Signal processing device and method

Abstract

The purpose of the present disclosure is to provide a signal processing device, a system, a method, and a non-transitory computer-readable medium that make it possible to estimate a location of signal generation by considering optical fiber installation information and optical fiber gauge length. A signal processing device (11) according to the present disclosure comprises: a candidate signal source generation means (111) for generating a plurality of candidate signal source locations; a composite data generation means (112) for calculating, on the basis of a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and the plurality of candidate signal source locations, distortion signals generated through signals generated from signal sources distorting optical fibers; an actual measurement data processing means (113) for receiving input of a phase difference signal of backscattered light in an optical fiber gauge length section at the time when an optical pulse signal is inputted to an optical fiber, and converting the phase difference signal to a distortion signal; and a candidate signal source condition selection means (114) for selecting, from among the plurality of calculated distortion signals, a specific distortion signal having the highest similarity to the distortion signal obtained through the conversion.

Description

[Technical Field]

[0001] The present disclosure relates to a signal processing device, a system, a method, and a non-transitory computer-readable medium, and more particularly to a signal processing device, a system, a method, and a non-transitory computer-readable medium that are capable of estimating the location of a signal generation taking into account optical fiber installation information and optical fiber gauge length. [Background technology]

[0002] Phase-Sensitive OTDRs (Phase-Sensitive Optical Time Domain Reflectometers) are known to use optical fiber sensing to detect vibrations and sounds occurring at any section of an optical fiber. An OTDR inputs a coherent optical pulse signal and detects the difference in the phase of backscattered light (Rayleigh scattered light) between two points on the optical fiber, thereby detecting the dynamic strain of the optical fiber in the phase difference evaluation section (gauge length section). This is also sometimes called a distributed acoustic sensing (DAS) device.

[0003] Non-Patent Document 1 discloses a method for estimating the position and direction of a signal source located away from an optical fiber based on the relationship between an acoustic signal detected on the optical fiber and the real-space distribution information of the optical fiber. Specifically, the method discloses a two-dimensional and three-dimensional sound source position estimation method using an optical fiber sensor with a coil-shaped sensor head.

[0004] Non-Patent Document 2 discloses that waveform amplitude is visualized and the performance of behavioral event detection by several CNN (Convolutional Neural Network) models is compared.

[0005] Non-Patent Document 3 discloses that a learning model is constructed from synthetic data of straight lines by utilizing the linearity of the trajectories of traffic vehicles that appear in waveform amplitude data.

[0006] Patent Document 1 discloses a method for detecting Brillouin scattered light generated in an optical fiber fixed to a structure that has a nonlinear shape and in which nonuniform strain occurs when displacement occurs, and measuring observed power spectrum data from the Brillouin scattered light. Patent Document 1 also discloses a method for theoretically calculating a model power spectrum shape of the Brillouin scattered light generated in response to the magnitude of the structure's displacement, fitting this model power spectrum shape to the observed power spectrum data, and calculating the displacement of the structure based on the fitted model power spectrum shape with the best-fitting curve. Patent Document 1 does not disclose estimating the signal generation position taking into account optical fiber installation information and optical fiber gauge length.

[0007] Patent Document 2 discloses an optical coherent sensor that includes a light source unit that generates optical pulses as probe light, a light receiving unit that coherently detects signal light generated in a measurement object by the probe light to generate a beat signal, and a calculation unit to which the beat signal is input. Furthermore, Patent Document 2 discloses that the calculation unit includes an optical information acquiring means, an accuracy degradation avoiding means, and a phase difference information acquiring means, and the optical information acquiring means acquires, for each optical pulse, from the beat signal, the distribution of the intensity and phase of the signal light with respect to the reception time of the signal light, the accuracy degradation avoiding means sets a reference time, and the phase difference information acquiring means acquires the phase difference with respect to the reception time of the signal light as the phase difference between the reception times where tk>tj>ti and the difference between t and ti is the reference time, and acquires the distribution of the phase difference with respect to the reception time of the signal light. Patent Document 2 does not disclose estimating the generation position of a signal by taking into account optical fiber installation information and optical fiber gauge length. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-047699 [Patent Document 2] Japanese Patent Publication No. 2020-159915 [Non-patent literature]

[0009] [Non-Patent Document 1] J. Liang, et al., "Distributed acoustic sensing for 2D and 3D acoustic source localization," Opt. Lett. 44, 1690-1693 (2019) [Non-patent document 2] Y. Shi, et al., “An Event Recognition Method for Φ-OTDR Sensing System Based on Deep Learning”, Sensors, 19, 3421 (2019) [Non-patent document 3] C. Narisetty, et al., “Overcoming challenges of distributed fiber-optic sensing for highway traffic monitoring”, J. of the Transportation Research Board, 2, 2675 (2021) Summary of the Invention [Problem to be solved by the invention]

[0010] As described above, OTDR detects the dynamic distortion (distortion signal) of an optical fiber over a gauge length by detecting the difference (phase difference) between two points on the optical fiber. The phase difference acquired by OTDR varies greatly depending on the installation status of the optical fiber and the set value of the optical fiber gauge length. In signal location estimation methods, the generation position of the signal that caused the distortion signal is estimated based on the distortion signal detected by OTDR. Therefore, in order to perform more accurate position estimation, it is necessary to detect the distortion signal while taking into account the installation status of the optical fiber and the optical fiber gauge length, and to estimate the generation position of the signal based on the detected distortion signal.

[0011] An object of the present disclosure is to provide a signal processing device, a system, a method, and a non-transitory computer-readable medium that solves the above-mentioned problems. [Means for solving the problem]

[0012] The signal processing device according to the present disclosure includes: a signal source candidate generating means for generating a plurality of signal source candidate positions; a synthetic data generating means for calculating a distortion signal generated when a signal generated from a signal source distorts an optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the candidate signal source positions; a measurement data processing means for receiving a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber, and converting the phase difference signal into a distortion signal; a signal source candidate condition selection means for selecting a predetermined distorted signal having the highest similarity to the converted distorted signal from the plurality of calculated distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the position where the signal is generated; Equipped with.

