspect of the manhole locating system is a manhole locating system connected to an end of an optical fiber for locating a manhole on a path of the optical fiber, wherein a hit is applied to the manhole cover. And measuring the time change of the scattered light from the optical fiber from the end by measuring the time change of the scattered light intensity distribution in the longitudinal direction of the optical fiber.
  • the hitting position on the optical fiber is specified by making a determination based on the time change at each position of the scattered light intensity distribution, and the hitting position on the optical fiber and the manhole hit against the lid
  • a signal processing unit that specifies a position represented by an optical fiber length from the end of the manhole by associating the position with the position on the map. .
  • An eighth aspect of the manhole location specifying system further comprising a vibration mechanism that applies a predetermined vibration to the lid as the blow by a specified frequency, time timing or pulsing,
  • the signal processing unit detects the vibration due to the impact by performing a filter process for extracting the predetermined vibration component on the signal of the time change at each position of the scattered light intensity distribution.
  • a ninth aspect of the manhole location specifying system further includes a vibration mechanism that applies a predetermined vibration by a specified frequency, temporal timing, or pulsation to the lid as the blow.
  • the signal processing unit detects the vibration due to the impact by performing a filter process for extracting the predetermined vibration component on the signal of the time change at each position of the scattered light intensity distribution.
  • the position of the manhole represented by the optical fiber length measured by a remote test or the like can be determined by simply hitting the lid at the site without opening the manhole. Can be associated with each other. This makes it possible to specify the position of the manhole to be worked during operation of the optical fiber line and to convert the position data represented by the optical fiber length into a database, thereby contributing to route determination during maintenance and the like.
  • vibration position identification technology using optical fiber vibration sensing and vibration imparting, even if the SNR (signal-to-noise ratio) of the measured signal is extremely low, vibration due to impact can be easily achieved. Can be detected.
  • SNR signal-to-noise ratio
  • FIG. 1 is a diagram illustrating a configuration of a system according to a first exemplary embodiment of the present invention. It is a figure showing composition of an optical fiber vibration sensor. It is a figure showing the image of the waveform group measured by the vibration sensor of an optical fiber. It is a figure showing a subject of a vibration position specification method of Embodiment 3 of the present invention. It is a figure which shows the vibration position identification system of Embodiment 3 of this invention. It is a figure showing the composition figure of the vibration position specific device of Embodiment 3 of the present invention.
  • FIG. 13 is a diagram illustrating a flowchart of a vibration position specifying method according to a third embodiment of the present invention.
  • FIG. 14 is a diagram illustrating a specific example of a vibration position specifying method according to a third embodiment of the present invention.
  • FIGS. 1 The configuration of the system according to the first embodiment of the present invention is shown in FIGS.
  • a manhole cover is hit, a vibration is applied to the optical fiber 3 installed in the manhole 1-n (n is an integer of 1 or more), and the longitudinal distribution of the vibration is measured.
  • a manhole position specifying system having the vibration sensor 2 for specifying the position of the manhole 1-n designated only by the optical fiber length from the optical communication aggregation building 4 from the result obtained from the measurement will be described.
  • the vibration sensor 2 is installed in the optical communication aggregation building 4.
  • the vibration sensor 2 has an optical measuring device 5a for measuring the longitudinal distribution of the vibration, and a signal processing unit 5b for specifying the position of the manhole from the result obtained from the measurement.
  • the measuring method is an optical time domain backscattering measuring method. Threshold determination, filter processing, and the like, which will be described later, are performed by a computer (computer) in the signal processing unit 5b.
  • the communication interface is also built in the signal processing unit 5b.
  • the manhole whose position represented by the optical fiber length of the manhole to be operated by the inundation detection module or the like is known as 1-1.
  • 1-1 The manhole whose position represented by the optical fiber length of the manhole to be operated by the inundation detection module or the like.
  • n is an integer of 2 or more
  • workers near the manhole but the manhole to be operated only with the fiber length is unknown.
  • the optical fiber 3 passing through the manhole to be specified by the optical fiber vibration sensor 2 in the communication building is measured.
  • the worker hits the manhole without opening the lid.
  • the vibration propagates to the entire housing of the manhole, and the vibration also vibrates the optical cable in the manhole.
  • the vibration is detected by the vibration sensor 2 of the optical fiber, and is represented by the optical fiber length.
  • the position can be associated with the position of the manhole on the map when working on site. This association is sequentially performed for the manholes 1-1 to 1-n, and a manhole having light existing at the same fiber length as the optical fiber length known as the position of the manhole to be worked on in advance is specified.
  • the timing may be adjusted by telephone or the like. Even if there is only a worker who hits, the vibration sensor 2 of the optical fiber is provided with a communication interface such as an Ethernet (registered trademark) terminal and an IP control function, and the worker who hits the mobile device such as a smartphone. It is possible to adjust the timing by operating the terminal by remote communication.
  • a communication interface is provided to the signal processing unit 5b of the optical fiber vibration sensor 2 so that, when a manhole is hit, the impact and the measurement of the optical fiber by the vibration sensor 2 are synchronized using the communication interface.
  • the vibration of the impact is detected by simultaneously performing the impact and the measurement by one manhole hitter and measuring the waveform.
  • a method may be employed in which the measurement is continuously performed by the vibration sensor 2 and an impact is made during that time.
  • the measurement waveform may be checked by a worker who measures the communication waveform in the communication building, or the measurement result may be remotely transmitted to the worker who is hit by the communication means to check the measurement result.
  • the waveform due to the impact is detected by measuring the time change of the scattered light from a specific position in the optical fiber.
  • the resolution at the time of measuring the distribution of vibration with the vibration sensor needs to be about several meters or less in consideration of specifying the position of the manhole. At this time, if the range expressed by the fiber length for searching the manhole is about 100 m, for example, You need to look at ten waveforms, and you will search for them while hitting them.
  • FIG. 3 shows an image of a group of measured waveforms.
  • the manhole position specifying method of the present embodiment includes the following steps (S1) to (S3).
  • the vibration sensor 2 measures the time-change waveform of the scattered light from each point of the optical fiber 3 when the manhole cover on the path of the optical fiber 3 is hit.
  • the vibration position of the optical fiber 3 is measured distributionally (S1).
  • the generation of the vibration due to the impact is determined by the threshold value of the magnitude of the scattered light change.
  • the position is measured (S2).
  • the optical communication aggregation building The position of the manhole specified only by the optical fiber length from is specified (S3). That is, the manhole position specifying method according to the present embodiment uses the time change of the scattered light from the optical fiber 3 when the cover of the manhole 1-n on the path of the optical fiber 3 is hit with the end thereof.
  • the waveform due to the vibration appears strongly against the disturbance, if the fluctuation of the waveform due to the impact vibration is determined based on the threshold value, the waveform can be selected from a number of time waveforms in the position range to be searched in the optical fiber. If the position where the movement exceeds the threshold value is detected, the hit position and the optical fiber length can be easily associated. At this time, the worker may give a blow by any method. For example, a very simple method such as hitting with a hammer having a size that can be held with one hand or jumping over a lid may be used, and the magnitude, rhythm, frequency, etc. of the impact may be arbitrarily set. Since there is basically no disturbance, vibration can be detected by threshold value determination, so that the hitting method is not limited and the vibration position can be automatically detected.
  • the vibration is extracted using various parameters of the vibration due to the impact.
  • an exciter which is a vibrating speaker or a speaker (a mechanism for generating vibration) is used to control parameters for applied vibration.
  • a known encoding is performed on the vibration waveform 6 such as the frequency of the vibration, the timing at which the vibration is applied, and the intensity modulation such as pulsing of the vibration waveform 6, and the impact is performed.
  • the signal processing unit 5b performs filter processing for detecting the known encoding. For example, a time-varying waveform 7 of the scattered light at each point is multiplied by a sine wave of a known frequency, and a band-pass filter is applied in a range including the frequency (a fixed frequency component is used by using a frequency filter). Is extracted), and a filtering process synchronized with the pulsed waveform and the impact timing is performed, and the respective points are compared. By performing this filtering, the optical measurement device 5a detects the vibration generated by intentionally striking out of various noises added to the manhole.
  • the signal processing unit 5b associates the position represented by the optical fiber length on the sensor waveform detected by the vibration sensor of the optical fiber with the position on the map of the manhole where the actual impact was applied,
  • the position of the manhole specified only by the optical fiber length from the optical communication aggregation building is specified.
  • a disturbance is a wide-band vibration in which a large number of frequencies are mixed, such a known encoded vibration can be extracted by a filter process. Therefore, the vibration position can be detected from the distance at which the waveform exists. With this processing, the vibration position can be automatically detected.
  • the frequency applied by the above-mentioned impact must be a vibration of a low frequency corresponding to an audible range of 5 kHz or less.
  • low-frequency vibrations are less attenuated and are more likely to propagate, so it is convenient to vibrate the entire housing of the manhole.
  • the frequencies of the exciters and speakers are set.
  • the vibration on the order of kHz corresponds to the just unpleasant frequency in the audible range. Therefore, if the frequency is further reduced to about 100 Hz or less, the vibration can be hardly left on the ear.
  • the immersion detection module detects submersion by bending the optical fiber when the optical closure in the manhole is submerged and causing optical loss on purpose.
  • the optical cable in the optical fiber communication line includes a loop-shaped optical fiber having both ends in a communication building, which is a maintenance cord, and the inundation detection module is installed on the maintenance cord. Even if flooding causes optical loss in the maintenance cord and makes it difficult to measure from one end, OTDR can measure vibration at one end, so the other end in the same communication building can be measured. By performing the measurement from, the manhole position can be specified without any problem.
