Optical cable route general survey method and device based on optical fiber vibration sensing

Abstract

The invention relates to the technical field of optical cable route general survey, and discloses an optical cable route general survey method and device based on optical fiber vibration sensing, and the method comprises the steps: knocking at an optical cable pile point, and remotely controlling a pulse light source to send an optical pulse to an optical cable; collecting a vibration signal of the optical fiber, and dynamically adjusting the pulse width of the optical pulse; recognizing a knocking event in the vibration signal, and intercepting a knocking vibration fragment from the vibration signal; calculating characteristic parameters of the knocking vibration segment, and performing knocking feedback based on the characteristic parameters; calculating the optical cable length of the optical cable pile point, and recording latitude and longitude coordinates of the optical cable pile point; and determining the optical cable trend of the optical cable pile point through knocking, and drawing a routing diagram of the optical cable based on the latitude and longitude coordinates of the optical cable pile point, the optical cable length and the optical cable trend. According to the invention, the general survey efficiency of the optical cable route is improved, automatic drawing and visual display of the optical cable route are realized, and an optical cable network is convenient to manage and maintain.

Description

Technical Field

[0001] The present invention relates to the technical field of optical cable route survey, and in particular to an optical cable route survey method and device based on optical fiber vibration sensing. Background Art

[0002] In the traditional survey of optical cable routes, manual field surveys and some simple test equipment are mainly relied on. The early method was usually for construction personnel to conduct field visits along possible optical cable routes to check the optical cable identification and related facilities, but this method is extremely inefficient, especially in the case of long distances and complex terrain, and requires a lot of manpower and time costs. In recent years, some test equipment based on electrical principles have emerged, such as using similar principles of cable fault testers to detect optical cables. However, these devices have many limitations when applied to optical cables. On the one hand, electrical test methods are easily affected by external electromagnetic interference, resulting in inaccurate test results. On the other hand, electrical test equipment has low detection sensitivity for some minor faults and potential problems of optical cables, and it is difficult to meet the requirements of modern communications for high-precision detection of optical cables.

[0003] In terms of optical cable routing positioning, existing technical means also have obvious deficiencies. Traditional methods often lack accurate positioning means when determining the direction of optical cables. For example, in a complex underground pipe network environment, optical cables are intertwined with other pipelines, and it is easy to deviate if the direction of optical cables is judged only by manual experience and simple markings. Moreover, when the optical cable is buried deep or the surrounding environment changes (such as soil settlement, construction disturbance, etc.), it is difficult for traditional positioning methods to accurately determine the actual position of the optical cable, which increases the difficulty of optical cable maintenance and troubleshooting. In the field of optical cable vibration detection, although there are some studies and applications of optical fiber vibration sensors, there are still many problems in the actual optical cable route survey. Existing optical fiber vibration sensors have weak signal recognition capabilities when facing complex environmental noise. For example, in environments such as strong winds and near busy roads, the noise generated by environmental vibrations will mask the vibration signals of the optical cable itself, making it difficult to conduct an effective optical cable route survey based on vibration detection. In addition, the analysis and processing of vibration signals are not sophisticated enough, and it is impossible to accurately extract key characteristic parameters that can reflect the status and routing information of the optical cable, resulting in a lack of accuracy and reliability in the judgment of the optical cable route.

[0004] In summary, the existing optical cable route survey technology has many defects in terms of efficiency, accuracy, anti-interference ability and precision, and it is difficult to adapt to the needs of the rapid development of the modern communications industry. New technological breakthroughs are needed to solve these problems.

[0005] For example, the Chinese patent application with publication number CN118890094A discloses an optical cable survey instrument and an optical cable survey method and system, wherein the optical cable survey instrument includes a vibration sensing module, a signal amplifying circuit, a controllable switch module, a signal detection circuit, and an optical fiber interface connected to the sensing end of the vibration sensing module, wherein the signal interface of the vibration sensing module is electrically connected to the signal detection circuit through the signal amplifying circuit and the controllable switch module respectively, the signal detection circuit is used to determine and collect vibration state information of the optical cable to be surveyed at the target routing node based on the photoelectric detection signal, and the controllable switch module is used to control the electrical connection between the signal amplifying circuit and the signal detection circuit. This application can not only ensure the accuracy of the optical cable survey results by controlling the on and off of the controllable switch module, but also determine the identity of the optical cable connected to the optical cable survey instrument from multiple optical cables to be surveyed, thereby simplifying the identity confirmation process.

