Tube well lid or rod line vibration signal space-time validity verification receiving system

Abstract

The invention discloses a tube well lid or rod line vibration signal space-time validity verification receiving system. The system comprises an acquisition scheduling module, an emission control module, a spectral line fusion module, a feature analysis module, a parameter optimization module and an alarm storage module. The acquisition scheduling module is used for synchronously acquiring well lid or rod line vibration signals and strain temperature signals through an optical fiber sensing link; the emission control module dynamically adjusts pulse parameters according to strain temperature distribution and emits a detection signal; the spectral line fusion module carries out fusion processing on the vibration and strain temperature signals, inhibits interference and generates high-precision vibration data; the feature analysis module extracts time and space features to generate a validity event; the parameter optimization module automatically adjusts detection parameters according to event characteristics and historical errors; and the alarm storage module stores and outputs alarm data including the well lid or rod road position, the vibration intensity, the temperature change and the confidence coefficient to the monitoring platform, thereby realizing accurate monitoring and low false alarm identification of well lid or rod road abnormity.

Description

Technical Field

[0001] This invention relates to the field of fiber optic sensing and monitoring technology, and in particular to a spatiotemporal validity verification and receiving system for vibration signals from manhole covers or poles. Background Technology

[0002] With the continuous expansion of urban infrastructure and the increasing number and scale of underground pipe networks, the safe operation of manhole covers or poles is of great significance to urban traffic and public safety. Loosening, displacement, or even loss of manhole covers or poles can lead to safety accidents such as vehicle damage and pedestrian injuries. In recent years, distributed fiber optic sensing technology has begun to be applied to the condition monitoring of manhole covers or poles due to its advantages such as long-distance monitoring, resistance to electromagnetic interference, and no need for independent power supply. However, in existing technologies, common systems often use single Rayleigh scattering vibration monitoring or Brillouin scattering strain and temperature monitoring, and they usually operate in a time-sharing manner, making it difficult to achieve simultaneous acquisition and comprehensive analysis of the two types of signals. Specifically, existing technologies mainly have the following shortcomings: a single detection method cannot simultaneously obtain dynamic vibration information and environmental strain and temperature information of manhole covers or poles, resulting in insufficient evidence for event identification. Traditional signal processing methods are difficult to effectively suppress link noise and pulse sidelobe interference, easily leading to false alarms or missed alarms. Most systems use fixed pulse widths, transmission power, and threshold values, lacking the ability to adaptively adjust according to the field environment and historical detection results. The alarm data output by existing systems often only includes time and location, lacking multi-dimensional information such as vibration intensity, temperature change, and confidence level, which is not conducive to managers quickly and accurately judging the nature of the event.

[0003] Therefore, how to provide a spatiotemporal validity verification and receiving system for vibration signals from manhole covers or poles is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] One objective of this invention is to propose a spatiotemporal validity verification and receiving system for vibration signals from manhole covers or poles. This invention synchronously acquires vibration signals and strain temperature signals from the location of the manhole cover or pole within the same detection cycle, and combines dual-polarization complementary sequence matched filtering and phase compensation processing to achieve interference suppression and high-precision extraction of zero sidelobes from the vibration signals. It has the advantages of high detection accuracy, low false alarm rate and fast response speed.

[0005] The spatiotemporal validity verification and receiving system for vibration signals from manhole covers or pole lines according to an embodiment of the present invention includes the following modules:

[0006] The data acquisition and scheduling module uses distributed optical fiber sensing links deployed in the monitoring areas of wells or poles to synchronously acquire Rayleigh scattering vibration echo signals and Brillouin scattering strain temperature echo signals in a time-division or wavelength-division multiplexing manner to generate raw acquisition data.

[0007] The transmission control module adjusts the pulse length, polarization state, and transmission power of the dual-polarized Golay complementary sequence pulse of Rayleigh detection based on the strain temperature distribution of Brillouin detection in the original acquired data, and transmits the adjusted pulse signal to the distributed optical fiber sensing link.

[0008] The spectral fusion module receives and adjusts the transmitted Rayleigh and Brillouin echo signals, extracts the Rayleigh scattering spectrum and performs matched filtering and complementary correlation processing, and simultaneously extracts the Brillouin scattering spectrum and generates reference data. In the same process, the reference data is used to perform phase compensation and interference suppression on the Rayleigh signal to generate a zero-sidelobe vibration timing signal.

[0009] The feature analysis module receives zero-sidelobe vibration time-series signals, extracts time-series and spectral features, calculates inter-frame similarity and correlation coefficients between adjacent nodes, and generates a spatiotemporally valid event set.

[0010] The parameter optimization module receives the spatiotemporal validity event set and historical detection errors, updates the Brillouin pulse width, transmit power and Rayleigh detection threshold, and feeds the updated parameters back to the transmit control module.

[0011] The alarm storage module receives spatiotemporal validity event sets and generates alarm data.

[0012] Optionally, the method for verifying the spatiotemporal validity of vibration signals from manhole covers or poles specifically includes:

[0013] S1. By deploying distributed optical fiber sensing links in the monitoring area of ​​the manhole or pole and covering the location of the manhole cover or pole, the Rayleigh scattering vibration echo signal generated by the vibration of the manhole cover or pole and the Brillouin scattering strain temperature echo signal of the optical fiber segment at the location of the manhole cover or pole are simultaneously acquired in time-division multiplexing or wavelength-division multiplexing mode to generate raw acquisition data.

[0014] S2. Based on the Brillouin strain temperature distribution in the original acquired data, periodically adjust the pulse length, polarization state, and transmission power of the dual-polarized Golay complementary sequence used for Rayleigh detection in the monitoring area of ​​manhole covers or pole lines to form the adjusted transmission parameters;

[0015] S3. Use the adjusted transmission parameters to transmit pulse signals to the distributed optical fiber sensing link and receive the corresponding Rayleigh and Brillouin echo signals.

[0016] S4. Extract the scattering spectrum from the Rayleigh echo signal and perform matched filtering and complementary correlation processing. Extract the scattering spectrum from the Brillouin echo signal and calculate the frequency shift and strain temperature reference data to obtain the zero sidelobe vibration time series signal corresponding to the vibration event of the manhole cover or pole.

[0017] S5. Extract time-series and spectral features from the zero-sidelobe vibration time-series signal, calculate the feature similarity between consecutive frames and the feature correlation coefficient of spatially adjacent manhole cover or pole detection points, and generate a spatiotemporal validity event set of the manhole cover or pole vibration signal.

[0018] S6. Based on the spatiotemporal validity event set and historical detection errors, update the Brillouin pulse width, transmission power and Rayleigh detection threshold;

[0019] S7. Generate alarm data containing the location of manhole cover or pole, timestamp, vibration intensity, temperature change and confidence level based on the spatiotemporal validity event set, and save it to the database. At the same time, output the alarm data to the monitoring platform.

[0020] Optionally, S1 specifically includes:

[0021] S11. Lay distributed optical fiber sensing links along a predetermined path in the monitoring area of ​​the manhole or pole, so that the optical fiber continuously covers each manhole cover or pole location. Connect one end to the optical pulse transmitter and the other end to the optical signal receiver, and measure the total length of the link to calibrate the position of the optical fiber segment corresponding to the manhole cover or pole.

[0022] S12. In each detection cycle, the optical pulse emitting device is triggered according to the set time interval to emit Rayleigh scattering detection optical pulse signal and Brillouin scattering detection optical pulse signal respectively. The two types of optical pulse signals are allocated different time intervals through time division multiplexing or different wavelengths through wavelength division multiplexing.

[0023] S13. When the optical pulse signal propagates in the optical fiber link, Rayleigh scattering echo signal and Brillouin scattering echo signal are generated in the optical fiber segment covering the manhole cover or pole. The optical signal receiving device receives the echo signal and performs photoelectric conversion.