  • the optical pulse travels back and forth through the optical fiber to be measured when the optical fiber is incident from only one side of the optical communication aggregation building. Vibration having a cycle longer than time can be measured to detect the vibration of impact. In addition, it is possible to detect a vibration that sets the frequency of the impact applied to the manhole to a frequency longer than the round-trip time of the light pulse.
  • the signal processing unit 5b can be realized by a computer and a program, and the program can be recorded on a recording medium or provided through a network.
  • the position of the manhole can be managed by the fiber length from the communication building.
  • the position of the manhole can be specified by the length of the optical fiber from the communication building.
  • the maintenance cord has no light loss due to submergence or the like, so that both ends can be used without any problem. Therefore, in this case, it is also possible to use an interferometer as a sensor system.
  • the optical measurement device 5a is an OTDR or an optical interferometer.
  • the interferometer receives continuous light instead of pulses from both ends of the optical fiber, there is no waiting time such as a round trip time, and thus there is no fundamental limitation on the measurement vibration frequency.
  • the vibration frequency when hitting may be arbitrary. However, as described in the first embodiment, a low frequency is desirable in consideration of the influence on the surroundings and the propagation to the manhole.
  • the manhole position represented by the measured optical fiber length is determined on the map, the position of the manhole is determined according to the optical fiber length, so that the route of the optical fiber on the map can be determined. For example, it becomes possible to know where the branch is on the MH route on the map, and it is possible to reliably specify a complicated underground wiring such as a branch or a turn. With the maintenance of the wiring route database, when manhole work is performed in the event of an abnormality such as flooding, a position specifying work for each work is not required, and more efficient work can be realized.
  • the SNR signal-to-noise ratio
  • a predetermined vibration at a specified frequency is applied to the manhole cover as a blow, and the spectrum of the envelope is calculated for the signal of the time change at each position of the acquired scattered light intensity distribution.
  • the light Identify the position of the manhole on the measurement.
  • FIG. 5 also shows the waveform of the signal generated when the manhole 1-n is hit with the lid (i).
  • the vertical axis indicates the vibration intensity, and the horizontal axis indicates time.
  • FIG. 5 also shows the vibration waveform of the optical fiber 403 when the cover of the manhole 401-n is hit (ii).
  • the vertical axis indicates the vibration intensity, and the horizontal axis indicates time. Vibration peaks appear when the lid is tapped.
  • FIG. 5 also shows a vibration waveform of the optical fiber 403 when the cover of the manhole 401-n is not hit (iii).
  • the vertical axis indicates the vibration intensity, and the horizontal axis indicates time. Vibration peaks appear when the lid is tapped.
  • FIG. 6 shows a configuration diagram of an optical fiber vibration sensing device 402 which is a device for specifying a vibration position.
  • the optical fiber vibration sensing device 402 includes an optical fiber reflection measurement unit 501 that measures the vibration of the optical fiber 403, a fiber vibration waveform with respect to a time-varying signal, and data obtained by the spectrum analysis unit 504 and the spectrum peak analysis unit 505.
  • a data storage unit 502 for storing the envelope, an envelope analysis unit 503 for calculating the envelope at each position, a spectrum analysis unit 504 for analyzing the spectrum for the envelope of the vibration waveform at each position of the optical fiber, and a manhole.
  • a spectrum peak analysis unit 505 for specifying a position where a peak is obtained at a position where a manhole is hit and a position having a peak at a frequency at which a specific manhole is hit.
  • the position of the manhole hit is specified by using the envelope analysis and the spectrum analysis on the optical fiber vibration sensing result.
  • the processing procedure of the present embodiment will be described below with reference to FIG. FIG. 8 shows the results of the envelope analysis and the spectrum analysis.
  • the manhole 401-n is hit at a specific frequency (step 11).
  • a known signal (control signal) is given so that it can be detected by signal processing.
  • the frequency at which the manhole 401-n is hit is known.
  • FIG. 8A shows the measured vibration waveform at each distance.
  • FIG. 4 is an enlarged view of FIG.
  • FIG. 8B shows the result of the calculation of the envelope.
  • the vertical axis indicates distance (m)
  • the horizontal axis indicates time (s).
  • FIG. 8C shows a vibration waveform when the distance is 1817 m.
  • the envelope at the position where the vibration is applied becomes a pulse train having a repetition frequency that matches the frequency at which the lid of the manhole 401-n is hit.
  • the envelope at the position where no vibration is applied is flat.
  • step 14 Analyze the spectrum (distance-time domain vibration waveform) for the envelope at each position (step 14).
  • the spectrum of the envelope of the vibration waveform at each position of the optical fiber obtained in step 13 is analyzed by the spectrum analyzer 504 in FIG.
  • the spectrum at the position where the manhole 401-n is hit has a peak at the frequency at which the manhole 401-n is hit, but the spectrum at the position where the manhole 401-n is not hit has no peak.
  • step 15 a filtering process is performed by the spectrum peak analysis unit 505 in FIG. 6 to detect vibration due to impact.
  • a predetermined vibration at a specified frequency is applied to the manhole cover as a blow, and the spectrum of the envelope is calculated for the signal of the time change at each position of the acquired scattered light intensity distribution.
  • the present invention can be applied to a technology for specifying and specifying the position of a manhole through which an optical fiber communication line passes by expressing the length of an optical fiber from a communication aggregation building.

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Abstract

The present invention addresses the problem of associating a manhole and a position represented by an optical fiber length and specifying the position of a manhole to be worked without opening the cover of the manhole. This manhole position specification method includes: a first step for measuring a time variation in scattered light from an optical fiber from an end of the optical fiber when an impact blow is applied to the cover of a manhole on the path of the optical fiber, and thereby acquiring the time variation of the scattered-light intensity distribution in the longitudinal direction of the optical fiber; a second step for specifying the position of the impact blow on the optical fiber by determining the occurrence of vibration due to the impact blow on the basis of the time variation at each position in the scattered-light intensity distribution; and a third step for associating the position of the impact blow on the optical fiber and the map position of the manhole to which the impact blow was applied to the cover thereof, and thereby specifying the position of the manhole represented by the optical fiber length from the end.

Description

マンホール位置特定方法及びマンホール位置特定システムManhole position specifying method and manhole position specifying system
　本発明は、光ファイバ通信線路が通っているマンホールの位置を通信集約ビルからの光ファイバ長で表現して特定する技術である。 The present invention is a technology for specifying the position of a manhole through which an optical fiber communication line passes by expressing the position of the manhole by an optical fiber length from a communication aggregation building.
　従来、光ファイバ通信線路が収容されているマンホール内で作業が必要な場合、地図とマンホールの名前を参考に作業をするマンホールを特定して作業をする。作業を行う理由が、管理しているマンホールの名前に基づいた理由、例えば、～交差点にある～という名前のマンホール内でケーブル接続をする、など理由とマンホールの名前が結びついていれば地図とデータベースから作業すべきマンホールの位置を特定できる。また、ＯＴＤＲ（Ｏｐｔｉｃａｌ Ｔｉｍｅ Ｄｏｍａｉｎ Ｒｅｆｌｅｃｔｏｍｅｔｏｒｙ：光時間領域後方散乱測定法）による遠隔光試験により、光ファイバが格納された光クロージャが水没しているかを検知する浸水検知モジュール（非特許文献２）などを遠隔監視するときや光ファイバ線路上の光損失試験を行う場合は、光ファイバ通信経路における、ＯＴＤＲからの光ファイバの距離で場所を特定する。例えばどこかのマンホール内が浸水し、光クロージャが水没したことをＯＴＤＲで検知した場合、通信ビルからの距離で判断する。このとき、経路とマンホールの位置が記載されたデータベースを参考に作業すべきマンホールを特定する。 Conventionally, when work is required in the manhole where the optical fiber communication line is housed, specify the manhole to work with reference to the map and the name of the manhole and work. If the reason for performing the work is based on the name of the manhole being managed, for example, connecting a cable inside the manhole named ~ at the intersection ~, if the reason and the manhole name are linked, a map and database Can identify the position of the manhole to be operated. In addition, an immersion detection module (Non-Patent Document 2) for detecting whether an optical closure containing an optical fiber is submerged by a remote light test using OTDR (Optical Time Domain Reflectometry: Optical Time Domain Backscattering Measurement Method). When monitoring remotely or performing an optical loss test on an optical fiber line, the location is specified by the distance of the optical fiber from the OTDR in the optical fiber communication path. For example, when the inside of a manhole is submerged and the optical closure is submerged, the OTDR detects the distance from the communication building. At this time, the manhole to be operated is specified with reference to a database in which the route and the position of the manhole are described.
　遠隔で光ファイバ上の状態を測定する技術として上記ＯＴＤＲを応用した振動センサがある（非特許文献１）。この振動センサでは、光ファイバに動きがあった場合に、その長さが微小に変化する時間変化を検知することで光ファイバの振動とそのファイバ長で表した位置を測定することが可能である分布型センサである。また、光ファイバの長さの微小変化による振動を検知する分布型センサとして、ＯＴＤＲによるもの以外にも干渉計を用いたものもある（非特許文献３）。 振動 As a technology for remotely measuring a state on an optical fiber, there is a vibration sensor to which the OTDR is applied (Non-patent Document 1). With this vibration sensor, when the optical fiber moves, it is possible to measure the vibration of the optical fiber and the position represented by the fiber length by detecting the time change in which the length changes minutely. It is a distributed sensor. As a distributed sensor for detecting vibration due to a minute change in the length of an optical fiber, there is a sensor using an interferometer other than the sensor using OTDR (Non-Patent Document 3).
