Distributed displacement sensing phase demodulation method and apparatus, and device

Abstract

A distributed displacement sensing phase demodulation method, comprising: determining an IQ demodulation initial phase and an IQ signal amplitude on the basis of an IQ signal (S101); performing a phase decoupling operation on the IQ demodulation initial phase, and sequentially subtracting from the IQ demodulation initial phase an initial phase of an optical fiber sensing signal sensing position, an initial phase of a laser pulse source and an accumulated phase along paths in a transmission process, so as to obtain a displacement sensing phase to be measured (S102); performing phase unwinding processing on the displacement sensing phase to be measured, so as to obtain an unwound displacement sensing phase to be measured (S103); performing calculation on the basis of the unwound displacement sensing phase to be measured, so as to obtain displacement sensing data (S104); determining a coherent fading position in the displacement sensing data on the basis of the IQ signal amplitude, and eliminating the impact of coherent fading by using linear interpolation of adjacent normal points, so as to obtain displacement sensing data that has been subjected to coherent fading noise suppression (S105); and transposing, into data recorded in trace order, the displacement sensing data that has been subjected to coherent fading noise suppression, and performing denoising by means of subsequent data processing, so as to obtain final phase-demodulated displacement sensing data (S106). By means of the phase demodulation method, displacement sensing phase demodulation can be realized, and distributed displacement response information of a wave field to be measured is recovered. In addition, further provided are a distributed displacement sensing phase demodulation apparatus, and an electronic device and a readable storage medium.

Description

Distributed displacement sensing phase demodulation method, device and equipment Technical Field

[0001] The present invention relates to the technical field of optical fiber sensing signal demodulation, and in particular to a distributed displacement sensing phase demodulation method, a distributed displacement sensing phase demodulation device, an electronic device and a computer-readable storage medium. Background Art

[0002] Fiber-optic distributed acoustic sensing (DAS) utilizes Rayleigh backscattering in optical fibers to acquire vibration information around them through phase demodulation. Serving as both a sensing and transmission medium, the optical fiber continuously senses acoustic vibration information around the fiber and records it through high-density temporal and spatial sampling. This technology has been widely applied in applications such as borehole seismic data acquisition, dam safety monitoring, perimeter security, and pipeline monitoring. Fiber-optic DAS primarily exploits the Rayleigh backscattering generated by laser light propagating through optical fibers. When the surrounding medium vibrates, the Rayleigh backscattering also changes accordingly. Through coherent detection and phase demodulation of this optical signal, the vibration wave field or strain information of the medium can be obtained. Since the demodulated phase output is generally based on the phase difference between adjacent points according to the gauge length, the output is actually local strain. When the phase difference is differentiated with respect to time before output, the output becomes the local strain rate.

[0003] Fiber optic DAS generally uses a phase-sensitive optical time domain reflectometer Phase demodulation is used to obtain the phase information of Rayleigh backscattering. However, since this phase information is path-dependent and nonlinear with external disturbances, its practical application is severely hampered. Current phase demodulation methods primarily overcome nonlinear effects and improve the signal-to-noise ratio by calculating phase differences within a scale and performing local averaging. However, this method loses low-wavenumber wavefield information and prevents the noise level from being reduced to an ideal level. Many experts, both domestically and internationally, are dedicated to researching phase demodulation with a high signal-to-noise ratio.

[0004] Research indicates that there is currently no method for phase demodulation based on fiber-optic distributed displacement sensing. Existing methods for distributed acoustic wave sensing phase demodulation can only achieve velocity sensing phase demodulation, and these phase demodulation results have many deficiencies in practical applications. Therefore, there is an urgent need to accurately and efficiently perform phase demodulation for displacement sensing down to zero frequency while maintaining broadband wavefield information.

[0005] Summary of the Invention

[0006] The purpose of the embodiments of the present invention is to provide a distributed displacement sensing phase demodulation method, at least to solve the technical problem that there is no phase demodulation method based on optical fiber distributed displacement sensing in the prior art.

[0007] In order to achieve the above-mentioned purpose, in the first aspect, a distributed displacement sensing phase demodulation method is provided, wherein the phase demodulation method comprises the following steps: determining an IQ demodulation initial phase ω0(i, j) and an IQ signal amplitude A(i, j) based on an IQ signal; performing a phase decoupling operation on the IQ demodulation initial phase ω0(i, j), and subtracting the initial phase of the optical fiber sensing signal sensing position from the IQ demodulation initial phase ω0(i, j) in sequence; Laser pulse source initial phase and the accumulated phase of the transmission process path Get the displacement sensor phase to be measured The displacement sensing phase to be measured is subjected to phase unwrapping processing to obtain the unwrapped displacement sensing phase to be measured; the displacement sensing data is calculated based on the unwrapped displacement sensing phase to be measured; the coherent fading position in the displacement sensing data is determined based on the IQ signal amplitude, and the influence of coherent fading is eliminated by linear interpolation of adjacent normal points to obtain the displacement sensing data after coherent fading noise suppression; the displacement sensing data after coherent fading noise suppression is transposed into track sequence recording data, and denoised through subsequent data processing to obtain the final displacement sensing demodulated phase data.

