Global phase quadrature demodulation method and device for optical fiber sensing data

Abstract

This invention discloses a global phase quadrature demodulation method and apparatus for fiber optic sensing data. The method includes: acquiring initial fiber optic sensing IQ data; determining the corresponding direct phase value based on the initial fiber optic sensing IQ data; performing a light source phase correction operation on the direct phase to obtain first processed data; performing a receiver point initial phase correction operation on the first processed data to obtain second processed data; performing a light source linear phase correction operation on the second processed data to obtain third processed data; performing a receiver point linear phase correction operation on the third processed data to obtain fourth processed data; and performing phase dewinding processing and near-DC component removal processing on the fourth processed data to obtain globally phase demodulated data. By analyzing various influencing factors of the initial fiber optic sensing IQ data and adopting corresponding data optimization processing methods, the problems existing in the acquisition process of fiber optic sensing data are overcome, and the accuracy of fiber optic sensing data is improved.

Description

Technical Field

[0001] This invention relates to the field of fiber optic sensor data demodulation technology, specifically to a global phase quadrature demodulation method for fiber optic sensor data, a global phase quadrature demodulation device for fiber optic sensor data, and a computer-readable storage medium. Background Technology

[0002] With the continuous development of science and technology, fiber optic technology is being applied to various fields of life and production. Fiber optic distributed acoustic sensing technology is a detection technology based on the Rayleigh scattering principle of optical fibers, and it is widely used in fields such as well seismic data acquisition, dam safety monitoring, and security.

[0003] In application, fiber optic distributed acoustic wave sensing technology uses fiber optic sensing devices to obtain Rayleigh scattering phase information based on in-phase / quadrature (I / Q) phase demodulation. The fiber optic cable serves as both the sensing medium and the transmission medium, enabling continuous sensing of acoustic wave vibrations or strain information around the fiber optic cable, and recording relevant data through high-density temporal and spatial sampling.

[0004] However, in practical applications, due to the nonlinear effects and frequency drift of laser propagation in optical fibers, phase information experiences cumulative phase drift, severely affecting the accuracy of phase demodulation and reducing the precision of fiber optic sensing data. Existing technologies can overcome these nonlinear effects and improve the signal-to-noise ratio by calculating phase differences within the gauge length and by local averaging. However, this phase demodulation method leads to the loss of low-wavenumber wavefield information and prevents noise levels from being reduced to ideal levels, thus causing significant challenges for technicians and failing to meet their current practical needs. Summary of the Invention

[0005] To overcome the aforementioned technical problems in the prior art, this invention provides a global phase quadrature demodulation method for fiber optic sensing data. By analyzing and optimizing the phase interference factors and nonlinear phase change factors in the initial fiber optic sensing IQ data, the accuracy of the fiber optic sensing data is effectively improved, meeting the practical needs of technicians.

[0006] To achieve the above objectives, embodiments of the present invention provide a global phase quadrature demodulation method for fiber optic sensing data. The method includes: acquiring initial fiber optic sensing IQ data; determining the corresponding direct phase value based on the initial fiber optic sensing IQ data; performing a light source phase correction operation on the direct phase to obtain first processed data; performing a receiver point initial phase correction operation on the first processed data to obtain second processed data; performing a light source linear phase correction operation on the second processed data to obtain third processed data; performing a receiver point linear phase correction operation on the third processed data to obtain fourth processed data; and performing phase dewinding processing and near-DC component removal processing on the fourth processed data to obtain globally phase demodulated data.

[0007] Preferably, the initial fiber optic sensing IQ data is acquired from multiple sensing locations on the fiber optic cable. Based on the initial fiber optic sensing IQ data, the corresponding direct phase value is determined, and a light source phase correction operation is performed on the direct phase to obtain the first processed data. This includes: determining a preset reference position j0 from the multiple sensing locations on the fiber optic cable; and obtaining the direct phase value corresponding to the preset reference position from the initial fiber optic sensing IQ data. direct phase value Characterized as: Where I(i,j) is the in-phase signal in the initial fiber optic sensing IQ data, Q(i,j) is the quadrature signal in the initial fiber optic sensing IQ data, i is the sampling time, and j is the sampling position; based on direct phase values Determine the phase change factor of the light source Light source phase change factor Characterized as: Where n1 is the number of sample points for statistical light source phase; based on the first preset rule and the light source phase change factor, the initial fiber optic sensing IQ data is subjected to light source phase correction operation to obtain the first processed data. The first preset rule is characterized as follows: .

