Double-k method-based double-channel information fusion vibration positioning device and method

Abstract

The invention relates to the technical field of optical fiber sensing, in particular to a dual-channel information fusion vibration positioning device and method based on a dual-k method, and aims to improve a traditional single-channel amplitude demodulation phi-OTDR (AD-phi-OTDR) system to obtain a device with a dual-channel phase-sensitive optical time domain reflectometer module. Firstly, vibration signals are collected through a dual-channel amplitude demodulation phi-OTDR system, then the optimal sampling number is designed through the relation between the vibration frequency and the sampling period, the time consumed by system vibration positioning is shortened, the operation efficiency of the system is improved, then vibration positioning is conducted through a dual-k method, and finally vibration is judged through dual-channel information fusion. According to the invention, the authenticity of the signal is improved through dual-channel cross validation. And a dual-channel data fusion mechanism is used for effective discrimination, so that the anti-interference performance of the system is improved, and the reliability of vibration signal discrimination is further improved.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber sensing technology, and in particular to a dual-channel information fusion vibration positioning device and method based on a double-K method. Background Art

[0002] Phase-sensitive optical time-domain reflectometry (φ-OTDR) uses a single optical fiber to achieve omnidirectional and continuous distributed detection of small disturbances across space. Its advantages include simple structure, high sensing accuracy, and multi-point disturbance detection. Therefore, φ-OTDR is widely used in geological surveys, oil pipeline safety monitoring, video conferencing, border security, intrusion alarms, and other fields. With the continuous progress of the nation and society, spatial positioning technology based on φ-OTDR has also developed rapidly in recent years to meet the needs of production and life. In oil pipeline safety monitoring applications, spatial positioning technology can be used to promptly locate and alert the source of pipeline leaks, preventing major losses and eliminating safety hazards. In video conferencing applications, spatial positioning technology can detect the speaker's position, allowing cameras to locate the speaker in real time. In intrusion alarm applications, spatial positioning technology can be used to locate the intrusion site, allowing for timely response and safeguarding national security.

[0003] However, when using φ-OTDR for real-time data acquisition and spatial positioning over a wide coverage area, the amount of data required will increase significantly. Traditional demodulation methods, such as orthogonal demodulation, Hilbert transform demodulation, and three-port coupler demodulation, increase the time required to demodulate large amounts of data exponentially, failing to meet real-time requirements. Furthermore, the φ-OTDR system's extended data processing time increases spatial positioning response time, preventing timely and effective spatial positioning and alarms, resulting in significant losses for the system's users. Summary of the Invention

[0004] The purpose of the present invention is to provide a dual-channel information fusion vibration positioning device and method based on the double-k method, design the spatial phase shift angle, then construct the spatial phase shift matrix, and then demodulate the phase information of each sensor unit. Finally, a multiple signal classification algorithm is used for spatial positioning, thereby solving the problem that the traditional φ-OTDR demodulation algorithm takes a long time to demodulate large data.

[0005] To achieve the above object, the present invention provides a dual-channel information fusion vibration positioning device based on the double-k method, comprising a dual-channel phase-sensitive optical time domain reflectometer module and two sets of sensing optical fibers;

[0006] The dual-channel phase-sensitive optical time-domain reflectometer module includes a laser, a signal generator, a signal acquisition and processing module and two sensing paths;

[0007] Each sensing path is composed of a laser, a 90:10 optical splitter, an acousto-optic modulator, a signal generator, a circulator, a sensing fiber, a polarization modulator, a 50:50 coupler, a balanced detector, and a signal acquisition and processing module, wherein the laser, the signal generator, and the signal acquisition and processing module are shared by the two sensing paths;

[0008] The output end of the laser in the sensing path is connected to the input end of the 90:10 optical splitter, one output end of the 90:10 optical splitter is connected to one input end of the acousto-optic modulator, and the other output end of the 90:10 optical splitter is connected to one input end of the 50:50 coupler; the output end of the signal generator is connected to the other input end of the acousto-optic modulator, the output end of the acousto-optic modulator is connected to the first port of the circulator, the second port of the circulator is connected to the sensing optical fiber, and the third port of the circulator is connected to the other input end of the 50:50 coupler; the output end of the 50:50 coupler is connected to the input end of the balanced detector, and the output end of the balanced detector is connected to the input end of the signal acquisition and processing module.