　遠隔試験では、試験した光ファイバ上の距離でのみ場所を特定する。光ファイバ長で作業すべきマンホールを特定する場合、経路上のすべてのマンホールの位置が光ファイバ長としてデータベースに記載されていれば問題ない。しかし、光ファイバ長は、接続部などでの予長の長さで地図上の距離に比べて大きく異なり、また、経路上のケーブルでの分岐や接続等を追加したりすることにより随時変更される。このため、マンホールの位置を表す指標としての光ファイバ長は信頼性のある指標ではない。したがって、遠隔試験により光ファイバ長で作業すべき位置がわかっても、マンホールの名前が分からないため、現場で道路等の通行を止めて、蓋を開けて水没等の作業すべきマンホールを確認するしかなく、大きな時間と労力がかかってしまい、またそのような大きな稼働をかけて蓋を開けて確認しても作業すべきマンホールではない可能性も高く、何度もこのような大きな稼働のかかる作業を繰り返さなければならない。 In the remote test, the location is specified only by the distance on the tested optical fiber. When specifying the manhole to be operated by the optical fiber length, there is no problem if the positions of all manholes on the route are described in the database as the optical fiber length. However, the length of the optical fiber differs greatly from the distance on the map due to the length of the pre-length at the connection part, and may be changed as necessary by adding a branch or connection with a cable on the route. You. For this reason, the optical fiber length as an index indicating the position of the manhole is not a reliable index. Therefore, even if the position to be worked on is determined by the optical fiber length through remote testing, the name of the manhole is not known, so stop traffic on the road at the site, open the lid and check the manhole to be worked, such as submersion. It takes a lot of time and effort, and even if you open the lid after such a large operation, it is highly likely that it is not a manhole to work, and it takes such a large operation many times You have to repeat the work.
　また、光ファイバ振動センシングと振動付与を用いた振動位置特定技術において、測定結果のＳＮＲ（signal-to-noise ratio：信号対雑音比）が低いため、振動位置を特定することは困難なことがあった。 In addition, in the vibration position identification technology using optical fiber vibration sensing and vibration application, it is difficult to identify the vibration position because the SNR (signal-to-noise ratio) of the measurement result is low. there were.
　本発明では、従来技術の上記問題を鑑み、蓋を開けずに、光ファイバ長とマンホールの位置を対応づけて、作業すべきマンホールの位置の特定、マンホールの光ファイバ長での位置特定によって地図上のルートを明確にすること、データベース上で光ファイバ長によるマンホールの位置の管理を可能とすることを目的とする。 In the present invention, in consideration of the above-described problems of the related art, without opening the lid, the optical fiber length is associated with the manhole position, the position of the manhole to be worked is specified, and the position is specified by the manhole optical fiber length. The purpose of the present invention is to clarify the above route and to enable the management of manhole positions by the length of optical fibers on a database.
　また、光ファイバ振動センシングと振動付与を用いた振動位置特定技術において、測定結果に信号処理を施し振動位置の特定を容易にすることを目的とする。 Another object of the present invention is to provide a vibration position specifying technique using optical fiber vibration sensing and vibration imparting, in which signal processing is performed on a measurement result to facilitate specifying a vibration position.
　このような目的を達成するため、本発明のマンホール位置特定方法の第１の態様は、光ファイバの経路上のマンホールの蓋に対して打撃を加えたときの前記光ファイバからの散乱光の時間変化を前記光ファイバの端部から測定することで前記光ファイバの長手方向の散乱光強度分布の時間変化を取得する第１ステップと、前記打撃による振動発生を前記散乱光強度分布の各位置における時間変化に基づいて判定することで前記光ファイバ上の打撃位置を特定する第２ステップと、前記光ファイバ上の前記打撃位置と前記蓋に対して打撃を加えた前記マンホールの地図上の位置とを対応させることで、当該マンホールの前記端部からの光ファイバ長で表された位置を特定する第３ステップと、を含む。 In order to achieve such an object, a first aspect of the manhole position specifying method according to the present invention is a method for detecting the time of scattered light from the optical fiber when a hit is applied to the manhole cover on the optical fiber path. A first step of obtaining a temporal change in a scattered light intensity distribution in the longitudinal direction of the optical fiber by measuring a change from an end of the optical fiber, and generating vibration due to the impact at each position of the scattered light intensity distribution. A second step of specifying a hitting position on the optical fiber by determining based on a time change, and a position on the map of the manhole that has hit the hitting position and the lid on the optical fiber; And a third step of specifying a position represented by an optical fiber length from the end of the manhole.
　マンホール位置特定方法の第２の態様は、第１の態様に、前記第１ステップでは、前記蓋に対して、前記打撃として、指定した周波数、時間的タイミング又はパルス化による所定の振動を加え、前記第２ステップでは、前記散乱光強度分布の各位置における時間変化の信号に対して、前記所定の振動の成分を抽出するフィルタ処理を施すことで、前記打撃による振動を検出する。 In a second aspect of the manhole position specifying method, in the first aspect, in the first step, a predetermined vibration is applied to the lid as the blow, at a designated frequency, temporal timing, or pulsing, In the second step, the vibration due to the impact is detected by performing a filtering process for extracting the predetermined vibration component on the signal of the time change at each position of the scattered light intensity distribution.
　マンホール位置特定方法の第３の態様は、第２の態様に、前記第１ステップでは、前記蓋に対して、前記打撃として、指定した周波数による所定の振動を加え、前記第２ステップでは、前記散乱光強度分布の各位置における時間変化の信号に対して、包絡線のスペクトルを算出し、該スペクトルにおいて前記指定した周波数のピークを抽出するフィルタ処理を施すことで、前記打撃による振動を検出する。 In a third aspect of the manhole position specifying method, in the second aspect, in the first step, a predetermined vibration at a specified frequency is applied to the lid as the impact, and in the second step, The signal of the time change at each position of the scattered light intensity distribution is calculated by calculating a spectrum of an envelope and performing a filtering process for extracting a peak of the specified frequency in the spectrum, thereby detecting the vibration due to the impact. .
　マンホール位置特定方法の第４の態様は、第１の態様乃至第３の態様のうち一態様に、前記第１ステップでは、前記打撃と前記散乱光の時間変化の測定とを通信用インターフェースを用いて同期させる。 According to a fourth aspect of the manhole position specifying method, in one aspect of the first to third aspects, in the first step, the impact and the measurement of the time change of the scattered light are measured using a communication interface. To synchronize.
　マンホール位置特定方法の第５の態様は、第１の態様乃至第４の態様のうち一態様に、前記第１ステップでは、前記散乱光の時間変化の測定に光パルスを入射して発生る後方散乱光を測定する光時間領域後方散乱測定法を用い、前記打撃の周波数を前記光パルスが前記光ファイバを往復する時間よりも周期が長い周波数とする。 According to a fifth aspect of the manhole position specifying method, in one aspect of the first to fourth aspects, in the first step, a backward pulse generated by applying a light pulse to the measurement of the time change of the scattered light is provided. An optical time domain backscatter measurement method for measuring scattered light is used, and the frequency of the impact is set to a frequency having a period longer than the time when the light pulse reciprocates in the optical fiber.
　マンホール位置特定方法の第６の態様は、第１の態様乃至第４の態様のうち一態様に、前記第１ステップでは、前記光ファイバに対して、両端から光干渉計を用いることで前記散乱光の時間変化を測定する方法を用いる。 According to a sixth aspect of the manhole position specifying method, in the first aspect, the scattering of the optical fiber may be performed by using an optical interferometer from both ends of the optical fiber. A method of measuring a time change of light is used.
　マンホール位置特定システムの第７の態様は、光ファイバの端部に接続され、前記光ファイバの経路上のマンホールの位置を特定するマンホール位置特定システムにおいて、前記マンホールの蓋に対して打撃が加えられたときの前記光ファイバからの散乱光の時間変化を前記端部から測定することで前記光ファイバの長手方向の散乱光強度分布の時間変化を取得する光測定器と、前記打撃による振動発生を前記散乱光強度分布の各位置における時間変化に基づいて判定することで前記光ファイバ上の打撃位置を特定し、前記光ファイバ上の前記打撃位置と前記蓋に対して打撃を加えられた前記マンホールの地図上の位置とを対応させることで、当該マンホールの前記端部からの光ファイバ長で表された位置を特定する信号処理部と、を備える。 A seventh aspect of the manhole locating system is a manhole locating system connected to an end of an optical fiber for locating a manhole on a path of the optical fiber, wherein a hit is applied to the manhole cover. And measuring the time change of the scattered light from the optical fiber from the end by measuring the time change of the scattered light intensity distribution in the longitudinal direction of the optical fiber. The hitting position on the optical fiber is specified by making a determination based on the time change at each position of the scattered light intensity distribution, and the hitting position on the optical fiber and the manhole hit against the lid A signal processing unit that specifies a position represented by an optical fiber length from the end of the manhole by associating the position with the position on the map. .
　マンホール位置特定システムの第８の態様は、第７の態様に、前記蓋に対して、前記打撃として、指定した周波数、時間的タイミング又はパルス化による所定の振動を加える振動機構をさらに備え、前記信号処理部は、前記散乱光強度分布の各位置における時間変化の信号に対して、前記所定の振動の成分を抽出するフィルタ処理を施すことで、前記打撃による振動を検出する。 An eighth aspect of the manhole location specifying system according to the seventh aspect, further comprising a vibration mechanism that applies a predetermined vibration to the lid as the blow by a specified frequency, time timing or pulsing, The signal processing unit detects the vibration due to the impact by performing a filter process for extracting the predetermined vibration component on the signal of the time change at each position of the scattered light intensity distribution.