[0008] Preferably, a receiving point initial phase correction operation is performed on the first processed data to obtain the second processed data, including: the first processed data The initial fiber optic sensing data is extracted, which is generated based on the initial fiber optic sensing IQ data collected during the initial sampling time when there is no external acoustic wave influence; the initial phase factor of the receiving point is determined based on the initial fiber optic sensing IQ data. Initial phase factor at the receiving point Characterized as: Where i0 is the initial sampling time without external sound wave influence, and n2 is the number of sampling points for the initial phase of the receiver; based on the second preset rule and the initial phase factor of the receiver. For the first processed data Perform initial phase correction at the receiving point to obtain the second processed data. The second preset rule is characterized as follows: .

[0009] Preferably, a linear phase correction operation is performed on the second processed data to obtain the third processed data, including: based on the second processed data... Perform a linear phase analysis of the light source to obtain the linear phase parameters of the light source corresponding to the preset reference position. The linear phase parameters of the light source include the first phase intercept b. i and the first gradient k i Based on the third preset rule and the linear phase parameter of the light source, the second processed data is processed. Perform linear phase correction of the light source to obtain the third-processed data. The third preset rule is represented as: .

[0010] Preferably, a receiver-point linear phase correction operation is performed on the third-processed data to obtain the fourth-processed data, including: based on the third-processed data... Obtain the linear phase parameters of the receiving point corresponding to the start time. The linear phase parameters of the receiving point include the second phase intercept b. j Second gradient k j Based on the fourth preset rule and the linear phase parameters of the receiving point, the third processed data is processed... Perform a linear phase correction operation at the receiving point to obtain the fourth processed data. The fourth preset rule is represented as: .

[0011] Accordingly, the present invention also provides a global phase quadrature demodulation device for fiber optic sensing data. The device includes: an initial data acquisition unit for acquiring initial fiber optic sensing IQ data; a light source phase correction unit for determining the corresponding direct phase value based on the initial fiber optic sensing IQ data, performing a light source phase correction operation on the direct phase, and obtaining first processed data; a receiver point initial phase correction unit for performing a receiver point initial phase correction operation on the first processed data, and obtaining second processed data; a light source linear phase correction unit for performing a light source linear phase correction operation on the second processed data, and obtaining third processed data; a receiver point linear phase correction unit for performing a receiver point linear phase correction operation on the third processed data, and obtaining fourth processed data; and a processing unit for performing phase dewinding processing and near-DC component removal processing on the fourth processed data, and obtaining globally phase demodulated data.

[0012] Preferably, the initial fiber optic sensing IQ data is acquired from multiple sensing locations on the fiber optic cable, and the light source phase correction unit includes: a reference position determination module, used to determine a preset reference position j0 from the multiple sensing locations on the fiber optic cable; and a reference information acquisition module, used to acquire the direct phase value corresponding to the preset reference position from the initial fiber optic sensing IQ data. direct phase value Characterized as: Where I(i,j) is the in-phase signal in the initial fiber optic sensing IQ data, Q(i,j) is the quadrature signal in the initial fiber optic sensing IQ data, i is the sampling time, and j is the sampling position; the light source phase change factor determination module is used to determine the phase change factor based on the direct phase value. Determine the phase change factor of the light source Light source phase change factor Characterized as: Where n1 is the number of sample points for the statistical light source phase; the light source phase correction module is used to correct the phase based on the first preset rule and the light source phase change factor. Perform a light source phase correction operation on the initial fiber optic sensing IQ data to obtain the first processed data. The first preset rule is characterized as follows: .

[0013] Preferably, the receiving point initial phase correction unit includes: an initial data acquisition module, used for acquiring data after the first processing. The module extracts initial fiber optic sensing data, which is generated based on initial fiber optic sensing IQ data collected during the initial sampling time when there is no external acoustic wave influence. A receiver point initial phase factor determination module is used to determine the receiver point initial phase factor based on the initial fiber optic sensing IQ data. Initial phase factor at the receiving point Characterized as: Where i0 is the initial sampling time without external sound wave influence, and n2 is the number of sampling points for the initial phase of the receiver; the receiver initial phase correction module is used to correct the initial phase of the receiver based on the second preset rule and the receiver initial phase factor. For the first processed data Perform initial phase correction at the receiving point to obtain the second processed data. The second preset rule is characterized as follows: .