[0024] S14. Record the signal propagation time corresponding to the optical fiber segment at the location of the manhole cover or pole, and calculate the distance between the location of the manhole cover or pole and the receiving end based on the speed of light propagation in the optical fiber.

[0025] S15. Mark the sampling time and spatial location of the Rayleigh scattering and Brillouin scattering signals collected from the manhole cover or pole location, and organize the collection results into raw collection data arranged in time and spatial order.

[0026] Optionally, S2 specifically includes:

[0027] S21. Extract the Brillouin scattering echo signal of the optical fiber segment covering the manhole cover or pole location from the original acquired data to obtain the average strain value ε of the optical fiber segment in the current detection cycle. cur With average temperature value T cur And read the average strain value ε corresponding to the previous detection cycle. preWith average temperature value T pre ;

[0028] S22. Calculate the strain change rate Δε and temperature change rate ΔT of the manhole cover or fiber optic segment in the current detection cycle, and compare them with the preset strain threshold ε. th and temperature threshold T th Compare and determine the pulse length adjustment amount L. adj Transmit power adjustment amount P adj and polarization state selection marker Pol sel :

[0029] When |Δε|≥ε th Or |ΔT|≥T th At that time, L adj >0;

[0030] When both are below the threshold, L adj <0;

[0031] P adj Proportional to |ΔT|, and P adj ≤P max ;

[0032] Pol sel Choose between horizontal or vertical polarization based on the instantaneous polarization state of the optical fiber in the manhole cover or pole section;

[0033] S23. Based on the adjusted final pulse length L final and the system sampling frequency f s With fiber group velocity v g Determine the code length N required for the Golay sequence to ensure that the pulse covers the spatial range of the manhole cover or pole section in the optical fiber;

[0034] S24. Generate and bind dual-polarized Golay complementary sequences:

[0035] S241. Initialize two base sequences;

[0036] S242. Generate higher-order sequences sequentially according to the recursive expansion rule until the sequence length reaches or exceeds N;

[0037] S243. Extract the first N bits as the final complementary sequences G1 and G2;

[0038] S244. Modulate G1 to a horizontally polarized light pulse and G2 to a vertically polarized light pulse;

[0039] S245, Keep the polarization switching delay at a fixed value τ pol And register the launch sequence in the launch control module;

[0040] S25. Complete pulse parameter configuration: Set the final pulse length L final =L base +L adj Set the final transmit power P final =P base +P adj , will L final P final Pol sel Combined with the generated G1 and G2, they form the emission parameter set for the current detection period;

[0041] S26. Store the set of launch parameters in the launch control module.

[0042] Optionally, S3 specifically includes:

[0043] S31. Retrieve the set of launch parameters for the current detection period from the launch control module;

[0044] S32. Control the pulse modulator at the transmitting end according to the L set in the parameter set. final The output light pulses are used to load G1 into the horizontal polarization channel and G2 into the vertical polarization channel, respectively, according to Pol sel The dual-polarized pulses are emitted in the specified sequence.

[0045] S33. Set the light source emission power to P. final And maintain a stable output during the pulse emission cycle;

[0046] S34. The pulse signal encoded with dual-polarized Golay complementary sequence is transmitted to the monitoring area of ​​the manhole cover or pole via an optical fiber link, corresponding to the optical fiber segment covering the location of the manhole cover or pole.

[0047] S35. At the same time as the transmitter transmits the pulse signal, the receiver synchronously starts the photodetector to receive the Rayleigh scattering echo signal and Brillouin scattering echo signal returned along the distributed optical fiber sensing link in real time.

[0048] S36. Perform photoelectric conversion on the received echo signal, extract and record the signal type (Rayleigh or Brillouin), polarization channel, and corresponding timestamp t for each sampling point. recv ;

[0049] S37. The echo signals of the fiber optic segments covering the manhole cover or pole location are individually marked and associated with the transmission parameters of this detection cycle, organized into the raw acquisition data of the current detection cycle, and stored in the data buffer area.

[0050] Optionally, S4 specifically includes:

[0051] S41. Read the Rayleigh echo signal sequence r(n) and Brillouin echo signal sequence b(n) covering the fiber segment at the location of the manhole cover or pole from the current detection cycle buffer.

[0052] S42. Perform bandpass filtering and Hanning window weighting on r(n) and b(n) respectively to generate the weighted signal r. w (n), b w (n);

[0053] S43, r w (n) Perform a Fast Fourier Transform to obtain the frequency domain complex spectrum R(f), and take r w (n) The amplitude spectrum is normalized according to the maximum amplitude to obtain the Rayleigh scattering spectrum S. R (f), b w (n) Perform the same processing to obtain the Brillouin scattering spectrum S B (f), where f is the frequency index;

[0054] S44. Construct a dual-polarization matched filter based on the transmitted Golay complementary sequences G1(n) and G2(n). The frequency domain response is: Where H k (f) represents the frequency response of the matched filter; FFT(G) k (n)) is the frequency domain representation of the Golay sequence; conj[·] represents the complex conjugate operation; |·| represents the amplitude operation;

[0055] S45, S R (f) is multiplied point by point in the frequency domain with H1(f) and H2(f) respectively to obtain the matched filtering results Y1(f) and Y2(f); inverse fast Fourier transform is performed on Y1(f) and Y2(f) respectively to obtain the time-domain matched signals y1(n) and y2(n);

[0056] S46. Perform cross-correlation operation:

[0057] With fixed reference sequences G1(n) and G2(n), the matched signal is slid along the sampling points and multiplied point-by-point with the corresponding Golay sequence at each delay position, and the results are accumulated to obtain the cross-correlation sequence R. k (τ);

[0058] By adding R1(τ) and R2(τ) point by point at the same delay position, the Rayleigh signal after sidelobe suppression is obtained;

[0059] S47, in S B (f) finds the frequency f with the largest amplitude. peak Subtracting the center frequency f0 from the Brillouin frequency shift yields the Brillouin shift: Δf B =f peak -f0, based on the strain coefficient K calibrated by the system.ε and temperature coefficient K T , will Δf B Convert to reference strain ε ref and reference temperature T ref ;

[0060] S48. Calculate the phase compensation amount: in The strain phase coefficient, The phase compensation amount is applied to R as the temperature phase coefficient. sum (τ), to obtain the phase correction signal R corr (τ);

[0061] S49. Extract R within the delay range of the physical location of the manhole cover or pole. corr (τ) local signal; based on the local signal of the most recent detection cycle, the average is calculated point by point to form a special background template B for manhole cover or pole section. bg (τ);

[0062] S410. Subtract the phase correction signal of the current period from the background template point by point to obtain the background-removed signal;

[0063] S411. Detect continuous sample segments whose amplitude exceeds the noise threshold in the background signal and use them as candidate segments for manhole cover or pole vibration events.

[0064] S412. Map the detected vibration event candidate segments to physical locations and event occurrence times, and record the vibration intensity; combine them to generate a zero-sidelobe time-series signal V for the vibration events of manhole covers or poles. zp (τ), save to the cache.

[0065] Optionally, S5 specifically includes:

[0066] S51. Read the zero-sidelobe vibration timing signal V after background subtraction from the current detection cycle buffer. zp (τ);

[0067] S52, V zp (τ) is divided into a continuous set of time frames according to the acquisition time sequence. The number of sampling points in each frame is a fixed set value, and there is no overlap between frames.

[0068] S53. For each frame: calculate its time-domain features and frequency-domain features;

[0069] S54. The similarity of the temporal and frequency domain features of two adjacent frames is evaluated separately, and the evaluation results are expressed as a ratio from 0 to 1.

