KR20230075001A - Fiber-Optic Distributed Acoustic Sensor and measuring method thereof - Google Patents

Fiber-Optic Distributed Acoustic Sensor and measuring method thereof Download PDF

Info

Publication number
KR20230075001A
KR20230075001A KR1020210161153A KR20210161153A KR20230075001A KR 20230075001 A KR20230075001 A KR 20230075001A KR 1020210161153 A KR1020210161153 A KR 1020210161153A KR 20210161153 A KR20210161153 A KR 20210161153A KR 20230075001 A KR20230075001 A KR 20230075001A
Authority
KR
South Korea
Prior art keywords
interest
signal
section
optical fiber
light
Prior art date
Application number
KR1020210161153A
Other languages
Korean (ko)
Other versions
KR102652916B1 (en
Inventor
정효영
김영호
김희운
김명진
기송도
이헌수
김상중
유민우
박수연
Original Assignee
한국광기술원
한국철도공사
주식회사 에니트
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 한국광기술원, 한국철도공사, 주식회사 에니트 filed Critical 한국광기술원
Priority to KR1020210161153A priority Critical patent/KR102652916B1/en
Publication of KR20230075001A publication Critical patent/KR20230075001A/en
Application granted granted Critical
Publication of KR102652916B1 publication Critical patent/KR102652916B1/en

Links

Images

Classifications

    • 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
    • G01H9/004—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means using fibre optic sensors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
    • G01D5/35354—Sensor working in reflection
    • G01D5/35358—Sensor working in reflection using backscattering to detect the measured quantity
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
    • G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
    • G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
    • G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
    • G01D5/35383—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using multiple sensor devices using multiplexing techniques
    • G01D5/35393—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using multiple sensor devices using multiplexing techniques using frequency division multiplexing
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
    • G06F17/10—Complex mathematical operations

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Data Mining & Analysis (AREA)
  • Mathematical Analysis (AREA)
  • Mathematical Optimization (AREA)
  • Computational Mathematics (AREA)
  • Pure & Applied Mathematics (AREA)
  • Databases & Information Systems (AREA)
  • Software Systems (AREA)
  • General Engineering & Computer Science (AREA)
  • Algebra (AREA)
  • Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

Abstract

The present invention relates to a distributed optical fiber acoustic sensor, which comprises: a light source unit that emits light; an optical circulator that outputs light, emitted from the light source unit and input to an input end, to a sensing end and outputs light, traveling reversely from the sensing end, to a detection end; a sensing optical fiber connected to the sensing end and installed to be distributed over a measurement target area; an optical detection unit that detects Rayleigh backscattered light output from the detection end of the optical circulator; and a control unit that stores a reference impulse response signal received from the optical detection unit by performing control so that a reference impulse light is output from the light source unit in a full-section detection mode in which an acoustic signal for the entire area of the sensing optical fiber is detected and processes an acoustic signal for a section of interest of the sensing optical fiber from a fine response signal output in response to a section of interest from the optical detection unit by performing control so that a section-of-interest filtering optical signal, resulting from reflecting a section-of-interest filtering function in a reference impulse response signal, is output from the light source unit. Measurement precision for the section of interest may be enhanced.

Description

분포형 광섬유 음향센서 및 그 음향측정방법{Fiber-Optic Distributed Acoustic Sensor and measuring method thereof}Distributed optical fiber acoustic sensor and its acoustic measurement method {Fiber-Optic Distributed Acoustic Sensor and measuring method thereof}

본 발명은 분포형 광섬유 음향센서 및 그 음향측정방법에 관한 것으로서, 상세하게는 관심구간에 대한 음향신호의 검출 정밀도를 향상시킬 수 있도록 된 분포형 광섬유 음향센서 및 그 음향측정방법에 관한 것이다.The present invention relates to a distributed optical fiber acoustic sensor and an acoustic measurement method thereof, and more particularly, to a distributed optical fiber acoustic sensor capable of improving detection accuracy of an acoustic signal for a section of interest and a acoustic measurement method thereof.

광섬유를 10km 내외의 장거리에 걸쳐 설치하여 운영하는 분포형 광섬유 센서는 국내 등록특허 제10-1223105호 등 다양하게 게시되어 있다.Distributed optical fiber sensors that install and operate optical fibers over long distances of around 10 km have been posted in various ways, such as Korean Patent No. 10-1223105.

이러한 분포형 광섬유 센서는 광섬유 내 산란현상을 이용하며, 이때 광섬유 케이블의 특정 위치에 작용하는 물리량에 따라 다르게 반사되어 돌아오는 광섬유 내 후방 산란광의 세기를 측정하는 것으로 온도 이외에도 변형 등 다양한 물리량을 검출하도록 구축될 수 있다..Distributed optical fiber sensors use the scattering phenomenon within the optical fiber, and measure the intensity of the backscattered light within the optical fiber that is reflected differently depending on the physical quantity acting on a specific position of the optical fiber cable. can be built...

이러한 분포형 광섬유 센서 중 레일레이(Rayleigh) 산란을 이용하는 광섬유 음향센서(DAS: Distributed Acoustic Sensor)가 있다.Among these distributed optical fiber sensors, there is a distributed acoustic sensor (DAS) using Rayleigh scattering.

광섬유 음향센서는 광섬유 내부를 진행하는 광으로부터 광섬유의 밀도의 불균일 분포에 기인하여 발생하는 산란광을 측정하는 센서로, 펄스광의 세기에 비례하는 후방 산란광을 얻을 수 있다. The optical fiber acoustic sensor is a sensor that measures scattered light generated from light traveling inside the optical fiber due to non-uniform distribution of the density of the optical fiber, and can obtain back scattered light proportional to the intensity of the pulsed light.