[0014] Preferably, the light source linear phase correction unit includes: a light source linear phase analysis module, used for analyzing the second processed data. Perform a linear phase analysis of the light source to obtain the linear phase parameters of the light source corresponding to the preset reference position. The linear phase parameters of the light source include the first phase intercept b. i and the first gradient ki The light source linear phase correction module is used to correct the second processed data based on the third preset rule and the light source linear phase parameters. Perform linear phase correction of the light source to obtain the third-processed data. The third preset rule is represented as: .

[0015] Preferably, the receiver point linear phase correction unit includes: a receiver point linear phase analysis module, used for analyzing the third processed data. Obtain the linear phase parameters of the receiving point corresponding to the start time. The linear phase parameters of the receiving point include the second phase intercept b. j Second gradient k j The receiver point linear phase correction module is used to correct the third-processed data based on the fourth preset rule and the receiver point linear phase parameters. Perform a linear phase correction operation at the receiving point to obtain the fourth processed data. The fourth preset rule is represented as: .

[0016] On the other hand, the present invention also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the global phase quadrature demodulation method for fiber optic sensing data provided by the present invention.

[0017] The present invention has at least the following technical effects through the technical solution provided by the present invention:

[0018] By analyzing the factors affecting the initial fiber optic sensing IQ data directly acquired based on DAS, including changes in light source phase, fiber refractive index, and nonlinear phase drift, and by adopting corresponding data optimization methods, the aforementioned problems in the acquisition process of fiber optic sensing data are effectively overcome. This significantly improves the accuracy of the final acquired fiber optic sensing data, provides strong data support for subsequent accurate data analysis, and meets the actual needs of technical personnel.

[0019] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 This is a flowchart illustrating the specific implementation of the global phase quadrature demodulation method for fiber optic sensing data provided in this embodiment of the invention.

[0022] Figure 2 This is the phase diagram of the optical fiber information directly demodulated in the global phase orthogonal demodulation method for optical fiber sensing data provided in this embodiment of the invention;

[0023] Figure 3 This is a schematic diagram of the fiber optic sensing IQ data after performing light source phase correction in the global phase orthogonal demodulation method for fiber optic sensing data provided in this embodiment of the invention;

[0024] Figure 4 This is a schematic diagram of the fiber optic sensing data after initial phase correction at the receiving point in the global phase orthogonal demodulation method for fiber optic sensing data provided in this embodiment of the invention.

[0025] Figure 5 This is a schematic diagram of the fiber optic sensing data after linear phase correction of the light source and the receiving point in the global phase orthogonal demodulation method for fiber optic sensing data provided in this embodiment of the invention.

[0026] Figure 6 This is a schematic diagram of the fiber optic sensing data after near-DC component removal processing in the global phase quadrature demodulation method for fiber optic sensing data provided in this embodiment of the invention.

[0027] Figure 7 This is a schematic diagram of the global phase quadrature demodulation device for fiber optic sensing data provided in an embodiment of the present invention. Detailed Implementation

[0028] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0029] In this invention, the terms "system" and "network" are used interchangeably. "Multiple" refers to two or more; therefore, in this invention, "multiple" can also be understood as "at least two." "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / ", unless otherwise specified, generally indicates that the preceding and following related objects have an "or" relationship. Furthermore, it should be understood that in the description of this invention, terms such as "first" and "second" are used only for descriptive purposes and should not be construed as indicating or implying relative importance or order.

[0030] Please see Figure 1 This invention provides a global phase quadrature demodulation method for fiber optic sensing data, the method comprising:

[0031] S10) Acquire initial fiber optic sensing IQ data;

[0032] S20) Determine the corresponding direct phase value based on the initial fiber optic sensing IQ data, perform a light source phase correction operation on the direct phase, and obtain the first processed data;

[0033] S30) Perform initial phase correction operation on the first processed data to obtain the second processed data;

[0034] S40) Perform a linear phase correction operation on the second processed data to obtain the third processed data;

[0035] S50) Perform a linear phase correction operation on the receiving point of the third processed data to obtain the fourth processed data;

[0036] S60) Perform phase dewinding and near-DC component removal processing on the fourth processed data to obtain global phase demodulated data.