[0070] S55. The temporal similarity and frequency similarity are weighted and synthesized according to a pre-set ratio coefficient to obtain the comprehensive similarity score between each two frames.

[0071] S56. In the spatial domain, select the previous and next manhole cover or pole detection points adjacent to the current manhole cover or pole location, and extract their zero sidelobe vibration signal sequences within the same detection cycle; compare the consistency of these adjacent manhole cover or pole signals with the current manhole cover or pole signal in waveform change trends and peak distribution to generate a spatial correlation score.

[0072] S57. Combine the inter-frame comprehensive similarity score and the spatial correlation score according to preset logical conditions for judgment:

[0073] When the overall inter-frame similarity is higher than the temporal similarity threshold and the spatial correlation score is higher than the spatial consistency threshold, the signal corresponding to the frame is determined to be a valid manhole cover or pole vibration event.

[0074] Conversely, it is determined to be an invalid event;

[0075] S58. Record the signal that is determined to be a valid event as an event unit;

[0076] S59. Combine all valid event units according to time sequence and spatial location of manhole cover or pole line to generate a spatiotemporal valid event set of manhole cover or pole line vibration signal and store it in the cache area.

[0077] Optionally, S6 specifically includes:

[0078] S61. Obtain the spatiotemporal validity event set of the vibration signal of the manhole cover or pole line generated in the current detection cycle, and extract the following event feature parameters:

[0079] N is the number of valid events for each manhole cover or pole location in the current period. evt ;

[0080] The rate of change ΔN in the number of valid events between two adjacent periods;

[0081] The mean vibration intensity A of each event in the current periodic event set avg ;

[0082] Spatial correlation mean R avg The mean inter-frame similarity S avg ;

[0083] S62. Extract the number of false alarms M corresponding to the above-mentioned manhole cover or pole location from historical detection records. false Number of missed detections M miss Configured parameters include Brillouin pulse width w B Transmit power PB With Rayleigh detection threshold T R Calculate the false negative rate and false positive rate of the current detection cycle relative to the historical cycle window;

[0084] S63. If ΔN<0, it means that the number of manhole cover or pole events in the current cycle has decreased significantly, and there are gap frames in two consecutive cycles. Combined with the trend of increasing missed detection rate, Brillouin pulse width update is performed.

[0085] S64, If A avg Significantly lower than the historical average strength of the manhole cover or pole location, or the spatial correlation score R. avg If the signal drops significantly, it is determined to be signal attenuation or increased local link loss, and the transmit power is updated.

[0086] S65, If the inter-frame similarity score S avg The decrease compared to the previous period exceeds the system fluctuation stability threshold, or the spatial correlation score R. avg If the rate of decline exceeds a set threshold, Rayleigh threshold adaptive update will be performed.

[0087] S66, Update the Brillouin pulse width Transmit power and Rayleigh threshold The transmission control module and the detection threshold control module are written, and the application is limited to the fiber segment corresponding to the current physical location of the manhole cover or pole in the next detection cycle, while the parameters of other segments remain unchanged.

[0088] Optionally, S7 specifically includes: extracting the location of the manhole cover or pole, occurrence time, vibration amplitude, temperature change, and correlation score of each valid event based on the spatiotemporal valid event set; converting these into absolute timestamps and finding the geographic coordinates; calculating the normalized vibration intensity and alarm confidence based on weighted coefficients; generating alarm data containing the location of the manhole cover or pole, timestamp, vibration intensity, temperature change, and confidence; forming an alarm dataset in chronological order; writing it into the alarm database; and outputting it to the monitoring system in real time through the monitoring platform interface.

[0089] The beneficial effects of this invention are:

[0090] (1) This invention achieves high-precision fusion and anti-interference detection of multi-source data by synchronously acquiring Rayleigh vibration and Brillouin strain temperature signals within the same detection cycle, and by using dual-polarized Golay complementary sequence transmission and zero sidelobe signal processing, which greatly improves the detection rate of abnormal events of manhole covers or poles and reduces the false alarm rate.

[0091] (2) This invention drives adaptive optimization of detection parameters through event set analysis based on spatiotemporal correlation. It can dynamically adjust pulse length, polarization mode, transmission power and detection threshold, so that the system can maintain stable and reliable monitoring performance under different traffic flow, climate and environmental interference.

[0092] (3) This invention generates multi-dimensional alarm data including the location of manhole cover or pole, timestamp, normalized vibration intensity, temperature change and alarm confidence, writes it into the database in real time and pushes it to the monitoring platform, thereby realizing rapid perception and accurate location of abnormal events, significantly shortening response time and improving the efficiency of municipal emergency response. Attached Figure Description

[0093] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0094] Figure 1 This is a structural framework diagram of the spatiotemporal validity verification and receiving system for vibration signals from manhole covers or poles proposed in this invention.

[0095] Figure 2 This is a flowchart of the spatiotemporal validity verification and receiving method for vibration signals from manhole covers or poles proposed in this invention.

[0096] Figure 3 This is a schematic diagram of the dual-polarized Golay complementary sequence generation and pulse emission control process proposed in this invention. Detailed Implementation

[0097] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0098] refer to Figure 1-3 The system for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines includes the following modules:

[0099] The data acquisition and scheduling module uses distributed optical fiber sensing links deployed in the monitoring areas of wells or poles to synchronously acquire Rayleigh scattering vibration echo signals and Brillouin scattering strain temperature echo signals in a time-division or wavelength-division multiplexing manner to generate raw acquisition data.

[0100] The transmission control module adjusts the pulse length, polarization state, and transmission power of the dual-polarized Golay complementary sequence pulse of Rayleigh detection based on the strain temperature distribution of Brillouin detection in the original acquired data, and transmits the adjusted pulse signal to the distributed optical fiber sensing link.

[0101] The spectral fusion module receives and adjusts the transmitted Rayleigh and Brillouin echo signals, extracts the Rayleigh scattering spectrum and performs matched filtering and complementary correlation processing, and simultaneously extracts the Brillouin scattering spectrum and generates reference data. In the same process, the reference data is used to perform phase compensation and interference suppression on the Rayleigh signal to generate a zero-sidelobe vibration timing signal.

[0102] The feature analysis module receives zero-sidelobe vibration time-series signals, extracts time-series and spectral features, calculates inter-frame similarity and correlation coefficients between adjacent nodes, and generates a spatiotemporally valid event set.

[0103] The parameter optimization module receives the spatiotemporal validity event set and historical detection errors, updates the Brillouin pulse width, transmit power and Rayleigh detection threshold, and feeds the updated parameters back to the transmit control module.

[0104] The alarm storage module receives spatiotemporal validity event sets and generates alarm data.

[0105] In this embodiment, the method for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines specifically includes:

[0106] S1. By deploying distributed optical fiber sensing links in the monitoring area of ​​the manhole or pole and covering the location of the manhole cover or pole, the Rayleigh scattering vibration echo signal generated by the vibration of the manhole cover or pole and the Brillouin scattering strain temperature echo signal of the optical fiber segment at the location of the manhole cover or pole are simultaneously acquired in time-division multiplexing or wavelength-division multiplexing mode to generate raw acquisition data.

[0107] S2. Based on the Brillouin strain temperature distribution in the original acquired data, periodically adjust the pulse length, polarization state, and transmission power of the dual-polarized Golay complementary sequence used for Rayleigh detection in the monitoring area of ​​manhole covers or pole lines to form the adjusted transmission parameters;

[0108] S3. Use the adjusted transmission parameters to transmit pulse signals to the distributed optical fiber sensing link and receive the corresponding Rayleigh and Brillouin echo signals.