그런데, 단발 형태의 펄스광을 송출하는 광섬유 음향센서의 경우 잡음에 의한 측정정밀도가 떨어질 수 있어 신호대 잡음비를 더욱 향상시키면서 관심구간에 대한 검출 정밀도를 향상시킬 수 있는 방안이 요구되고 있다.However, in the case of an optical fiber acoustic sensor that transmits pulsed light in the form of a single shot, measurement accuracy due to noise may be deteriorated, so there is a need for a method that can improve the detection accuracy for the section of interest while further improving the signal-to-noise ratio.

본 발명은 상기와 같은 요구사항을 해결하기 위하여 창안된 것으로서, 센싱광섬유의 일부 관심구간에 대한 측정 정밀도를 향상시킬 수 있도록 지원하는 분포형 광섬유 음향센서 및 그 음향측정방법을 제공하는데 그 목적이 있다.The present invention was invented to solve the above requirements, and the purpose of the present invention is to provide a distributed optical fiber acoustic sensor and its acoustic measurement method that support improving the measurement accuracy for a section of interest in a sensing optical fiber. .

상기의 목적을 달성하기 위하여 본 발명에 따른 분포형 광섬유 음향센서는 광을 출사하는 광원부와; 상기 광원부에서 출사되어 입력단으로 입력된 광을 센싱단으로 출력하고, 상기 센싱단에서 역으로 진행하는 광을 검출단으로 출력하는 광써큘레이터와; 상기 센싱단에 접속되어 측정대상 영역에 분포되게 설치된 센싱광섬유와; 상기 광써큘레이터의 검출단에서 출력되는 레일레이 역산란광을 검출하는 광검출부와; 상기 센싱광섬유 전체 영역에 대한 음향신호를 검출하는 전구간검출모드에서는 상기 광원부에서 기준 임펄스광이 출력되게 제어하여 상기 광검출부로부터 수신된 기준 임펄스 응답신호를 저장하고, 상기 센싱광섬유에 대해 관심구간으로 설정된 영역에 대해서만 필터링된 파인 응답신호를 얻는 관심구간검출모드에서는 상기 기준 임펄스 응답신호에 관심구간 필터링 함수가 반영된 관심구간필터링 광신호가 상기 광원부에서 출력되게 제어하여 상기 광검출부에서 관심구간에 대응하여 출력되는 파인 응답신호로부터 상기 센싱광섬유의 관심구간에 대한 음향신호를 처리하는 제어유니트;를 구비한다.In order to achieve the above object, a distributed optical fiber acoustic sensor according to the present invention includes a light source unit for emitting light; an optical circulator for outputting light emitted from the light source unit and input through an input terminal to a sensing terminal, and outputting light traveling backward from the sensing terminal to a detection terminal; sensing optical fibers connected to the sensing end and installed to be distributed in a measurement target area; a photodetector for detecting Rayleigh back-scattered light output from the detection end of the optical circulator; In the full-duration detection mode for detecting the acoustic signal for the entire area of the sensing optical fiber, the light source unit controls the output of reference impulse light, stores the reference impulse response signal received from the optical detection unit, and sets the sensing optical fiber as a section of interest. In the ROI detection mode in which a fine response signal filtered only for a region is obtained, the ROI filtering optical signal in which the ROI filtering function is reflected in the reference impulse response signal is controlled to be output from the light source unit, and the photodetector outputs corresponding to the ROI and a control unit that processes the acoustic signal for the section of interest of the sensing optical fiber from the fine response signal.

또한, 상기 제어유니트는 상기 기준 임펄스광 또는 상기 관심구간 필터링 광신호에 대응되는 파형신호를 생성하여 상기 광원부에 출력하는 주파수 복합신호 생성부와; 상기 전구간 검출모드에서는 상기 기준 임펄스광에 대응되는 파형신호가 생성되게 상기 주파수 복합신호 생성부를 제어하고, 상기 관심구간 검출모드에서는 상기 관심구간 필터링 광신호에 대응되는 파형 신호가 생성되게 상기 주파수 복합신호 생성부를 제어하며, 상기 광검출부에서 출력되는 신호를 처리하는 신호처리부;를 구비한다.In addition, the control unit may include a frequency composite signal generating unit generating a waveform signal corresponding to the reference impulse light or the ROI filtering optical signal and outputting the generated waveform signal to the light source unit; In the full section detection mode, the frequency composite signal generating unit is controlled to generate a waveform signal corresponding to the reference impulse light, and in the section of interest detection mode, the frequency composite signal is generated to generate a waveform signal corresponding to the section of interest filtered optical signal. and a signal processing unit which controls the generator and processes the signal output from the photodetector.

본 발명의 일 측면에 따르면, 상기 제어유니트는 상기 전구간 검출모드에서 검출된 기준 임펄스 응답신호로부터 설정된 이벤트에 대응되는 음향신호가 발생된 구간에 대해 관심구간으로 설정하고, 설정된 관심구간에 대해 상기 관심구간 검출모드를 수행한다.According to one aspect of the present invention, the control unit sets a section of interest for a section in which an acoustic signal corresponding to a set event is generated from the reference impulse response signal detected in the full section detection mode as a section of interest, and sets the section of interest to the set section of interest. Execute section detection mode.