[0008] In a second aspect, a distributed displacement sensing phase demodulation device is provided, and the phase demodulation device may include: an initial phase and amplitude determination unit, a phase decoupling operation unit, a phase unwinding processing unit, a displacement sensing determination unit, a coherent fading noise suppression unit, and a subsequent processing unit; the initial phase and amplitude determination unit is used to determine the IQ demodulation initial phase and the IQ signal amplitude based on the IQ signal; the phase decoupling operation unit is used to perform a phase decoupling operation on the IQ demodulation initial phase, and subtract the initial phase of the optical fiber sensing signal sensing position, the initial phase of the laser pulse source, and the accumulated phase of the transmission process path from the IQ demodulation initial phase in sequence to obtain the displacement sensing phase to be measured; the phase The deconvolution processing unit is used to perform phase deconvolution processing on the displacement sensing phase to be measured to obtain the deconvolution displacement sensing phase to be measured; the displacement sensing determination unit is used to calculate the displacement sensing data based on the deconvolution displacement sensing phase to be measured; the coherent fading noise suppression unit is used to determine the coherent fading position in the displacement sensing data based on the IQ signal amplitude, eliminate the influence of coherent fading by linear interpolation of adjacent normal points, and obtain the displacement sensing data after the coherent fading noise is suppressed; the subsequent processing unit is used to transpose the displacement sensing data after the coherent fading noise is suppressed into track sequence recording data, and perform denoising through subsequent data processing to obtain the final displacement sensing demodulated phase data.

[0009] In a third aspect, an electronic device is provided, comprising a processor and a memory, wherein the memory stores at least one computer program, and the at least one computer program is loaded and executed by one or more of the above-mentioned processors so that the processor executes the above-mentioned distributed displacement sensing phase demodulation method.

[0010] In a fourth aspect, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores at least one program code, and the program code is loaded and executed by a processor to enable the computer to execute the above-mentioned distributed displacement sensing phase demodulation method.

[0011] One of the above technical solutions has the following beneficial effects:

[0012] (1) The distributed displacement sensing phase demodulation method provided by the above technical solution recovers the distributed displacement response information of the wave field to be measured by performing a series of phase decoupling operations on the initial phase of IQ demodulation, and fully maintains the low-frequency and low-wavenumber information, which can improve the practical application effect of optical fiber sensing;

[0013] (2) The distributed displacement sensing phase demodulation method provided by the above technical solution fills the technical gap in the existing technology that there is no phase demodulation method based on optical fiber distributed displacement sensing. In actual production applications, it is of great significance to improve the quality of optical fiber sensing data acquisition, protect low-frequency and low-wavenumber wave field information, and match processing with traditional detectors.

[0014] Other features and advantages of the embodiments of the present invention will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0016] FIG1 is a flow chart of a distributed displacement sensing phase demodulation method provided by one embodiment of the present invention;

[0017] FIG2 is an IQ demodulation initial phase diagram of an optical fiber IQ signal provided by one embodiment of the present invention;

[0018] FIG3 is a diagram showing a phase-shifted demodulated record of an optical fiber IQ signal according to an embodiment of the present invention;

[0019] FIG4 is an unwound recording image after phase shift demodulation according to an embodiment of the present invention;

[0020] FIG5 is a diagram of a normal track sequence record after transposition provided by one embodiment of the present invention;

[0021] FIG6 is a structural block diagram of a distributed displacement sensing phase demodulation device provided by one embodiment of the present invention;

[0022] FIG7 is a structural block diagram of an electronic device provided by an embodiment of the present invention.

[0023] Explanation of the reference numerals 101 - initial phase and amplitude determination unit, 102 - phase decoupling operation unit, 103 - phase dewrapping processing unit, 104 - displacement sensing determination unit, 105 - coherent fading noise suppression unit, 106 - subsequent processing unit, 201 - processor, 202 - memory. DETAILED DESCRIPTION

[0024] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0025] In the present invention, unless otherwise indicated, directional terms such as "upper, lower, top, and bottom" are generally used to describe the relative positions of components relative to the directions shown in the drawings, or relative to the vertical, perpendicular, or gravitational directions. "First," "second," etc. are merely for convenience of description and distinction and should not be construed as indicating or implying relative importance.

[0026] It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "installation" and "connection" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integrated connection; direct connection, indirect connection, wired connection, or wireless connection. Those skilled in the art will understand the specific meanings of the above terms in the present invention depending on the specific circumstances.