[0006] For example, a Chinese patent application with publication number CN117579138A discloses an optical cable intelligent routing survey instrument, which includes a device host, a tested optical fiber and a vibration motor; the device host is connected to the tested optical fiber, the tested optical fiber is laid in a dispersed manner, the vibration motor is placed on one side of the laid tested optical fiber, the vibration motor is used to generate a vibration frequency to affect the transmission of the tested optical fiber, a laser is arranged in the device host, the laser is connected to the tested optical fiber, the laser is used to transmit an optical signal 1 to the tested optical fiber, the optical signal 1 is transmitted in the tested optical fiber, and is affected by the vibration frequency generated by the vibration motor to form an optical signal 2, the OTDR detection module and the vibration detection module are used to demodulate the optical signal 2 transmitted by the tested optical fiber and obtain data results, the data results include the breakpoint position and the direction of the tested light; the mobile terminal is used to receive and view the data results transmitted by the device host. The invention has the effect of determining the breakpoint position and reducing human resources.

[0007] The above patent applications all have the problem raised by the background technology: when facing complex environmental noise, the signal recognition capability is weak.

[0008] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgement or any form of suggestion that the information constitutes the prior art already known to ordinary technicians in this field. Summary of the invention

[0009] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method and device for surveying optical cable routes based on optical fiber vibration sensing, so as to improve the survey efficiency of optical cable routes and realize automatic drawing and intuitive display of optical cable routes.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions: On the one hand, the present invention provides a method for surveying optical cable routes based on optical fiber vibration sensing, comprising the following steps: S1: tap on the optical cable stake and remotely control the pulse light source to send optical pulses to the optical cable; S2: collecting a vibration signal of the optical fiber, and dynamically adjusting the pulse width of the optical pulse based on a vibration parameter of the vibration signal; S3: identifying a knocking event in the vibration signal, and intercepting a knocking vibration segment from the vibration signal; the knocking vibration segment is a segment of the vibration signal corresponding to the knocking event; S4: calculating characteristic parameters of the knocking vibration segment, and performing knocking feedback based on the characteristic parameters; S5: Calculating the length of the optical cable at the optical cable stake point based on the knocking vibration segment, and recording the longitude and latitude coordinates of the optical cable stake point; S6: Determine the direction of the optical cable at the optical cable stake point by tapping, and draw a routing map of the optical cable based on the latitude and longitude coordinates of the optical cable stake point, the length of the optical cable, and the direction of the optical cable.

[0011] As a preferred solution of the optical cable route survey method based on optical fiber vibration sensing of the present invention, wherein: the vibration signal of the optical fiber is a backscattered Rayleigh signal of a light pulse; The vibration parameters of the vibration signal include an amplitude parameter and a frequency parameter; the vibration parameters are calculated as follows: filtering and denoising the vibration signal; uniformly sampling the vibration signal to obtain the amplitudes of N sampling points; calculating the average of the amplitudes of the N sampling points as the amplitude parameter; performing frequency domain transformation on the vibration signal, and extracting the peak frequency of the vibration signal as the frequency parameter.

[0012] As a preferred solution of the optical cable route survey method based on optical fiber vibration sensing of the present invention, the method of dynamically adjusting the pulse width of the optical pulse is as follows: Set the amplitude threshold and frequency threshold of the vibration signal; calculate the adjustment amount of the pulse width; Set the maximum value of the pulse width, denoted as ; Set the minimum value of pulse width, recorded as ; Adjust the pulse width, the formula is as follows: ; Wherein, w represents the adjusted pulse width of the optical pulse; Indicates the initial value of the pulse width, Indicates the adjustment amount of the pulse width; if w is greater than , then set the pulse width to ; If w is less than , then set the pulse width to .

[0013] As a preferred solution of the optical cable route survey method based on optical fiber vibration sensing of the present invention, the calculation formula of the adjustment amount of the pulse width is as follows: ; in, represents the adjustment amount of the pulse width; A represents the amplitude parameter; represents the amplitude threshold; f represents the frequency parameter; represents the frequency threshold; Indicates the first adjustment factor. When the amplitude parameter A is greater than the amplitude threshold , The value is 1, otherwise, The value is 0; Represents the second adjustment factor. When the frequency parameter f is greater than the frequency threshold , The value is 1, otherwise, The value is 0; represents the weight coefficient of the amplitude parameter, Represents the weight coefficient of the frequency parameter.