또한, 상기의 목적을 달성하기 위하여 본 발명에 따른 분포형 광섬유 음향센서의 음향 측정방법은 가. 상기 광원부에서 기준 임펄스광이 출력되게 제어하여 상기 광검출부로부터 상기 센싱광섬유 전체 영역에 대한 기준 임펄스 응답신호를 수신하여 저장하는 단계와; 나. 상기 센싱광섬유의 일부 영역에 대해서만 필터링된 파인 응답신호를 상기 광검출부로부터 얻도록 상기 센싱광섬유에 대해 관심구간을 설정하는 단계와; 다. 상기 기준 임펄스 응답신호에 상기 관심구간에 해당하는 관심구간 필터링 함수가 반영된 관심구간필터링 광신호가 상기 광원부에서 출력되게 제어하는 단계와; 라. 상기 광검출부에서 출력되는 파인 응답신호를 수신하는 단계;를 포함한다.In addition, in order to achieve the above object, the acoustic measurement method of the distributed optical fiber acoustic sensor according to the present invention is a. controlling the output of the reference impulse light from the light source unit to receive and store the reference impulse response signal for the entire area of the sensing optical fiber from the photodetector; me. setting a period of interest for the sensing optical fiber so as to obtain a filtered fine response signal from the optical detector only for a partial area of the sensing optical fiber; all. controlling a region-of-interest filtering optical signal in which a region-of-interest filtering function corresponding to the region of interest is reflected in the reference impulse response signal is output from the light source unit; la. and receiving a fine response signal output from the photodetector.

본 발명에 따른 분포형 광섬유 음향센서 및 그 음향측정방법에 의하면, 센싱광섬유의 분포영역 중 관심구간에 대한 필터링된 응답신호를 얻을 수 있어 관심구간에 대한 측정 정밀도를 향상시킬 수 있는 장점을 제공한다. According to the distributed optical fiber acoustic sensor and its acoustic measurement method according to the present invention, it is possible to obtain a filtered response signal for the section of interest among the distribution area of the sensing optical fiber, thereby providing an advantage of improving measurement accuracy for the section of interest. .

도 1은 본 발명에 따른 분포형 광섬유 음향센서를 나타내 보인 도면이고,
도 2는 도 1의 분포형 광섬유 음향센서의 관심구간 음향측정 과정을 나타내 보인 플로우도이고,
도 3은 도 1의 센싱광섬유의 관심구간에 대해 응답신호를 얻기 위해 적용되는 관심구간 필터링 함수를 설명하기 위한 도면이다.1 is a view showing a distributed optical fiber acoustic sensor according to the present invention,
Figure 2 is a flow diagram showing the process of measuring the sound of the segment of interest of the distributed optical fiber acoustic sensor of Figure 1,
FIG. 3 is a diagram for explaining a filtering function for a section of interest applied to obtain a response signal for a section of interest of the sensing optical fiber of FIG. 1 .

이하, 첨부된 도면을 참조하면서 본 발명의 바람직한 실시예에 따른 분포형 광섬유 음향센서 및 그 음향측정방법을 더욱 상세하게 설명한다.Hereinafter, a distributed optical fiber acoustic sensor and a method for measuring acoustics thereof according to a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

도 1은 본 발명에 따른 분포형 광섬유 음향센서를 나타내 보인 도면이다.1 is a view showing a distributed optical fiber acoustic sensor according to the present invention.

도 1을 참조하면, 본 발명에 따른 분포형 광섬유 음향센서(100)는 광원부(110), 광써큘레이터(120), 센싱광섬유(130), 광검출부(140), 제어유니트(160) 및 출력부(180)를 구비한다.Referring to FIG. 1, the distributed optical fiber acoustic sensor 100 according to the present invention includes a light source unit 110, an optical circulator 120, a sensing optical fiber 130, an optical detection unit 140, a control unit 160, and an output A portion 180 is provided.

광원부(110)는 제어유니트(160)로부터의 제어신호에 대응하는 광을 출사한다.The light source unit 110 emits light corresponding to a control signal from the control unit 160 .

광원부(110)는 광원(112) 및 파형발생부(114)로 구축되어 있다.The light source unit 110 is constructed with a light source 112 and a waveform generator 114.

광원(112)은 파형발생부(114)에서 출력되는 파형에 대응되는 광을 출력한다.The light source 112 outputs light corresponding to the waveform output from the waveform generator 114 .

파형발생부(114)는 제어유니트(160)의 주파수 복합신호 생성부(161)에서 출력되는 파형신호에 대응되는 파형의 광이 출사되게 광원(112)을 구동한다. The waveform generator 114 drives the light source 112 so that light of a waveform corresponding to the waveform signal output from the frequency composite signal generator 161 of the control unit 160 is emitted.

광써큘레이터(120)는 광원부(110)에서 출사되어 입력단(120a)으로 입력된 광을 센싱단(120b)으로 출력하고, 센싱단(120b)에서 역으로 진행하는 광을 검출단(120c)으로 출력한다.The optical circulator 120 outputs the light emitted from the light source unit 110 and input through the input end 120a to the sensing end 120b, and the light traveling backward from the sensing end 120b to the detection end 120c. print out

센싱광섬유(130)는 광써큘레이터(120)의 센싱단(120b)에 접속되어 측정대상 영역에 분포되게 설치되어 있다.The sensing optical fiber 130 is connected to the sensing end 120b of the optical circulator 120 and is installed to be distributed over the area to be measured.

센싱광섬유(130)는 음향신호를 수신하여 진단에 이용하기 위한 시설물 예를 들면, 변압기, 수전반 및 배전반과 같은 함체 내부의 장착대상 요소들에 장착될 수 있다.The sensing optical fiber 130 may be installed in a facility for receiving an acoustic signal and using it for diagnosis, for example, a mounting target element inside an enclosure such as a transformer, switchboard, and switchboard.