　マンホール位置特定システムの第９の態様は、第８の態様に、前記蓋に対して、前記打撃として、指定した周波数、時間的タイミング又はパルス化による所定の振動を加える振動機構をさらに備え、前記信号処理部は、前記散乱光強度分布の各位置における時間変化の信号に対して、前記所定の振動の成分を抽出するフィルタ処理を施すことで、前記打撃による振動を検出する。 A ninth aspect of the manhole location specifying system according to the eighth aspect, further includes a vibration mechanism that applies a predetermined vibration by a specified frequency, temporal timing, or pulsation to the lid as the blow. The signal processing unit detects the vibration due to the impact by performing a filter process for extracting the predetermined vibration component on the signal of the time change at each position of the scattered light intensity distribution.
　本発明の技術を用いることにより、遠隔試験などで測定される光ファイバ長で表されるマンホールの位置を、マンホールを開けることなく、現場で蓋に打撃を加えるだけで、光ファイバ長と地図上の場所の対応付けが可能となる。これにより光ファイバ線路運用時における作業対象マンホールの位置特定や、光ファイバ長で表された位置データをデータベース化し、保守時などのルート確定などに貢献することができる。 By using the technology of the present invention, the position of the manhole represented by the optical fiber length measured by a remote test or the like can be determined by simply hitting the lid at the site without opening the manhole. Can be associated with each other. This makes it possible to specify the position of the manhole to be worked during operation of the optical fiber line and to convert the position data represented by the optical fiber length into a database, thereby contributing to route determination during maintenance and the like.
　光ファイバ振動センシングと振動付与を用いた振動位置特定技術において、測定された信号のＳＮＲ（信号対雑音比：signal-to-noise ratio）が極めて低い場合であっても、打撃による振動を容易に検出することができる。 In vibration position identification technology using optical fiber vibration sensing and vibration imparting, even if the SNR (signal-to-noise ratio) of the measured signal is extremely low, vibration due to impact can be easily achieved. Can be detected.
本発明の実施形態１のシステムの構成を示す図である。FIG. 1 is a diagram illustrating a configuration of a system according to a first exemplary embodiment of the present invention. 光ファイバの振動センサの構成を示す図である。It is a figure showing composition of an optical fiber vibration sensor. 光ファイバの振動センサで測定される波形群のイメージを示す図である。It is a figure showing the image of the waveform group measured by the vibration sensor of an optical fiber. 本発明の実施形態３の振動位置特定方法の課題を示す図である。It is a figure showing a subject of a vibration position specification method of Embodiment 3 of the present invention. 本発明の実施形態３の振動位置特定システムを示す図である。It is a figure which shows the vibration position identification system of Embodiment 3 of this invention. 本発明の実施形態３の振動位置特定装置の構成図を示す図である。It is a figure showing the composition figure of the vibration position specific device of Embodiment 3 of the present invention. 本発明の実施形態３の振動位置特定方法のフローチャートを示す図である。FIG. 13 is a diagram illustrating a flowchart of a vibration position specifying method according to a third embodiment of the present invention. 本発明の実施形態３の振動位置特定方法の具体例を示す図である。FIG. 14 is a diagram illustrating a specific example of a vibration position specifying method according to a third embodiment of the present invention.
　以下、本発明のマンホール位置特定システム及びマンホール位置特定方法の形態について、図を用いて詳細に説明する。但し、本発明は以下に示す実施の形態の記載内容に限定されず、本明細書等において開示する発明の趣旨から逸脱することなく形態および詳細を様々に変更し得ることは当業者にとって自明である。なお、以下に説明する発明の構成において、同一部分または同様な機能を有する部分には同一の符号を用い、その繰り返しの説明は省略する場合がある。 Hereinafter, embodiments of the manhole position specifying system and the manhole position specifying method of the present invention will be described in detail with reference to the drawings. However, it is obvious to those skilled in the art that the present invention is not limited to the description of the embodiments below and that various changes can be made in form and detail without departing from the spirit of the invention disclosed in this specification and the like. is there. Note that in the structures of the invention described below, the same portions or portions having similar functions are denoted by the same reference numerals, and description thereof may not be repeated.
実施形態１ Embodiment 1
　本発明に係る第一の実施形態のシステムの構成を図１～２に示す。図１にマンホールの蓋に対して打撃を与えられ、マンホール１－ｎ（ｎは、１以上の整数）に設置されている光ファイバ３に振動を印加され、その振動の長手方向分布を測定し、測定から得られた結果から、光通信集約ビル４からの光ファイバ長でのみ指定されたマンホール１－ｎの位置を特定する振動センサ２を有するマンホール位置特定システムを説明する。本実施形態では、振動センサ２は、光通信集約ビル４内に設置されている。振動センサ２は、その振動の長手方向分布を測定する光測定器５aと、その測定から得られた結果からマンホールの位置を特定する信号処理部５ｂとを有する。なお、本実施形態では、その測定の方法は、光時間領域後方散乱測定法である。後述のしきい値判定やフィルタ処理等は信号処理部５ｂ内の計算機（コンピュータ）によって実施する。通信インターフェースも信号処理部５ｂに内蔵されている。 (1) The configuration of the system according to the first embodiment of the present invention is shown in FIGS. In FIG. 1, a manhole cover is hit, a vibration is applied to the optical fiber 3 installed in the manhole 1-n (n is an integer of 1 or more), and the longitudinal distribution of the vibration is measured. A manhole position specifying system having the vibration sensor 2 for specifying the position of the manhole 1-n designated only by the optical fiber length from the optical communication aggregation building 4 from the result obtained from the measurement will be described. In the present embodiment, the vibration sensor 2 is installed in the optical communication aggregation building 4. The vibration sensor 2 has an optical measuring device 5a for measuring the longitudinal distribution of the vibration, and a signal processing unit 5b for specifying the position of the manhole from the result obtained from the measurement. In the present embodiment, the measuring method is an optical time domain backscattering measuring method. Threshold determination, filter processing, and the like, which will be described later, are performed by a computer (computer) in the signal processing unit 5b. The communication interface is also built in the signal processing unit 5b.
　浸水検知モジュールなどにより作業をすべきマンホールの光ファイバ長で表した位置が分かっているマンホールを１－１とする。このとき、マンホール１－１の周りには、対象外のマンホール１－２～１－ｎ（ｎは２以上の整数）までいくつもあるとする。マンホール付近には作業員がいるが、ファイバ長でしか作業すべきマンホールが分かっていない状態である。このときに、作業員は従来であれば一つ一つマンホールを開けることになるが、道路を通行止めにしたり、安全対策をしたりしながら開けることになり、また開けても作業すべきマンホールではない可能性も高い。 マ ン The manhole whose position represented by the optical fiber length of the manhole to be operated by the inundation detection module or the like is known as 1-1. At this time, it is assumed that there are a number of non-target manholes 1-2 to 1-n (n is an integer of 2 or more) around the manhole 1-1. There are workers near the manhole, but the manhole to be operated only with the fiber length is unknown. At this time, workers would have to open manholes one by one in the past, but they would have to open while blocking roads and taking safety measures. Not likely.
　本発明ではこの蓋を開ける作業をする前に、通信ビル内の光ファイバの振動センサ２で特定したいマンホールを通っている光ファイバ３を測定する。そして、その測定と同時に作業員は蓋を開けず、マンホールに打撃を加える。マンホールに打撃が加わると、マンホールの筐体全体に振動が伝搬することにより、その振動がマンホール内の光ケーブルも振動させ、その振動を光ファイバの振動センサ２によって検知し、光ファイバ長で表した位置と、現場で作業するときの地図上のマンホールの位置を対応付けることができる。この対応付けを１－１～１－ｎのマンホールで順次行っていき、あらかじめ作業すべきマンホールの位置としてわかっていた光ファイバ長と同じファイバ長に光存在するマンホールを特定する。 In the present invention, before performing the work of opening the lid, the optical fiber 3 passing through the manhole to be specified by the optical fiber vibration sensor 2 in the communication building is measured. At the same time as the measurement, the worker hits the manhole without opening the lid. When a shock is applied to the manhole, the vibration propagates to the entire housing of the manhole, and the vibration also vibrates the optical cable in the manhole. The vibration is detected by the vibration sensor 2 of the optical fiber, and is represented by the optical fiber length. The position can be associated with the position of the manhole on the map when working on site. This association is sequentially performed for the manholes 1-1 to 1-n, and a manhole having light existing at the same fiber length as the optical fiber length known as the position of the manhole to be worked on in advance is specified.
　これにより、作業すべきマンホールの位置を間違えずに蓋を開けることができ、作業の効率を大きく上げることができる。 This allows the lid to be opened without mistake in the position of the manhole to be worked, and the work efficiency can be greatly increased.
　打撃と測定のタイミングについては、打撃を加える作業員と通信ビル内でセンサでの測定をする作業員の二人がいる場合は電話等であわせればよい。もし打撃を加える作業員しかいなかったとしても、光ファイバの振動センサ２にイーサネット（登録商標）端子やＩＰ制御機能などの通信インターフェースを備えさせて、打撃する作業員がスマートフォンなどのようなモバイル端末を用いて遠隔通信により操作することでタイミングを合わせることは可能である。光ファイバの振動センサ２の信号処理部５ｂに通信用インターフェースを付与し、マンホールでの打撃の際に打撃とその光ファイバの振動センサ２での測定をその通信用インターフェースを用いた同期を行うことにより、打撃と測定をマンホールの打撃者一人で同時に行い波形を測定することで、打撃の振動を検出する。また、振動センサ２による測定をし続ける状態にしておいて、その間に打撃をするという方法でもよい。 タ イ ミ ン グ About the timing of the impact and the measurement, if there are two workers, one who performs the impact and one who performs the measurement with the sensor in the communication building, the timing may be adjusted by telephone or the like. Even if there is only a worker who hits, the vibration sensor 2 of the optical fiber is provided with a communication interface such as an Ethernet (registered trademark) terminal and an IP control function, and the worker who hits the mobile device such as a smartphone. It is possible to adjust the timing by operating the terminal by remote communication. A communication interface is provided to the signal processing unit 5b of the optical fiber vibration sensor 2 so that, when a manhole is hit, the impact and the measurement of the optical fiber by the vibration sensor 2 are synchronized using the communication interface. Thus, the vibration of the impact is detected by simultaneously performing the impact and the measurement by one manhole hitter and measuring the waveform. Alternatively, a method may be employed in which the measurement is continuously performed by the vibration sensor 2 and an impact is made during that time.