[0013] The system according to the present disclosure comprises: A distributed acoustic sensing (DAS) device; a signal processing device; The distributed acoustic sensing device includes: a phase difference detection means for detecting a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber; The signal processing device includes: a signal source candidate generating means for generating a plurality of signal source candidate positions; a synthetic data generating means for calculating a distortion signal generated when a signal generated from a signal source distorts an optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the candidate signal source positions; a measured data processing means for receiving the phase difference signal and converting the phase difference signal into the distortion signal; and a signal source candidate condition selection means for selecting a predetermined distorted signal that is most similar to the converted distorted signal from the plurality of calculated distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the position where the signal is generated.

[0014] The method according to the present disclosure comprises: generating a plurality of candidate signal source locations; calculating a distortion signal generated by a signal generated from a signal source distorting the optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the signal source candidate positions; a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber is input, and the phase difference signal is converted into a distortion signal; selecting a predetermined distorted signal that is most similar to the converted distorted signal from the calculated plurality of distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the source position of the signal; Equipped with.

[0015] The present disclosure provides a non-transitory computer-readable medium, comprising: generating a plurality of candidate signal source locations; calculating a distortion signal generated by a signal generated from a signal source distorting the optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the signal source candidate positions; a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber is input, and the phase difference signal is converted into a distortion signal; selecting a predetermined distorted signal that is most similar to the converted distorted signal from the calculated plurality of distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the source position of the signal; A program that causes a computer to execute the above is stored. [Effects of the Invention]

[0016] According to the present disclosure, it is possible to provide a signal processing device, system, method, and non-transitory computer-readable medium that are capable of estimating the origination position of a signal taking into account optical fiber installation information and optical fiber gauge length. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram illustrating a system according to a first embodiment. [Figure 2] 1 is a block diagram illustrating a signal processing device according to a first embodiment. [Figure 3] FIG. 1 is a schematic diagram illustrating the operation of a distributed acoustic sensing (DAS) device. [Figure 4] FIG. 10 is a schematic diagram illustrating the influence of gauge length. [Figure 5] 4 is a flowchart illustrating an operation of a signal source candidate generating means according to the first embodiment. [Figure 6] 4 is a flowchart illustrating an operation of a synthetic data generating means according to the first embodiment. [Figure 7A] 4 is a flowchart illustrating the operation of a composite data storage means according to the first embodiment. [Figure 7B] 3 is a schematic diagram illustrating a storage table of a composite data storage means according to the first embodiment. FIG. [Figure 8]4 is a flowchart illustrating the operation of a measurement data processing means according to the first embodiment. [Figure 9] 4 is a flowchart illustrating an operation of a signal source candidate condition selecting means according to the first embodiment. [Figure 10] FIG. 1 is a schematic diagram showing a specific example of a system according to a first embodiment. [Figure 11] 2 is a block diagram illustrating the processing contents of each element of the signal processing device according to the first embodiment. FIG. [Figure 12A] 4 is a schematic diagram illustrating the similarity in the signal source candidate condition selecting means according to the first embodiment. FIG. [Figure 12B] 4 is a schematic diagram illustrating the similarity in the signal source candidate condition selecting means according to the first embodiment. FIG. [Figure 12C] 4 is a schematic diagram illustrating the similarity in the signal source candidate condition selecting means according to the first embodiment. FIG. [Figure 12D] 4 is a schematic diagram illustrating the similarity in the signal source candidate condition selecting means according to the first embodiment. FIG. [Figure 13] FIG. 10 is a block diagram illustrating a signal processing device according to a second embodiment. [Figure 14] FIG. 10 is a schematic diagram illustrating a divided space according to the second embodiment. [Figure 15] 10 is a flowchart illustrating the operation of the signal processing device according to the second embodiment. [Figure 16] FIG. 10 is a schematic diagram illustrating a divided space according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding elements are designated by the same reference numerals, and for clarity of explanation, duplicate explanations will be omitted as necessary.

[0019] [Embodiment 1] <Configuration> FIG. 1 is a block diagram illustrating a system according to the first embodiment. FIG. 2 is a block diagram illustrating a signal processing device according to the first embodiment.

[0020] As shown in FIG. 1, a system 10 according to the first embodiment includes a distributed acoustic sensing (DAS) device 12 and a signal processing device 11.

[0021] As shown in FIG. 2, the signal processing device 11 includes a signal source candidate generating means 111, a synthetic data generating means 112, an actual measurement data processing means 113, and a signal source candidate condition selecting means 114.

[0022] The signal source candidate generating means 111 generates a plurality of signal source candidate positions. The signal source candidate positions indicate candidate positions of the signal source. The signal may be, for example, a mechanical vibration, a physical vibration, and / or a sound signal (acoustic signal). The signal source may be, for example, a sound source, and indicates the position from which the sound originates. The signal source may also indicate, for example, the position from which the vibration occurs.

[0023] When generating signal source candidate positions, the signal source candidate generating means 111 does not generate signal source candidate positions blindly. Optical fiber sensors are installed to detect sounds and vibrations emitted from signal sources, and the signal source candidate generating means 111 may generate signal source candidate positions based on optical fiber installation information that indicates the installation status of the optical fiber. For example, if the optical fiber is installed in a straight line, the signal source candidate positions are generated at equal intervals along the optical fiber. Also, if the optical fiber is installed to surround a specified space or a specified area, the specified space is divided into a mesh, and signal source candidate positions are generated in each divided area.

[0024] That is, the signal source candidate generating means 111 generates, as multiple signal source candidate positions, positions within multiple first divided spaces obtained by dividing a predetermined space including an optical fiber into a mesh-like configuration, or multiple positions along the optical fiber.

[0025] The composite data generating means 112 calculates the distortion signal generated when the signal generated from the signal source distorts the optical fiber based on multiple pieces of optical fiber installation information, multiple optical fiber gauge lengths, and multiple candidate signal source locations. The optical fiber gauge length may also be simply referred to as the gauge length. A sensor that uses optical fiber as a sensor medium is called an optical fiber sensor.

[0026] In addition, in the first embodiment, the distortion signal generated by the signal generated from the signal source distorting the optical fiber is calculated, but this is not limited to this. The signal generated as a result of the signal generated from the signal source affecting the optical fiber may also be calculated as composite data. Therefore, the distortion signal is sometimes referred to as composite data.