[0037] In this embodiment of the invention, an optical fiber is first laid out at the location to be detected and fully coupled to the location. A DAS (Distributed Acoustic Sensor) is connected to one end of the optical fiber. The DAS instrument emits a laser pulse, and the IQ (In-phase / Quadrature) information of Rayleigh scattering of the light pulse is obtained through a coherent detection method. This information is then analyzed to obtain the corresponding optical fiber information. However, in existing technologies, if the optical fiber information is directly demodulated, the obtained information will have significant deviations due to the presence of a large amount of interference. For example, please refer to [reference needed]. Figure 2 The above-mentioned fiber optic information is a phase diagram of directly demodulated fiber optic information provided in the embodiments of the present invention. Therefore, in order to solve the technical problems existing in the prior art and improve the accuracy of fiber optic information, the above-acquired fiber optic information is optimized.

[0038] In one possible implementation, initial fiber optic sensing IQ data is first acquired. For example, after the fiber optic cable emits light pulses at a certain frequency, the DAS acquires the corresponding IQ information I(i,j) and Q(i,j), where i represents the i-th sampling time and j represents the j-th position number of the DAS data. In this embodiment of the invention, the initial fiber optic sensing IQ data includes phase information. This phase information Determined based on the following calculation rules: After obtaining the initial fiber optic sensing IQ data, the initial fiber optic sensing IQ data is further corrected.

[0039] In this embodiment of the invention, the initial fiber optic sensing IQ data is acquired from multiple sensing locations on the fiber optic cable. Based on the initial fiber optic sensing IQ data, a corresponding direct phase value is determined. A light source phase correction operation is performed on the direct phase to obtain first processed data. This includes: determining a preset reference position j0 from the multiple sensing locations on the fiber optic cable; and acquiring the direct phase value corresponding to the preset reference position from the initial fiber optic sensing IQ data. direct phase value Characterized as: Where I(i,j) is the in-phase signal in the initial fiber optic sensing IQ data, Q(i,j) is the quadrature signal in the initial fiber optic sensing IQ data, i is the sampling time, and j is the sampling position; based on the reference phase information Determine the phase change factor of the light source Light source phase change factor Characterized as: Where n1 is the number of sample points for statistical light source phase; based on the first preset rule and the light source phase change factor, the initial fiber optic sensing IQ data is subjected to light source phase correction operation to obtain the first processed data. The first preset rule is characterized as follows: .

[0040] In one possible implementation, after acquiring initial fiber sensing IQ data from multiple sensing locations on the fiber, a preset reference position is first determined from these multiple sensing locations. For example, the middle reference position j0 of the fiber under test can be selected as the preset reference position. Then, the data acquired at each sampling time is statistically analyzed at this preset reference position to obtain the time-varying phase change factor of the fiber's light source. The change factor It can be determined by taking the average (or median) of multiple points: Where n1 is the number of sample points for statistical light source phase, at this time, the initial fiber optic sensing IQ data can be subjected to light source phase correction operation according to the first preset rule to obtain the first processed data. The first preset rule is characterized as follows: Please see Figure 3 This is a schematic diagram of the fiber optic sensing IQ data after performing light source phase correction according to an embodiment of the present invention.

[0041] In this embodiment of the invention, the initial fiber optic sensing IQ data is analyzed to obtain the light source phase change factor of the fiber optic cable. Phase correction is then performed on the initial fiber optic sensing IQ data based on this light source phase change factor, thereby obtaining fiber optic information after preliminary correction. This effectively eliminates the influence of light source phase change on the fiber optic information and improves data accuracy. To further eliminate influencing factors in the initial fiber optic sensing IQ data and improve data accuracy, a further initial phase correction operation at the receiving point is performed on the data after the first processing.

[0042] In this embodiment of the invention, performing a receiving point initial phase correction operation on the first processed data to obtain the second processed data includes: the first processed data... The initial fiber optic sensing data is extracted, which is generated based on the initial fiber optic sensing IQ data collected during the initial sampling time when there is no external acoustic wave influence; the initial phase factor of the receiving point is determined based on the initial fiber optic sensing data. Initial phase factor at the receiving point Characterized as: Where i0 is the initial sampling time without external sound wave influence, and n2 is the number of sampling points for the initial phase of the receiver; based on the second preset rule and the initial phase factor of the receiver. For the first processed data Perform initial phase correction at the receiving point to obtain the second processed data. The second preset rule is characterized as follows: .