[0109] S4. Extract the scattering spectrum from the Rayleigh echo signal and perform matched filtering and complementary correlation processing. Extract the scattering spectrum from the Brillouin echo signal and calculate the frequency shift and strain temperature reference data. In the same processing flow, use the reference data to perform phase compensation and interference suppression on the Rayleigh signal to obtain the zero sidelobe vibration time series signal corresponding to the vibration event of the manhole cover or pole.

[0110] S5. Extract time-series and spectral features from the zero-sidelobe vibration time-series signal, calculate the feature similarity between consecutive frames and the feature correlation coefficient of spatially adjacent manhole cover or pole detection points, and generate a spatiotemporal validity event set of the manhole cover or pole vibration signal.

[0111] S6. Based on the spatiotemporal validity event set and historical detection errors, update the Brillouin pulse width, transmission power and Rayleigh detection threshold;

[0112] S7. Generate alarm data containing the location of manhole cover or pole, timestamp, vibration intensity, temperature change and confidence level based on the spatiotemporal validity event set, and save it to the database. At the same time, output the alarm data to the monitoring platform.

[0113] In this embodiment, S1 specifically includes:

[0114] S11. Lay distributed optical fiber sensing links along a predetermined path in the monitoring area of ​​the manhole or pole, so that the optical fiber continuously covers each manhole cover or pole location. Connect one end to the optical pulse transmitter and the other end to the optical signal receiver, and measure the total length of the link to calibrate the position of the optical fiber segment corresponding to the manhole cover or pole.

[0115] S12. In each detection cycle, the optical pulse emitting device is triggered according to the set time interval to emit Rayleigh scattering detection optical pulse signal and Brillouin scattering detection optical pulse signal respectively. The two types of optical pulse signals are allocated different time intervals through time division multiplexing or different wavelengths through wavelength division multiplexing.

[0116] S13. When the optical pulse signal propagates in the optical fiber link, Rayleigh scattering echo signal and Brillouin scattering echo signal are generated in the optical fiber segment covering the manhole cover or pole. The optical signal receiving device receives the echo signal and performs photoelectric conversion.

[0117] S14. Record the signal propagation time corresponding to the optical fiber segment at the location of the manhole cover or pole, and calculate the distance between the location of the manhole cover or pole and the receiving end based on the speed of light propagation in the optical fiber.

[0118] S15. Mark the sampling time and spatial location of the Rayleigh scattering and Brillouin scattering signals collected from the manhole cover or pole location, and organize the collection results into a dataset arranged in time and spatial order.

[0119] S16. Store the dataset of manhole cover or pole location data for this inspection cycle in the data cache area.

[0120] In this embodiment, S2 specifically includes:

[0121] S21. Extract the Brillouin scattering echo signal of the optical fiber segment covering the manhole cover or pole location from the original acquired data, and analyze it to obtain the average strain value ε of the optical fiber segment in the current detection cycle. cur With average temperature value T cur And read the average strain value ε corresponding to the previous detection cycle. pre With average temperature value T pre ;

[0122] S22. Calculate the strain change rate and temperature change rate of the manhole cover or fiber optic segment in the current detection cycle:

[0123]

[0124] Where, ε min With T min To avoid the minimum reference value where the denominator is zero;

[0125] S23. Compare Δε and ΔT with the preset strain threshold ε respectively. th and temperature threshold T th By comparison, the pulse length adjustment amount L is obtained. adj Transmit power adjustment amount P adj and polarization state selection marker Pol sel The calculation rules are as follows:

[0126] When |Δε|≥ε th Or |ΔT|≥T th At that time, L adj >0;

[0127] When both are below the threshold, L adj <0;

[0128] P adj Proportional to |ΔT|, and P adj ≤P max ;

[0129] Pol sel Choose between horizontal or vertical polarization based on the instantaneous polarization state of the optical fiber in the manhole cover or pole section;

[0130] S24. Based on the final pulse length L final The code length N required to calculate the Golay sequence:

[0131]

[0132] Among them, f s v is the system sampling frequency. g The group velocity of light in the optical fiber is rounded up. Ensure the code length is an integer;

[0133] S25. Generate and bind dual-polarized Golay complementary sequences according to the following steps:

[0134] Initialize the base sequences A1 = [1] and B1 = [1];

[0135] Recursive expansion: A i+1 =[A i B i ],Bi+1 =[A i ,-B i ];

[0136] Repeat the expansion until the sequence length is ≥ N, and truncate the first N bits as G1 and G2;

[0137] Modulate G1 to a horizontally polarized light pulse, and modulate G2 to a vertically polarized light pulse;

[0138] Keep the polarization switching delay a fixed value τ pol And register the launch sequence in the launch control module;

[0139] S26. Set the final transmit power: P final =P base +P adj ; and (L final ,P final ,Pol sel The parameters G1 and G2 are combined to form the set of emission parameters for the current detection period.

[0140] S27. Synchronize the dual-polarized Golay complementary sequence pulse with the Brillouin detection reference pulse after parameter configuration, so that the two types of pulses are emitted in the same detection period and the polarization, pulse length and emission power are consistent; store the emission parameter set in the emission control module.

[0141] In this embodiment, S3 specifically includes:

[0142] S31. Retrieve the set of transmission parameters for the current detection cycle from the transmission control module, including the final pulse length L. final Final transmit power P final Polarization state selection marker Pol sel And the complementary sequences G1 and G2 of Golay;

[0143] S32. Control the pulse modulator at the transmitting end according to the L set in the parameter set. final The output light pulses are used to load G1 into the horizontal polarization channel and G2 into the vertical polarization channel, respectively, according to Pol sel The dual-polarized pulses are emitted in the specified sequence.

[0144] S33. Set the light source emission power to P. final And maintain a stable output during the pulse emission cycle;

[0145] S34. The pulse signal encoded with dual-polarized Golay complementary sequence is transmitted to the monitoring area of ​​the manhole cover or pole via an optical fiber link, corresponding to the optical fiber segment covering the location of the manhole cover or pole.

[0146] S35. At the same time as the transmitter transmits the pulse signal, the receiver synchronously starts the photodetector to receive the Rayleigh scattering echo signal and Brillouin scattering echo signal returned along the distributed optical fiber sensing link in real time.

[0147] S36. Perform photoelectric conversion on the received echo signal, extract and record the signal type (Rayleigh or Brillouin), polarization channel, and corresponding timestamp t for each sampling point. recv ;

[0148] S37. The echo signals of the fiber optic segments covering the manhole cover or pole location are individually marked and associated with the transmission parameters of this detection cycle, organized into the raw acquisition data of the current detection cycle, and stored in the buffer area.

[0149] In this embodiment, S4 specifically includes:

[0150] S41. Read the Rayleigh echo signal sequence r(n) and Brillouin echo signal sequence b(n) of the fiber segment covering the manhole cover or pole location from the current detection cycle buffer, where n is the sampling point index, r(n) represents the Rayleigh signal amplitude, and b(n) represents the Brillouin signal amplitude.

[0151] S42. Perform bandpass filtering and Hanning window weighting on r(n) and b(n) respectively:

[0152] The center frequency of the bandpass filter is set to the center frequency of the system's transmitted pulse, and its bandwidth covers the main lobe range of the pulse spectrum.