[0027] The composite data generating means 112 calculates the distortion signal values ​​of the optical fiber in the number of (the number of pieces of optical fiber installation information) x (the number of pieces of gauge lengths) x (the number of pieces of signal source candidate locations). To this end, the composite data generating means 112, for example, sets the optical fiber installation information and the optical fiber gauge length to fixed values ​​and calculates the distortion signal of the optical fiber when the signal source candidate locations are changed. Also, for example, the composite data generating means 112 sets the optical fiber installation information and the signal source candidate locations to fixed values ​​and calculates the distortion signal of the optical fiber when the optical fiber gauge length is changed. Also, for example, the composite data generating means 112 sets the optical fiber gauge length and the signal source candidate locations to fixed values ​​and calculates the distortion signal of the optical fiber when the optical fiber installation information is changed.

[0028] That is, the composite data generating means 112 calculates distortion signals of a plurality of optical fibers when at least one of the optical fiber installation information, the optical fiber gauge length, and the signal source candidate positions is changed.

[0029] The phase difference signal acquired by the distributed acoustic sensing device 12 is input to the measured data processing means 113. The measured data processing means 113 converts the input phase difference signal into a distorted signal. The method for converting the phase difference signal into a distorted signal will be described in detail later.

[0030] The signal source candidate condition selection means 114 selects a predetermined distorted signal that is most similar to the converted distorted signal from among the calculated plurality of distorted signals. The method for selecting the most similar predetermined distorted signal will be described in detail below. The signal source candidate condition selection means 114 selects a predetermined signal source candidate position that corresponds to the selected predetermined distorted signal from among the plurality of signal source candidate positions. The signal source candidate condition selection means 114 estimates the selected predetermined signal source candidate position as the signal generation position, i.e., the signal source.

[0031] In addition, when the signal source candidate generating means 111 generates positions within a plurality of first divided spaces obtained by dividing a predetermined space including an optical fiber into a mesh-like shape as a plurality of signal source candidate positions, the signal source candidate condition selecting means 114 may select a predetermined signal source candidate position from the plurality of first divided spaces and estimate the predetermined signal source candidate position to be the position where the signal is generated.

[0032] The signal processing device 11 may further include a composite data storage means 115 for storing a plurality of distortion signals calculated by the composite data generation means 112. In this case, the composite data storage means 115 stores the optical fiber installation information, the optical fiber gauge length, the candidate signal source positions, and the distortion signals obtained as a result of the calculation in association with each other.

[0033] The distributed acoustic sensing device 12 has a phase difference detection means (not shown) that detects a phase difference signal of backscattered light in a long optical fiber gauge section when an optical pulse signal is input to the optical fiber. The distributed acoustic sensing device 12 is a device that detects a phase difference signal of backscattered light in a long optical fiber gauge section using distributed acoustic sensing that uses optical fiber as a sensor medium. The distributed acoustic sensing device 12 may also use an existing communication optical fiber as a sensor.

[0034] The signal source candidate condition selection means 114 may narrow the selection range for selecting a predetermined distortion signal from among the calculated multiple distortion signals based on the optical fiber installation information and optical fiber gauge length of the optical fiber to which the optical pulse signal is input.

[0035] <Effects> When estimating the signal generation position, the position varies greatly depending on the optical fiber installation status and the set value of the optical fiber gauge length. The signal processing device 11 (or system 10) according to the first embodiment selects a predetermined distortion signal that is most similar to the actually measured distortion signal from among multiple pieces of composite data (distortion signals) calculated based on the optical fiber installation information, the optical fiber gauge length, and the candidate signal source positions, and estimates the candidate signal source position corresponding to the predetermined distortion signal as the signal generation position. The signal processing device 11 (or system 10) according to the first embodiment estimates the signal generation position taking the optical fiber installation information and the optical fiber gauge length into consideration, thereby enabling more accurate position estimation.

[0036] That is, according to embodiment 1, it is possible to provide a signal processing device, system, method, and non-transitory computer-readable medium that can estimate the signal generation position taking into account optical fiber installation information and optical fiber gauge length, thereby enabling more accurate position estimation of the signal generation position.

[0037] Furthermore, the system 10 according to the first embodiment can reduce the cost of the system because it can convert existing communication optical fibers into sensors and use them as distributed acoustic sensing devices.

[0038] Furthermore, in the system 10 according to the first embodiment, by supplying power only to the box of the optical fiber sensor, the entire optical fiber becomes a sensor medium, and the phase difference signal can be received from the DAS device. Therefore, according to the first embodiment, the number of parts to be powered can be reduced (power saving) compared to when the signal generation position is estimated using an electronically operated vibration sensor or microphone.

[0039] Furthermore, the system 10 according to the first embodiment uses an optical fiber sensor in which an optical fiber is used as a sensor. The optical fiber sensor has a sensor medium made of glass, and therefore is electromagnetically resistant and / or corrosion resistant.

[0040] <Operation of the DAS device> FIG. 3 is a schematic diagram illustrating the operation of a distributed acoustic sensing (DAS) device.

[0041] As shown in FIG. 3, when no signal is generated from the signal source, the optical fiber remains in a non-vibrating state without being affected and does not expand or contract. On the other hand, when a signal is generated from the signal source, the optical fiber is distorted by the signal, and the optical fiber enters a vibrating state and expands and contracts. The distributed acoustic sensing (DAS) device measures the strain ΔL of the optical fiber through the phase difference signal of the backscattered light in the gauge length interval. The optical fiber has a plurality of gauges and operates as an independent vibrating / acoustic optical fiber sensor in each gauge length interval. In Embodiment 1, the distributed acoustic sensing device transmits the phase difference signal obtained when a signal is generated from the signal source to the signal processing device 11.

[0042] <Influence of gauge length> FIG. 4 is a schematic diagram illustrating the influence of the gauge length. The left diagram in FIG. 4 is a schematic diagram illustrating the state of vibration generated from the signal source when the gauge length is short. The right diagram in FIG. 4 is a schematic diagram illustrating the state of vibration generated from the signal source when the gauge length is long.

[0043] The DAS device inputs a coherent optical pulse signal and detects the difference in the phase of the backscattered light between two points on the optical fiber with a phase to detect the dynamic strain (strain signal) of the optical fiber in the phase difference evaluation interval (gauge length interval). The gauge length is the distance (length) between two points on the optical fiber.

[0044] Here, as the gauge length increases, the phase difference between the non-vibration state and the vibration state increases, resulting in a higher SN ratio (signal-to-noise ratio), and the distance between measurement points on the gauge increases, resulting in a lower accuracy (spatial resolution) for estimating the signal source candidate locations.On the other hand, as the gauge length decreases, the phase difference between the non-vibration state and the vibration state decreases, resulting in a lower SN ratio (signal-to-noise ratio), and the distance between measurement points on the gauge decreases, resulting in a higher accuracy (spatial resolution) for estimating the signal source candidate locations.