[0043] In one possible implementation, after obtaining the aforementioned first processed data... Then, from the first processed data The initial fiber optic sensing data is extracted from the data. This initial fiber optic sensing IQ data is collected starting when there is no external acoustic wave interference. Therefore, this initial fiber optic sensing IQ data includes initial data without external acoustic wave interference. Correspondingly, this data is extracted after the first processing. This also includes the corresponding initial fiber optic sensing data, which is the fiber optic sensing data collected at time i0 when there is no external acoustic wave influence. This data is then processed from the first set of data. After extracting the initial fiber optic sensing data, the initial phase factor of the receiving point at each detection location is determined based on the initial fiber optic sensing data. The initial phase factor of the receiving point It can be determined by taking the average (or median) of multiple points: Where i0 is the initial sampling time without external sound wave influence, and n2 is the number of sampling points for the initial phase of the receiving point. At this time, further sampling is performed according to the second preset rule and the initial phase factor of the receiving point. The first processed data The second preset rule for performing initial phase correction at the receiving point can be characterized as follows: Based on the initial phase correction operation at the receiving point described above, the corresponding second processed data is obtained. At this point, further processing of the second-processed data... For instructions on performing linear phase correction of the light source, please refer to [link / reference]. Figure 4 This is a schematic diagram of the fiber optic sensing data after initial phase correction of the receiving point provided in an embodiment of the present invention.

[0044] In this embodiment of the invention, performing a linear phase correction operation on the second processed data to obtain third processed data includes: based on the second processed data... Perform a linear phase analysis of the light source to obtain the linear phase parameters of the light source corresponding to a preset reference position; then, based on a third preset rule and the linear phase parameters of the light source, process the second processed data. Perform linear phase correction of the light source to obtain the third processed data. The third preset rule is represented as: .

[0045] In one possible implementation, after acquiring the data after the second processing described above... Subsequently, a multi-scale phase linear transformation scan is performed near position j0 at each time i to obtain the linear phase parameters of the light source near position j0. These linear phase parameters include, but are not limited to, the phase intercept b. i and gradient k i At this point, the second processed data is processed according to the third preset rule and the aforementioned linear phase parameters of the light source. Perform linear phase correction of the light source to obtain the third-processed data. The third preset rule can be characterized as: At this point, further processing of the third-order data... To perform receiver point linear phase correction, please refer to [link / reference]. Figure 5 This is a schematic diagram of fiber optic sensing data after linear phase correction of the light source and receiving point, provided in an embodiment of the present invention.

[0046] In this embodiment of the invention, performing a receiver point linear phase correction operation on the third processed data to obtain fourth processed data includes: based on the third processed data... Obtain the linear phase parameters of the receiving point corresponding to the start time. The linear phase parameters of the receiving point include the second phase intercept b. j Second gradient k j Based on the fourth preset rule and the linear phase parameters of the receiving point, the third processed data is processed... Perform a linear phase correction operation at the receiving point to obtain the fourth processed data. The fourth preset rule is represented as: .

[0047] In one possible implementation, based on the third processed data For each detection location, a multi-scale phase linear change scan is performed near time i0 to obtain the linear phase parameters of the receiving point near time i0 for each detection location. For example, the linear phase parameters of the receiving point include, but are not limited to, the phase intercept bj and the gradient kj. Then, the third-processed data is further processed using the fourth preset rule and the above-mentioned linear phase parameters of the receiving point. Perform a linear phase correction operation at the receiving point to obtain the corresponding fourth-processed data. The fourth preset rule can be characterized as: At this point, the data correction process for the initial fiber optic sensing IQ data was completed, and accurate fiber optic sensing data was obtained.

[0048] It will be readily apparent to those skilled in the art that, depending on actual needs, technicians may continue to repeat the above steps on subsequently acquired fiber optic sensing data. For example, they may acquire fiber optic sensing data obtained from artificial seismic source excitation or passive monitoring and perform the above optimization, or repeatedly acquire fiber optic sensing data multiple times and perform the above optimization to obtain more accurate calibrated fiber optic sensing data. All of these should fall within the protection scope of the embodiments of the present invention, and will not be elaborated further here.

[0049] In this embodiment of the invention, by analyzing the time-varying light source phase factor and the initial phase factor at different receiving points in the initial fiber optic sensing IQ data, the fiber optic sensing data is optimized based on the phase factor. Furthermore, by combining the linear parameters acquired during the fiber optic sensing data acquisition process and performing linear phase correction on the fiber optic sensing data, the accuracy of the fiber optic sensing data is further improved by overcoming the influence of light source phase variation on the accuracy of the fiber optic sensing data, as well as the influence of fiber refractive index variation and nonlinear phase drift. This significantly improves the accuracy of the final fiber optic sensing data and meets the practical needs of technical personnel.