[0153] The sampling points are multiplied point by point with the bandpass filter coefficients and accumulated to perform convolution operations, removing noise components below the center frequency and parasitic components above the bandwidth limit;

[0154] Generate Hanning window weights w(n) with the same length as the signal, and multiply the filtered result point by point with w(n) to obtain the weighted signal r. w (n), b w (n);

[0155] S43, r w (n) Perform a Fast Fourier Transform to obtain the frequency domain complex spectrum R(f), take its amplitude spectrum and normalize it according to the maximum amplitude to obtain the Rayleigh scattering spectrum S. R (f), b w (n) Perform the same processing to obtain the Brillouin scattering spectrum S B (f), where f is the frequency index;

[0156] S44. Construct a dual-polarization matched filter based on the transmitted Golay complementary sequences G1(n) and G2(n). The frequency domain response is:

[0157]

[0158] Among them, H k (f) represents the frequency response of the matched filter; FFT(G) k (n)) is the frequency domain representation of the Golay sequence; conj[·] represents the complex conjugate operation; |·| represents the amplitude operation;

[0159] S45, S R (f) is multiplied point by point in the frequency domain with H1(f) and H2(f) respectively to obtain the matched filtering results Y1(f) and Y2(f); inverse fast Fourier transform is performed on Y1(f) and Y2(f) respectively to obtain the time-domain matched signals y1(n) and y2(n);

[0160] S46. Perform cross-correlation operation:

[0161] With fixed reference sequences G1(n) and G2(n), the matched signal is slid along the sampling points and multiplied point-by-point with the corresponding Golay sequence at each delay position, and the results are accumulated to obtain the cross-correlation sequence:

[0162]

[0163] Where τ is the delay index, N g The length of the Golay sequence;

[0164] Add R1(τ) and R2(τ) point by point at the same delay position to obtain the Rayleigh signal after sidelobe suppression: R sum (τ)=R1(τ)+R2(τ);

[0165] S47, in S B (f) finds the frequency f with the largest amplitude. peak Subtracting the center frequency f0 from the Brillouin frequency shift yields the Brillouin shift: Δf B =f peak -f0, based on the strain coefficient K calibrated by the system. ε and temperature coefficient K T , will Δf B Convert to reference strain ε ref and reference temperature T ref ;

[0166] S48. Calculate the phase compensation amount: in The strain phase coefficient, The phase compensation amount is applied to R as the temperature phase coefficient. sum (τ), to obtain the phase correction signal:

[0167] S49. Extract R within the delay range of the physical location of the manhole cover or pole. corr Local signal of (τ);

[0168] Based on the local signals from the most recent detection cycle, average the signals point by point to create a special background template for manhole covers or pole sections:

[0169]

[0170] S410. Subtract the phase correction signal of the current period from the background template point by point to obtain the background-removed signal;

[0171] S411. Detect consecutive sample segments in the background signal whose amplitude exceeds the noise threshold and use them as candidate segments for manhole cover or pole vibration events; the noise threshold is the mean of the background noise plus 3 times the standard deviation of the background noise, and the number of consecutive sample points exceeding the threshold is not less than 3.

[0172] S412. Map the detected vibration event candidate segments to physical locations and event occurrence times, and record the vibration intensity; combine them to generate a zero-sidelobe time-series signal V for the vibration events of manhole covers or poles. zp (τ), save to the cache.

[0173] In this embodiment, S5 specifically includes:

[0174] S51. Read the zero-sidelobe vibration timing signal V after background subtraction from the current detection cycle buffer. zp (τ);

[0175] S52, V zp (τ) is divided into a continuous set of time frames according to the acquisition time sequence. The number of sampling points in each frame is a fixed set value, and there is no overlap between frames.

[0176] S53, For each frame:

[0177] Calculate its time-domain characteristics: intra-frame average amplitude, peak amplitude, root mean square value, concentration of signal amplitude variation, and waveform shape characteristics;

[0178] Calculate frequency domain characteristics: After converting the frame signal to the frequency domain, the energy distribution, energy concentration locations, and frequencies of energy peaks are obtained;

[0179] S54. Evaluate the similarity of the temporal and frequency domain features of two adjacent frames respectively:

[0180] In the time domain, similarity is measured by comparing the relative closeness of various statistical feature values ​​of adjacent frames;

[0181] In the frequency domain, similarity is measured by comparing the similarity of the energy distribution patterns and energy peak positions of adjacent frames;

[0182] The evaluation results are expressed as a ratio from 0 to 1, with the closer the value is to 1, the higher the similarity.

[0183] S55. The time-domain similarity and frequency-domain similarity are weighted and synthesized according to a pre-set ratio coefficient to obtain a comprehensive similarity score between each two frames. This score reflects the consistency of the signal in terms of time variation and frequency spectrum variation.

[0184] S56. In the spatial domain, select the previous and next manhole cover or pole detection points adjacent to the current manhole cover or pole location, and extract their zero sidelobe vibration signal sequences within the same detection cycle; compare the consistency of these adjacent manhole cover or pole signals with the current manhole cover or pole signal in waveform change trends and peak distribution to obtain a spatial correlation score.

[0185] S57. Combine the inter-frame comprehensive similarity score and the spatial correlation score according to preset logical conditions for judgment:

[0186] When the overall inter-frame similarity is higher than the temporal similarity threshold and the spatial correlation score is higher than the spatial consistency threshold, the signal corresponding to the frame is determined to be a valid manhole cover or pole vibration event.

[0187] Conversely, it is determined to be an invalid event;

[0188] S58. Record the signals that are determined to be valid events as event units. Each event unit includes: the physical location of the manhole cover or pole, the time of the event, the inter-frame comprehensive similarity score, and the spatial correlation score.

[0189] S59. Combine all valid event units according to time sequence and spatial location of manhole cover or pole line to generate a spatiotemporal valid event set of manhole cover or pole line vibration signal, and store it in the event buffer area for subsequent alarm generation and data analysis modules to call.

[0190] In this embodiment, S6 specifically includes:

[0191] S61. Obtain the spatiotemporal validity event set of the vibration signal of the manhole cover or pole line generated in the current detection cycle, and extract the following event feature parameters:

[0192] N is the number of valid events for each manhole cover or pole location in the current period. evt ;

[0193] The rate of change ΔN in the number of valid events between two adjacent periods;

[0194] The mean vibration intensity A of each event in the current periodic event set avg ;

[0195] Spatial correlation mean Ravg The mean inter-frame similarity S avg ;

[0196] S62. Extract the number of false alarms M corresponding to the above-mentioned manhole cover or pole location from historical detection records. false Number of missed detections M miss Configured parameters include Brillouin pulse width w B Transmit power P B With Rayleigh detection threshold T R ;

[0197] The false negative rate and false positive rate of the current detection period relative to the historical period window are calculated as follows:

[0198] False negative rate = M miss / (N evt +M miss );

[0199] False alarm rate = M false / (M false +N evt );

[0200] S63. If ΔN < 0, it indicates that the number of manhole cover or pole events in the current cycle has significantly decreased, and there are gaps in frames between two consecutive cycles. Combined with the trend of increasing missed detection rate, Brillouin pulse width update is performed:

[0201] Set the compensation coefficient k w ;

[0202] The new pulse width is calculated as follows:

[0203]

[0204] Where, k w ,k ' w The correction scaling factor set for the system ensures that the width adjustment increment is proportional to the event discontinuity and the intensity of missed detections;

[0205] S64, If A avg Significantly lower than the historical average strength of the manhole cover or pole location, or the spatial correlation score R. avg If the signal drops significantly, it is determined to be signal attenuation or increased local link loss, and a transmit power increase operation is performed:

[0206] Calculate the difference ΔA = A avg,hist -A avg ;

[0207] Increase transmission power proportionally:

[0208]

[0209] Where, k P ,k R This is the power regulation coefficient;

[0210] S65, If the inter-frame similarity score S avg The decrease compared to the previous period exceeds the system fluctuation stability threshold, or the spatial correlation score R. avg If the rate of decline exceeds a set threshold, Rayleigh threshold adaptive update will be performed.

[0211] Calculate offset

[0212] The threshold has been updated as follows:

[0213]

[0214] Where, k T ,k ' R The adjustment ratio parameter set for the system ensures that the stability of threshold adjustment response event recognition decreases.