[0045] As described above, there is a trade-off between the S / N ratio and the accuracy of estimating the signal source candidate location depending on the gauge length. Therefore, if you try to improve the accuracy of estimating the signal source candidate location by shortening the gauge length, the S / N ratio will decrease, and therefore the detection performance will decrease. On the other hand, if you try to improve the detection performance by increasing the S / N ratio by increasing the gauge length, the accuracy of estimating the signal source candidate location will decrease. In other words, it is necessary to measure the phase difference signal with the gauge length set to an optimal value. The gauge length must be within a specified length.

[0046] <Operation of the signal processing device> The operation of the signal processing device according to the first embodiment will be described. In this example, a sound source will be taken as an example of the signal source. <Input information> As shown in FIG. 2, the input information input to the signal source candidate generating means 111 of the signal processing device 11 includes the signal source candidate positions, optical fiber installation information, and (optical fiber) gauge length.

[0047] The signal source candidate position is, for example, the position x of the sound source (signal source). s teeth, x s =(x s , y s , z s ) (1) In addition, the expansion / contraction S of the optical fiber at the measurement point at this time can be expressed as S(x, x s , t). For example, when an acoustic signal propagates through air with a sound speed of c, the expansion / contraction S of the optical fiber at the measurement point can be expressed as S(x, x s, t)=F[ct-|x s -x(d)|] (2) It can be assumed that: where F is a function of the acoustic signal. Moreover, environmental noise that appears according to the laying information of the optical fiber may be formulated and added to the expansion / contraction S.

[0048] The optical fiber installation information is the layout and installation environment of the optical fiber to be installed. The layout can be, for example, coiled or linear. The installation environment can be, for example, overhead line or ground installation. The properties of the measurement results (how the optical fiber is distorted) vary depending on the optical fiber installation information. If the optical fiber is installed in a coiled shape, the measurement point is regarded as a point. If the optical fiber is installed in a linear shape, the measurement point is regarded as a line. A coiled shape is, for example, the state of an overhead line attached to a utility pole. Note that, depending on the installation status of the optical fiber, large environmental noise may be added to the background. For example, in the case of an overhead line, background noise caused by wind may be added.

[0049] As already mentioned, the optical fiber installation information sets the shape and distribution of the optical fiber, such as a straight line or a coil. Here, for example, when a sensor such as a DAS device is used, the position of the measurement point of the optical fiber is expressed as a function of the length d, with the coordinate x(d) being expressed as follows: x(d)=(x(d), y(d), z(d)) (3) It can be set as: Here, the length d is the length of the optical fiber from the sensor to the measurement point.

[0050] The gauge length G is as shown in Fig. 3. The signal source candidate condition selection means 114 selects predetermined synthetic data with the highest similarity from among a plurality of synthetic data sets in which the same value as the gauge length set when the actual measurement data was acquired was set, and estimates the signal source candidate position corresponding to the predetermined synthetic data as the sound source.

[0051] The operation of each element of the signal processing device 11 will now be described. <Signal source candidate generation means> FIG. 5 is a flowchart illustrating the operation of the signal source candidate generating means according to the first embodiment.

[0052] 5, the signal source candidate generating means 111 lists candidate conditions for a signal source (step S101). For example, the signal source candidate generating means 111 lists candidate conditions for a sound source, such as the coordinate x s =(x s , y s , z s When listing candidate positions of a signal source, the signal source candidate generating means 111 divides a predetermined space into a mesh shape, and lists positions within the meshes as candidate signal source positions, the number of which is equal to the number of divided mesh patterns. Furthermore, when listing candidates for a moving signal source (e.g., a signal emitted from a vehicle traveling along an optical fiber), the signal source candidate generating means 111 lists candidates for the speed of movement. In this case, multiple positions along the optical fiber may be listed as multiple candidate signal source positions.

[0053] The signal source candidate generating means 111 generates signal sources for all patterns, the number of which corresponds to the number of candidates (step S102).

[0054] <Means for generating synthetic data> FIG. 6 is a flowchart illustrating the operation of the synthetic data generating means according to the first embodiment.

[0055] As shown in Fig. 6, the composite data generating means 112 generates composite data (distortion signal) of data obtained by optical fiber sensing from input information for all patterns of candidate signal sources (step S103). The input information includes optical fiber installation information, gauge length, and candidate signal source positions. The composite data generating means 112 generates a distortion signal by combining phase difference signals obtained by optical fiber sensing for all patterns in which each piece of input information fluctuates within a predetermined range. Note that optical fiber sensing can detect vibrations occurring in any section of the optical fiber as a phase difference signal.

[0056] That is, the composite data generating means 112 generates composite data using the optical fiber installation information, the gauge length G, and the signal source candidate positions.

[0057] Specifically, the synthetic data generating means 112 first calculates the distortion (strain signal) ε of the optical fiber caused by the acoustic signal in the gauge length section of the optical fiber. sim (d, t) is calculated as the synthetic data. The distortion signal ε sim (d, t) is expressed as in equation (4).

[0058] TIFF0007750373000001.tif1485(4) where d is the length of the optical fiber from the sensor to the measurement point, t is the time, and G is the gauge length. Also, S(x, x s , t) is the expansion and contraction of the optical fiber, and x s is the position of the sound source. x(s) is the coordinate x(s)=(x(s), y(s), z(s)), and s is the integration variable.

[0059] The synthetic data generating means 112 generates a distorted signal ε , which is synthetic data for the number of signal source candidates generated by the signal source candidate generating means 111. sim Generate (d, t).

[0060] <Synthetic Data Storage Means> FIG. 7A is a flowchart illustrating the operation of the composite data storage means according to the first embodiment. FIG. 7B is a schematic diagram illustrating a storage table of the composite data storage means according to the first embodiment.

[0061] 7A, the combined data storage means 115 stores the generated combined data (distortion signals) for all patterns of candidate signal source positions together with the conditions used for calculation, such as optical fiber installation information, gauge length, and candidate signal source positions (step S104). s =(x s , y s , z s) candidate conditions (candidate positions) are listed, and the coordinates of the sound source x are used as conditions for the synthesized data that generated the candidate positions. s is assigned and stored.