[0009] The output end of the signal acquisition and processing module is connected to the host computer. The laser is a high-power narrow-linewidth laser with a spectral linewidth of 3kHz, a central wavelength of 1550.15nm, a maximum output power of 100mW, and a power instability of less than 1%; the bandwidth of the balanced detector is 200MHz, and the detection response is 0.9A / W.

[0010] Furthermore, the present invention also proposes a dual-channel information fusion vibration positioning method based on the double-k method, which uses the dual-channel information fusion vibration positioning device based on the double-k method, including the following steps:

[0011] Step 1: The amplitude information of each sampling point on the sensing optical fiber is collected in different paths and reorganized into an intermediate frequency matrix in the signal acquisition and processing module;

[0012] Step 2: Design the optimal number of sampling strips M0 as:

[0013] M0=1 / (f s ×T p )

[0014] Among them, f s is the vibration signal frequency, T p is the sampling period;

[0015] Step 3: Design the differential step size of each sensing channel in the dual-channel phase-sensitive optical time-domain reflectometer module;

[0016] Step 4: Use the signal acquisition and processing module to fuse the backscattered Rayleigh scattering data collected by each sensing path to obtain a judgment result.

[0017] Optionally, during the execution of step 1, the balanced detector implements photoelectric heterodyne detection in the sensing path and outputs an intermediate frequency signal to the signal acquisition and processing module. The signal acquisition and processing module adopts an IQ orthogonal demodulation scheme to obtain the RBS amplitude signal strength at each sampling point on the sensing optical fiber.

[0018] Optionally, in step 1, two intermediate frequency matrices are obtained by recombining the two sensing channels respectively;

[0019] The expression of the first intermediate frequency matrix D1[M,N] is as follows:

[0020]

[0021] in, represents the intensity of the nth sampling point on the sensing fiber 1 under the mth sampling pulse, m = 1, 2, ..., M is the number of detection pulses; n = 1, 2, ..., N, N is the number of vibration sampling points on the sensing fiber;

[0022] The expression of the second intermediate frequency matrix D2[M,N] is as follows:

[0023]

[0024] in, It represents the intensity of the nth sampling point on the sensing fiber 2 under the mth sampling pulse, where m = 1, 2, ..., M is the number of detection pulses; and n = 1, 2, ..., N, where N represents the number of vibration sampling points on the sensing fiber.

[0025] Optionally, in step 3, the differential step length of sensing channel 1 is designed to be a first differential step length k1, and the second differential step length of sensing channel 2 is designed to be k2;

[0026] The differential step size of sensing channel 1 is the first differential step size k1:

[0027] k1=α×M0

[0028] The differential step size of sensing channel 2 is the second differential step size k2:

[0029] k2=β×k1

[0030] Among them, α is the first step length coefficient, 0<α<1; β is the second step length coefficient, 0<β<1; the first step length coefficient α and the second step length coefficient β satisfy the following relationship:

[0031] Optionally, the data fusion process in step 4 includes the following steps:

[0032] Step 4.1: Calculate the amplitude difference accumulation curve based on the backscattered Rayleigh data of each sensing path;

[0033] Step 4.2: Calculate the gain curves corresponding to the amplitude difference accumulation curves on the two sensing paths respectively, where each gain curve contains the gain values ​​of N sampling positions;

[0034] Step 4.3: Binarize the gain curves on the two sensing paths respectively and compare them with a preset gain threshold to obtain a binary digital curve of the vibration detection signal;

[0035] Step 4.4: Fuse the binary digital curves on the two sensing paths and perform a logical OR operation on the digital values ​​at the same sampling position on the digital curves to determine whether there is a vibration event at the sampling position.

[0036] When the digital values ​​of the digital curves on the two sensing paths at the same sampling position are both false, it means that the sensing optical fiber has no vibration at the sampling position; otherwise, it is determined that the sensing optical fiber has vibration at the sampling position.