[0027] In order to solve the technical problem of the lack of a phase demodulation method based on optical fiber distributed displacement sensing in the prior art, a technical solution of the present invention provides a distributed displacement phase demodulation method, which realizes displacement sensing phase demodulation by utilizing the initial phase of each optical fiber sensing position contained in the initial demodulation phase, the initial phase of the laser pulse source, the accumulated phase of the transmission process path and the gradual decoupling of the signal to be measured.

[0028] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0029] In a first aspect, an embodiment of the present invention provides a distributed displacement sensing phase demodulation method. Referring to FIG1 , the method includes the following steps:

[0030] Step S101: Determine an IQ demodulation initial phase ω0(i, j) and an IQ signal amplitude A(i, j) based on an IQ signal.

[0031] Specifically, using fiber optic distributed acoustic wave sensing acquisition instrument Connected to the optical fiber coupled to the environment to be measured, it emits narrow-linewidth, highly coherent optical pulses at a certain frequency. Through the IQ demodulator, IQ signals at different observation points at different times are obtained. The IQ signals are the in-phase signal I(i,j) and the quadrature signal Q(i,j). After various corrections are made to the IQ signals, IQ phase demodulation is performed. Here, i represents the i-th sampling time sequence number, and j represents the j-th optical fiber sensing signal sensing position sequence number. It should be noted that multiple optical fibers are deployed in the environment to be measured, and each optical fiber has a corresponding deployment position, which is the optical fiber sensing signal sensing position.

[0032] Based on the above IQ signal, the IQ demodulation initial phase ω0(i, j) and the IQ signal amplitude A(i, j) can be calculated, which can be specifically characterized as follows:

[0033] Where ω0(i,j) is the initial phase of IQ demodulation at the j-th optical fiber sensing signal sensing position at the i-th sampling moment; Q(i,j) is the orthogonal signal at the j-th optical fiber sensing signal sensing position at the i-th sampling moment; I(i,j) is the in-phase signal at the j-th optical fiber sensing signal sensing position at the i-th sampling moment; A(i,j) is the IQ signal amplitude at the j-th optical fiber sensing signal sensing position at the i-th sampling moment.

[0034] Step S102: Perform phase decoupling operation on the IQ demodulation initial phase ω0(i,j), and subtract the initial phase of the optical fiber sensing signal sensing position from the IQ demodulation initial phase ω0(i,j) in sequence. Laser pulse source initial phase and the accumulated phase of the transmission process path Get the displacement sensor phase to be measured

[0035] Specifically, the optical fiber distributed sensing acquisition instrument is an instrument with a phase-sensitive optical time domain reflectometer as its core. The IQ demodulation initial phase ω0 of the optical fiber sensing signal sensing position j at sampling time i consists of four parts, namely, the initial phase of each optical fiber sensing signal sensing position, Laser pulse source initial phase Transmission process path accumulation phase and the phase shift of the signal to be measured Right now:

[0036] Where ω0(i,j) is the initial phase of IQ demodulation of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; is the displacement sensing phase to be measured at the jth optical fiber sensing signal sensing position at the i-th sampling moment; is the initial phase of the j-th optical fiber sensing signal sensing position; is the initial phase of the laser pulse source at the i-th sampling moment; is the accumulated phase of the transmission path of the jth optical fiber sensing signal sensing position at the i-th sampling moment.

[0037] Step S103: performing phase unwrapping processing on the displacement sensing phase to be measured to obtain the unwrapped displacement sensing phase to be measured.

[0038] Step S104: Calculate and obtain displacement sensing data according to the displacement sensing phase to be measured after unwinding.

[0039] Specifically, the required displacement sensing data D(i, j) can be calculated using the following formula.

[0040] Where D(i,j) is the displacement sensing data of the jth optical fiber sensing signal sensing position at the i-th sampling moment; is the displacement sensing phase to be measured at the jth optical fiber sensing signal sensing position at the i-th sampling moment; λ is the wavelength of the laser pulse, which is generally 1550nm; n is the refractive index of the optical fiber, which is generally 1.46; C ε It is the refractive index strain parameter. For different optical fibers, its value is generally between -0.16 and -0.63.

[0041] Step S105: determining the coherent fading position in the displacement sensing data based on the IQ signal amplitude, eliminating the influence of the coherent fading by linear interpolation of adjacent normal points, and obtaining the displacement sensing data after the coherent fading noise is suppressed.

[0042] Step S106: Transpose the displacement sensing data after the coherent fading noise is suppressed into track sequence recording data, and perform denoising through subsequent data processing to obtain final displacement sensing demodulated phase data.

[0043] Furthermore, in a possible implementation, in step S102, a phase decoupling operation is performed on the IQ demodulation initial phase ω0(i, j), and the initial phase of the optical fiber sensing signal sensing position is sequentially subtracted from the IQ demodulation initial phase ω0(i, j). Laser pulse source initial phase and the accumulated phase of the transmission process path Get the displacement sensor phase to be measured The process may include but is not limited to the following sub-steps S1021 to S1027.