[0062] More specifically, as shown in FIG. 7B, the composite data storage means 115 stores in a table the calculation results for regions R1 to R9 of a first divided space, which is obtained by dividing a predetermined space shown in FIG. 10 (described later) into a mesh pattern. The composite data storage means 115 stores the composite data #1 together with the information on the optical fiber installation information (straight + coiled), the gauge length (4 m), and the signal source candidate position (5,5,0) used when the composite data #1 was calculated. The composite data storage means 115 stores the composite data #2 together with the information on the optical fiber installation information (straight + coiled), the gauge length (4 m), and the signal source candidate position (15,5,0) used when the composite data #2 was calculated. The composite data storage means 115 similarly stores the calculation results for regions R3 to R9 in a table.

[0063] The optical fiber installation information = linear + coiled indicates that the optical fiber is installed in a linear and circular shape (called a coiled shape) as shown in the left diagram of Fig. 10. The signal source candidate positions indicate the center positions of each of the regions R1 to R9 in the first divided space, which is obtained by dividing a predetermined space into a mesh shape as shown in the right diagram of Fig. 10.

[0064] <Measurement data processing means> FIG. 8 is a flowchart illustrating the operation of the measured data processing means according to the first embodiment.

[0065] 8, the measured data processing means 113 converts the measured phase difference signal so that it matches the format of the distortion signal, which is synthetic data (step S105). For example, when the synthetic data generating means 112 calculates the distortion (distortion signal) of the optical fiber, it converts the phase difference signal Δφ of the backscattered light obtained by the DAS device into a dynamic distortion signal ε(d, t) of the optical fiber. In this case, the distortion signal ε(d, t) is expressed as in equations (5) and (6).

[0066] The phase difference signal Δφ is measured, for example, by a DAS device, and is the phase difference signal of backscattered light in the optical fiber gauge length section when an optical pulse signal is input to the optical fiber.

[0067] TIFF0007750373000002.tif1565(5)

[0068] TIFF0007750373000003.tif798(6)

[0069] where: φ0 is the reference phase. λ is the optical wavelength of the optical pulse signal, which is 1.55 μm. n is the refractive index of the optical fiber. G is the gauge length. ξ is the photoelastic magnification, which is set to 0.78.

[0070] When the format of the combined data is a phase difference signal, the conversion as shown in equation (5) does not need to be performed.

[0071] <Means for selecting signal source candidate conditions> FIG. 9 is a flowchart illustrating the operation of the signal source candidate condition selecting means according to the first embodiment.

[0072] As shown in FIG. 9, the signal source candidate condition selection means 114 selects synthetic data of a certain condition from among a plurality of synthetic data calculated in advance and stored in the synthetic data storage means 115, based on the signal source conditions (signal source speed, signal source coordinate position (signal source candidate position), waveform, etc.) (step S106).

[0073] The signal source candidate condition selection means 114 determines whether the synthesized data under the selected condition has the highest similarity to the actually measured synthesized data (step S107).

[0074] If the selected composite data has the highest similarity to the actually measured data (step S107: Yes), the signal source candidate condition selection means 114 selects the selected composite data as predetermined composite data and outputs the signal source candidate conditions (signal source candidate positions) corresponding to the predetermined composite data (step S108).

[0075] If the selected synthetic data does not have the highest similarity to the actually measured data (step S107: No), the signal source candidate condition selecting means 114 returns to step S106.

[0076] The synthesized data is, for example, the above-mentioned distorted signal, and the condition is, for example, the coordinate position of the signal source (position of the signal source candidate). Therefore, the operations from step S106 to step S108 can be summarized as follows.

[0077] The signal source candidate condition selection means 114 selects a predetermined distorted signal that is most similar to the distorted signal obtained by actual measurement from among a plurality of pre-calculated distorted signals, and estimates the signal source candidate position corresponding to the predetermined distorted signal as the signal generation position. Note that the distorted signal obtained by actual measurement is a distorted signal obtained by converting the phase difference signal obtained by actual measurement.

[0078] Here, selecting the predetermined synthesized data with the highest similarity means selecting the synthesized data (distortion signal) ε sim The objective is to select the signal that maximizes the similarity between the measured synthetic data (distortion signal) ε and the signal ε.

[0079] Specifically, multiple ε sim The two-dimensional cross-correlation function between the data (d, t) and ε(d, t) is calculated, and the ε that maximizes the similarity is calculated. sim Find (d, t).

[0080] Also, ε simThe amplitudes of (d, t) and ε(d, t) are visualized, and template matching between the images (e.g., SSD (Sum of Squared Difference) or NCC (Normalized Cross Correlation)) is used to find the ε that maximizes the similarity. sim (d, t) may also be found.

[0081] The signal source candidate condition selection means 114 finds the maximum similarity in this way, and estimates the position of the signal source by determining that the coordinates where the similarity is maximum are the originating position of the signal source.

[0082] <Specific example of the first embodiment> The following describes an example of estimating the position of a sound source (signal source) in an area surrounded by a straight optical fiber and a coiled optical fiber. FIG. 10 is a schematic diagram showing a specific example of the system according to the first embodiment.

[0083] As shown in Figure 10, when estimating the position of a sound source in a two-dimensional space in an area (predetermined space) surrounded by a straight optical fiber and a coiled optical fiber, it is necessary to estimate from which area in areas R1 to R9 a sound (assuming an explosion) is coming from. This specific example is applied to detecting the location of an abnormal sound or a dangerous explosion. The first divided space obtained by dividing the predetermined space into a mesh pattern is defined as areas R1 to R9.

[0084] The signal source candidate position is considered to exist in one of the regions R1 to R9 obtained by dividing the space (region) surrounded by the optical fiber into a mesh. Note that the number of divisions into the mesh may be increased to improve the spatial resolution of the estimation results.

[0085] In this example, the optical fiber installation information is as follows: from the starting point where the distributed acoustic sensing (DAS) device 12 is located, proceed in a straight line a first length in a first direction, draw a circle with a perimeter of a second length, proceed in a second direction perpendicular to the first direction, draw a circle with a perimeter of the second length, proceed in the opposite direction to the first direction, draw a circle with a perimeter of the second length, proceed in the opposite direction to the second direction, draw a circle with a perimeter of the second length. The first length is 30 m (meters), and the second length is 50 m.