[0014] As a preferred solution of the optical cable route survey method based on optical fiber vibration sensing of the present invention, wherein: the characteristic parameters of the knocking vibration segment include average amplitude, instability, and attenuation speed; The average amplitude of the cable pile point is recorded as , is the mean amplitude of the striking vibration segment; the instability is recorded as , is the standard deviation of the amplitude of the striking vibration segment; the decay rate is recorded as , calculated as follows: Select two observation points on the optical cable on the same side of the optical cable pile point, denoted as P and Q respectively; the distance between point P and the optical cable pile point is , the distance between point Q and the cable pile point is ,and Greater than ; Locate points P and Q in the vibration signal and record the amplitude at point P, denoted as ; record the amplitude at point Q, denoted as ; Calculate the decay rate using the following formula: .

[0015] As a preferred solution of the optical cable route survey method based on optical fiber vibration sensing of the present invention, wherein: the knocking feedback includes knocking position feedback and knocking force feedback; The tapping position feedback is specifically as follows: Set the decay speed threshold, denoted as If the decay rate Greater than , then feedback will be given as a prompt to change the tapping position; The tapping force feedback is as follows: Set the minimum threshold of the average amplitude, denoted as ; Set the maximum threshold of the average amplitude, denoted as ; Set the instability threshold, denoted as ; If the average amplitude Less than , and the decay rate No more than , then feedback will be given to increase the tapping force; If the average amplitude Greater than , and the instability Greater than , then the feedback will be a prompt to reduce the tapping force.

[0016] As a preferred solution of the optical cable route survey method based on optical fiber vibration sensing of the present invention, the characteristic parameters of the knocking vibration segment also include a vibration frequency ratio; the vibration frequency ratio is recorded as , the calculation method is as follows: perform spectrum analysis on the knocking vibration segment and extract the peak frequency; the vibration frequency ratio is the average amplitude Ratio to peak frequency; The tapping feedback also includes tapping frequency feedback, which is as follows: Set the minimum threshold of the frequency ratio, denoted as ; Set the maximum threshold of the frequency ratio, denoted as If the frequency ratio Less than , then feedback will be given to reduce the tapping frequency; If the frequency ratio Greater than , then the prompt to increase the tapping frequency will be fed back.

[0017] As a preferred solution of the optical cable route survey method based on optical fiber vibration sensing of the present invention, the method of determining the direction of the optical cable at the optical cable stake point by tapping is as follows: Taking the optical cable stake point as the center, select a test point within a radius of R; Tap each test point, and extract the tapping vibration segment corresponding to each test point based on the vibration signal; Calculate the average amplitude and frequency of the knocking vibration segment corresponding to each test point; Calculate the deviation between each test point and the optical cable stake point; mark the test point with the smallest deviation from the optical cable stake point as a routing point; the calculation formula of the deviation is as follows: ; Among them, g represents the deviation between any test point and the optical cable stake point; Represents the average amplitude of any test point; Indicates the main frequency of any test point; Indicates the frequency of the optical cable stake point; Calculating the length of the optical cable at the routing point and recording the longitude and latitude coordinates of the routing point; The direction of the optical cable at the optical cable point is determined based on the optical cable length at the optical cable point and the optical cable length at the routing point.

[0018] As a preferred solution of the optical cable route survey method based on optical fiber vibration sensing of the present invention, wherein: the longitude and latitude coordinates of the optical cable stake point are obtained by a mobile terminal containing a GPS positioning module held by a construction worker; the optical cable length of the optical cable stake point is the length of the optical cable segment between the optical cable stake point and the transmitting end; the transmitting end is the optical cable port where a pulse light source sends an optical pulse to the optical cable; the optical cable length of the routing point is the length of the optical cable segment between the routing point and the transmitting end; The method for determining the direction of the optical cable at the optical cable point based on the optical cable length of the optical cable point and the optical cable length of the routing point is as follows: if the optical cable length of the optical cable point is greater than the optical cable length of the routing point, the optical cable direction of the optical cable point is to extend from the routing point to the optical cable point; if the optical cable length of the optical cable point is less than the optical cable length of the routing point, the optical cable direction of the optical cable point is to extend from the optical cable point to the routing point.