　測定波形も通信ビル内で測定する作業員が確認する方法でもよいし、上記の通信手段により、打撃する作業員に遠隔で測定結果を送信し確認する方法でもよい。 も The measurement waveform may be checked by a worker who measures the communication waveform in the communication building, or the measurement result may be remotely transmitted to the worker who is hit by the communication means to check the measurement result.
　しかし、一般的にマンホールの上は車や人の通行、雨や風などの外乱が大きく、作業員が打撃を加えなくても、この外乱により、マンホールは振動をしており、マンホール内の光ファイバも振動をしている。外乱に対して簡単に打撃を抽出するために、大きく振動させるという方法もあるが、大きな振動を加えるために大きな装置などを使うのであれば、蓋を開けてマンホールを特定することと稼働が変わらなくなり、簡単にマンホール位置を特定するという目的に合わない。したがって、蓋を開けずにマンホールを特定する打撃は交通を止めることなく、簡単なものでなければならない。このため、簡単な小さな打撃でも、この外乱に対して特定することが必要である。 However, in general, disturbances such as traffic of cars and people, rain and wind are large on the manhole, and even if workers do not hit the manhole, the disturbance causes the manhole to vibrate and the light in the manhole The fiber is also oscillating. In order to easily extract the impact against disturbance, there is a method of vibrating greatly, but if a large device is used to apply large vibration, opening the lid and specifying the manhole is different from operation. It is not suitable for the purpose of easily specifying the manhole position. Therefore, the blow to identify the manhole without opening the lid must be simple without stopping traffic. For this reason, it is necessary to identify even a simple small blow against this disturbance.
　また、打撃による波形は、光ファイバ中の特定の位置から散乱光の時間変化を測定するという形で検出される。振動センサで振動を分布測定する際の分解能は、マンホール位置を特定することを考えると数ｍ程度以下であることが必要で、このときマンホールを探すファイバ長で表す範囲が例えば１００ｍくらいだとすると、数十個の波形を見る必要があり、その波形を打撃しながら探すことになる。測定される波形群のイメージを図３に示す。 波形 The waveform due to the impact is detected by measuring the time change of the scattered light from a specific position in the optical fiber. The resolution at the time of measuring the distribution of vibration with the vibration sensor needs to be about several meters or less in consideration of specifying the position of the manhole. At this time, if the range expressed by the fiber length for searching the manhole is about 100 m, for example, You need to look at ten waveforms, and you will search for them while hitting them. FIG. 3 shows an image of a group of measured waveforms.
　これらの条件を踏まえてマンホール位置を特定する流れを説明する。本実施形態のマンホール位置特定方法は、以下のステップ（Ｓ１）～（Ｓ３）を含んでいる。光通信集約ビル４において、振動センサ２により、光ファイバ３の経路上のマンホールの蓋に対して打撃を加えたときの光ファイバ３の各地点からの散乱光の時間変化波形を測定することで光ファイバ３の振動位置を分布的に測定する（Ｓ１）。次に、光ファイバの振動センサ２による測定結果における光ファイバ３の各地点からの散乱光の時間変化波形において、打撃による振動発生を散乱光変化の大きさのしきい値により判定することで打撃位置を測定する（Ｓ２）。次に、測定された散乱光の時間変化波形上の光ファイバ長で表された打撃位置と、蓋に対して打撃を加えたマンホールの地図上の位置とを対応させることで、光通信集約ビルからの光ファイバ長でのみ指定されたマンホールの位置を特定する（Ｓ３）。すなわち、本実施形態のマンホール位置特定方法は、光ファイバ３の経路上のマンホール１－ｎの蓋に対して打撃を加えたときの光ファイバ３からの散乱光の時間変化を光ファイバ３の端部から測定することで光ファイバ３の長手方向の散乱光強度分布の時間変化を取得する第１ステップと、打撃による振動発生を散乱光強度分布の各位置における時間変化に基づいて判定することで光ファイバ３上の打撃位置を特定する第２ステップと、光ファイバ３上の打撃位置と蓋に対して打撃を加えたマンホール１－ｎの地図上の位置とを対応させることで、当該マンホールの端部からの光ファイバ長で表された位置を特定する第３ステップと、を含む。 流 れ The flow of specifying the manhole position based on these conditions will be described. The manhole position specifying method of the present embodiment includes the following steps (S1) to (S3). In the optical communication aggregation building 4, the vibration sensor 2 measures the time-change waveform of the scattered light from each point of the optical fiber 3 when the manhole cover on the path of the optical fiber 3 is hit. The vibration position of the optical fiber 3 is measured distributionally (S1). Next, in the time variation waveform of the scattered light from each point of the optical fiber 3 in the measurement result of the optical fiber vibration sensor 2, the generation of the vibration due to the impact is determined by the threshold value of the magnitude of the scattered light change. The position is measured (S2). Next, by associating the impact position represented by the optical fiber length on the measured time-varying scattered light waveform with the map position of the manhole where the impact was applied to the lid, the optical communication aggregation building The position of the manhole specified only by the optical fiber length from is specified (S3). That is, the manhole position specifying method according to the present embodiment uses the time change of the scattered light from the optical fiber 3 when the cover of the manhole 1-n on the path of the optical fiber 3 is hit with the end thereof. A first step of obtaining a temporal change in the scattered light intensity distribution in the longitudinal direction of the optical fiber 3 by measuring from the section, and determining the occurrence of vibration due to the impact based on the temporal change at each position in the scattered light intensity distribution. By associating the hitting position on the optical fiber 3 with the hitting position on the optical fiber 3 and the position on the map of the manhole 1-n that has hit the lid, the manhole of the manhole is identified. A third step of specifying a position represented by an optical fiber length from the end.
　まず、探したい範囲において、交通がほとんどない地域など、外乱がほとんどない場合を考える。この場合、外乱に対して振動による波形が強く出るため、打撃振動による波形の揺れをしきい値により判定すれば、光ファイバ中の探したい位置範囲の中の多数の時間波形の中からそのしきい値を超えた動きのあった位置を検出すれば容易に打撃位置と光ファイバ長が対応づけられる。また、このときに作業員は打撃を任意の方法で与えればよい。例えば、片手で持てる大きさのハンマーで叩いたり、蓋の上で飛び跳ねるなどのような非常に簡易な方法で、しかも打撃の大きさやリズム、周波数なども任意でよい。基本的に外乱がないため、しきい値判定により、振動を検出できるため、打撃方法に制限はなく、振動位置も自動的に検出できる。 First, consider the case where there is almost no disturbance in the area you want to find, such as an area with little traffic. In this case, since the waveform due to the vibration appears strongly against the disturbance, if the fluctuation of the waveform due to the impact vibration is determined based on the threshold value, the waveform can be selected from a number of time waveforms in the position range to be searched in the optical fiber. If the position where the movement exceeds the threshold value is detected, the hit position and the optical fiber length can be easily associated. At this time, the worker may give a blow by any method. For example, a very simple method such as hitting with a hammer having a size that can be held with one hand or jumping over a lid may be used, and the magnitude, rhythm, frequency, etc. of the impact may be arbitrarily set. Since there is basically no disturbance, vibration can be detected by threshold value determination, so that the hitting method is not limited and the vibration position can be automatically detected.