[0086] In addition to the above expressions, the optical fiber installation information can also be expressed as the optical fiber distribution x(d). x(d)=(x(d), y(d)) (7) where d is the length of the optical fiber from the distributed acoustic sensing device 12 to the measurement point. When expressing optical fiber installation information using equation (7), the coil part is regarded as a point and the straight part as a line. Note that in order to provide a realistic distribution, the coil part may be regarded as a circle with a radius of r.

[0087] FIG. 11 is a block diagram illustrating the processing contents of each element of the signal processing device according to the first embodiment.

[0088] As shown in FIG. 11, for example, a model called an impulse signal S is used as the explosion sound. S(x, x s , t)=Aδ[ct-|x s -x(d)|] (8) where A is a constant and δ is a δ function.

[0089] In order to obtain a more realistic signal, a waveform obtained in advance may be used instead of the impulse signal S.

[0090] Furthermore, if it is known that steady environmental noise exists in a part of the optical fiber, this information may be added as noise to equation (8).

[0091] |ε of the region R1 to the region R9 in the signal source candidate condition selection means 114 sim The similarity between |(d, t)| and |ε(d, t)| is calculated using, for example, a two-dimensional cross-correlation function. To improve performance, (optional) template matching may be used.

[0092] FIG. 12A is a schematic diagram illustrating the similarity in the signal source candidate condition selecting means according to the first embodiment. FIG. 12A shows an example in which a sound (assuming an explosion) occurs in region R5.

[0093] 12A, the signal source candidate condition selection means 114 compares one of the multiple pieces of synthetic data stored in the synthetic data storage means 115 with the vibration amplitude data obtained by converting a phase difference signal measured by the DAS device into a distorted signal by the measured data processing means 113. The signal source candidate condition selection means 114 compares the synthetic data and the vibration amplitude data for each of the regions R1 to R9 using template matching. The signal source candidate condition selection means 114 may visualize the similarity obtained as a result of the comparison.

[0094] Specifically, the signal source candidate condition selection means 114 uses template matching to compare the synthesized data and vibration amplitude data for region R1. As a result, the signal source candidate condition selection means 114 obtains a similarity of "73." Next, the signal source candidate condition selection means 114 compares the synthesized data and amplitude data for region R2. As a result, the signal source candidate condition selection means 114 obtains a similarity of "65." Thereafter, the signal source candidate condition selection means 114 compares the synthesized data and vibration amplitude data for each of regions R3 to R9 to obtain a similarity.

[0095] Then, the signal source candidate condition selecting means 114 selects the synthesized data with the highest similarity from the acquired similarities. In this example, the synthesized data with the highest similarity is the synthesized data of region R5. Therefore, the signal source candidate condition selecting means 114 estimates region R5 as the position of the sound source as the signal source candidate position estimation result.

[0096] FIG. 12B is a schematic diagram illustrating the similarity in the signal source candidate condition selecting means according to the first embodiment. FIG. 12B shows an example in which a sound (presumably an explosion) occurs in region R3.

[0097] 12B, the signal source candidate condition selection means 114 uses template matching to compare the synthesized data and amplitude data for each of regions R1 to R9, and obtains the similarity between regions R1 to R9. From the obtained similarities, the signal source candidate condition selection means 114 selects the synthesized data with the highest similarity, i.e., the synthesized data with a similarity of "39." Because the region corresponding to the synthesized data with a similarity of "39" is region R3, the signal source candidate condition selection means 114 estimates region R3 as the position of the sound source as the signal source candidate position estimation result.

[0098] FIG. 12C is a schematic diagram illustrating the similarity in the signal source candidate condition selecting means according to the first embodiment. FIG. 12C shows an example in which a sound (presumably an explosion) occurs in region R7.

[0099] 12C, the signal source candidate condition selection means 114 uses template matching to compare the synthesized data and amplitude data for each of regions R1 to R9, and obtains the similarity between regions R1 to R9. From the obtained similarities, the signal source candidate condition selection means 114 selects the synthesized data with the highest similarity, i.e., the synthesized data with a similarity of "45". Because the region corresponding to the synthesized data with a similarity of "45" is region R7, the signal source candidate condition selection means 114 estimates region R7 as the position of the sound source as the signal source candidate position estimation result.

[0100] FIG. 12D is a schematic diagram illustrating the similarity in the signal source candidate condition selecting means according to the first embodiment. FIG. 12D shows an example in which a sound (presumably an explosion) occurs in region R4.

[0101] 12D, the signal source candidate condition selection means 114 uses template matching to compare the synthesized data and amplitude data for each of regions R1 to R9, and acquires the similarity between regions R1 to R9. From the acquired similarities, the signal source candidate condition selection means 114 selects the synthesized data with the highest similarity, i.e., the synthesized data with a similarity of "49." Because the region corresponding to the synthesized data with a similarity of "49" is region R4, the signal source candidate condition selection means 114 estimates region R4 as the position of the sound source as the signal source candidate position estimation result.

[0102] <Features> The features of the first embodiment are as follows. In order to detect the characteristics of signals around the optical fiber, a simulation is performed using a theoretical model that inputs the optical fiber installation state, the waveform of the vibration source, and the gauge length, with multiple candidate signal sources prepared in advance. The condition (position) of the vibration source that has the highest similarity between the synthesized data obtained by simulating the optical fiber sensing data and the actually measured data is selected. The selected condition (position) is set as the generation position of the signal source.

[0103] [Embodiment 2] <Configuration> FIG. 13 is a block diagram illustrating a signal processing device according to the second embodiment. FIG. 14 is a schematic diagram illustrating a divided space according to the second embodiment.

[0104] As shown in Figures 13 and 14, the signal processing device 21 according to the second embodiment differs from the signal processing device 11 according to the first embodiment in that it selects a predetermined signal source candidate position from among a plurality of second divided spaces obtained by further dividing the first divided space into a mesh pattern, and estimates the predetermined signal source candidate position as the position where the signal is generated.

[0105] 13, in a first step, the signal source candidate condition selecting means 214 estimates a predetermined signal source candidate position (sound source position) from a space divided into a 3×3 mesh (first divided space). After that, in a second step, the signal source candidate condition selecting means 214 feeds back the predetermined signal source candidate position to the signal source candidate generating means 211, and again estimates the signal generation position from a space (second divided space) obtained by further dividing the space including the estimated predetermined signal source candidate position into meshes.