[0037] The present invention provides a dual-channel information fusion vibration positioning device and method based on the double-k method. This device improves the traditional single-channel amplitude demodulation φ-OTDR (AD-φ-OTDR) system to obtain a device with a dual-channel phase-sensitive optical time-domain reflectometer module. The device first collects vibration signals using the dual-channel amplitude demodulation φ-OTDR system, then uses the relationship between vibration frequency and sampling period to design the optimal number of sampling bars, reducing the time spent on system vibration positioning and improving the system's operating efficiency. The double-k method is then used to locate vibrations, and finally, vibrations are determined through dual-channel information fusion. The present invention improves signal authenticity through dual-channel cross-validation. Effective discrimination is achieved using a dual-channel data fusion mechanism, improving the system's anti-interference performance and further enhancing the reliability of vibration signal discrimination. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0039] Figure 1 It is a structural schematic diagram of a dual-channel information fusion vibration positioning device based on the double-k method of the present invention.

[0040] Figure 2 The present invention is a flow chart of a dual-channel information fusion vibration positioning method based on the double-k method.

[0041] Figure 3It is a schematic diagram of a single-channel gain curve for vibration positioning using a traditional ADM algorithm in a specific embodiment of the present invention.

[0042] Figure 4 3 is a schematic diagram of a first amplitude difference accumulation curve of the sensing channel 1 in a specific embodiment of the present invention.

[0043] Figure 5 3 is a schematic diagram of a second amplitude difference accumulation curve of the sensing channel 2 in a specific embodiment of the present invention. DETAILED DESCRIPTION

[0044] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0045] See also Figure 1 , the present invention provides a dual-channel information fusion vibration positioning device based on the double-k method, including a dual-channel phase-sensitive optical time domain reflectometer module and two sets of sensing optical fibers;

[0046] The dual-channel phase-sensitive optical time-domain reflectometer module includes a laser, a signal generator, a signal acquisition and processing module and two sensing paths;

[0047] Each sensing path is composed of a laser, a 90:10 optical splitter, an acousto-optic modulator, a signal generator, a circulator, a sensing fiber, a polarization modulator, a 50:50 coupler, a balanced detector, and a signal acquisition and processing module, wherein the laser, the signal generator, and the signal acquisition and processing module are shared by the two sensing paths;

[0048] The output end of the laser in the sensing path is connected to the input end of the 90:10 optical splitter, one output end of the 90:10 optical splitter is connected to one input end of the acousto-optic modulator, and the other output end of the 90:10 optical splitter is connected to one input end of the 50:50 coupler; the output end of the signal generator is connected to the other input end of the acousto-optic modulator, the output end of the acousto-optic modulator is connected to the first port of the circulator, the second port of the circulator is connected to the sensing optical fiber, and the third port of the circulator is connected to the other input end of the 50:50 coupler; the output end of the 50:50 coupler is connected to the input end of the balanced detector, and the output end of the balanced detector is connected to the input end of the signal acquisition and processing module.

[0049] The output end of the signal acquisition and processing module is connected to the host computer. The laser is a high-power narrow-linewidth laser with a spectral linewidth of 3kHz, a central wavelength of 1550.15nm, a maximum output power of 100mW, and a power instability of less than 1%; the bandwidth of the balanced detector is 200MHz, and the detection response is 0.9A / W.

[0050] Specifically, when using a traditional single-channel AD-φ-OTDR to locate vibration, the single channel relies on a single signal path. This makes it susceptible to environmental noise or local interference in complex environments and over long distances, leading to false or missed vibration signal detection. This present invention improves the single-channel AD-φ-OTDR system by employing dual-channel cross-validation to enhance signal authenticity. This dual-channel data fusion mechanism effectively distinguishes the system, improving its anti-interference performance and further enhancing the reliability of vibration signal detection.

[0051] Furthermore, the present invention also proposes a dual-channel information fusion vibration positioning method based on the double-k method, which uses the dual-channel information fusion vibration positioning device based on the double-k method, including the following steps:

[0052] Step 1: The amplitude information of each sampling point on the sensing optical fiber is collected in different paths and reorganized into an intermediate frequency matrix in the signal acquisition and processing module;

[0053] Step 2: Design the optimal number of sampling strips M0 as:

[0054] M0=1 / (f s ×T p )

[0055] Among them, f s is the vibration signal frequency, T p is the sampling period;

[0056] Step 3: Design the differential step size of each sensing channel in the dual-channel phase-sensitive optical time-domain reflectometer module;

[0057] Step 4: Use the signal acquisition and processing module to fuse the backscattered Rayleigh scattering data collected by each sensing path to obtain a judgment result.