　次に、外乱が大きいため、ハンマーで叩くなどの簡単な方法の打撃では振動の検出がしきい値判定という簡易な方法では難しい場合を説明する。この場合は、打撃による振動の様々なパラメータを用いて抽出する。例えば打撃する方法として、振動スピーカーであるエキサイターや、スピーカー（振動を起こす機構）を使って、加える振動に対してパラメータをコントロールする。具体的には、振動の周波数や、振動を付与するタイミング、振動波形６に対するパルス化などの強度変調など、振動波形６に対して既知となる符号化を実施して、打撃する。そして、探したい範囲の多数の波形において、その既知の符号化を検出するフィルタ処理を信号処理部５ｂで行う。例えば各地点の散乱光の時間変化波形７に対して既知の周波数の正弦波を乗算する、その周波数が含まれている範囲でバンドパスフィルタをかける（周波数フィルタを用いて、固定の周波数の成分を抽出する）、パルス化波形や打撃タイミングと同期したフィルタ処理をする、などして各地点について比較する。このフィルタ処理をすることで、マンホールに加わる種々の雑音の中から故意に打撃することで発生した振動を光測定器５ａで検出する。次いで、信号処理部５ｂで、その光ファイバの振動センサで検知されたセンサ波形上の光ファイバ長で表された位置と、実際の打撃を加えたマンホールの地図上の位置を対応させることで、その光通信集約ビルからの光ファイバ長でのみ指定されたマンホールの位置を特定する。一般に外乱は多数の周波数が混在した広帯域な振動のため、このような既知の符号化の振動はフィルタ処理により抽出できるため、その波形が存在している距離から振動位置が検出できる。この処理により、自動的に振動位置の検出が可能である。 Next, a case will be described in which it is difficult to detect a vibration by a simple method such as threshold value determination by a simple method such as hitting with a hammer due to a large disturbance. In this case, the vibration is extracted using various parameters of the vibration due to the impact. For example, as a method of hitting, an exciter which is a vibrating speaker or a speaker (a mechanism for generating vibration) is used to control parameters for applied vibration. Specifically, a known encoding is performed on the vibration waveform 6 such as the frequency of the vibration, the timing at which the vibration is applied, and the intensity modulation such as pulsing of the vibration waveform 6, and the impact is performed. Then, for a large number of waveforms in a range to be searched, the signal processing unit 5b performs filter processing for detecting the known encoding. For example, a time-varying waveform 7 of the scattered light at each point is multiplied by a sine wave of a known frequency, and a band-pass filter is applied in a range including the frequency (a fixed frequency component is used by using a frequency filter). Is extracted), and a filtering process synchronized with the pulsed waveform and the impact timing is performed, and the respective points are compared. By performing this filtering, the optical measurement device 5a detects the vibration generated by intentionally striking out of various noises added to the manhole. Next, the signal processing unit 5b associates the position represented by the optical fiber length on the sensor waveform detected by the vibration sensor of the optical fiber with the position on the map of the manhole where the actual impact was applied, The position of the manhole specified only by the optical fiber length from the optical communication aggregation building is specified. Generally, since a disturbance is a wide-band vibration in which a large number of frequencies are mixed, such a known encoded vibration can be extracted by a filter process. Therefore, the vibration position can be detected from the distance at which the waveform exists. With this processing, the vibration position can be automatically detected.
　次に、振動位置を分布測定する光ファイバの振動センサについて説明する。 Next, an optical fiber vibration sensor for measuring the distribution of vibration positions will be described.
　センサの方式としてＯＴＤＲを用いる場合を説明する。ＯＴＤＲで振動を検出する場合、パルスを光ファイバの片端から入射するため、往復の時間を待つ必要がある。光ファイバ通信線路のファイバ長を１０ｋｍ程度とすると、その往復時間は、光ファイバ中の光速を２×１０8ｍ／ｓとすると、１００μｓとなる。１００μｓで各地点からの散乱光が１点ずつ測定されるため、各地点での時間変化波形は１００μｓで１点、つまり、１０ｋＳａｍｐｌｅ／ｓとなる。したがって、サンプリング定理より、１０ｋｍの光ファイバに対するＯＴＤＲでの振動測定は最高５ｋＨｚまでの振動が測定できることになる。このため、上記の打撃で加える周波数は５ｋＨｚ以下の可聴域に相当する低い周波数の振動でなければならない。実際、低周波数振動の方が減衰が小さく振動が伝搬しやすいため、マンホールの筐体全体を振動させるためには都合がよい。このことを踏まえて、上記のエキサイターやスピーカーの周波数を設定する。このとき、ｋＨｚオーダーの振動は可聴域のちょうど耳障りな周波数に相当するため、更に低周波数、１００Ｈｚ程度以下にすると、耳に残りにくく振動させることができる。 A case where OTDR is used as a sensor method will be described. When detecting vibration by OTDR, it is necessary to wait for a round-trip time because a pulse is incident from one end of the optical fiber. If the fiber length of the optical fiber communication line is about 10 km, the round trip time is 100 μs if the speed of light in the optical fiber is 2 × 10 8 m / s. Since the scattered light from each point is measured one point at a time in 100 μs, the time-varying waveform at each point is one point in 100 μs, that is, 10 kSample / s. Therefore, according to the sampling theorem, the vibration measurement by the OTDR with respect to the optical fiber of 10 km can measure the vibration up to 5 kHz. For this reason, the frequency applied by the above-mentioned impact must be a vibration of a low frequency corresponding to an audible range of 5 kHz or less. In fact, low-frequency vibrations are less attenuated and are more likely to propagate, so it is convenient to vibrate the entire housing of the manhole. Based on this, the frequencies of the exciters and speakers are set. At this time, the vibration on the order of kHz corresponds to the just unpleasant frequency in the audible range. Therefore, if the frequency is further reduced to about 100 Hz or less, the vibration can be hardly left on the ear.
　本実施形態では、浸水検知モジュールなどで作業しなければいけないマンホールが発生した場合を想定している。浸水検知モジュールはマンホール内の光クロージャが水没した場合に光ファイバに曲げを作りわざと光損失を起こすことによって水没を検知する。光ファイバ通信線路での光ケーブルには、保守用心線という両端が通信ビルにある、ループ状の光ファイバが含まれており、浸水検知モジュールは、この保守用心線に設置されている。浸水により、保守用心線に光損失が発生し、一方の端部からの測定が困難となった場合でも、ＯＴＤＲであれば片端で振動が測定できるため、同じ通信ビル内にある他方の端部から測定を行うことにより、問題なくマンホール位置特定が可能である。光ファイバの振動センサとして光パルスを入射して発生する後方散乱光を測定するＯＴＤＲを用い、光ファイバの光通信集約ビルの片側からのみの入射で、測定対象の光ファイバを光パルスが進む往復時間よりも周期が長い振動を測定して、打撃の振動を検出できる。また、マンホールに加える打撃の周波数を光パルスの往復時間よりも周期が長い周波数にする振動を検出できる。 In the present embodiment, it is assumed that a manhole that needs to be worked with a flood detection module or the like occurs. The immersion detection module detects submersion by bending the optical fiber when the optical closure in the manhole is submerged and causing optical loss on purpose. The optical cable in the optical fiber communication line includes a loop-shaped optical fiber having both ends in a communication building, which is a maintenance cord, and the inundation detection module is installed on the maintenance cord. Even if flooding causes optical loss in the maintenance cord and makes it difficult to measure from one end, OTDR can measure vibration at one end, so the other end in the same communication building can be measured. By performing the measurement from, the manhole position can be specified without any problem. Using an OTDR that measures backscattered light generated by inputting an optical pulse as an optical fiber vibration sensor, the optical pulse travels back and forth through the optical fiber to be measured when the optical fiber is incident from only one side of the optical communication aggregation building. Vibration having a cycle longer than time can be measured to detect the vibration of impact. In addition, it is possible to detect a vibration that sets the frequency of the impact applied to the manhole to a frequency longer than the round-trip time of the light pulse.
　また、もちろん保守用心線だけでなく、通常の通信用光ファイバを通してでも打撃の測定により対象のマンホールを通信ビルからの光ファイバ長により特定することは可能である。 も ち ろ ん Also, it is possible to specify the target manhole based on the length of the optical fiber from the communication building by measuring the impact not only through the maintenance cord but also through the ordinary communication optical fiber.
　信号処理部５ｂはコンピュータとプログラムによっても実現でき、プログラムを記録媒体に記録することも、ネットワークを通して提供することも可能である。 The signal processing unit 5b can be realized by a computer and a program, and the program can be recorded on a recording medium or provided through a network.
実施形態２ Embodiment 2
　本実施形態では、設備を管理するデータベース上にマンホールの位置を通信ビルからのファイバ長で管理できるようデータを加えることを想定する。この場合も実施形態１と同じように、マンホールの位置を通信ビルからの光ファイバ長により特定可能である。このとき、保守用心線は、実施形態１と異なり、水没などによる光損失はないため、両端を問題なく使うことができる。したがって、この場合は、センサの方式として干渉計を用いることも可能である。本実施形態では、光測定器５ａは、ＯＴＤＲ又は光干渉計である。干渉計は、光ファイバの両端から、パルスではなく連続光を入射するため、往復時間等の待ち時間は発生しないため、測定振動周波数に原理的な制限はない。打撃するときの振動周波数も任意のものでよい。ただし実施形態１にも記載した通り、周囲への影響やマンホールへの伝搬を考えると低周波数が望ましい。 In this embodiment, it is assumed that data is added to the database for managing facilities so that the position of the manhole can be managed by the fiber length from the communication building. In this case, as in the first embodiment, the position of the manhole can be specified by the length of the optical fiber from the communication building. At this time, unlike the first embodiment, the maintenance cord has no light loss due to submergence or the like, so that both ends can be used without any problem. Therefore, in this case, it is also possible to use an interferometer as a sensor system. In the present embodiment, the optical measurement device 5a is an OTDR or an optical interferometer. Since the interferometer receives continuous light instead of pulses from both ends of the optical fiber, there is no waiting time such as a round trip time, and thus there is no fundamental limitation on the measurement vibration frequency. The vibration frequency when hitting may be arbitrary. However, as described in the first embodiment, a low frequency is desirable in consideration of the influence on the surroundings and the propagation to the manhole.
　このように測定された光ファイバ長で表されるマンホール位置は地図上でも位置が確定するため、この光ファイバ長に合わせて順序づければ光ファイバの地図上の経路も確定することができる。例えば、地図上のＭＨ経路において分岐がどこにあるかが分かるようになり、分岐や折り返しなどの複雑な地下配線を確実に特定することができる。この配線ルートのデータベースの整備により、浸水等の異常時のマンホール作業をする際に、作業時ごとの位置特定作業が不要となり、より効率的な作業が実現できる。 マ ン Since the manhole position represented by the measured optical fiber length is determined on the map, the position of the manhole is determined according to the optical fiber length, so that the route of the optical fiber on the map can be determined. For example, it becomes possible to know where the branch is on the MH route on the map, and it is possible to reliably specify a complicated underground wiring such as a branch or a turn. With the maintenance of the wiring route database, when manhole work is performed in the event of an abnormality such as flooding, a position specifying work for each work is not required, and more efficient work can be realized.