광검출부(140)는 광써큘레이터(120)의 검출단(120c)에서 출력되는 레일레이 역산란광을 검출하여 전기적 신호로 출력한다. 여기서 레일레이 역산란광은 센싱광섬유(130)에서 입사된 펄스광에 대응되어 산란되어 역으로 진행되어 센싱단(120b) 및 검출단(120c)을 통해 출력되는 광신호이다.The light detector 140 detects the Rayleigh back-scattered light output from the detection end 120c of the optical circulator 120 and outputs it as an electrical signal. Here, the Rayleigh back-scattered light is an optical signal that is scattered in response to the pulsed light incident from the sensing optical fiber 130 and then propagated in reverse to be output through the sensing end 120b and the detection end 120c.

광검출부(140)에는 검출단(120c)에서 출력되는 광으로부터 레일레이 역산란광을 필터링하는 파장필터와 파장필터에서 출력되는 광의 세기에 대응되는 전기적 신호를 출력하는 광검출기로 구축될 수 있다.The photodetector 140 may include a wavelength filter for filtering Rayleigh back-scattered light from the light output from the detector 120c and a photodetector for outputting an electrical signal corresponding to the intensity of light output from the wavelength filter.

제어유니트(160)는 전구간 검출모드와 관심구간 검출모드에 대응되는 광이 광원부(110)에서 출사되게 제어하고, 광검출부(140)에서 수신된 음향신호를 처리한다.The control unit 160 controls the light corresponding to the entire section detection mode and the section of interest detection mode to be emitted from the light source unit 110 and processes the sound signal received from the photodetector 140 .

제어유니트(160)는 센싱광섬유(130) 전체 영역에 대한 음향신호를 검출하는 전구간검출모드에서는 광원부(110)에서 기준 임펄스광(Pa)이 출력되게 제어하여 광검출부(140)로부터 수신된 기준 임펄스 응답신호(h(t))를 저장하고, 센싱광섬유(130)에 대해 관심구간으로 설정된 영역에 대해서만 필터링된 파인 응답신호(hdesign(t))를 얻는 관심구간검출모드에서는 기준 임펄스 응답신호(h(t))에 관심구간 필터링 함수(gdesign(t))가 반영된 관심구간필터링 광신호(Pb)가 광원부(110)에서 출력되게 제어하여 광검출부(140)에서 관심구간에 대응하여 출력되는 파인 응답신호(hdesign(t))로부터 센싱광섬유(130)의 관심구간에 대한 음향신호를 처리한다.The control unit 160 controls the reference impulse light Pa from the light source unit 110 to be output in the full-length detection mode for detecting the acoustic signal for the entire area of the sensing optical fiber 130 so that the reference impulse received from the light detection unit 140 In the interest section detection mode in which the response signal h(t) is stored and the filtered fine response signal h design (t) is obtained only for the region set as the interest section for the sensing optical fiber 130, the reference impulse response signal ( The light source unit 110 controls the light source unit 110 to output the ROI filtering optical signal Pb, in which the ROI filtering function g design (t) is reflected in h(t), so that the photodetector 140 outputs the signal corresponding to the ROI. The acoustic signal for the section of interest of the sensing optical fiber 130 is processed from the fine response signal h design (t).

제어유니트(160)는 주파수 복합신호 생성부(161)와, 신호처리부(170)를 구비한다.The control unit 160 includes a frequency composite signal generation unit 161 and a signal processing unit 170.

주파수 복합신호 생성부(161)는 기준 임펄스광(Pa) 또는 관심구간 필터링 광신호(Pb)에 대응되는 파형신호를 생성하여 광원부(110)에 출력한다.The frequency composite signal generation unit 161 generates a waveform signal corresponding to the reference impulse light Pa or the POI filtering light signal Pb and outputs it to the light source unit 110 .

여기서, 기준 임펄스광(Pa)은 도 1에 도시된 바와 같이 사각펄스형태의 파형을 갖는 단펄스이며, 관심구간 필터링 광신호(Pb)는 센싱광섬유(130)에 대해 관심구간 이외의 영역에 대해서는 응답신호를 상쇄시키고, 관심구간에 대해서만 응답신호를 생성할 수 있도록 생성된 신호를 말한다. Here, the reference impulse light Pa is a short pulse having a square pulse shape waveform as shown in FIG. It refers to a signal generated to cancel the response signal and generate a response signal only for the section of interest.

신호처리부(170)는 센싱광섬유(130)에서 음향에 대응되어 역으로 반사되는 레일레이 역산란광에 대해 광검출부(140)에서 출력되는 신호로부터 센싱광섬유(130)의 위치별 음향신호를 분석처리하고, 분석처리결과를 출력부(180)를 통해 출력한다.The signal processing unit 170 analyzes and processes the acoustic signal for each position of the sensing optical fiber 130 from the signal output from the optical detector 140 for the Rayleigh back-scattered light that is reflected back in response to the sound in the sensing optical fiber 130, and , the analysis processing result is output through the output unit 180.

또한, 신호처리부(170)는 전구간 검출모드에서는 기준 임펄스광(Pa)에 대응되는 파형신호가 생성되게 주파수 복합신호 생성부(161)를 제어하고, 관심구간 검출모드에서는 관심구간 필터링 광신호(Pb)에 대응되는 파형 신호가 생성되게 주파수 복합신호 생성부(161)를 제어하며, 광검출부(140)에서 출력되는 신호를 처리한다.In addition, the signal processor 170 controls the frequency composite signal generation unit 161 to generate a waveform signal corresponding to the reference impulse light Pa in the full section detection mode, and in the section of interest detection mode, the section of interest filtering light signal Pb ) and controls the frequency composite signal generation unit 161 to generate a waveform signal corresponding to , and processes a signal output from the photodetector 140 .