[0019] In a second aspect, the present invention provides an optical cable route survey device based on optical fiber vibration sensing, comprising a pulse light source, an optical fiber vibration sensor, a data processing module, a data storage module, and an intelligent mobile terminal; wherein: The pulse light source is used to send light pulses to the optical cable; the pulse light source adjusts the pulse width sent to the optical cable based on the adjustment instruction of the data processing module; The optical fiber vibration sensor is used to collect the vibration signal of the optical fiber, identify the knocking event in the vibration signal, and intercept the knocking vibration segment; The data processing module is used to calculate the adjustment amount of the pulse width and send an instruction to adjust the pulse width to the pulse light source; the data processing module is also used to calculate the characteristic parameters of the knocking vibration segment and send a corresponding prompt of the knocking feedback to the mobile intelligent terminal; The data storage module is used to store the relevant information of the optical cable pile point, including the longitude and latitude coordinates, the length of the optical cable, the direction of the optical cable, the number of the optical cable, the type of the pile point, and the name of the pile point; The intelligent mobile terminal is used to remotely control the start of the pulse light source and receive corresponding prompts of tapping feedback; the intelligent mobile terminal is also used to obtain the longitude and latitude coordinates of the optical cable pile points; the intelligent mobile terminal also includes GIS software for drawing and displaying the optical cable routing map.

[0020] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: The present invention improves the efficiency of the survey of optical cable routes. Construction workers can use a portable mobile terminal to knock on the optical cable pile point and remotely control the pulse light source to send optical pulses. The optical cable route survey can be completed without the cooperation of multiple people, which greatly saves manpower and time costs. The pulse width of the optical pulse is dynamically adjusted based on the amplitude parameter and frequency parameter of the vibration signal, so as to collect more comprehensive and accurate vibration information, while avoiding signal overlap and confusion.

[0021] According to the characteristic parameters of the knocking vibration segment, it can accurately provide feedback on the knocking position, knocking force, and knocking frequency, so that construction personnel can adjust the knocking method in time to ensure the quality of the vibration signal. By determining the direction of the optical cable and drawing the optical cable route map in combination with information such as longitude and latitude coordinates, the accuracy and completeness of the optical cable route survey are improved. Various detailed information on the optical cable pile points are stored and imported into the geographic information system to realize the automatic drawing and intuitive display of the optical cable route, which is convenient for the management and maintenance of the optical cable network. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. 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 creative labor. Among them: Figure 1 A flow chart of the optical cable route survey method based on optical fiber vibration sensing provided by the present invention; Figure 2 A flow chart of a method for determining the direction of an optical cable by tapping an optical cable stake point provided by the present invention. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0024] Example 1 This embodiment introduces a method for surveying optical cable routes based on optical fiber vibration sensing. Figure 1, the method comprises the following steps: S1: tap on the optical cable stake and remotely control the pulse light source to send optical pulses to the optical cable; Construction workers knock on points where target optical cables may exist, such as the manhole cover of the optical cable manhole, and at the same time send remote commands to turn on the pulse light source. This enables a single person to use a portable mobile terminal (such as a smartphone) to perform a vibration sensor test on the optical cable, thereby completing the optical cable route survey without the need for multiple people to cooperate, greatly improving the efficiency of the optical cable route survey.

[0025] S2: collecting a vibration signal of the optical fiber, and dynamically adjusting the pulse width of the optical pulse based on a vibration parameter of the vibration signal; The vibration signal of the optical fiber is a backward Rayleigh scattered signal of the optical pulse; an optical filter can be used to separate the backward Rayleigh scattered signal. For example, the Rayleigh scattered light signal is filtered out from the mixed light signal by a bandpass filter or a notch filter according to the wavelength range of the Rayleigh scattered signal and the wavelengths of other possible interfering light signals (such as Raman scattered light signals, etc.). The central wavelength of the Rayleigh scattered signal is substantially the same as the wavelength of the light pulse of the light source. By setting the filtering bandwidth near this wavelength, the Rayleigh scattered light signal can be selectively allowed to pass through while blocking light signals of other wavelengths.

[0026] The vibration parameters of the vibration signal include an amplitude parameter and a frequency parameter; the vibration parameters are calculated as follows: filtering and denoising the vibration signal; uniformly sampling the vibration signal to obtain the amplitudes of N sampling points; calculating the average of the amplitudes of the N sampling points as the amplitude parameter; performing frequency domain transformation on the vibration signal, and extracting the peak frequency of the vibration signal as the frequency parameter.