[0058] like Figure 2 The following is an execution flow of the dual-channel information fusion vibration positioning method based on the double-k method, which is further explained in conjunction with specific embodiments and execution steps:

[0059] Step 1: In the sensing path, a balanced detector performs opto-heterodyne detection and outputs an intermediate frequency (IF) signal to the signal acquisition and processing module. This module uses an IQ quadrature demodulation scheme to obtain the RBS amplitude signal strength at each sampling point on the sensing fiber.

[0060] The dual-channel phase-sensitive time domain reflectometer φ-OTDR performs photoelectric heterodyne detection on the backscattered Rayleigh signal generated by the sensing optical fiber 1 in the sensing channel 1 through the balanced detector 1. The output intermediate frequency signal is subjected to IQ quadrature demodulation in the signal acquisition and processing module, that is, the intermediate frequency signal Y1 is multiplied by the sine signal and cosine signal of the same frequency respectively to obtain the quadrature demodulation I1 component Q1 component, and is obtained by The amplitude information of each sampling point on the sensing optical fiber 1 is obtained, and is reorganized into the first intermediate frequency matrix D1[M,N] in the signal acquisition and processing module according to the number N of vibration sampling points on the sensing optical fiber in the sensing channel 1 and the number M of pulses of the collected backward Rayleigh scattered light.

[0061]

[0062] in, represents the intensity of the nth sampling point on the sensing fiber 1 under the mth sampling pulse, where m = 1, 2, ..., M is the number of detection pulses, and n = 1, 2, ..., N, where N is the number of vibration sampling points on the sensing fiber.

[0063] The dual-channel phase-sensitive time domain reflectometer φ-OTDR performs photoelectric heterodyne detection on the backscattered Rayleigh signal generated by the sensing fiber 2 in the sensing channel 2 through the balanced detector 2. The output intermediate frequency signal is subjected to IQ quadrature demodulation in the signal acquisition and processing module, that is, the intermediate frequency signal Y2 is multiplied by the sine signal and cosine signal of the same frequency respectively to obtain the quadrature demodulation I2 component Q2 component, and is obtained by The amplitude information of each sampling point on the sensing optical fiber 2 is obtained, and is reorganized into a second intermediate frequency matrix D2[M,N] in the signal acquisition and processing module according to the number N of vibration sampling points on the sensing optical fiber in the sensing channel 2 and the number M of pulses of the collected backward Rayleigh scattered light.

[0064]

[0065] in, represents the intensity of the nth sampling point on sensing fiber 2 under the mth sampling pulse, where m = 1, 2, ..., M is the number of detection pulses. n = 1, 2, ..., N, where N is the number of vibration sampling points on the sensing fiber. In this embodiment, the RBS amplitude signals of 300 detection pulses were collected, i.e., M = 300; the spatial sampling interval δ of the data acquisition card in the signal acquisition and processing module is 0.2 m, and the total length L of the sensing fiber is 1.4 km, i.e., N = L / δ = 7000.

[0066] Step 2: Design the optimal number of sampling strips M0 as:

[0067] M0=1 / (f s ×T p )

[0068] Among them, f s is the vibration signal frequency, T p is the sampling period.

[0069] Because the dual-channel phase-sensitive time-domain reflectometer (φ-OTDR) signal acquisition and processing module uses continuous sampling to collect data, the amount of data sampled is very large, which in turn reduces system operating efficiency. Therefore, this paper studies the optimal number of data items required for system vibration positioning and uses the relationship between vibration frequency and sampling period to set the optimal number of sampling items, thereby reducing the time consumed by the system vibration positioning and improving system operating efficiency.

[0070] Step 3: Design the differential step size of each sensing channel of the dual-channel phase-sensitive time domain reflectometer φ-OTDR respectively. Design the differential step size of sensing channel 1 as the first differential step size k1, and design the second differential step size k2 of sensing channel 2.