신호처리부(170)는 전구간 검출모드에서 검출된 기준 임펄스 응답신호로부터 설정된 이벤트에 대응되는 음향신호가 발생된 구간에 대해 관심구간으로 설정하고, 설정된 관심구간에 대해 관심구간 검출모드를 수행하도록 구축될 수 있다. 여기서, 이벤트는 수신된 음향신호의 레벨이 설정된 기준 레벨 이상 검출된 경우, 특정 주파수 대역의 음향신호가 수신된 경우 등 진단하고자 하는 환경에 따라 적절하게 적용하면 된다. 이러한 신호 처리부(170)의 측정과정을 도 2를 통해 설명한다.The signal processing unit 170 is configured to set a section in which an acoustic signal corresponding to an event set from the reference impulse response signal detected in the full section detection mode is generated as a section of interest and to perform a section of interest detection mode for the set section of interest. can Here, the event may be appropriately applied according to the environment to be diagnosed, such as when the level of the received acoustic signal is detected above a set reference level or when an acoustic signal of a specific frequency band is received. A measurement process of the signal processing unit 170 will be described with reference to FIG. 2 .

먼저, 전구간 검출모드용 기준임펄스광(Pa)이 광원부(110)에서 출력되게 제어하고(단계 210), 광검출부(140)로부터 센싱광섬유(130) 전체 영역에 대한 기준 임펄스 응답신호(h(t))를 수신하여 저장한다(단계 220).First, the reference impulse light (Pa) for all detection modes is controlled to be output from the light source unit 110 (step 210), and the reference impulse response signal (h(t) for the entire area of the sensing optical fiber 130 from the light detection unit 140 )) is received and stored (step 220).

이후, 수신된 기준 임펄스 응답신호(h(t))로부터 분석된 음향신호에 설정된 이벤트가 발생했는 지를 판단한다(단계 230). 단계 230에서 이벤트에 대응되는 음향신호가 발생된 영역을 관심구간으로 설정한다(단계 240).Thereafter, it is determined whether a set event has occurred in the acoustic signal analyzed from the received reference impulse response signal h(t) (step 230). In step 230, an area where an acoustic signal corresponding to an event is generated is set as a region of interest (step 240).

이후, 광원부(110)를 제어하여 설정된 관심구간에 대응되는 관심구간 필터링 광신호가 출력되게 하고(단계 250), 관심구간에 대해 광검출부(140)로부터 수신된 파인응답 신호로 음향을 측정한다(단계 260).Thereafter, the light source unit 110 is controlled to output a segment-of-interest filtering optical signal corresponding to the set segment of interest (step 250), and sound is measured with the fine response signal received from the photodetector 140 for the segment of interest (step 250). 260).

이러한 측정과정은 설정된 측정 주기마다 수행하도록 구축될 수 있다.This measurement process may be constructed to be performed at each set measurement period.

한편, 출력부(180)는 전송대상 수신처로 생성정보를 송신하는 통신인터페이스 또는 생성정보를 표시하는 표시부가 적용될 수 있다.Meanwhile, the output unit 180 may be a communication interface for transmitting generation information to a transmission destination or a display unit for displaying generation information.

이하에서는 이러한 분포형 광섬유 음향센서(100)의 관심구간 정밀 측정과정을 더욱 상세하게 설명한다.Hereinafter, a process of precisely measuring the region of interest of the distributed optical fiber acoustic sensor 100 will be described in more detail.

먼저, 도 3에 도시된 바와 같이 x방향으로 연장된 전체 센싱광섬유(130)에서 관심 구간을

Figure pat00001
설정한 경우 대응되는 관심시간(t0, t1)은 아래의 수학식 1과 같다.First, as shown in FIG. 3, a section of interest is determined from all sensing optical fibers 130 extending in the x direction.
Figure pat00001
When set, the corresponding time of interest (t0, t1) is shown in Equation 1 below.

Figure pat00002
Figure pat00002

또한, 앞서 설명된 기준 임펄스광(Pa)에 대한 센싱광섬유(130)의 응답신호인 기준 임펄스 응답신호

Figure pat00003
에 앞서 설명된 관심구간 필터링함수(
Figure pat00004
)가 컨벌루션(convolution)된 형태의 파인 응답신호(hdesign(t))는
Figure pat00005
에서만 값을 갖도록
Figure pat00006
를 적용하면 되고, 이를 반영한 제1조건이 아래의 수학식2로 표현된다.In addition, a reference impulse response signal that is a response signal of the sensing optical fiber 130 to the reference impulse light Pa described above
Figure pat00003
The interest interval filtering function described above (
Figure pat00004
) is convolved, and the fine response signal (h design (t)) is
Figure pat00005
to have a value only in
Figure pat00006
, and the first condition reflecting this is expressed by Equation 2 below.

Figure pat00007
Figure pat00007

여기서, ★는 컨벌루션(convolution) 연산자, rect는 도 3에 도시된 바와 같이 to와 t1 사이 구간에서만 1의 값을 갖는 사각함수이다. Here, ★ is a convolution operator, and rect is a square function having a value of 1 only in the interval between to and t1 as shown in FIG. 3 .

상기 수학식2를 푸리에(Fourier)변환을 통해 시간영역에서 응답신호를 주파수 영역의 전달함수로 변경하면 아래의 수학식3과 같이 표현된다.If the response signal in the time domain is changed to a transfer function in the frequency domain through Equation 2 through Fourier transform, it is expressed as Equation 3 below.