[0027] The method for dynamically adjusting the pulse width of the optical pulse is as follows: Set the amplitude threshold and frequency threshold of the vibration signal; calculate the adjustment amount of the pulse width, the formula is as follows: ; in, represents the adjustment amount of the pulse width; A represents the amplitude parameter; represents the amplitude threshold; f represents the frequency parameter; represents the frequency threshold; Indicates the first adjustment factor. When the amplitude parameter A is greater than the amplitude threshold , The value is 1, otherwise, The value is 0; Represents the second adjustment factor. When the frequency parameter f is greater than the frequency threshold , The value is 1, otherwise, The value is 0; represents the weight coefficient of the amplitude parameter, The weight coefficients representing the frequency parameters are set by those skilled in the art based on actual needs.

[0028] Set the maximum value of the pulse width, denoted as ; Set the minimum value of pulse width, recorded as ; Adjust the pulse width, the formula is as follows: ; Wherein, w represents the adjusted pulse width of the optical pulse; Indicates the initial value of the pulse width; if w is greater than , then set the pulse width to ; If w is less than , then set the pulse width to .

[0029] When the amplitude parameter of the vibration signal is greater than the amplitude threshold, it means that the optical fiber vibrates violently. In this case, the pulse width can be appropriately increased. Because a larger vibration amplitude may cause the scattering and reflection of the optical signal in the optical fiber to be more complicated, increasing the pulse width can allow the optical pulse to have more time to interact with the vibration area in the optical fiber, thereby collecting more comprehensive vibration information. For the vibration frequency, if the frequency parameter is higher than the frequency threshold, it means that the vibration changes rapidly. At this time, the pulse width can be appropriately reduced. High-frequency vibration will cause the optical signal to change multiple times in a short period of time. A narrower pulse width can capture these rapidly changing vibration signals more timely and avoid signal overlap and confusion. At the same time, in order to avoid excessive adjustment, set the pulse width limit of the adjustment so that the adjustment limit of the pulse width is within a reasonable range.

[0030] S3: identifying a knocking event in the vibration signal, and intercepting a knocking vibration segment from the vibration signal; the knocking vibration segment is a segment of the vibration signal corresponding to the knocking event; The vibration signal, i.e. the backscattered Rayleigh signal, will normally gradually weaken as the length of the optical fiber increases, showing a relatively smooth attenuation trend. When the optical fiber is not struck, the vibration signal is relatively stable, with some small fluctuations, which are mainly caused by factors such as environmental background noise and weak natural vibrations of the optical fiber (such as micro-vibrations of the optical fiber caused by temperature changes and slight air flow). When a strike occurs, an obvious fluctuation area will appear in the vibration signal. This fluctuation area corresponds to the strike event, and is characterized by a sudden increase in the signal amplitude, followed by complex changes over a period of time, including fluctuations in the signal amplitude and possible frequency changes. By analyzing the area where the vibration signal deviates from the normal attenuation trend, the signal change range associated with the strike can be determined. The time interval corresponding to this change range contains information about the location of the strike point.

[0031] S4: calculating characteristic parameters of the knocking vibration segment, and performing knocking feedback based on the characteristic parameters; The characteristic parameters of the knocking vibration segment include average amplitude, vibration frequency ratio, instability, and decay speed; The average amplitude of the cable pile point is recorded as , is the mean amplitude of the vibration segments; the mean amplitude shows whether the vibration signal is strong enough to ensure accurate perception and analysis. If the signal strength is too weak, the feature information may not be effectively extracted, affecting the calculation of the optical cable routing and other parameters. The instability is recorded as , is the standard deviation of the amplitude of the tapping vibration segment; instability can measure the fluctuation of the vibration signal. If the fluctuation is too large, it may indicate that the tapping is unstable or there is other interference. A stable vibration signal helps to improve the accuracy of data processing and analysis. The vibration frequency ratio is recorded as , the calculation method is as follows: perform spectrum analysis on the knocking vibration segment and extract the peak frequency; the vibration frequency ratio is the average amplitude The ratio of the vibration frequency to the peak frequency can provide a comprehensive indicator to determine whether the current vibration state is in an optimal balance range. For example, if the amplitude is too large and the frequency is too low, the optical fiber will be overstrained, or if the frequency is too high and the amplitude is too small, the signal will be difficult to detect.