[0215] S66, Update the Brillouin pulse width Transmit power and Rayleigh threshold The transmission control module and the detection threshold control module are written, and the application is limited to the fiber segment corresponding to the current physical location of the manhole cover or pole in the next detection cycle, while the parameters of other segments remain unchanged.

[0216] In this embodiment, S7 specifically includes:

[0217] S71. From the spatiotemporal validity event set of the current detection cycle, read the unique identifier, manhole cover or pole physical location number, event occurrence time index, maximum vibration amplitude value, temperature change value, temporal similarity score and spatial correlation score of each valid event.

[0218] S72. Convert the event's time index into an absolute timestamp, set the time precision to milliseconds, and search for and obtain the geographic coordinates corresponding to the manhole cover or pole in the location mapping table based on the physical location number of the manhole cover or pole.

[0219] S73. Calculate the ratio of the maximum vibration amplitude value of each event to the reference vibration amplitude value calibrated by the system, and use the result as the normalized vibration intensity value. This normalized value is used to eliminate the comparability difference of vibration amplitude between different detection cycles.

[0220] S74. Calculate the alarm confidence level for each event:

[0221] Multiply the temporal similarity score of the event by the first weighting coefficient set by the system;

[0222] Multiply the spatial relevance score of the event by the second weighting coefficient set by the system;

[0223] The product of the two factors is added together to obtain the alarm confidence level of the event. The sum of the first weighting coefficient and the second weighting coefficient is 1, and the alarm confidence level ranges from 0 to 1.

[0224] S75. Combine the geographical location of the manhole cover or pole, absolute timestamp, normalized vibration intensity value, temperature change value and alarm confidence into an alarm recording unit. The alarm recording unit is a structured data entity composed of the above five fields.

[0225] S76. Sort all alarm record units in the current detection period in order of timestamp from earliest to latest to form the alarm dataset for this detection period.

[0226] S77. Write the alarm dataset into the alarm database table. The database table contains the following fields: alarm unique identifier, manhole cover or pole number, manhole cover or pole geographical coordinates, alarm timestamp, normalized vibration intensity, temperature change value, and alarm confidence level. The database writing process adopts a transaction commit mechanism to ensure data consistency and integrity.

[0227] S78. The alarm dataset is transmitted to the monitoring system in real time through the data interface of the monitoring platform. The output data format is structured text format and binary data format. The field content includes all five core fields of the alarm record unit.

[0228] S79. Generate an alarm data output log. The log records the output time, the number of output data entries, and the output target information. Store the log file in the system log management module for subsequent alarm tracing and statistical analysis.

[0229] Example 1:

[0230] To verify the effectiveness of the technical solution of this invention in a real environment, the spatiotemporal validity verification and receiving system for vibration signals from manhole covers or poles of this invention was deployed in a key municipal road manhole cover or pole safety monitoring project in a coastal port city. This city experiences heavy port traffic, with daily traffic exceeding 40,000 vehicles on the main roads and port connecting roads, of which heavy freight vehicles account for approximately 35%. Vehicle impacts, combined with the humid and salty coastal climate, make manhole covers or poles prone to loosening, subsidence, or detachment, and most anomalies cannot be detected in time during manual inspections. The pilot area included the main port road and two adjacent branch roads, totaling 2.8 kilometers in length, covering 240 manhole covers or poles, including 156 round cast iron manhole covers or poles and 84 anti-theft rectangular manhole covers or poles, all of which were connected to the fiber optic sensing monitoring system of this invention.

[0231] During deployment, the data acquisition and scheduling module continuously lays distributed fiber optic sensing links along the road, reserving a 2-meter fiber optic slack at each manhole cover or pole location to ensure signal coverage without blind spots. The detection cycle is set to 2 minutes, employing time-division multiplexing to sequentially transmit Rayleigh and Brillouin detection pulses within the same cycle, with a 2.5-millisecond interval between the two types of pulses to ensure time synchronization between the vibration signal and the strain-temperature signal. The transmission control module adjusts the length of the dual-polarized Golay complementary sequence pulses in real time based on temperature fluctuations (daily variation range of ±3.8℃ in the initial pilot phase) and strain changes (±12με) obtained from Brillouin detection, dynamically switching between 40 and 48 nanoseconds, and switching between horizontal and vertical polarization at a 0.5-second cycle to ensure signal stability even under high humidity, low temperature, and heavy vehicle traffic.

[0232] In the signal processing stage, the spectral fusion module uses complementary correlation and matched filtering to suppress the sidelobes of the Rayleigh signal and combines it with Brillouin strain-temperature data for phase compensation, reducing the original sidelobe peak value from -17dB to -31dB, effectively reducing the crosstalk between adjacent manhole covers or poles (8-12 meters range). The feature analysis module calculates the inter-frame similarity and spatial correlation of the vibration signal of each manhole cover or pole. In the initial pilot phase, the inter-frame similarity threshold was set to 0.78 and the spatial correlation threshold was set to 0.85. Events below the threshold were marked as potential anomalies, and the parameter optimization module adjusted the detection parameters based on the historical detection records of the event, such as increasing the Brillouin pulse width, increasing the transmission power, or lowering the detection threshold.

[0233] During the three-month pilot operation, the system of this invention provided continuous 24 / 7 monitoring, which was compared with the traditional manual inspection method (every 7-10 days). One group of 120 manhole covers or poles covered by manual inspection continued to be inspected in the original manner, while another group of 120 manhole covers or poles were monitored in real time by the system of this invention. The comparison results are as follows:

[0234] Table 1 Comparison of the effects of traditional manual inspection and the system of the present invention

[0235] index Traditional manual inspection This invention system Number of anomalies detected (incidents) 23 37 Average time to detect anomalies (hours) 46 7 False alarm rate 16.8％ 7.1％ underreporting rate 26.4％ 11.5％ Event response time (hours) 34 12 Completion rate 83.2％ 93.7％ Incidents / emergencies during the pilot program (number of incidents) 3 0

[0236] The data shows that the system of this invention improved the number of anomaly detections by approximately 60.9% compared to traditional methods, mainly due to the reduction of missed detections caused by real-time monitoring. The average anomaly detection time was shortened from the traditional 46 hours to 7 hours, significantly reducing the exposure time of potential hazards. The false alarm rate decreased from 16.8% to 7.1%, thanks to the system's introduction of strain temperature data during detection to eliminate non-fault-related vibrations caused by temperature differences and thermal expansion and contraction. The false alarm rate decreased by approximately 56%, indicating that the system maintains a high detection rate even in complex traffic environments. The event response time was shortened to less than 12 hours, enabling municipal maintenance teams to handle hazards more quickly, with a completion rate of 93.7%. During the entire pilot period, the monitoring team of this invention did not experience any accidents or incidents related to manhole covers or poles, while the traditional inspection team still experienced 3 minor accidents.

[0237] In a typical case occurring in the early morning of April 18, 2025, a rectangular anti-theft manhole cover or pole on a main road in the port area experienced loosening of its fixing bolts due to continuous driving by heavy trucks. During a single data acquisition, the system detected a significant difference between the vibration spectrum characteristics of the manhole cover or pole and its historical characteristics, with the inter-frame similarity dropping to 0.54 (below the set threshold of 0.78) and the spatial correlation score being only 0.39 (below the set threshold of 0.85). The zero-sidelobe signal output by the spectral fusion module showed an abnormal peak duration that was relatively long and highly consistent with the strain data measured by Brillouin. The parameter optimization module immediately marked the event as high-risk and generated an alarm message with a confidence level of 0.91 within 90 seconds, pushing it to the municipal monitoring center. After receiving the alarm, maintenance personnel replaced and reinforced the manhole cover or pole by 8:00 AM that same day, avoiding traffic risks during the morning rush hour. If the original manual inspection cycle had been followed, this problem might not have been discovered for 2-3 days.