[0050] However, the fiber optic sensing data processed as described above is the raw fiber optic sensing data, so further conversion and optimization processing is required to obtain usable fiber optic sensing phase demodulated data.

[0051] In this embodiment of the invention, performing phase dewinding processing on the fourth processed data to obtain globally phase demodulated data includes: processing the fourth processed data... Perform a phase unwinding operation to obtain the corresponding acoustic wave field data; perform near-DC component removal processing on the acoustic wave field data to obtain global phase demodulated data.

[0052] In one possible implementation, the acquired fourth processed data is... Further phase unwinding is performed to obtain the required acoustic wave field data. To further eliminate low-frequency noise after linear phase correction, the acoustic wave field data is also processed to remove near-DC components, obtaining true global demodulated phase data. Please refer to [link to relevant documentation]. Figure 6 This is a schematic diagram of the fiber optic sensing data after near-DC component removal processing provided in an embodiment of the present invention.

[0053] In this embodiment of the invention, by analyzing the noise or influencing factors in the fiber optic sensing data according to the detection process of the fiber optic sensing data, and performing precise data optimization processing, accurate fiber optic sensing data is obtained, providing strong data support for subsequent data processing and applications.

[0054] The global phase quadrature demodulation device for fiber optic sensing data provided in the embodiments of the present invention will be described below with reference to the accompanying drawings.

[0055] Please see Figure 7 Based on the same inventive concept, embodiments of the present invention provide a global phase quadrature demodulation device for fiber optic sensing data. The device includes: an initial data acquisition unit for acquiring initial fiber optic sensing IQ data; a light source phase correction unit for determining the corresponding direct phase value based on the initial fiber optic sensing IQ data, performing a light source phase correction operation on the direct phase, and obtaining first processed data; a receiver point initial phase correction unit for performing a receiver point initial phase correction operation on the first processed data, and obtaining second processed data; a light source linear phase correction unit for performing a light source linear phase correction operation on the second processed data, and obtaining third processed data; a receiver point linear phase correction unit for performing a receiver point linear phase correction operation on the third processed data, and obtaining fourth processed data; and a processing unit for performing phase dewinding processing and near-DC component removal processing on the fourth processed data, and obtaining globally phase demodulated data.

[0056] In this embodiment of the invention, the initial fiber optic sensing IQ data is acquired from multiple sensing locations on the fiber optic cable. The light source phase correction unit includes: a reference position determination module, used to determine a preset reference position j0 from the multiple sensing locations on the fiber optic cable; and a reference information acquisition module, used to acquire the direct phase value corresponding to the preset reference position from the initial fiber optic sensing IQ data. direct phase value Characterized as: Where I(i,j) is the in-phase signal in the initial fiber optic sensing IQ data, Q(i,j) is the quadrature signal in the initial fiber optic sensing IQ data, i is the sampling time, and j is the sampling position; the light source phase change factor determination module is used to determine the phase change factor based on the direct phase value. Determine the phase change factor of the light source Light source phase change factor Characterized as: Where n1 is the number of sample points for the statistical light source phase; the light source phase correction module is used to correct the phase based on the first preset rule and the light source phase change factor. Perform a light source phase correction operation on the initial fiber optic sensing IQ data to obtain the first processed data. The first preset rule is characterized as follows: .

[0057] In this embodiment of the invention, the receiving point initial phase correction unit includes: a starting data acquisition module, used for acquiring data after the first processing. The module extracts initial fiber optic sensing data, which is generated based on initial fiber optic sensing IQ data collected during the initial sampling time when there is no external acoustic wave influence. A receiver point initial phase factor determination module is used to determine the receiver point initial phase factor based on the initial fiber optic sensing IQ data. Initial phase factor at the receiving point Characterized as: Where i0 is the initial sampling time without external sound wave influence, and n2 is the number of sampling points for the initial phase of the receiver; the receiver initial phase correction module is used to correct the initial phase of the receiver based on the second preset rule and the receiver initial phase factor. For the first processed data Perform initial phase correction at the receiving point to obtain the second processed data. The second preset rule is characterized as follows: .