[0106] <Operation> FIG. 15 is a flowchart illustrating the operation of the signal processing device according to the second embodiment. FIG. 16 is a schematic diagram illustrating a divided space according to the second embodiment.

[0107] As shown in FIG. 15, the signal source candidate generating means 211 further lists candidate conditions for the signal source using the signal source information based on the candidate conditions for the signal source (step S201).

[0108] For example, based on the coordinates of the signal source candidate positions, the coordinates of the sound source x s =(x s , y s , z s 16, when region R5 is input as a signal source candidate position among regions R1 to R9 in the specific example of the first embodiment, the predetermined space (region) R5 is divided into meshes, and regions R5-1 to R5-9, which are candidate conditions for the signal source, are listed.

[0109] The synthetic data generating means 212 generates all patterns of signal sources corresponding to the number of candidate conditions (step S202).

[0110] In detail, the following operations are performed. (Step 1) A region R5 (first divided space) including the estimated predetermined signal source candidate position is fed back to the signal source candidate generating means 211. (Step 2) The signal source candidate generating means 211 further subdivides and divides the region R5 into meshes to generate new signal source candidate positions (defined as regions R5-1 to R5-9, which are referred to as a plurality of second divided spaces). (Step 3) Calculations (simulations) are performed for regions R5-1 to R5-9, and synthetic data is generated and stored. (Step 4) The signal source candidate condition selecting means 214 selects a predetermined signal source candidate position from among the plurality of second divided spaces, estimates the predetermined signal source candidate position as the signal generation position, and outputs it. (Step 5) Repeat steps 1 to 4 until the desired accuracy is achieved.

[0111] The signal processing device 21 according to the second embodiment estimates a rough area of ​​the signal generation position in a first stage, and estimates the signal generation position in more detail from the estimated area in a second stage. As a result, the signal processing device 21 according to the second embodiment can estimate the signal generation position (position of the signal source) more precisely than the signal processing device 11 according to the first embodiment.

[0112] As a method for accurately estimating the signal generation position, as in the signal processing device 21 according to the second embodiment, there is also a method for dividing the entire predetermined space into fine meshes in the first stage. This method requires storing synthetic data corresponding to the number of divisions, which requires a large storage capacity. On the other hand, the synthetic data generating means 212 according to the second embodiment divides in the second stage only the region (space) including the predetermined signal source candidate position estimated in the first stage, and therefore can reduce the storage capacity compared to the method for dividing the entire predetermined space.

[0113] <Features> The embodiment makes it possible to perform analysis taking into consideration the dependency of the optical fiber installation status and gauge length setting, which are properties specific to optical fiber sensing. The embodiment does not require the collection of actual measurement data in advance, and therefore allows highly accurate estimation of the generation position of a signal source for unknown data. The present invention can be applied to signal source location estimation using techniques based on time-of-arrival detection, thereby further improving the accuracy of the estimation. For example, the present invention can determine an estimation range by template matching with synthetic data, and then narrow down the estimation range to perform a detailed location estimation using only measurement points with a high signal-to-noise ratio. The embodiments are applicable to systems for detecting the location of an anomalous acoustic signal source and systems for estimating the velocity of a signal source from a moving object moving along an optical fiber.

[0114] In the above embodiment, the present invention has been described as being configured as hardware, but the present invention is not limited to this. The present invention can also be realized by having a CPU (Central Processing Unit) execute a computer program to perform the processing of each component.

[0115] In the above embodiments, the program can be stored and supplied to a computer using various types of non-transitory computer-readable media. Non-transitory computer-readable media include various types of tangible storage media. Examples of non-transitory computer-readable media include magnetic recording media (specifically, flexible disks, magnetic tapes, and hard disk drives), magneto-optical recording media (specifically, magneto-optical disks), CD-ROMs (Read Only Memory), CD-Rs, CD-R / Ws, semiconductor memories (specifically, mask ROMs, PROMs (Programmable ROMs), and EPROMs (Erasable PROMs)), flash ROMs, and RAMs (Random Access Memory). The program may also be supplied to a computer by various types of transitory computer-readable media. Examples of transitory computer-readable media include electrical signals, optical signals, and electromagnetic waves. The transitory computer-readable media can supply the program to a computer via a wired communication path such as an electric wire or optical fiber, or via a wireless communication path.

[0116] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the invention.

[0117] The present invention is not limited to the above-described embodiment, and can be modified as appropriate within the scope of the invention.