Figure pat00008
Figure pat00008

Figure pat00009
Figure pat00009

여기서, F는 푸리에 변환을 의미하고, H(f)는 h(t)에 대해 퓨리에 변환된 함수,

Figure pat00010
는
Figure pat00011
에 대해 퓨리에 변환된 함수를 의미한다.Here, F means Fourier transform, H(f) is a Fourier transform function for h(t),
Figure pat00010
Is
Figure pat00011
It means the Fourier transform function for .

따라서, 관심구간 필터링함수(

Figure pat00012
)에 대해 주파수 영역에 대해서는 위 수학식 3을 통해 미리 측정한
Figure pat00013
와, 알고 있는
Figure pat00014
값을 이용하여
Figure pat00015
를 산출하고, 이를 시간함수로 변환하여
Figure pat00016
를 관심구간 필터링함수로 적용하여 앞서 설명된 바와 같은 관심구간 필터링 광신호를 생성하면 된다.Therefore, the interest interval filtering function (
Figure pat00012
) For the frequency domain, pre-measured through Equation 3 above
Figure pat00013
wow, you know
Figure pat00014
using the value
Figure pat00015
Calculate and convert it into a time function
Figure pat00016
Apply as the ROI filtering function to generate the POI filtering optical signal as described above.

이상에서 설명된 분포형 광섬유 음향센서 및 그 음향측정방법에 의하면, 센싱광섬유의 분포영역 중 관심구간에 대한 필터링된 응답신호를 얻을 수 있어 관심구간에 대한 측정 정밀도를 향상시킬 수 있는 장점을 제공한다. According to the above-described distributed optical fiber acoustic sensor and its acoustic measurement method, it is possible to obtain a filtered response signal for the section of interest among the distribution area of the sensing optical fiber, thereby providing an advantage of improving the measurement precision for the section of interest. .

110: 광원부 120: 광써큘레이터
130: 센싱광섬유 140: 광검출부
160: 제어유니트 180: 출력부110: light source unit 120: optical circulator
130: sensing optical fiber 140: light detection unit
160: control unit 180: output unit

Claims (7)

광을 출사하는 광원부와;
상기 광원부에서 출사되어 입력단으로 입력된 광을 센싱단으로 출력하고, 상기 센싱단에서 역으로 진행하는 광을 검출단으로 출력하는 광써큘레이터와;
상기 센싱단에 접속되어 측정대상 영역에 분포되게 설치된 센싱광섬유와;
상기 광써큘레이터의 검출단에서 출력되는 레일레이 역산란광을 검출하는 광검출부와;
상기 센싱광섬유 전체 영역에 대한 음향신호를 검출하는 전구간검출모드에서는 상기 광원부에서 기준 임펄스광이 출력되게 제어하여 상기 광검출부로부터 수신된 기준 임펄스 응답신호를 저장하고, 상기 센싱광섬유에 대해 관심구간으로 설정된 영역에 대해서만 필터링된 파인 응답신호를 얻는 관심구간검출모드에서는 상기 기준 임펄스 응답신호에 관심구간 필터링 함수가 반영된 관심구간필터링 광신호가 상기 광원부에서 출력되게 제어하여 상기 광검출부에서 관심구간에 대응하여 출력되는 파인 응답신호로부터 상기 센싱광섬유의 관심구간에 대한 음향신호를 처리하는 제어유니트;를 구비하는 것을 특징으로 하는 분포형 광섬유 음향센서.a light source unit that emits light;
an optical circulator for outputting light emitted from the light source unit and input through an input terminal to a sensing terminal, and outputting light traveling backward from the sensing terminal to a detection terminal;
sensing optical fibers connected to the sensing end and installed to be distributed in a measurement target area;
a photodetector for detecting Rayleigh back-scattered light output from the detection end of the optical circulator;
In the full-duration detection mode for detecting the acoustic signal for the entire area of the sensing optical fiber, the light source unit controls the output of reference impulse light, stores the reference impulse response signal received from the optical detection unit, and is set as a section of interest for the sensing optical fiber. In the ROI detection mode in which a fine response signal filtered only for a region is obtained, the ROI filtering optical signal in which the ROI filtering function is reflected in the reference impulse response signal is controlled to be output from the light source unit to be output corresponding to the ROI from the photodetector. A distributed optical fiber acoustic sensor comprising a control unit for processing an acoustic signal for a section of interest of the sensing optical fiber from a fine response signal. 제1항에 있어서, 상기 제어유니트는
상기 기준 임펄스광 또는 상기 관심구간 필터링 광신호에 대응되는 파형신호를 생성하여 상기 광원부에 출력하는 주파수 복합신호 생성부와;
상기 전구간 검출모드에서는 상기 기준 임펄스광에 대응되는 파형신호가 생성되게 상기 주파수 복합신호 생성부를 제어하고, 상기 관심구간 검출모드에서는 상기 관심구간 필터링 광신호에 대응되는 파형 신호가 생성되게 상기 주파수 복합신호 생성부를 제어하며, 상기 광검출부에서 출력되는 신호를 처리하는 신호처리부;를 구비하는 것을 특징으로 하는 분포형 광섬유 음향센서.The method of claim 1, wherein the control unit
a frequency composite signal generation unit for generating a waveform signal corresponding to the reference impulse light or the ROI filtering optical signal and outputting the generated waveform signal to the light source unit;
In the full section detection mode, the frequency composite signal generation unit is controlled to generate a waveform signal corresponding to the reference impulse light, and in the section of interest detection mode, the frequency composite signal is generated to generate a waveform signal corresponding to the section of interest filtered optical signal. Distributed optical fiber acoustic sensor, characterized in that it comprises a signal processor for controlling the generator and processing the signal output from the photodetector. 제2항에 있어서, 상기 제어유니트는
상기 전구간 검출모드에서 검출된 기준 임펄스 응답신호로부터 설정된 이벤트에 대응되는 음향신호가 발생된 구간에 대해 관심구간으로 설정하고, 설정된 관심구간에 대해 상기 관심구간 검출모드를 수행하는 것을 특징으로 하는 분포형 광섬유 음향센서.The method of claim 2, wherein the control unit
Distributed type characterized in that a section in which an acoustic signal corresponding to an event set from the reference impulse response signal detected in the full section detection mode is generated is set as a section of interest, and the section of interest detection mode is performed for the set section of interest. Fiber optic acoustic sensor. 제3항에 있어서, 상기 관심구간 필터링 함수(
Figure pat00017
)는
아래의 제1조건을 만족하고,
Figure pat00018