実施形態３ Embodiment 3
　光ファイバ振動センシングと振動付与を用いた振動位置特定技術において、図４に示すように、測定結果のＳＮＲ（signal-to-noise ratio：信号対雑音比）が低いため、振動位置を特定することは困難なことがあった。図４の縦軸は距離（ｍ）、横軸は時間（ｓ）を示す。 In the vibration position identification technology using optical fiber vibration sensing and vibration application, as shown in Fig. 4, the SNR (signal-to-noise ratio) of the measurement result is low, so the vibration position must be specified. Was difficult. The vertical axis in FIG. 4 indicates distance (m), and the horizontal axis indicates time (s).
　本実施形態では、マンホールの蓋に対して、打撃として、指定した周波数による所定の振動を加え、取得した散乱光強度分布の各位置における時間変化の信号に対して、包絡線のスペクトルを算出し、該スペクトルにおいて指定した周波数のピークを抽出するフィルタ処理を施すことで、打撃による振動を検出する。 In the present embodiment, a predetermined vibration at a specified frequency is applied to the manhole cover as a blow, and the spectrum of the envelope is calculated for the signal of the time change at each position of the acquired scattered light intensity distribution. By performing a filter process for extracting a peak of a designated frequency in the spectrum, vibration due to impact is detected.
　マンホールの蓋に既知の振動を付与し、マンホール蓋の下にある光ファイバ４０３を振動させ、光ファイバ４０３の振動を通信ビル内に設置された光ファイバ振動センシング装置４０２で検出することで、光計測上のマンホールの位置を特定する。 By applying a known vibration to the manhole cover, vibrating the optical fiber 403 below the manhole cover, and detecting the vibration of the optical fiber 403 with the optical fiber vibration sensing device 402 installed in the communication building, the light Identify the position of the manhole on the measurement.
　図５には、マンホール１－ｎの蓋をたたいた時に生じる信号の波形も示す（i）。縦軸は振動の強度、横軸は時間を示す。図５には、マンホール４０１－ｎの蓋をたたいた時の光ファイバ４０３の振動波形も示す（ii）。縦軸は振動の強度、横軸は時間を示す。蓋をたたいた時の振動のピークが現れている。図５には、マンホール４０１－ｎの蓋をたたいていない時の光ファイバ４０３の振動波形も示す（iii）。縦軸は振動の強度、横軸は時間を示す。蓋をたたいた時の振動のピークが現れている。 FIG. 5 also shows the waveform of the signal generated when the manhole 1-n is hit with the lid (i). The vertical axis indicates the vibration intensity, and the horizontal axis indicates time. FIG. 5 also shows the vibration waveform of the optical fiber 403 when the cover of the manhole 401-n is hit (ii). The vertical axis indicates the vibration intensity, and the horizontal axis indicates time. Vibration peaks appear when the lid is tapped. FIG. 5 also shows a vibration waveform of the optical fiber 403 when the cover of the manhole 401-n is not hit (iii). The vertical axis indicates the vibration intensity, and the horizontal axis indicates time. Vibration peaks appear when the lid is tapped.
　図６に、振動位置特定の装置である光ファイバ振動センシング装置４０２の構成図を示す。光ファイバ振動センシング装置４０２は、光ファイバ４０３の振動を計測する光ファイバ反射計測部５０１と、時間変化の信号に対するファイバの振動波形とスペクトル解析部５０４及びスペクトルピーク解析部５０５で得られたデータとを保存するデータ保存部５０２と、各位置における包絡線を算出する包絡線解析部５０３と、光ファイバの各位置における振動波形の包絡線に対してスペクトルを解析するスペクトル解析部５０４と、マンホールを叩いた周波数において、ピークが得られる位置がマンホールを叩いた位置と特定マンホールを叩いた周波数でピークを持つ位置を特定するスペクトルピーク解析部５０５と、を備えている。 FIG. 6 shows a configuration diagram of an optical fiber vibration sensing device 402 which is a device for specifying a vibration position. The optical fiber vibration sensing device 402 includes an optical fiber reflection measurement unit 501 that measures the vibration of the optical fiber 403, a fiber vibration waveform with respect to a time-varying signal, and data obtained by the spectrum analysis unit 504 and the spectrum peak analysis unit 505. A data storage unit 502 for storing the envelope, an envelope analysis unit 503 for calculating the envelope at each position, a spectrum analysis unit 504 for analyzing the spectrum for the envelope of the vibration waveform at each position of the optical fiber, and a manhole. At the beat frequency, there is provided a spectrum peak analysis unit 505 for specifying a position where a peak is obtained at a position where a manhole is hit and a position having a peak at a frequency at which a specific manhole is hit.
　本実施形態では、光ファイバ振動センシング結果に対して、包絡線解析とスペクトル解析を用いることで、叩いたマンホールの位置を特定する。以下に本実施形態の処理手順を図７を用いて示す。図８は、包絡線解析とスペクトル解析の結果を示す。 In the present embodiment, the position of the manhole hit is specified by using the envelope analysis and the spectrum analysis on the optical fiber vibration sensing result. The processing procedure of the present embodiment will be described below with reference to FIG. FIG. 8 shows the results of the envelope analysis and the spectrum analysis.
　マンホール４０１－ｎのふたを特定の周波数で叩く（手順１１）。信号処理で検出できるように既知の信号（対照信号）を与える。本実施形態では、マンホール４０１－ｎを叩く周波数を既知としている。 叩 The manhole 401-n is hit at a specific frequency (step 11). A known signal (control signal) is given so that it can be detected by signal processing. In the present embodiment, the frequency at which the manhole 401-n is hit is known.
　光ファイバ振動センシングと振動付与を用いた振動位置特定技術において、図４に示すように、測定結果のＳＮＲが低いため、振動位置を特定することは困難なことがあった。そこで、振動位置特定技術において、振動位置の特定を容易にするために図４の測定結果に信号処理を施す。 (4) In the vibration position specifying technique using the optical fiber vibration sensing and the vibration imparting, it was sometimes difficult to specify the vibration position because the SNR of the measurement result was low as shown in FIG. Therefore, in the vibration position specifying technique, signal processing is performed on the measurement result of FIG. 4 in order to easily specify the vibration position.
　光ファイバ振動センシングで光ファイバの各距離における振動波形（距離－時間領域の振動波形）を測定する（手順１２）。手順１１と同時に光ファイバ振動センシングで光ファイバ長手方向に沿った各位置における振動波形を測定する。測定された各距離における振動波形は、図８（ａ）となる。なお、図４は、図８（ａ）の拡大図である。 Measure the vibration waveform (distance-time domain vibration waveform) at each distance of the optical fiber by optical fiber vibration sensing (procedure 12). Simultaneously with step 11, the vibration waveform at each position along the longitudinal direction of the optical fiber is measured by the optical fiber vibration sensing. FIG. 8A shows the measured vibration waveform at each distance. FIG. 4 is an enlarged view of FIG.
　各位置における振動波形に対して包絡線を算出する（手順１３）。手順１２で得られた光ファイバの各位置における振動波形の包絡線を算出する。包絡線の算出の結果は、図８（ｂ）に示す。図８（ｂ）の縦軸は距離（ｍ）、横軸は時間（ｓ）を示す。距離が１８１７ｍの時の振動波形を図８（ｃ）に示す。振動が付与された位置の包絡線は、マンホール４０１－ｎの蓋を叩いた周波数と一致する繰り返し周波数を持つパルス列となる。一方、振動が付与されていない位置の包絡線は、平坦なものとなる。 算出 Calculate the envelope for the vibration waveform at each position (step 13). The envelope of the vibration waveform at each position of the optical fiber obtained in step 12 is calculated. FIG. 8B shows the result of the calculation of the envelope. In FIG. 8B, the vertical axis indicates distance (m), and the horizontal axis indicates time (s). FIG. 8C shows a vibration waveform when the distance is 1817 m. The envelope at the position where the vibration is applied becomes a pulse train having a repetition frequency that matches the frequency at which the lid of the manhole 401-n is hit. On the other hand, the envelope at the position where no vibration is applied is flat.
　各位置の包絡線に対してスペクトル（距離－時間領域の振動波形）を解析する（手順１４）。手順１３で得られた光ファイバの各位置における振動波形の包絡線に対してスペクトルを図６のスペクトル解析部５０４で解析する。マンホール４０１－ｎを叩いた位置のスペクトルは、マンホール４０１－ｎを叩いた周波数でピークを持つが、マンホールを叩いていない位置のスペクトルはピークを持たない。 ス ペ ク ト ル Analyze the spectrum (distance-time domain vibration waveform) for the envelope at each position (step 14). The spectrum of the envelope of the vibration waveform at each position of the optical fiber obtained in step 13 is analyzed by the spectrum analyzer 504 in FIG. The spectrum at the position where the manhole 401-n is hit has a peak at the frequency at which the manhole 401-n is hit, but the spectrum at the position where the manhole 401-n is not hit has no peak.
　マンホール４０１－ｎを叩いた周波数において、ピークが得られる位置がマンホールを叩いた位置と特定マンホールを叩いた周波数でピークを持つ位置を特定する（手順１５.）。この工程は、図６のスペクトルピーク解析部５０５でフィルタ処理を行い、打撃による振動を検出する。 (4) In the frequency at which the manhole 401-n is struck, the position at which a peak is obtained is specified as the position at which the manhole is struck and the position at which the peak is obtained at the frequency at which the specific manhole is struck (step 15.). In this step, a filtering process is performed by the spectrum peak analysis unit 505 in FIG. 6 to detect vibration due to impact.