[0044] Sub-step S1021: For the j-th optical fiber sensing signal sensing position without external acoustic wave signal, select several time sampling values ​​for point-by-point statistical analysis to obtain the initial phase of the j-th optical fiber sensing signal sensing position.

[0045] Specifically, the initial phase of the jth optical fiber sensing signal sensing position is The calculation formula is:

[0046] In formula (5), is the initial phase of the j-th optical fiber sensing signal sensing position; m is the number of time sampling points selected for each sensing position before the signal to be measured arrives, that is, the number of time sampling points used to count the initial phase of the optical fiber sensing signal sensing position when the optical fiber is in a stationary state; ω0(i,j) is the IQ demodulation initial phase of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; i is the sampling time sequence number; j is the optical fiber sensing signal sensing position sequence number.

[0047] Sub-step S1022: Subtract the initial phase of the j-th optical fiber sensing signal sensing position from the IQ demodulation initial phase ω0(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment The first decoupling phase ω1(i, j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment is obtained.

[0048] That is, the calculation formula of the first decoupling phase ω1(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment is:

[0049] In formula (6), ω1(i, j) is the first decoupling phase of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; ω0(i, j) is the IQ demodulation initial phase of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; is the initial phase of the j-th optical fiber sensing signal sensing position.

[0050] Sub-step S1023: Determine the initial phase of the laser pulse source at the i-th sampling moment based on the linear relationship between the different first decoupling phases at the i-th sampling moment and the change in the optical fiber sensing signal sensing position. And the phase linear change factor k(i) at the i-th sampling moment.

[0051] Since the IQ demodulation initial phase ω0(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment should satisfy the following relationship:

[0052] Therefore, combining equations (6) and (7), it can be seen that the first decoupling phase ω1(i, j) after eliminating the initial phase influence of the optical fiber sensing signal sensing position is equal to the initial phase of the laser pulse source And the cumulative phase of the transmission process path The following relationship should be satisfied:

[0053] Here, if we assume The mean value in the fitting section is zero, which means it has no effect on the fitting parameter calculation. Then, the first decoupling phase ω1(i,j) at the i-th sampling moment and the optical fiber sensing signal sensing position j will form a linear function relationship, that is:

[0054] At this time, the linear fitting relationship between the first decoupling phase ω1(i,j) at the i-th sampling moment and the change of the optical fiber sensing signal sensing position j can be obtained by performing multi-point linear fitting on the curve of the change of the first decoupling phase ω1(i,j) at the i-th sampling moment and the change of the optical fiber sensing signal sensing position j. The intercept of the linear fitting relationship is the initial phase of the laser pulse source at the i-th sampling moment. The slope of the linear fitting relationship is the time-varying linear factor k(i) at the i-th sampling moment.

[0055] In addition, it should be noted that in order to eliminate To minimize the impact on fitting accuracy, the fitting segment should be selected at the far end of the fiber, where the measured signal is weaker and arrives later. To ensure fitting accuracy, the fitting segment should not be too short and should generally be at least one-quarter of the fiber length. The effects of phase wrapping should be considered during fitting, and unwrapping should be performed.

[0056] Sub-step S1024: Based on the phase linear variation factor k(i) at the i-th sampling moment, determine the cumulative phase of the transmission process path of the j-th optical fiber sensing signal sensing position at the i-th sampling moment

[0057] Specifically, by multiplying the phase linear change factor k(i) at the i-th sampling moment by the optical fiber sensing signal sensing position j, the cumulative phase of the transmission process path of the j-th optical fiber sensing signal sensing position at the i-th sampling moment can be obtained: Right now:

[0058] Where, is the accumulated phase of the transmission path of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; k(i) is the linear change factor over time at the i-th sampling moment.

[0059] Sub-step S1025: Subtract the initial phase of the laser pulse source at the i-th sampling moment from the first decoupling phase ω1(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment The second decoupling phase ω2(i, j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment is obtained.

[0060] Sub-step S1026: Subtract the accumulated phase of the transmission path of the j-th optical fiber sensing signal sensing position from the second decoupling phase ω2(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment The third decoupling phase ω3(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment is obtained.

[0061] Sub-step S1027: Determine the third decoupling phase ω3(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment as the displacement sensing phase to be measured at the j-th optical fiber sensing signal sensing position at the i-th sampling moment

[0062] Furthermore, in one possible implementation, to ensure demodulation accuracy, substeps S1021 to S1027 may be iteratively performed multiple times, and the third decoupling phase obtained by the final calculation is determined as the final displacement sensing phase to be measured. During each iterative calculation, the initial IQ demodulation phase ω0(i, j) in the current iterative process is updated to the third decoupling phase ω3(i, j) obtained in the previous iterative calculation.