여기서,
Figure pat00019
는 상기 기준 임펄스 응답신호이고, t0 및 t1은 관심구간
Figure pat00020
에 대응하는 관심 시간이며, ★는 컨벌루션(convolution) 연산자 이고, rect는 to와 t1 사이 관심구간에서만 1의 값을 갖는 사각함수이며,
상기 신호처리부는 상기 제1조건을 이용하여 알고 있는 상기 기준 임펄스 응답신호와 사각함수 값을 이용하여 상기 관심구간 필터링 함수를 산출하는 것을 특징으로 하는 분포형 광섬유 음향센서.The method of claim 3, wherein the interest interval filtering function (
Figure pat00017
)Is
Satisfy the first condition below,
Figure pat00018

here,
Figure pat00019
is the reference impulse response signal, and t0 and t1 are intervals of interest
Figure pat00020
is the time of interest corresponding to , ★ is a convolution operator, rect is a square function with a value of 1 only in the interval of interest between to and t1,
The distributed optical fiber acoustic sensor, characterized in that the signal processing unit calculates the interest section filtering function using the reference impulse response signal known using the first condition and a square function value. 광을 출사하는 광원부와, 상기 광원부에서 출사되어 입력단으로 입력된 광을 센싱단으로 출력하고, 상기 센싱단에서 역으로 진행하는 광을 검출단으로 출력하는 광써큘레이터와, 상기 센싱단에 접속되어 측정대상 영역에 분포되게 설치된 센싱광섬유와, 상기 광써큘레이터의 검출단에서 출력되는 레일레이 역산란광을 검출하는 광검출부와, 상기 광출부에서 출력되는 신호로부터 상기 센싱 광섬유가 설치된 영역의 음향을 측정하는 제어유니트를 구비하는 분포형 광섬유 음향센서의 음향 측정방법에 있어서,
가. 상기 광원부에서 기준 임펄스광이 출력되게 제어하여 상기 광검출부로부터 상기 센싱광섬유 전체 영역에 대한 기준 임펄스 응답신호를 수신하여 저장하는 단계와;
나. 상기 센싱광섬유의 일부 영역에 대해서만 필터링된 파인 응답신호를 상기 광검출부로부터 얻도록 상기 센싱광섬유에 대해 관심구간을 설정하는 단계와;
다. 상기 기준 임펄스 응답신호에 상기 관심구간에 해당하는 관심구간 필터링 함수가 반영된 관심구간필터링 광신호가 상기 광원부에서 출력되게 제어하는 단계와;
라. 상기 광검출부에서 출력되는 파인 응답신호를 수신하는 단계;를 포함하는 것을 특징으로 하는 분포형 광섬유 음향센서의 음향 측정방법.A light source unit for emitting light, an optical circulator for outputting light emitted from the light source unit and input to an input terminal to a sensing unit, and outputting light traveling backward from the sensing unit to a detection unit, connected to the sensing unit, Sensing optical fibers installed to be distributed in the area to be measured, a light detector detecting the Rayleigh back-scattered light output from the detection end of the optical circulator, and measuring the sound of the area where the sensing optical fiber is installed from the signal output from the light output unit In the acoustic measurement method of a distributed optical fiber acoustic sensor having a control unit to
go. controlling the output of the reference impulse light from the light source unit to receive and store the reference impulse response signal for the entire area of the sensing optical fiber from the photodetector;
me. setting a period of interest for the sensing optical fiber so as to obtain a filtered fine response signal from the optical detector only for a partial area of the sensing optical fiber;
all. controlling a region-of-interest filtering optical signal in which a region-of-interest filtering function corresponding to the region of interest is reflected in the reference impulse response signal is output from the light source unit;
la. Acoustic measurement method of a distributed optical fiber acoustic sensor, characterized in that it comprises a; step of receiving a fine response signal output from the photodetector. 제5항에 있어서, 상기 관심구간 필터링 함수(
Figure pat00021
)는
아래의 제1조건을 만족하고,
Figure pat00022

여기서,
Figure pat00023
는 상기 기준 임펄스 응답신호이고, t0 및 t1은 관심구간
Figure pat00024
에 대응하는 관심 시간이며, ★는 컨벌루션(convolution) 연산자 이고, rect는 to와 t1 사이 구간에서만 1의 값을 갖는 사각함수이며, 상기 제1조건을 이용하여 알고 있는 기준 임펄스 응답신호와 사각함수 값을 이용하여 상기 관심구간 필터링 함수를 산출하는 것을 특징으로 하는 분포형 광섬유 음향센서의 음향측정방법.The method of claim 5, wherein the interest interval filtering function (
Figure pat00021
)Is
Satisfy the first condition below,
Figure pat00022

here,
Figure pat00023
is the reference impulse response signal, and t0 and t1 are intervals of interest
Figure pat00024
is the time of interest corresponding to , ★ is a convolution operator, rect is a square function having a value of 1 only in the interval between to and t1, and the reference impulse response signal and the square function value known using the first condition Acoustic measurement method of the distributed optical fiber acoustic sensor, characterized in that for calculating the interest section filtering function using. 제6항에 있어서, 상기 나단계는 상기 기준 임펄스 응답신호로부터 설정된 이벤트에 대응되는 음향신호가 발생된 구간에 대해 관심구간으로 설정하는 것을 특징으로 하는 분포형 광섬유 음향센서의 음향측정방법.