[0058] In this embodiment of the invention, the light source linear phase correction unit includes: a light source linear phase analysis module, used for analyzing the second processed data. Perform a linear phase analysis of the light source to obtain the linear phase parameters of the light source corresponding to the preset reference position. The linear phase parameters of the light source include the first phase intercept b. i and the first gradient k i The light source linear phase correction module is used to correct the second processed data based on the third preset rule and the light source linear phase parameters. Perform linear phase correction of the light source to obtain the third-processed data. The third preset rule is represented as: .

[0059] In this embodiment of the invention, the receiving point linear phase correction unit includes: a receiving point linear phase analysis module, used for analyzing the third processed data. Obtain the linear phase parameters of the receiving point corresponding to the start time. The linear phase parameters of the receiving point include the second phase intercept b. j Second gradient k j The receiver point linear phase correction module is used to correct the third-processed data based on the fourth preset rule and the receiver point linear phase parameters. Perform a linear phase correction operation at the receiving point to obtain the fourth processed data. The fourth preset rule is represented as: .

[0060] In this embodiment of the invention, the processing unit is specifically used for: processing the fourth processed data. Perform a phase unwinding operation to obtain the corresponding acoustic wave field data; perform near-DC component removal processing on the acoustic wave field data to obtain global phase demodulated data.

[0061] Furthermore, embodiments of the present invention also provide a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the global phase quadrature demodulation method for fiber optic sensing data described in the present invention.

[0062] The optional embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the scope of the technical concept of the embodiments of the present invention, various simple modifications can be made to the technical solutions of the embodiments of the present invention, and these simple modifications all fall within the protection scope of the embodiments of the present invention.

[0063] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the embodiments of the present invention will not describe the various possible combinations separately.

[0064] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0065] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. A global phase quadrature demodulation method for fiber optic sensing data, characterized in that, The method includes: Acquire initial fiber optic sensing IQ data; Based on the initial fiber optic sensing IQ data, the corresponding direct phase value is determined, and a light source phase correction operation is performed on the direct phase to obtain the first processed data. Perform initial phase correction operation on the first processed data to obtain the second processed data; Perform a linear phase correction operation on the second-processed data to obtain the third-processed data; Perform a linear phase correction operation on the receiving point of the third-processed data to obtain the fourth-processed data; Phase dewinding and near-DC component removal are performed on the fourth processed data to obtain globally phase demodulated data.

2. The method according to claim 1, characterized in that, The initial fiber optic sensing IQ data is acquired from multiple sensing locations on the fiber optic cable. Based on the initial fiber optic sensing IQ data, the corresponding direct phase value is determined. A light source phase correction operation is performed on the direct phase to obtain the first processed data, including: Determine the preset reference position j0 from multiple sensing positions of the optical fiber; Obtain the direct phase value corresponding to the preset reference position from the initial fiber optic sensing IQ data. direct phase value Characterized as: Where I(i,j) is the in-phase signal in the initial fiber optic sensing IQ data, Q(i,j) is the quadrature signal in the initial fiber optic sensing IQ data, i is the sampling time, and j is the sampling position; Based on direct phase value Determine the phase change factor of the light source Light source phase change factor Characterized as: , where n1 is the number of sample points for the phase of the statistical light source; Based on the first preset rule and the light source phase change factor Perform a light source phase correction operation on the initial fiber optic sensing IQ data to obtain the first processed data. The first preset rule is characterized as follows: .

3. The method according to claim 2, characterized in that, Perform initial phase correction operation on the first processed data to obtain the second processed data, including: Data after first processing The starting fiber optic sensing data is extracted from the data, which is generated based on the initial fiber optic sensing IQ data collected at the initial sampling time when there is no external acoustic wave influence. Determine the initial phase factor of the receiver point based on the initial fiber optic sensing IQ data. Initial phase factor at the receiving point Characterized as: Where i0 is the initial sampling time without external sound wave influence, and n2 is the number of sampling points for the initial phase of the statistical receiving point; Based on the second preset rule and the initial phase factor of the receiving point For the first processed data Perform initial phase correction at the receiving point to obtain the second processed data. The second preset rule is characterized as follows: .