[0032] The decay rate is denoted as , calculated as follows: Select two observation points on the optical cable on the same side of the optical cable pile point, denoted as P and Q respectively; the distance between point P and the optical cable pile point is , the distance between point Q and the cable pile point is ,and Greater than ; Locate points P and Q in the vibration signal and record the amplitude at point P, denoted as ; record the amplitude at point Q, denoted as ; Calculate the decay rate using the following formula: .

[0033] When a knocking event occurs, an external force is applied to the optical fiber, causing it to vibrate. After the knocking event ends, the vibration of the optical fiber will gradually decay due to its own elasticity and damping characteristics. The decay rate reflects the attenuation of the vibration signal during the propagation process in the optical cable. Excessive attenuation may affect the detectability and accuracy of the signal, especially in long-distance optical cable lines.

[0034] The tapping feedback includes tapping position feedback, tapping force feedback, and tapping frequency feedback; The tapping position feedback is specifically as follows: Set the decay speed threshold, denoted as If the decay rate Greater than , then feedback will be given as a prompt to change the tapping position; When the attenuation rate is too fast, it is likely that the tapping position is too far from the optical cable and cannot effectively vibrate the optical cable, or there is an interference source near the tapping position, which prevents the vibration signal from being transmitted normally. In this case, a prompt to change the tapping position is sent to the mobile terminal, and a more appropriate tapping position suggestion is provided, such as near the optical cable connector.

[0035] The tapping force feedback is as follows: Set the minimum threshold of the average amplitude, denoted as ; Set the maximum threshold of the average amplitude, denoted as ; Set the instability threshold, denoted as ; If the average amplitude Less than , and the decay rate No more than , then feedback will be given to increase the tapping force; If the average amplitude Greater than , and the instability Greater than , then feedback will be given to reduce the tapping force; When the signal strength analysis shows that the vibration signal amplitude is too low and the signal attenuation is normal, it may be caused by insufficient tapping force. For example, in a low temperature environment, the elasticity of the optical fiber changes, and a greater tapping force is required to generate a sufficiently strong vibration signal. If the signal strength is too high and unstable, it may be caused by excessive tapping force. Excessive tapping force may generate too much noise interference, affecting the accuracy of the signal.

[0036] The tapping frequency feedback is as follows: Set the minimum threshold of the frequency ratio, denoted as ; Set the maximum threshold of the frequency ratio, denoted as If the frequency ratio Less than , the signal will be fed back to reduce the tapping frequency; this may be because the tapping frequency is too high, so the optical fiber does not have enough time to generate a large amplitude. At this time, reduce the tapping frequency to make the vibration-frequency ratio approach the ideal range, thereby optimizing the signal quality.

[0037] If the frequency ratio Greater than , then the prompt to increase the tapping frequency will be fed back; at this time, it may be because the tapping frequency is too low, resulting in the inability to transmit the energy of the optical fiber vibration in time, causing the accumulated amplitude to be large. Increasing the tapping frequency can make the ratio of amplitude to frequency more reasonable.

[0038] Based on the feedback of vibration signals, the tapping parameters are adjusted dynamically to ensure that the vibration signals contain sufficient and accurate information. For example, in a low temperature environment, the elasticity of the optical fiber may change, and the tapping force can be appropriately increased to ensure that sufficient vibration signals are generated; for different optical cable models, their internal structures and materials are different, and different tapping frequencies may be required to better stimulate vibration signals. Whether in the laboratory to study the basic vibration characteristics of optical fibers or in actual optical fiber monitoring systems (such as optical fiber communication line fault monitoring, optical fiber sensor applications, etc.), the vibration-frequency ratio can be well applied. As long as the upper and lower limits of the vibration-frequency ratio are set reasonably, the tapping frequency can be effectively adjusted to obtain a good quality Rayleigh scattering signal.

[0039] S5: Calculating the length of the optical cable at the optical cable stake point based on the knocking vibration segment, and recording the longitude and latitude coordinates of the optical cable stake point; The longitude and latitude coordinates of the optical cable stake point are obtained by a mobile terminal containing a GPS positioning module held by the construction personnel; the optical cable length of the optical cable stake point is the length of the optical cable section between the optical cable stake point and the transmitting end; the transmitting end is the optical cable port where a pulse light source sends optical pulses to the optical cable.