[0063] In order to verify the effectiveness and practicability of the distributed displacement sensing phase demodulation method of the present invention, an actual optical fiber of an oil well was used to Taking the collected IQ data as an example, the above-mentioned distributed displacement sensing phase demodulation method is used to perform displacement sensing phase demodulation on the IQ data.

[0064] First, the optical fiber is laid in the well, and the optical fiber distributed acoustic wave sensor receiving instrument is used to connect the optical fiber from the top to collect the The IQ data of the instrument is then used to measure the actual optical fiber of an oil well. Collect IQ data for displacement sensing phase demodulation processing, which may include the following processing steps:

[0065] (1) Imbalance correction is performed on the IQ signal outputs I(i, j) and Q(i, j) obtained at different observation points at different times to ensure the orthogonality of the IQ signals.

[0066] (2) The IQ demodulation initial phase ω0(i, j) of the IQ signal is calculated by formula (1), and the IQ signal amplitude A(i, j) of the IQ signal is calculated by formula (2).

[0067] (3) For each optical fiber sensing position without external acoustic wave signals, m time sampling values ​​are selected for point-by-point statistical analysis to obtain the Rayleigh backscattering superposition initial phase within the optical pulse width range of the optical fiber sensing signal sensing position j.

[0068] Here, m is the number of selected time sample points before the signal to be measured arrives at each sensing position, that is, the number of time sample points used to count the initial phase of the sensing position of the optical fiber sensing signal when the optical fiber is in a stationary state.

[0069] (4) The initial phase of IQ demodulation ω0(i,j) minus the initial phase of the corresponding optical fiber sensing signal sensing position After that, the first decoupling phase ω1(i, j) is obtained to eliminate the influence of the initial phase of each sensing position.

[0070] (5) The first decoupling phase ω1(i, j) corresponding to each sensing position at sampling time i is linearly fitted with the sensing position j of each optical fiber sensing signal to obtain the laser pulse phase at sampling time i. and the phase linear variation factor k(i).

[0071] Specifically, the first decoupling phase ω1(i,j) corresponding to each sensor position at sampling time i is calculated and determined first, that is, data points such as ω1(i,1), ω1(i,2)…ω1(i,j), ω1(i,j+1), ω1(i,j+2) corresponding to different sensor positions at sampling time i are obtained. Then, based on these data points, a curve of ω1 changing with sensor position at sampling time i is drawn. After multi-point linear fitting, the slope and intercept are obtained. The intercept is the laser pulse phase at sampling time i. The slope is the phase linear change factor k(i) at sampling time i.

[0072] (6) Calculate the cumulative phase of the transmission path using formula (10):

[0073] (7) Subtract the initial phase of each sensor position from the initial phase of IQ demodulation ω0(i,j) by formula (3) Laser pulse source initial phase and the accumulated phase of the transmission process path Get the displacement sensor phase to be measured

[0074] (8) To ensure the demodulation accuracy, use Repeat steps (3) to (7) by substituting ω0(i,j).

[0075] (9) The IQ displacement phase demodulation data obtained in the above steps is used for phase unwrapping, and the required displacement sensing data D(i, j) is calculated using formula (4).

[0076] (10) The amplitude of the IQ signal is used to determine the location of the fading noise and eliminate the influence of coherent fading.

[0077] (11) Repeat steps (1) to (10) for all I / Q signals to be demodulated and recorded, and transpose them to obtain the track sequence recording data required for subsequent processing. After completing the above steps, the IQ displacement sensing phase demodulation of the optical fiber acquisition data is completed.

[0078] (12) In order to further eliminate the residual phase low wavenumber noise, the subsequent data is processed to remove the zero wavenumber to obtain the final displacement sensing demodulation phase data.

[0079] (13) Resample the data according to actual needs and use existing technologies for subsequent processing and application.

[0080] Figure 2 shows the initial IQ demodulation phase of the fiber IQ signal; Figure 3 shows the displacement phase demodulation record of the fiber IQ signal; Figure 4 shows the unwound record after displacement phase demodulation; and Figure 5 shows the normal sequence record after transposition. Combining Figures 2-5, it can be seen that the phase information of the fiber-acquired data processed by this method represents the displacement sensing response information, achieving the goal of preserving information across the entire frequency band and highlighting effective seismic waves. Furthermore, this phase demodulation method does not require differential calculations based on gauge length, fully preserving the frequency characteristics of the signal. This significantly improves data quality and provides assurance for subsequent data processing and applications.

[0081] In addition, the implementation environment of this embodiment includes at least one terminal and a server, and the method is executed on the terminal or the server respectively. The terminal and the server can be connected in communication to realize the interactive transmission of information.

[0082] Among them, the terminal can be any electronic product that can interact with the user through one or more methods such as keyboard, touchpad, touch screen, voice interaction, etc., such as PC (Personal Computer), PPC (Pocket Personal Computer), tablet computer, etc.