[0238] In summary, this invention, by simultaneously acquiring multiple source signals within the same detection cycle, utilizing dual-polarized Golay complementary sequence dynamic control, introducing strain temperature compensation in spectral fusion, and combining spatiotemporal correlation analysis and historical data for adaptive optimization of detection parameters, enables the system to maintain high detection accuracy and low false alarm rate even in complex and variable municipal road environments, significantly improving the efficiency of detecting and handling anomalies in manhole covers or poles.

[0239] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A system for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines, characterized in that, Includes the following modules: The data acquisition and scheduling module uses distributed optical fiber sensing links deployed in the monitoring areas of wells or poles to synchronously acquire Rayleigh scattering vibration echo signals and Brillouin scattering strain temperature echo signals in a time-division or wavelength-division multiplexing manner to generate raw acquisition data. The transmission control module adjusts the pulse length, polarization state, and transmission power of the dual-polarized Golay complementary sequence pulse of Rayleigh detection based on the strain temperature distribution of Brillouin detection in the original acquired data, and transmits the adjusted pulse signal to the distributed optical fiber sensing link. The spectral fusion module receives and adjusts the transmitted Rayleigh and Brillouin echo signals, extracts the Rayleigh scattering spectrum and performs matched filtering and complementary correlation processing, and simultaneously extracts the Brillouin scattering spectrum and generates reference data. In the same process, the reference data is used to perform phase compensation and interference suppression on the Rayleigh signal to generate a zero-sidelobe vibration timing signal. The feature analysis module receives zero-sidelobe vibration time-series signals, extracts time-series and spectral features, calculates inter-frame similarity and correlation coefficients between adjacent nodes, and generates a spatiotemporally valid event set. The parameter optimization module receives the spatiotemporal validity event set and historical detection errors, updates the Brillouin pulse width, transmit power and Rayleigh detection threshold, and feeds the updated parameters back to the transmit control module. The alarm storage module receives spatiotemporal validity event sets and generates alarm data.

2. A method for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines, characterized in that, Includes the following steps: S1. By deploying distributed optical fiber sensing links in the monitoring area of ​​the manhole or pole and covering the location of the manhole cover or pole, the Rayleigh scattering vibration echo signal generated by the vibration of the manhole cover or pole and the Brillouin scattering strain temperature echo signal of the optical fiber segment at the location of the manhole cover or pole are simultaneously acquired in time-division multiplexing or wavelength-division multiplexing mode to generate raw acquisition data. S2. Based on the Brillouin strain temperature distribution in the original acquired data, periodically adjust the pulse length, polarization state, and transmission power of the dual-polarized Golay complementary sequence used for Rayleigh detection in the monitoring area of ​​manhole covers or pole lines to form the adjusted transmission parameters; S3. Use the adjusted transmission parameters to transmit pulse signals to the distributed optical fiber sensing link and receive the corresponding Rayleigh and Brillouin echo signals. S4. Extract the scattering spectrum from the Rayleigh echo signal and perform matched filtering and complementary correlation processing. Extract the scattering spectrum from the Brillouin echo signal and calculate the frequency shift and strain temperature reference data to obtain the zero sidelobe vibration time series signal corresponding to the vibration event of the manhole cover or pole. S5. Extract time-series and spectral features from the zero-sidelobe vibration time-series signal, calculate the feature similarity between consecutive frames and the feature correlation coefficient of spatially adjacent manhole cover or pole detection points, and generate a spatiotemporal validity event set of the manhole cover or pole vibration signal. S6. Based on the spatiotemporal validity event set and historical detection errors, update the Brillouin pulse width, transmission power and Rayleigh detection threshold; S7. Generate alarm data containing the location of manhole cover or pole, timestamp, vibration intensity, temperature change and confidence level based on the spatiotemporal validity event set, and save it to the database. At the same time, output the alarm data to the monitoring platform.

3. The method for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines according to claim 2, characterized in that, S1 specifically includes: S11. Lay distributed optical fiber sensing links along a predetermined path in the monitoring area of ​​the manhole or pole, so that the optical fiber continuously covers each manhole cover or pole location. Connect one end to the optical pulse transmitter and the other end to the optical signal receiver, and measure the total length of the link to calibrate the position of the optical fiber segment corresponding to the manhole cover or pole. S12. In each detection cycle, the optical pulse emitting device is triggered according to the set time interval to emit Rayleigh scattering detection optical pulse signal and Brillouin scattering detection optical pulse signal respectively. The two types of optical pulse signals are allocated different time intervals through time division multiplexing or different wavelengths through wavelength division multiplexing. S13. When the optical pulse signal propagates in the optical fiber link, Rayleigh scattering echo signal and Brillouin scattering echo signal are generated in the optical fiber segment covering the manhole cover or pole. The optical signal receiving device receives the echo signal and performs photoelectric conversion. S14. Record the signal propagation time corresponding to the optical fiber segment at the location of the manhole cover or pole, and calculate the distance between the location of the manhole cover or pole and the receiving end based on the speed of light propagation in the optical fiber. S15. Mark the sampling time and spatial location of the Rayleigh scattering and Brillouin scattering signals collected from the manhole cover or pole location, and organize the collection results into raw collection data arranged in time and spatial order.

4. The method for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines according to claim 2, characterized in that, S2 specifically includes: S21. Extract the Brillouin scattering echo signal of the optical fiber segment covering the manhole cover or pole location from the original acquired data to obtain the average strain value ε of the optical fiber segment in the current detection cycle. cur With average temperature value T cur And read the average strain value ε corresponding to the previous detection cycle. pre With average temperature value T pre ; S22. Calculate the strain change rate Δε and temperature change rate ΔT of the manhole cover or fiber optic segment in the current detection cycle, and compare them with the preset strain threshold ε. th and temperature threshold T th Compare and determine the pulse length adjustment amount L. adj Transmit power adjustment amount P adj and polarization state selection marker Pol sel : When |Δε|≥ε th Or |ΔT|≥T th At that time, L adj >0; When both are below the threshold, L adj <0; P adj Proportional to |ΔT|, and P adj ≤P max ; Pol sel Choose between horizontal or vertical polarization based on the instantaneous polarization state of the optical fiber in the manhole cover or pole section; S23. Based on the adjusted final pulse length L final and the system sampling frequency f s With fiber group velocity v g Determine the code length N required for the Golay sequence to ensure that the pulse covers the spatial range of the manhole cover or pole section in the optical fiber; S24. Generate and bind dual-polarized Golay complementary sequences: S241. Initialize two base sequences; S242. Generate higher-order sequences sequentially according to the recursive expansion rule until the sequence length reaches or exceeds N; S243. Extract the first N bits as the final complementary sequences G1 and G2; S244. Modulate G1 to a horizontally polarized light pulse and G2 to a vertically polarized light pulse; S245, Keep the polarization switching delay at a fixed value τ pol And register the launch sequence in the launch control module; S25. Complete pulse parameter configuration: Set the final pulse length L final =L base +L adj Set the final transmit power P final =P base +P adj , will L final P final Pol sel Combined with the generated G1 and G2, they form the emission parameter set for the current detection period; S26. Store the set of launch parameters in the launch control module.