[0040] The time when the knocking vibration segment occurs is recorded, and combined with the propagation speed of the optical signal in the optical fiber, the propagation distance of the optical signal can be obtained by multiplying the time by the speed, that is, the length of the optical cable segment between the optical cable pile point and the transmitting end.

[0041] S6: Determine the direction of the optical cable at the optical cable stake point by tapping, and draw a routing map of the optical cable based on the latitude and longitude coordinates of the optical cable stake point, the length of the optical cable, and the direction of the optical cable.

[0042] Reference Figure 2 The method of determining the direction of the optical cable by tapping the optical cable stake point is as follows: Taking the optical cable stake point as the center, select test points within a radius of R; the spacing between the test points should not be too large, and can be set to 0.2-0.5 meters to ensure full coverage of the possible optical cable direction range.

[0043] Tap at each test point and extract the corresponding tapping vibration segment of each test point based on the vibration signal; at each test point, the strength, frequency and position of each tapping are as close as possible to those at the optical cable pile point to ensure the comparability of the generated vibration signals.

[0044] Calculate the average amplitude and frequency of the knocking vibration segment corresponding to each test point; Calculate the deviation between each test point and the optical cable stake point; mark the test point with the smallest deviation from the optical cable stake point as a routing point; the calculation formula of the deviation is as follows: ; Among them, g represents the deviation between any test point and the optical cable stake point; Represents the average amplitude of any test point; Indicates the main frequency of any test point; Indicates the frequency of the optical cable stake point; Calculate the length of the optical cable at the routing point and record the longitude and latitude coordinates of the routing point; the length of the optical cable at the routing point is the length of the optical cable segment between the routing point and the transmitting end; The direction of the optical cable at the optical cable stake point is determined based on the optical cable length at the optical cable stake point and the optical cable length at the routing point; specifically, if the optical cable length at the optical cable stake point is greater than the optical cable length at the routing point, the direction of the optical cable at the optical cable stake point is extending from the routing point to the optical cable stake point; if the optical cable length at the optical cable stake point is less than the optical cable length at the routing point, the direction of the optical cable at the optical cable stake point is extending from the optical cable stake point to the routing point. The approximate direction angle of the optical cable can also be further calculated through the longitude and latitude coordinates of the optical cable stake point and the routing point.

[0045] Each time you obtain detailed information about a cable stake, you can create or update the stake in the route map, add or update the corresponding cable number, longitude and latitude coordinates, cable length, cable direction, detailed address, stake type (station, well, electric pole, optical cross box, etc.), stake name, and add notes, site photos and corresponding vibration signal waveforms, and calculate the offset between the actual point and the laying point data. Implementing the above solution for each cable stake can obtain the above detailed information for all cable stakes; importing the above information into the geographic information system (GIS) can automatically draw the complete cable route, accurately mark the cable direction, and intuitively display the distribution of the cable in the geographic space.

[0046] Example 2 This embodiment is the second embodiment of the present invention; based on the same inventive concept as the first embodiment, this embodiment introduces an optical cable route survey device based on optical fiber vibration sensing, including a pulse light source, an optical fiber vibration sensor, a data processing module, a data storage module, and an intelligent mobile terminal; wherein: The pulse light source is used to send light pulses to the optical cable; the pulse light source adjusts the pulse width sent to the optical cable based on the adjustment instructions of the data processing module; during the optical cable route survey, the construction personnel remotely control the pulse light source to send light pulses while knocking on the optical cable stakes, so that the light propagates in the optical cable and generates backward Rayleigh scattering signals for subsequent analysis.

[0047] The optical fiber vibration sensor is used to collect the vibration signal of the optical fiber, identify the knocking events in the vibration signal, and intercept the knocking vibration fragment. By filtering and collecting the vibration signal of the optical fiber, that is, the backscattered Rayleigh scattering signal of the light pulse, it can reflect the vibration of the optical cable when it is hit by external forces such as knocking.

[0048] The data processing module is used to calculate the adjustment amount of the pulse width and send an instruction to adjust the pulse width to the pulse light source; the data processing module is also used to calculate the characteristic parameters of the knocking vibration segment and send a corresponding prompt of the knocking feedback to the mobile intelligent terminal; The data storage module is used to store relevant information of the optical cable pile points, including latitude and longitude coordinates, optical cable length, optical cable direction, optical cable number, pile point type, and pile point name; it stores and updates the detailed information of each optical cable pile point after obtaining it, which is convenient for subsequent query and management, and also provides data support for drawing a complete optical cable routing map.