[Claim 7] The acoustic measurement method of a distributed optical fiber acoustic sensor according to claim 6, wherein, in step B, a section in which an acoustic signal corresponding to an event set from the reference impulse response signal is generated is set as a section of interest.
KR1020210161153A 2021-11-22 2021-11-22 Fiber-Optic Distributed Acoustic Sensor and measuring method thereof KR102652916B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020210161153A KR102652916B1 (en) 2021-11-22 2021-11-22 Fiber-Optic Distributed Acoustic Sensor and measuring method thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020210161153A KR102652916B1 (en) 2021-11-22 2021-11-22 Fiber-Optic Distributed Acoustic Sensor and measuring method thereof

Publications (2)

Publication Number Publication Date
KR20230075001A true KR20230075001A (en) 2023-05-31
KR102652916B1 KR102652916B1 (en) 2024-03-29

Family

ID=86543420

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020210161153A KR102652916B1 (en) 2021-11-22 2021-11-22 Fiber-Optic Distributed Acoustic Sensor and measuring method thereof

Country Status (1)

Country Link
KR (1) KR102652916B1 (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016021689A1 (en) * 2014-08-07 2016-02-11 古河電気工業株式会社 Optical fiber sensor, seismic prospecting method, method for measuring distribution of petroleum/natural gas reservoir layer, strain detection method, and method for specifying position of fissure in stratum
KR101817295B1 (en) * 2016-07-20 2018-01-10 한국광기술원 Fiber-Optic Distributed Acoustic Sensor
KR102048459B1 (en) * 2018-05-21 2019-11-25 한국과학기술연구원 Dual brillouin distributed optical fiber sensor and sensing method using brillouin scattering which allow high-speed event detection and precise measurement
KR20200002802A (en) * 2017-02-22 2020-01-08 씨엠티이 디벨로프먼트 리미티드 Optical Acoustic Sensing System and Method

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2016021689A1 (en) * 2014-08-07 2016-02-11 古河電気工業株式会社 Optical fiber sensor, seismic prospecting method, method for measuring distribution of petroleum/natural gas reservoir layer, strain detection method, and method for specifying position of fissure in stratum
KR101817295B1 (en) * 2016-07-20 2018-01-10 한국광기술원 Fiber-Optic Distributed Acoustic Sensor
KR20200002802A (en) * 2017-02-22 2020-01-08 씨엠티이 디벨로프먼트 리미티드 Optical Acoustic Sensing System and Method
KR102048459B1 (en) * 2018-05-21 2019-11-25 한국과학기술연구원 Dual brillouin distributed optical fiber sensor and sensing method using brillouin scattering which allow high-speed event detection and precise measurement

Also Published As

Publication number Publication date
KR102652916B1 (en) 2024-03-29

Similar Documents

Publication Publication Date Title
CN102197284B (en) fibre optic acoustic sensing
US9702975B2 (en) Lidar measuring system and lidar measuring method
US9631972B2 (en) Distributed fibre optic sensing
CN102292621B (en) Improvements in distributed fiber optic sensing
EP3477266B1 (en) Distributed acoustic sensing device using different coherent interrogating light patterns, and corresponding sensing method
US10151626B2 (en) Fibre optic distributed sensing
EP3237874B1 (en) Reflectometric vibration measurement system and relative method for monitoring multiphase flows
EP3237936B1 (en) Optical fiber vibration measurement system in multiphase flows with related method to monitor multiphase flows
JP2018146371A (en) Temperature-strain sensing device and temperature-strain sensing method
KR101817295B1 (en) Fiber-Optic Distributed Acoustic Sensor
US10365354B2 (en) Multi-target laser distance meter
CN110518969B (en) Optical cable vibration positioning device and method
KR20180134253A (en) Fiber-optic acoustic sensor module apparatus and system using coherent optical time-domain reflectormeter method
CN105865750A (en) Optical fiber defect detecting method and device
JPH0663872B2 (en) Distributed temperature sensor
KR102652916B1 (en) Fiber-Optic Distributed Acoustic Sensor and measuring method thereof
RU2730887C1 (en) Fiber-optic device for detecting vibration effects with phase recovery with reduced effect of instabilities of the recording interferometer
US11976963B2 (en) Fibre-optic acoustic sensor and associated measurement system, vehicle and measurement method
JP3063063B2 (en) Optical fiber temperature distribution measurement system
CN210327579U (en) Optical cable vibrating positioning device
CN210444271U (en) Optical cable vibrating positioning device
KR20230008462A (en) hyper-tube vehicle position and velocity measuring apparatus and method of measuring velocity of the same
RU2695098C1 (en) Fiber-optic device for recording vibration effects with separation of controlled sections
KR102394748B1 (en) Pulse code based Fiber-Optic Distributed Acoustic Sensor
CN110518968B (en) Optical cable vibration positioning device and method

Legal Events

Date Code Title Description
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
GRNT Written decision to grant