[0071] The differential step size of sensing channel 1 is the first differential step size k1:

[0072] k1=α×M0

[0073] The differential step size of sensing channel 2 is the second differential step size k2:

[0074] k2=β×k1

[0075] Among them, α is the first step length coefficient, 0<α<1; β is the second step length coefficient, 0<β<1; the first step length coefficient α and the second step length coefficient β satisfy the following relationship:

[0076] The traditional method of vibration positioning of the phase-sensitive time domain reflectometer φ-OTDR is the amplitude differential accumulation algorithm (ADM). This algorithm requires manual selection and measurement of the k value. This process takes a lot of time, and there is no basis for the selection of the k value, which often relies on previous experience. Due to the strong dependence of the traditional ADM algorithm on the vibration frequency, an inappropriate k value often leads to a decrease in the signal-to-noise ratio, thereby increasing the vibration missed detection rate of the system. The present invention first uses the designed optimal number of sampling strips to set the first differential step size of the sensing channel 1, and then imposes a certain limit on the second differential step size of the sensing channel 2. The second differential step size and the first differential step size have a coefficient relationship, so that the two differential step sizes are inconsistent, thereby avoiding an increase in the system missed detection rate due to the selection of a single differential step size.

[0077] Step 4: The signal acquisition and processing module performs fusion processing on the backscattered Rayleigh scattering data collected by each sensing path to obtain a judgment result.

[0078] The specific dual-channel data fusion method is as follows:

[0079] Step 4.1: Calculate the amplitude difference accumulation curve based on the backscattered Rayleigh data of each sensing path.

[0080] In sensing channel 1, a differential operation is performed on the first amplitude matrix D1[M,N] every first differential step k1 row, and the first amplitude differential accumulation curve is generated by accumulation. According to the first amplitude differential accumulation curve, the first detection amplitude at each optical fiber sampling point can be known.

[0081] The nth element of the first amplitude difference accumulation curve, that is, the first detection amplitude S at the nth fiber sampling point 1 (n) is:

[0082]

[0083] Among them, i=1,2,…,M0-k1, n=1,2,…N.

[0084] In sensing channel 2, a differential operation is performed on the second amplitude matrix D2[M,N] every second differential step k2 rows, and the values ​​are accumulated to generate a second amplitude differential accumulation curve. According to the second amplitude differential accumulation curve, the second detection amplitude at each optical fiber sampling point can be known.

[0085] The nth element of the second amplitude difference accumulation curve, that is, the second detection amplitude S at the nth fiber sampling point 2 (n) is:

[0086]

[0087] Among them, i=1,2,…,M0-k2, n=1,2,…N.

[0088] Step 4.2: Calculate the gain curves corresponding to the amplitude difference accumulation curves on the two sensing paths respectively, where each gain curve contains gain values ​​at N sampling positions.

[0089] In sensing channel 1, the first amplitude difference accumulation curve S 1 (n) The corresponding first gain curve S 1' (n) is:

[0090]

[0091] In sensing channel 2, the second amplitude difference accumulation curve S 2 (n) The corresponding second gain curve S 2' (n) is:

[0092]

[0093] Among them S 1(n) is the nth element of the first amplitude accumulation curve (i.e., the first detection amplitude at the nth fiber sampling point), max(S 1 (n)) represents the maximum value of n elements in the first amplitude accumulation curve. 2 (n) is the nth element of the second amplitude accumulation curve (i.e., the first detection amplitude at the nth fiber sampling point), max(S 2 (n)) represents the maximum value of n elements in the second amplitude accumulation curve. The unit of the gain curve is decibel (dB).

[0094] Step 4.3: Binarize the gain curves on the two sensing paths respectively and compare them with the preset gain threshold to obtain the binary digital curve of the vibration detection signal. 1' (n) The first digital curve corresponding to S 1” (n). In sensing channel 2, the first gain curve S 2' (n) The corresponding second digital curve is represented by S 2” (n).