5. The method for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines according to claim 2, characterized in that, S3 specifically includes: S31. Retrieve the set of launch parameters for the current detection period from the launch control module; S32. Control the pulse modulator at the transmitting end according to the L set in the parameter set. final The output light pulses are used to load G1 into the horizontal polarization channel and G2 into the vertical polarization channel, respectively, according to Pol sel The dual-polarized pulses are emitted in the specified sequence. S33. Set the light source emission power to P. final And maintain a stable output during the pulse emission cycle; S34. The pulse signal encoded with dual-polarized Golay complementary sequence is transmitted to the monitoring area of ​​the manhole cover or pole via an optical fiber link, corresponding to the optical fiber segment covering the location of the manhole cover or pole. S35. At the same time as the transmitter transmits the pulse signal, the receiver synchronously starts the photodetector to receive the Rayleigh scattering echo signal and Brillouin scattering echo signal returned along the distributed optical fiber sensing link in real time. S36. Perform photoelectric conversion on the received echo signal, extract and record the signal type (Rayleigh or Brillouin), polarization channel, and corresponding timestamp t for each sampling point. recv ; S37. The echo signals of the fiber optic segments covering the manhole cover or pole location are individually marked and associated with the transmission parameters of this detection cycle, organized into the raw acquisition data of the current detection cycle, and stored in the data buffer area.

6. The method for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines according to claim 2, characterized in that, S4 specifically includes: S41. Read the Rayleigh echo signal sequence r(n) and Brillouin echo signal sequence b(n) covering the fiber segment at the location of the manhole cover or pole from the current detection cycle buffer. S42. Perform bandpass filtering and Hanning window weighting on r(n) and b(n) respectively to generate the weighted signal r. w (n), b w (n); S43, r w (n) Perform a Fast Fourier Transform to obtain the frequency domain complex spectrum R(f), and take r w (n) The amplitude spectrum is normalized according to the maximum amplitude to obtain the Rayleigh scattering spectrum S. R (f), b w (n) Perform the same processing to obtain the Brillouin scattering spectrum S B (f), where f is the frequency index; S44. Construct a dual-polarization matched filter based on the transmitted Golay complementary sequences G1(n) and G2(n). The frequency domain response is: k = 1, 2; where H k (f) represents the frequency response of the matched filter; FFT(G) k (n)) is the frequency domain representation of the Golay sequence; conj[·] represents the complex conjugate operation; |·| represents the amplitude operation; S45, S R (f) is multiplied point by point in the frequency domain with H1(f) and H2(f) respectively to obtain the matched filtering results Y1(f) and Y2(f); inverse fast Fourier transform is performed on Y1(f) and Y2(f) respectively to obtain the time-domain matched signals y1(n) and y2(n); S46. Perform cross-correlation operation: With fixed reference sequences G1(n) and G2(n), the matched signal is slid along the sampling points and multiplied point-by-point with the corresponding Golay sequence at each delay position, and the results are accumulated to obtain the cross-correlation sequence R. k (τ); By adding R1(τ) and R2(τ) point by point at the same delay position, the Rayleigh signal after sidelobe suppression is obtained; S47, in S B (f) finds the frequency f with the largest amplitude. peak Subtracting the center frequency f0 from the Brillouin frequency shift yields the Brillouin shift: Δf B =f peak -f0, based on the strain coefficient K calibrated by the system. ε and temperature coefficient K T , will Δf B Convert to reference strain ε ref and reference temperature T ref ; S48. Calculate the phase compensation amount: in The strain phase coefficient, The phase compensation amount is applied to R as the temperature phase coefficient. sum (τ), to obtain the phase correction signal R corr (τ); S49. Extract R within the delay range of the physical location of the manhole cover or pole. corr (τ) local signal; based on the local signal of the most recent detection cycle, the average is calculated point by point to form a special background template B for manhole cover or pole section. bg (τ); S410. Subtract the phase correction signal of the current period from the background template point by point to obtain the background-removed signal; S411. Detect continuous sample segments whose amplitude exceeds the noise threshold in the background signal and use them as candidate segments for manhole cover or pole vibration events. S412. Map the detected vibration event candidate segments to physical locations and event occurrence times, and record the vibration intensity; combine them to generate a zero-sidelobe time-series signal V for the vibration events of manhole covers or poles. zp (τ), save to the cache.

7. The method for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines according to claim 2, characterized in that, S5 specifically includes: S51. Read the zero-sidelobe vibration timing signal V after background subtraction from the current detection cycle buffer. zp (τ); S52, V zp (τ) is divided into a continuous set of time frames according to the acquisition time sequence. The number of sampling points in each frame is a fixed set value, and there is no overlap between frames. S53. For each frame: calculate its time-domain features and frequency-domain features; S54. The similarity of the temporal and frequency domain features of two adjacent frames is evaluated separately, and the evaluation results are expressed as a ratio from 0 to 1. S55. The temporal similarity and frequency similarity are weighted and synthesized according to a pre-set ratio coefficient to obtain the comprehensive similarity score between each two frames. S56. In the spatial domain, select the previous and next manhole cover or pole detection points adjacent to the current manhole cover or pole location, and extract their zero sidelobe vibration signal sequences within the same detection cycle; compare the consistency of these adjacent manhole cover or pole signals with the current manhole cover or pole signal in waveform change trends and peak distribution to generate a spatial correlation score. S57. Combine the inter-frame comprehensive similarity score and the spatial correlation score according to preset logical conditions for judgment: When the overall inter-frame similarity is higher than the temporal similarity threshold and the spatial correlation score is higher than the spatial consistency threshold, the signal corresponding to the frame is determined to be a valid manhole cover or pole vibration event. Conversely, it is determined to be an invalid event; S58. Record the signal that is determined to be a valid event as an event unit; S59. Combine all valid event units according to time sequence and spatial location of manhole cover or pole line to generate a spatiotemporal valid event set of manhole cover or pole line vibration signal and store it in the cache area.

8. The method for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines according to claim 2, characterized in that, S6 specifically includes: S61. Obtain the spatiotemporal validity event set of the vibration signal of the manhole cover or pole line generated in the current detection cycle, and extract the following event feature parameters: N is the number of valid events for each manhole cover or pole location in the current period. evt ; The rate of change ΔN in the number of valid events between two adjacent periods; The mean vibration intensity A of each event in the current periodic event set avg ; Spatial correlation mean R avg The mean inter-frame similarity S avg ; S62. Extract the number of false alarms M corresponding to the above-mentioned manhole cover or pole location from historical detection records. false Number of missed detections M miss Configured parameters include Brillouin pulse width w B Transmit power P B With Rayleigh detection threshold T R Calculate the false negative rate and false positive rate of the current detection cycle relative to the historical cycle window; S63. If ΔN<0, it means that the number of manhole cover or pole events in the current cycle has decreased significantly, and there are gap frames in two consecutive cycles. Combined with the trend of increasing missed detection rate, Brillouin pulse width update is performed. S64, If A avg Significantly lower than the historical average strength of the manhole cover or pole location, or the spatial correlation score R. avg If the signal drops significantly, it is determined to be signal attenuation or increased local link loss, and the transmit power is updated. S65, If the inter-frame similarity score S avg The decrease compared to the previous period exceeds the system fluctuation stability threshold, or the spatial correlation score R. avg If the rate of decline exceeds a set threshold, Rayleigh threshold adaptive update will be performed. S66, Update the Brillouin pulse width Transmit power and Rayleigh threshold The transmission control module and the detection threshold control module are written, and the application is limited to the fiber segment corresponding to the current physical location of the manhole cover or pole in the next detection cycle, while the parameters of other segments remain unchanged.

9. The method for verifying the spatiotemporal validity of vibration signals from manhole covers or pole lines according to claim 2, characterized in that, S7 specifically includes: extracting the location of the manhole cover or pole, the time of occurrence, the vibration amplitude, the temperature change, and the correlation score for each valid event based on the spatiotemporal valid event set; converting these into absolute timestamps and finding the geographic coordinates; calculating the normalized vibration intensity and the alarm confidence level based on the weighted coefficient; generating alarm data containing the location of the manhole cover or pole, the timestamp, the vibration intensity, the temperature change, and the confidence level; forming an alarm dataset in chronological order; writing it into the alarm database; and outputting it to the monitoring system in real time through the monitoring platform interface.

Images