[0083] A server can be a single server or a server cluster consisting of multiple servers. It can also be a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN (Content Delivery Network), as well as big data and artificial intelligence platforms.

[0084] In the second aspect, an embodiment of the present invention provides a distributed displacement sensing phase demodulation device, see Figure 6, the phase demodulation device includes: an initial phase and amplitude determination unit 101, a phase decoupling operation unit 102, a phase unwrapping processing unit 103, a displacement sensing determination unit 104, a coherent fading noise suppression unit 105 and a subsequent processing unit 106.

[0085] The initial phase and amplitude determining unit 101 is configured to determine an IQ demodulation initial phase ω0(i, j) and an IQ signal amplitude A(i, j) based on the IQ signal.

[0086] Phase decoupling operation unit 102 is used to perform phase decoupling operation on the IQ demodulation initial phase ω0(i,j), and subtract the initial phase of the optical fiber sensing signal sensing position from the IQ demodulation initial phase ω0(i,j) in sequence. Laser pulse source initial phase and the accumulated phase of the transmission process path Get the displacement sensor phase to be measured

[0087] The phase unwrapping processing unit 103 is configured to perform phase unwrapping processing on the displacement sensing phase to be measured to obtain the unwrapped displacement sensing phase to be measured.

[0088] The displacement sensing determination unit 104 is configured to obtain displacement sensing data by calculation according to the displacement sensing phase to be measured after unwinding.

[0089] The coherent fading noise suppression unit 105 is used to determine the coherent fading position in the displacement sensing data based on the IQ signal amplitude, eliminate the influence of coherent fading by linear interpolation of adjacent normal points, and obtain the displacement sensing data after coherent fading noise suppression.

[0090] The subsequent processing unit 106 is used to convert the displacement sensing data after the coherent fading noise is suppressed into track sequence recording data, and perform denoising through subsequent data processing to obtain the final displacement sensing demodulated phase data.

[0091] Furthermore, in a possible embodiment, the phase decoupling operation unit 102 may include: an initial phase determination module for the optical fiber sensing signal sensing position, a first decoupling phase determination module, a laser pulse source initial phase and linear change factor determination module, a transmission process path accumulated phase determination module, a second decoupling phase determination module, a third decoupling phase determination module and a displacement sensing phase determination module.

[0092] The initial phase determination module of the optical fiber sensing signal sensing position is used to select a number of time sampling values ​​for the j-th optical fiber sensing signal sensing position without external acoustic wave signals and perform point-by-point statistical analysis to obtain the initial phase of the j-th optical fiber sensing signal sensing position.

[0093] The first decoupling phase determination module is used to subtract the initial phase of the j-th optical fiber sensing signal sensing position from the IQ demodulation initial phase ω0(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment The first decoupling phase ω1(i, j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment is obtained.

[0094] The laser pulse source initial phase and linear change factor determination module is used to determine the laser pulse source initial phase at the i-th sampling moment based on the linear relationship between the first decoupling phase at the i-th sampling moment and the change in the optical fiber sensing signal sensing position. and the time-varying linear factor k(i) at the i-th sampling moment.

[0095] The transmission process path cumulative phase determination module is used to determine the transmission process path cumulative phase of the j-th optical fiber sensing signal sensing position at the i-th sampling moment based on the time linear variation factor k(i) at the i-th sampling moment.

[0096] The second decoupling phase determination module is used to subtract the laser pulse source initial phase from the first decoupling phase ω1(i,j) The second decoupling phase ω2(i, j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment is obtained.

[0097] The third decoupling phase determination module is used to subtract the transmission process path accumulated phase from the second decoupling phase ω2(i,j) The third decoupling phase ω3(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment is obtained.

[0098] The displacement sensing phase determination module is used to determine the third decoupling phase ω3(i,j) as the displacement sensing phase to be measured at the jth optical fiber sensing signal sensing position at the i-th sampling moment.

[0099] It should be noted that the above-mentioned device only uses the division of the above-mentioned functional modules as an example to illustrate its functions. In actual applications, the above-mentioned functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above. In addition, the device provided in the above embodiment and the method provided in the above embodiment are based on the same concept. The specific implementation process is detailed in the method embodiment and will not be repeated here.

[0100] In the third aspect, an embodiment of the present invention further provides an electronic device, see Figure 7, the electronic device includes a processor 201 and a memory 202, and the memory stores at least one computer program, and the at least one computer program is loaded and executed by one or more of the above-mentioned processors to enable the processor to implement the distributed displacement sensing phase demodulation method in the above-mentioned embodiment.

[0101] Of course, the electronic device may also have components such as a wired or wireless network interface, a keyboard, and an input / output interface for input and output. The electronic device may also include other components for realizing various functions of the device, which will not be described in detail here.