[0095] In this embodiment, the preset gain threshold is 2.0 dB. Since each gain curve includes gain values ​​at N sampling locations, the gain values ​​at these N sampling locations are compared with the preset gain value to obtain digital values ​​at each of the N sampling locations. If the gain value at a particular sampling location is greater than 2.0 dB, a vibration event is determined to be present at that location, and the digital value at that location is represented as "1." Otherwise, a vibration event is determined to be absent at that location, and the digital value at that location is represented as "0."

[0096] Step 4.4: The binary digital curves on the two sensing paths are fused. By performing a logical OR operation on the digital values ​​at the same sampling location on the digital curves, it is determined whether there is a vibration event at that sampling location. Specifically, if the digital values ​​at the same sampling location on the digital curves on both sensing paths are both false, it indicates that the sensing fiber is not vibrating at that sampling location; otherwise, it is determined that the sensing fiber is vibrating at that sampling location.

[0097] The definition of the decision signal S for determining whether there is vibration at a certain sampling position of the sensing fiber is as follows:

[0098] S(n)=S 1” (n)∪S 2” (n)

[0099] The specific judgment rules are shown in Table 1:

[0100] Table 1 Dual-channel information fusion vibration recognition and judgment based on double-k method

[0101]

[0102] In this embodiment, the sensing fiber is a 1.4 km standard single-mode fiber. The acousto-optic modulator is driven by an arbitrary waveform generator with a bandwidth of 200 MHz. The generated detection pulse has a repetition period of 14 μs and a pulse width of 100 ns. The vibration event is excited by a piezoelectric ceramic stretcher (PZT) located at 480 m of the fiber. When the frequency of the driving PZT vibration signal is a sine wave signal of 500 Hz, the conventional single-channel gain curve S 0 like Figure 3 As shown. The first amplitude difference accumulation curve S of sensing channel 1 1 and the second amplitude difference accumulation curve S of sensing channel 2 2 Respectively as Figure 4 and Figure 5 When the differential step size is equal to the optimal number of samples M0 = 142, the amplitude differential accumulation curve S generated by the traditional ADM algorithm is 0 The signal-to-noise ratio at the vibration position is less than 2dB, and it is impossible to determine whether vibration exists. When the first differential step coefficient α of sensing channel 1 is 0.3, the second differential step coefficient β of sensing channel 2 is 0.2, the first differential step k1 is 42, and the second differential step k2 is 8, the first amplitude differential accumulation curve S generated by the first differential step of sensing channel 1 is 1 and the second amplitude difference accumulation curve S generated by the second step length of sensing channel 2 2 The signal-to-noise ratios at the vibration position are 7.0 dB and 3.0 dB, respectively, both greater than 2 dB. Therefore, the first digital S after the binarization of the first amplitude difference accumulation curve is 1 The second digital curve S after the binarization of the curve and the second amplitude difference accumulation curve 2 ” are all “1”, at this time the vibration judgment signal S is “1”, which can effectively locate the vibration.

[0103] The above disclosure is merely one or more preferred embodiments of the present invention, and certainly cannot be used to limit the scope of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiments and equivalent changes made in accordance with the claims of the present invention still fall within the scope of the invention.

Claims

1. A dual-channel information fusion vibration positioning device based on the double-k method, characterized in that: It includes a dual-channel phase-sensitive optical time-domain reflectometer module and two sets of sensing optical fibers; The dual-channel phase-sensitive optical time-domain reflectometer module includes a laser, a signal generator, a signal acquisition and processing module and two sensing paths; Each sensing path is composed of a laser, a 90:10 optical splitter, an acousto-optic modulator, a signal generator, a circulator, a sensing fiber, a polarization modulator, a 50:50 coupler, a balanced detector, and a signal acquisition and processing module, wherein the laser, the signal generator, and the signal acquisition and processing module are shared by the two sensing paths; The output end of the laser in the sensing path is connected to the input end of the 90:10 optical splitter, one output end of the 90:10 optical splitter is connected to one input end of the acousto-optic modulator, and the other output end of the 90:10 optical splitter is connected to one input end of the 50:50 coupler; the output end of the signal generator is connected to the other input end of the acousto-optic modulator, the output end of the acousto-optic modulator is connected to the first port of the circulator, the second port of the circulator is connected to the sensing optical fiber, and the third port of the circulator is connected to the other input end of the 50:50 coupler; the output end of the 50:50 coupler is connected to the input end of the balanced detector, and the output end of the balanced detector is connected to the input end of the signal acquisition and processing module.