　本実施形態では、マンホールの蓋に対して、打撃として、指定した周波数による所定の振動を加え、取得した散乱光強度分布の各位置における時間変化の信号に対して、包絡線のスペクトルを算出し、該スペクトルにおいて指定した周波数のピークを抽出するフィルタ処理を施すことで、打撃による振動を検出することができる。 In the present embodiment, a predetermined vibration at a specified frequency is applied to the manhole cover as a blow, and the spectrum of the envelope is calculated for the signal of the time change at each position of the acquired scattered light intensity distribution. By performing a filter process for extracting a peak at a specified frequency in the spectrum, vibration due to impact can be detected.
　なお、本発明は、上記実施形態そのままに限定されるものではなく、実施段階ではその要旨を逸脱しない範囲で構成要素を変形して具体化できる。また、上記実施形態に開示されている複数の構成要素の適宜な組合せにより種種の発明を形成できる。例えば、実施形態に示される全構成要素からいくつかの構成要素を削除しても良い。更に、異なる実施形態に亘る構成要素を適宜組み合わせても良い。 Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying constituent elements in an implementation stage without departing from the scope of the invention. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Further, components of different embodiments may be appropriately combined.
　本発明は、光ファイバ通信線路が通っているマンホールの位置を通信集約ビルからの光ファイバ長で表現して特定する技術に適用することができる。 The present invention can be applied to a technology for specifying and specifying the position of a manhole through which an optical fiber communication line passes by expressing the length of an optical fiber from a communication aggregation building.
１－１～１－ｎ、４０１－ｎ　マンホール
２　振動センサ
３、４０３　光ファイバ
４　光通信集約ビル
５ａ　光測定器
５ｂ　信号処理部
６　振動波形
７　振動を表す各地点の散乱光の時間変化波形
４０２　光ファイバ振動センシング装置
５０１　光ファイバ反射計測部
５０２　データ保存部
５０３　包絡線解析部
５０４　スペクトル解析部
５０５　スペクトルピーク解析部 1-1 to 1-n, 401-n Manhole 2 Vibration sensor 3, 403 Optical fiber 4 Optical communication aggregation building 5a Optical measuring instrument 5b Signal processing unit 6 Vibration waveform 7 Time change waveform 402 of scattered light at each point representing vibration Optical fiber vibration sensing device 501 Optical fiber reflection measurement unit 502 Data storage unit 503 Envelope analysis unit 504 Spectrum analysis unit 505 Spectrum peak analysis unit

Claims (9)

  1. 　光ファイバの経路上のマンホールの蓋に対して打撃を加えたときの前記光ファイバからの散乱光の時間変化を前記光ファイバの端部から測定することで前記光ファイバの長手方向の散乱光強度分布の時間変化を取得する第１ステップと、
    　前記打撃による振動発生を前記散乱光強度分布の各位置における時間変化に基づいて判定することで前記光ファイバ上の打撃位置を特定する第２ステップと、
    　前記光ファイバ上の前記打撃位置と前記蓋に対して打撃を加えた前記マンホールの地図上の位置とを対応させることで、当該マンホールの前記端部からの光ファイバ長で表された位置を特定する第３ステップと、
    　を含むマンホール位置特定方法。     By measuring the time change of scattered light from the optical fiber when hitting the manhole cover on the optical fiber path from the end of the optical fiber, the scattered light intensity in the longitudinal direction of the optical fiber is measured. A first step of obtaining a temporal change of the distribution;
    A second step of identifying a hitting position on the optical fiber by determining the generation of vibration due to the hitting based on a time change at each position of the scattered light intensity distribution,
    By associating the hitting position on the optical fiber with the position on the map of the manhole where the impact was applied to the lid, the position represented by the optical fiber length from the end of the manhole is specified. A third step to
    Manhole location method including.
  2. 　前記第１ステップでは、前記蓋に対して、前記打撃として、指定した周波数、時間的タイミング又はパルス化による所定の振動を加え、
    　前記第２ステップでは、前記散乱光強度分布の各位置における時間変化の信号に対して、前記所定の振動の成分を抽出するフィルタ処理を施すことで、前記打撃による振動を検出する、
    　請求項１に記載のマンホール位置特定方法。     In the first step, a predetermined vibration is applied to the lid as the blow, at a designated frequency, a temporal timing, or by pulsing,
    In the second step, the vibration due to the impact is detected by performing a filter process for extracting the predetermined vibration component on the signal of the time change at each position of the scattered light intensity distribution,
    The manhole position specifying method according to claim 1.
  3. 　前記第１ステップでは、前記蓋に対して、前記打撃として、指定した周波数による所定の振動を加え、
    　前記第２ステップでは、前記散乱光強度分布の各位置における時間変化の信号に対して、包絡線のスペクトルを算出し、該スペクトルにおいて前記指定した周波数のピークを抽出するフィルタ処理を施すことで、前記打撃による振動を検出する、
    　請求項２に記載のマンホール位置特定方法。     In the first step, a predetermined vibration at a designated frequency is applied to the lid as the impact,
    In the second step, for the signal of the time change at each position of the scattered light intensity distribution, the spectrum of the envelope is calculated, and by performing a filter process of extracting the peak of the specified frequency in the spectrum, Detecting vibration due to the impact,
    The manhole position specifying method according to claim 2.
  4. 　前記第１ステップでは、前記打撃と前記散乱光の時間変化の測定とを通信用インターフェースを用いて同期させる、
    　請求項１乃至請求項３のいずれか一項に記載のマンホール位置特定方法。     In the first step, the impact and the measurement of the time change of the scattered light are synchronized using a communication interface,
    The manhole position specifying method according to any one of claims 1 to 3.
  5. 　前記第１ステップでは、前記散乱光の時間変化の測定に光パルスを入射して発生る後方散乱光を測定する光時間領域後方散乱測定法を用い、前記打撃の周波数を前記光パルスが前記光ファイバを往復する時間よりも周期が長い周波数とする、
    　請求項１乃至請求項４のいずれか一項に記載のマンホール位置特定方法。     In the first step, a time change of the scattered light is measured by using an optical time domain backscatter measurement method of measuring a backscattered light generated by inputting a light pulse, and the frequency of the hit is determined by the light pulse. The frequency is longer than the period of the round trip of the fiber.
    The manhole position specifying method according to any one of claims 1 to 4.
  6. 　前記第１ステップでは、前記光ファイバに対して、両端から光干渉計を用いることで前記散乱光の時間変化を測定する方法を用いる、
    　請求項１乃至請求項４のいずれか一項に記載のマンホール位置特定方法。     In the first step, for the optical fiber, using a method of measuring the time change of the scattered light by using an optical interferometer from both ends,
    The manhole position specifying method according to any one of claims 1 to 4.
  7. 　光ファイバの端部に接続され、前記光ファイバの経路上のマンホールの位置を特定するマンホール位置特定システムにおいて、
    　前記マンホールの蓋に対して打撃が加えられたときの前記光ファイバからの散乱光の時間変化を前記端部から測定することで前記光ファイバの長手方向の散乱光強度分布の時間変化を取得する光測定器と、
    　前記打撃による振動発生を前記散乱光強度分布の各位置における時間変化に基づいて判定することで前記光ファイバ上の打撃位置を特定し、前記光ファイバ上の前記打撃位置と前記蓋に対して打撃を加えられた前記マンホールの地図上の位置とを対応させることで、当該マンホールの前記端部からの光ファイバ長で表された位置を特定する信号処理部と、
    　を備えるマンホール位置特定システム。     In a manhole position specifying system connected to an end of an optical fiber and for specifying a position of a manhole on a path of the optical fiber,
    The time change of the scattered light intensity distribution in the longitudinal direction of the optical fiber is obtained by measuring the time change of the scattered light from the optical fiber when the impact is applied to the manhole cover from the end. A light measuring instrument,
    The hitting position on the optical fiber is specified by determining the occurrence of vibration due to the hitting based on the time change at each position of the scattered light intensity distribution, and the hitting position and the lid on the optical fiber are hit. A signal processing unit that specifies the position represented by the optical fiber length from the end of the manhole by associating the position on the map of the manhole with the added,
    Manhole location system equipped with
  8. 　前記蓋に対して、前記打撃として、指定した周波数、時間的タイミング又はパルス化による所定の振動を加える振動機構をさらに備え、
    　前記信号処理部は、前記散乱光強度分布の各位置における時間変化の信号に対して、前記所定の振動の成分を抽出するフィルタ処理を施すことで、前記打撃による振動を検出する、
    　請求項７に記載のマンホール位置特定システム。     The lid further includes a vibration mechanism that applies a predetermined vibration by a designated frequency, a temporal timing, or pulsation as the impact,
    The signal processing unit detects the vibration due to the impact by performing a filtering process for extracting the component of the predetermined vibration on the signal of the time change at each position of the scattered light intensity distribution,
    The manhole location specifying system according to claim 7.
  9. 　前記振動機構は、前記蓋に対して、前記打撃として、指定した周波数による所定の振動を加え、
    　前記信号処理部は、前記散乱光強度分布の各位置における時間変化の信号に対して、包絡線のスペクトルを算出し、該スペクトルにおいて前記指定した周波数のピークを抽出するフィルタ処理を施すことで、前記打撃による振動を検出する、
    　請求項８に記載のマンホール位置特定システム。     The vibration mechanism applies a predetermined vibration at a specified frequency to the lid as the impact,
    The signal processing unit, for the signal of the time change at each position of the scattered light intensity distribution, calculates the spectrum of the envelope, and performs filter processing to extract the peak of the specified frequency in the spectrum, Detecting vibration due to the impact,
    The manhole location specifying system according to claim 8.
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