[0118] A part or all of the above-described embodiments can be described as, but not limited to, the following supplementary notes. (Appendix 1) a signal source candidate generating means for generating a plurality of signal source candidate positions; a synthetic data generating means for calculating a distortion signal generated when a signal generated from a signal source distorts an optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the candidate signal source positions; a measurement data processing means for receiving a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber, and converting the phase difference signal into a distortion signal; a signal source candidate condition selection means for selecting a predetermined distorted signal having the highest similarity to the converted distorted signal from the plurality of calculated distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the position where the signal is generated; A signal processing device comprising: (Appendix 2) the signal source candidate generating means generates, as the signal source candidate positions, positions within a plurality of first divided spaces obtained by dividing a predetermined space including the optical fiber into a mesh shape, or a plurality of positions along the optical fiber; the signal source candidate condition selection means selects the predetermined signal source candidate position from among a plurality of the first divided spaces, and estimates the predetermined signal source candidate position as the generation position of the signal; 2. The signal processing device of claim 1. (Appendix 3) the signal source candidate generating means generates a plurality of second divided spaces by further dividing the first divided space including the predetermined signal source candidate position into a mesh-like structure; the signal source candidate condition selection means selects the predetermined signal source candidate position from among the plurality of second divided spaces, and estimates the predetermined signal source candidate position as the generation position of the signal; 3. The signal processing device of claim 2. (Appendix 4) The optical fiber installation information is information that advances a first length in a straight line from a starting point in a first direction, drawing a circle with a perimeter of a second length, advances the first length in a second direction perpendicular to the first direction, drawing a circle with a perimeter of the second length, advances the first length in a direction opposite to the first direction, drawing a circle with a perimeter of the second length, and advances the first length in a direction opposite to the second direction, drawing a circle with a perimeter of the second length. 4. A signal processing device according to any one of claims 1 to 3. (Appendix 5) The length of each of the plurality of optical fiber gauge lengths is within a predetermined length. 5. A signal processing device according to any one of claims 1 to 4. (Appendix 6) further comprising a composite data storage means for storing the calculated plurality of distortion signals; 6. A signal processing device according to any one of claims 1 to 5. (Appendix 7) the combined data storage means stores the optical fiber installation information, the optical fiber gauge length, the signal source candidate positions, and the distortion signal obtained as a result of the calculation in association with each other; 7. The signal processing device according to claim 6. (Appendix 8) the signal source candidate generating means generates a plurality of signal source candidate positions based on the optical fiber installation information; 8. A signal processing device according to any one of claims 1 to 7. (Appendix 9) The signal source candidate condition selection means narrowing a selection range for selecting the predetermined distortion signal from the calculated plurality of distortion signals based on the optical fiber installation information and the optical fiber gauge length of the optical fiber to which the optical pulse signal is input; 9. A signal processing device according to any one of claims 1 to 8. (Appendix 10) A distributed acoustic sensing (DAS) device and a signal processing device are provided, The distributed acoustic sensing device includes: a phase difference detection means for detecting a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber; The signal processing device includes: a signal source candidate generating means for generating a plurality of signal source candidate positions; a synthetic data generating means for calculating a distortion signal generated when a signal generated from a signal source distorts an optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the candidate signal source positions; a measured data processing means for receiving the phase difference signal and converting the phase difference signal into the distortion signal; and a signal source candidate condition selection means for selecting a predetermined distorted signal having the highest similarity to the converted distorted signal from the plurality of calculated distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the position where the signal is generated. system. (Appendix 11) the signal source candidate generating means generates, as the signal source candidate positions, positions within a plurality of first divided spaces obtained by dividing a predetermined space including the optical fiber into a mesh shape, or a plurality of positions along the optical fiber; the signal source candidate condition selection means selects the predetermined signal source candidate position from among a plurality of the first divided spaces, and estimates the predetermined signal source candidate position as the generation position of the signal; 11. The system of claim 10. (Appendix 12) generating a plurality of candidate signal source locations; calculating a distortion signal generated by a signal generated from a signal source distorting the optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the signal source candidate positions; a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber is input, and the phase difference signal is converted into a distortion signal; selecting a predetermined distorted signal that is most similar to the converted distorted signal from the calculated plurality of distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the source position of the signal; A method for providing the above. (Appendix 13) generating a plurality of candidate signal source locations; calculating a distortion signal generated by a signal generated from a signal source distorting the optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the signal source candidate positions; a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber is input, and the phase difference signal is converted into a distortion signal; selecting a predetermined distorted signal that is most similar to the converted distorted signal from the calculated plurality of distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the source position of the signal; A non-transitory computer-readable medium on which a program for causing a computer to execute the program is stored. [Explanation of symbols]

[0119] 10: System 11: Signal processing device 111: Signal source candidate generation means 112: Synthetic data generation means 113: Measurement data processing means 114: Signal source candidate condition selection means 115: Synthetic data storage means 12: Distributed Acoustic Sensing (DAS) Device G: Gauge length ΔL: Strain of the optical fiber Δφ: Phase difference signal R1, R5, R9: area

Claims

1. a signal source candidate generating means for generating a plurality of signal source candidate positions; a synthetic data generating means for calculating a distortion signal generated when a signal generated from a signal source distorts an optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the candidate signal source positions; a measurement data processing means for receiving a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber, and converting the phase difference signal into a distortion signal; a signal source candidate condition selection means for selecting a predetermined distorted signal having the highest similarity to the converted distorted signal from the plurality of calculated distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the position where the signal is generated; A signal processing device comprising:

2. the signal source candidate generating means generates, as the signal source candidate positions, positions within a plurality of first divided spaces obtained by dividing a predetermined space including the optical fiber into a mesh shape, or a plurality of positions along the optical fiber; the signal source candidate condition selection means selects the predetermined signal source candidate position from among a plurality of the first divided spaces, and estimates the predetermined signal source candidate position as the generation position of the signal; The signal processing device according to claim 1 .

3. the signal source candidate generating means generates a plurality of second divided spaces by further dividing the first divided space including the predetermined signal source candidate position into a mesh-like structure; the signal source candidate condition selection means selects the predetermined signal source candidate position from among the plurality of second divided spaces, and estimates the predetermined signal source candidate position as the generation position of the signal; The signal processing device according to claim 2 .

4. The optical fiber installation information includes a first length in a straight line from a starting point in a first direction, drawing a circle with a circumference of a second length, a second length in a second direction perpendicular to the first direction, drawing a circle with a circumference of the second length, a first length in a direction opposite to the first direction, drawing a circle with a circumference of the second length, and a first length in a direction opposite to the second direction, drawing a circle with a circumference of the second length.

4. A signal processing device according to claim 1.

5. The length of each of the plurality of optical fiber gauge lengths is within a predetermined length.

5. A signal processing device according to claim 1.

6. further comprising a composite data storage means for storing the calculated plurality of distortion signals; 6. A signal processing device according to claim 1.

7. the combined data storage means stores the optical fiber installation information, the optical fiber gauge length, the signal source candidate positions, and the distortion signal obtained as a result of the calculation in association with each other; The signal processing device according to claim 6 .

8. the signal source candidate generating means generates a plurality of signal source candidate positions based on the optical fiber installation information; 8. A signal processing device according to claim 1.

9. The signal source candidate condition selection means narrowing a selection range for selecting the predetermined distortion signal from the calculated plurality of distortion signals based on the optical fiber installation information and the optical fiber gauge length of the optical fiber to which the optical pulse signal is input; 9. A signal processing device according to claim 1.

10. generating a plurality of candidate signal source locations; calculating a distortion signal generated by a signal generated from a signal source distorting the optical fiber based on a plurality of pieces of optical fiber installation information, a plurality of optical fiber gauge lengths, and a plurality of the signal source candidate positions; a phase difference signal of backscattered light in an optical fiber gauge length section when an optical pulse signal is input to the optical fiber is input, and the phase difference signal is converted into a distortion signal; selecting a predetermined distorted signal that is most similar to the converted distorted signal from the calculated plurality of distorted signals, selecting a predetermined signal source candidate position corresponding to the predetermined distorted signal from the plurality of signal source candidate positions, and estimating the predetermined signal source candidate position as the source position of the signal; A method for providing the above.

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