4. The method according to claim 3, characterized in that, Perform a linear phase correction operation on the second-processed data to obtain the third-processed data, including: Based on the second processed data Perform a linear phase analysis of the light source to obtain the linear phase parameters of the light source corresponding to the preset reference position. The linear phase parameters of the light source include the first phase intercept b. i and the first gradient k i ; Based on the third preset rule and the linear phase parameter of the light source, the second processed data is processed... Perform linear phase correction of the light source to obtain the third-processed data. The third preset rule is represented as: 。 5. The method according to claim 4, characterized in that, Perform a receiver-point linear phase correction operation on the third-processed data to obtain the fourth-processed data, including: Based on the third-processed data Obtain the linear phase parameters of the receiving point corresponding to the start time. The linear phase parameters of the receiving point include the second phase intercept b. j Second gradient k j ; Based on the fourth preset rule and the linear phase parameter of the receiving point, the third processed data is processed... Perform a linear phase correction operation at the receiving point to obtain the fourth processed data. The fourth preset rule is represented as: 。 6. A global phase quadrature demodulation device for fiber optic sensing data, characterized in that, The device includes: The initial data acquisition unit is used to acquire initial fiber optic sensing IQ data; The light source phase correction unit is used to determine the corresponding direct phase value based on the initial fiber optic sensing IQ data, perform a light source phase correction operation on the direct phase, and obtain the first processed data. The receiving point initial phase correction unit is used to perform a receiving point initial phase correction operation on the first processed data to obtain the second processed data; A light source linear phase correction unit is used to perform a light source linear phase correction operation on the second processed data to obtain the third processed data. The receiving point linear phase correction unit is used to perform a receiving point linear phase correction operation on the third processed data to obtain the fourth processed data. The processing unit is used to perform phase dewinding and near-DC component removal processing on the fourth processed data to obtain globally phase demodulated data.

7. The apparatus according to claim 6, characterized in that, The initial fiber optic sensing IQ data is acquired from multiple sensing locations on the fiber optic cable. The light source phase correction unit includes: The reference position determination module is used to determine a preset reference position j0 from multiple sensing positions of the optical fiber; The reference information acquisition module is used to acquire the direct phase value corresponding to the preset reference position from the initial fiber optic sensing IQ data. direct phase value Characterized as: Where I(i,j) is the in-phase signal in the initial fiber optic sensing IQ data, Q(i,j) is the quadrature signal in the initial fiber optic sensing IQ data, i is the sampling time, and j is the sampling position; The light source phase change factor determination module is used to determine the phase change factor based on the direct phase value. Determine the phase change factor of the light source Light source phase change factor Characterized as: , where n1 is the number of sample points for the phase of the statistical light source; A light source phase correction module is used to correct the phase of the light source based on a first preset rule and the light source phase change factor. Perform a light source phase correction operation on the initial fiber optic sensing IQ data to obtain the first processed data. The first preset rule is characterized as follows: .

8. The apparatus according to claim 7, characterized in that, The initial phase correction unit for the receiving point includes: The initial data acquisition module is used to acquire data after the first processing. The starting fiber optic sensing data is extracted from the data, which is generated based on the initial fiber optic sensing IQ data collected at the initial sampling time when there is no external acoustic wave influence. The receiver initial phase factor determination module is used to determine the receiver initial phase factor based on the initial fiber sensing IQ data. Initial phase factor at the receiving point Characterized as: Where i0 is the initial sampling time without external sound wave influence, and n2 is the number of sampling points for the initial phase of the statistical receiving point; The receiver initial phase correction module is used to correct the initial phase of the receiver based on a second preset rule and the receiver initial phase factor. For the first processed data Perform initial phase correction at the receiving point to obtain the second processed data. The second preset rule is characterized as follows: .

9. The apparatus according to claim 8, characterized in that, The light source linear phase correction unit includes: The light source linear phase analysis module is used to analyze the data based on the second processed data. Perform a linear phase analysis of the light source to obtain the linear phase parameters of the light source corresponding to the preset reference position. The linear phase parameters of the light source include the first phase intercept b. i and the first gradient k i ; The light source linear phase correction module is used to correct the second processed data based on a third preset rule and the light source linear phase parameters. Perform linear phase correction of the light source to obtain the third-processed data. The third preset rule is represented as: .

10. The apparatus according to claim 9, characterized in that, The receiving point linear phase correction unit includes: The receiver point linear phase analysis module is used to analyze the data based on the third-processed data. Obtain the linear phase parameters of the receiving point corresponding to the start time. The linear phase parameters of the receiving point include the second phase intercept b. j Second gradient k j ; The receiver point linear phase correction module is used to correct the third-processed data based on the fourth preset rule and the receiver point linear phase parameters. Perform a linear phase correction operation at the receiving point to obtain the fourth processed data. The fourth preset rule is represented as: .

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the program implements the global phase quadrature demodulation method for fiber optic sensing data as described in any one of claims 1-5.

Images