[0102] In a fourth aspect, an embodiment of the present invention further provides a computer-readable storage medium, which stores at least one program code, and the program code is loaded and executed by a processor to enable the computer to implement the distributed displacement sensing phase demodulation method in the above embodiment.

[0103] Optionally, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc (CD-ROM), a magnetic tape, a floppy disk, or an optical disc data storage device. Those skilled in the art will appreciate that all or part of the steps in the above-mentioned embodiment method can be accomplished by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for causing a single-chip microcomputer, a chip, or a processor to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc.

[0104] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0105] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0106] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A distributed displacement sensing phase demodulation method, characterized in that: The phase demodulation method comprises: Determine an IQ demodulation initial phase and an IQ signal amplitude based on the IQ signal; A phase decoupling operation is performed on the initial phase of IQ demodulation, and the initial phase of the sensing position of the optical fiber sensing signal, the initial phase of the laser pulse source, and the accumulated phase of the transmission process path are sequentially subtracted from the initial phase of IQ demodulation to obtain the displacement sensing phase to be measured; Performing phase unwrapping processing on the displacement sensor phase to be measured to obtain the unwrapped displacement sensor phase to be measured; The displacement sensing data is obtained by calculating the displacement sensing phase to be measured after unwinding; The coherent fading position in the displacement sensing data is determined based on the amplitude of the IQ signal, and the influence of the coherent fading is eliminated by linear interpolation of adjacent normal points to obtain the displacement sensing data after the coherent fading noise is suppressed. The displacement sensing data after coherent fading noise suppression is transposed into track sequence recording data, and denoised through subsequent data processing to obtain the final displacement sensing demodulated phase data.

2. The distributed displacement sensing phase demodulation method according to claim 1, characterized in that: The phase decoupling operation is performed on the initial phase of the IQ demodulation, and the initial phase of the optical fiber sensing signal sensing position, the initial phase of the laser pulse source, and the accumulated phase of the transmission process path are sequentially subtracted from the initial phase of the IQ demodulation to obtain the displacement sensing phase to be measured, including: For the jth optical fiber sensor signal sensing position without external acoustic wave signal, select several time sampling values ​​for point-by-point statistical analysis to obtain the initial phase of the jth optical fiber sensor signal sensing position Subtract the initial phase of the jth optical fiber sensor signal sensing position from the IQ demodulation initial phase ω0(i,j) of the jth optical fiber sensor signal sensing position at the i-th sampling time Obtain the first decoupling phase ω1(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; Based on the linear relationship between the different first decoupling phases at the i-th sampling moment and the sensing position of the optical fiber sensing signal, the initial phase of the laser pulse source at the i-th sampling moment is determined. and the time-varying linear factor k(i) at the i-th sampling moment; Based on the time-varying linear factor k(i) at the i-th sampling moment, the accumulated phase of the transmission path of the j-th optical fiber sensing signal sensing position at the i-th sampling moment is determined Subtract the laser pulse source initial phase from the first decoupled phase ω1(i,j) Obtain the second decoupling phase ω2(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; Subtract the transmission process path accumulated phase from the second decoupled phase ω2(i,j) Obtain the third decoupling phase ω3(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; The third decoupling phase ω3(i,j) is determined as the displacement sensing phase to be measured at the jth optical fiber sensing signal sensing position at the i-th sampling moment 3. The distributed displacement sensing phase demodulation method according to claim 2, characterized in that: Performing multiple phase decoupling operations on the third decoupling phase, and determining the third decoupling phase finally obtained by the operation as the displacement sensing phase to be measured; In each iterative operation, the IQ demodulation initial phase in the current iterative process is updated to the third decoupling phase obtained in the previous iterative operation.

4. The distributed displacement sensing phase demodulation method according to claim 2, characterized in that: The calculation formula of the initial phase of the optical fiber sensing signal sensing position is: in, is the initial phase of the jth optical fiber sensing signal sensing position, m is the number of time samples used for statistics at each sensing position before the signal to be measured arrives, that is, when the optical fiber is in an undisturbed and static state, ω0(i,j) is the IQ demodulation initial phase of the jth optical fiber sensing signal sensing position at the ith sampling moment, i is the sampling time sequence number, and j is the optical fiber sensing signal sensing position sequence number.

5. The distributed displacement sensing phase demodulation method according to claim 2, characterized in that: The initial phase of the laser pulse source at the i-th sampling moment is determined based on the linear relationship between the different first decoupling phases at the i-th sampling moment and the sensing position of the optical fiber sensing signal. and the time-varying linear factor k(i) at the i-th sampling moment, including: Determine a number of first decoupling phases corresponding to different optical fiber sensing signal sensing positions at the i-th sampling moment; Perform multi-point linear fitting on a number of first decoupling phases corresponding to different optical fiber sensing signal sensing positions at the i-th sampling moment to obtain a linear fitting relationship between the first decoupling phase at the i-th sampling moment and the optical fiber sensing signal sensing position; The intercept of the linear fitting relationship is determined as the initial phase of the laser pulse source at the i-th sampling moment The slope of the linear fitting relationship is determined as the time-dependent linear variation factor k(i) at the i-th sampling moment.