2. The dual-channel information fusion vibration positioning device based on the double-k method according to claim 1, characterized in that: The output end of the signal acquisition and processing module is connected to the host computer. The laser is a high-power narrow-linewidth laser with a spectral linewidth of 3kHz, a central wavelength of 1550.15nm, a maximum output power of 100mW, and a power instability of less than 1%; the bandwidth of the balanced detector is 200MHz, and the detection response is 0.9A / W.

3. A dual-channel information fusion vibration positioning method based on the double-k method, using the dual-channel information fusion vibration positioning device based on the double-k method according to any one of claims 1 or 2, characterized in that: The following steps are involved: Step 1: The amplitude information of each sampling point on the sensing optical fiber is collected in different paths and reorganized into an intermediate frequency matrix in the signal acquisition and processing module; Step 2: Design the optimal number of sampling strips M0 as: M0=1 / (f s ×T p ) Among them, f s is the vibration signal frequency, T p is the sampling period; Step 3: Design the differential step size of each sensing channel in the dual-channel phase-sensitive optical time-domain reflectometer module; Step 4: Use the signal acquisition and processing module to fuse the backscattered Rayleigh scattering data collected by each sensing path to obtain a judgment result.

4. The dual-channel information fusion vibration positioning method based on the double-k method according to claim 3, characterized in that: During the execution of step 1, the balanced detector implements optoelectronic heterodyne detection in the sensing path and outputs an intermediate frequency signal to the signal acquisition and processing module. The signal acquisition and processing module uses an IQ quadrature demodulation scheme to obtain the RBS amplitude signal strength at each sampling point on the sensing fiber.

5. The dual-channel information fusion vibration positioning device and method based on the double-k method according to claim 4, characterized in that: In step 1, two intermediate frequency matrices are obtained by recombining the two sensing channels respectively; The expression of the first intermediate frequency matrix D1[M,N] is as follows: in, represents the intensity of the nth sampling point on the sensing fiber 1 under the mth sampling pulse, m = 1, 2, ..., M is the number of detection pulses; n = 1, 2, ..., N, N is the number of vibration sampling points on the sensing fiber; The expression of the second intermediate frequency matrix D2[M,N] is as follows: in, It represents the intensity of the nth sampling point on the sensing fiber 2 under the mth sampling pulse, where m = 1, 2, ..., M is the number of detection pulses; and n = 1, 2, ..., N, where N represents the number of vibration sampling points on the sensing fiber.

6. The dual-channel information fusion vibration positioning device and method based on the double-k method according to claim 5, characterized in that: In step 3, the differential step size of sensing channel 1 is designed to be the first differential step size k1, and the second differential step size of sensing channel 2 is designed to be k2; The differential step size of sensing channel 1 is the first differential step size k1: k1=α×M0 The differential step size of sensing channel 2 is the second differential step size k2: k2=β×k1 Among them, α is the first step length coefficient, 0<α<1; β is the second step length coefficient, 0<β<1; the first step length coefficient α and the second step length coefficient β satisfy the following relationship:

7. The dual-channel information fusion vibration positioning device and method based on the double-k method according to claim 6, characterized in that: The data fusion process in step 4 includes the following steps: Step 4.1: Calculate the amplitude difference accumulation curve based on the backscattered Rayleigh data of each sensing path; Step 4.2: Calculate the gain curves corresponding to the amplitude difference accumulation curves on the two sensing paths respectively, where each gain curve contains the gain values ​​of N sampling positions; Step 4.3: Binarize the gain curves on the two sensing paths respectively and compare them with a preset gain threshold to obtain a binary digital curve of the vibration detection signal; Step 4.4: Fuse the binary digital curves on the two sensing paths and perform a logical OR operation on the digital values ​​at the same sampling position on the digital curves to determine whether there is a vibration event at the sampling position. When the digital values ​​of the digital curves on the two sensing paths at the same sampling position are both false, it means that the sensing optical fiber has no vibration at the sampling position; otherwise, it is determined that the sensing optical fiber has vibration at the sampling position.

Images