6. The distributed displacement sensing phase demodulation method according to claim 2, characterized in that: The calculation formula of the displacement sensing data is: Where D(i,j) is the displacement sensing data of the jth optical fiber sensing signal sensing position at the i-th sampling moment, is the displacement sensing phase to be measured at the jth optical fiber sensing signal sensing position at the i-th sampling moment, λ is the wavelength of the laser pulse, n is the optical fiber refractive index, and n is generally 1.46, C ε is the refractive index strain parameter. For different optical fibers, C ε The value ranges from -0.16 to -0.

63.

7. A distributed displacement sensing phase demodulation device, characterized in that: The phase demodulation device comprises: an initial phase and amplitude determination unit, a phase decoupling operation unit, a phase unwrapping processing unit, a displacement sensing determination unit, a coherent fading noise suppression unit and a subsequent processing unit; An initial phase and amplitude determination unit, configured to determine an IQ demodulation initial phase and an IQ signal amplitude based on the IQ signal; A phase decoupling operation unit is used to perform a phase decoupling operation on an initial phase of IQ demodulation, and to sequentially subtract an initial phase of the optical fiber sensing signal sensing position, an initial phase of the laser pulse source, and an accumulated phase of the transmission process path from the initial phase of IQ demodulation to obtain a displacement sensing phase to be measured; A phase unwinding processing unit is used to perform phase unwinding processing on the displacement sensing phase to be measured, so as to obtain the unwound displacement sensing phase to be measured; A displacement sensing determination unit, used for calculating and obtaining displacement sensing data according to the displacement sensing phase to be measured after unwinding; A coherent fading noise suppression unit is used to determine the coherent fading position in the displacement sensing data based on the IQ signal amplitude, eliminate the influence of coherent fading by linear interpolation of adjacent normal points, and obtain the displacement sensing data after the coherent fading noise is suppressed; The subsequent processing unit is used to transpose the displacement sensing data after the coherent fading noise is suppressed into the track sequence recording data, and perform denoising through subsequent data processing to obtain the final displacement sensing demodulation phase data.

8. The distributed displacement sensing phase demodulation device according to claim 7, characterized in that: The phase decoupling operation unit includes: an initial phase determination module for the optical fiber sensing signal sensing position, a first decoupling phase determination module, a laser pulse source initial phase and linear change factor determination module, a transmission process path accumulation phase determination module, a second decoupling phase determination module, a third decoupling phase determination module and a displacement sensing phase determination module; The initial phase determination module of the optical fiber sensing signal sensing position is used to select a number of time sampling values ​​for the jth optical fiber sensing signal sensing position without external acoustic wave signals for point-by-point statistical analysis to obtain the initial phase of the jth optical fiber sensing signal sensing position. The first decoupling phase determination module is used to subtract the initial phase of the jth optical fiber sensing signal sensing position from the IQ demodulation initial phase ω0(i,j) of the jth optical fiber sensing signal sensing position at the i-th sampling moment Obtain the first decoupling phase ω1(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; The laser pulse source initial phase and linear change factor determination module is used to determine the laser pulse source initial phase at the i-th sampling moment based on the linear relationship between the first decoupled phase at the i-th sampling moment and the change in the optical fiber sensing signal sensing position. and the time-varying linear factor k(i) at the i-th sampling moment. The transmission process path cumulative phase determination module is used to determine the transmission process path cumulative phase of the jth optical fiber sensing signal sensing position at the i-th sampling moment based on the time-varying linear factor k(i) at the i-th sampling moment. The second decoupling phase determination module is used to subtract the initial phase of the laser pulse source from the first decoupling phase ω1(i,j) Obtain the second decoupling phase ω2(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; The third decoupling phase determination module is used to subtract the transmission process path accumulated phase from the second decoupling phase ω2(i,j) Obtain the third decoupling phase ω3(i,j) of the j-th optical fiber sensing signal sensing position at the i-th sampling moment; The displacement sensing phase determination module is used to determine the third decoupling phase ω3(i,j) as the displacement sensing phase to be measured at the jth optical fiber sensing signal sensing position at the i-th sampling moment.

9. An electronic device, characterized in that: The electronic device includes a processor and a memory, wherein the memory stores at least one computer program, and the at least one computer program is loaded and executed by one or more of the above processors so that the processor executes the distributed displacement sensing phase demodulation method described in any one of claims 1 to 6.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores at least one program code, and the program code is loaded and executed by a processor to enable a computer to execute the distributed displacement sensing phase demodulation method according to any one of claims 1 to 6.

Images