[0049] The smart mobile terminal is used to remotely control the start of the pulse light source and receive corresponding prompts of tapping feedback; the smart mobile terminal is also used to obtain the longitude and latitude coordinates of the optical cable pile points; the smart mobile terminal also includes GIS software for drawing and displaying optical cable routing maps. The smart mobile terminal facilitates construction personnel to start route surveys and adjustment operations in a timely manner on site, thereby improving survey efficiency.

[0050] The specific functions of the above modules are realized by referring to the relevant contents of the optical cable route survey method based on optical fiber vibration sensing described in Example 1, which will not be elaborated here.

[0051] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0052] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the purpose and scope of protection of the present invention, which are all within the protection of the present invention.

Claims

1. A method for surveying optical cable routes based on optical fiber vibration sensing, characterized in that: The following steps are involved: S1: tap on the optical cable stake and remotely control the pulse light source to send optical pulses to the optical cable; S2: collecting a vibration signal of the optical fiber, and dynamically adjusting the pulse width of the optical pulse based on a vibration parameter of the vibration signal; S3: identifying a knocking event in the vibration signal, and intercepting a knocking vibration segment from the vibration signal; the knocking vibration segment is a segment of the vibration signal corresponding to the knocking event; S4: calculating characteristic parameters of the knocking vibration segment, and performing knocking feedback based on the characteristic parameters; S5: Calculating the length of the optical cable at the optical cable stake point based on the knocking vibration segment, and recording the longitude and latitude coordinates of the optical cable stake point; S6: Determine the direction of the optical cable at the optical cable stake point by tapping, and draw a routing map of the optical cable based on the latitude and longitude coordinates of the optical cable stake point, the length of the optical cable, and the direction of the optical cable.

2. The optical cable route survey method based on optical fiber vibration sensing as claimed in claim 1, characterized in that: The vibration signal of the optical fiber is a backscattered Rayleigh signal of the optical pulse; The vibration parameters of the vibration signal include an amplitude parameter and a frequency parameter; the vibration parameters are calculated as follows: filtering and denoising the vibration signal; uniformly sampling the vibration signal to obtain the amplitudes of N sampling points; calculating the average of the amplitudes of the N sampling points as the amplitude parameter; performing frequency domain transformation on the vibration signal, and extracting the peak frequency of the vibration signal as the frequency parameter.

3. The optical cable route survey method based on optical fiber vibration sensing as claimed in claim 2, characterized in that: The method for dynamically adjusting the pulse width of the optical pulse is as follows: Set the amplitude threshold and frequency threshold of the vibration signal; calculate the adjustment amount of the pulse width, recorded as ; Set the maximum value of the pulse width, denoted as ; Set the minimum value of pulse width, recorded as ; Adjust the pulse width; set the initial value of the pulse width to ,Will and Add them together to get the adjusted pulse width of the light pulse, denoted as w; If w is greater than , then set the pulse width to ; If w is less than , then set the pulse width to .

4. The optical cable route survey method based on optical fiber vibration sensing as claimed in claim 3, characterized in that: The pulse width adjustment amount is calculated as follows: Setting a first adjustment amount and a second adjustment amount of the pulse width; If the amplitude parameter is greater than the amplitude threshold, assigning a value to the first adjustment amount based on the difference between the amplitude parameter and the amplitude threshold; otherwise, the first adjustment amount is 0; If the frequency parameter is greater than the frequency threshold, assigning a value to the second adjustment amount based on the difference between the frequency parameter and the frequency threshold; Otherwise, the second adjustment amount is 0; The first adjustment amount and the second adjustment amount are weightedly summed to obtain the pulse width adjustment amount.

5. The optical cable route survey method based on optical fiber vibration sensing as claimed in claim 4, characterized in that: The characteristic parameters of the knocking vibration segment include average amplitude, instability, and decay speed; The average amplitude of the cable pile point is recorded as , is the mean amplitude of the striking vibration segment; the instability is recorded as , is the standard deviation of the amplitude of the striking vibration segment; the decay rate is recorded as , calculated as follows: Select two observation points on the optical cable on the same side of the optical cable pile point, denoted as P and Q respectively; the distance between point P and the optical cable pile point is , the distance between point Q and the cable pile point is ,and Greater than ; Locate points P and Q in the vibration signal and record the amplitude at point P, denoted as ; record the amplitude at point Q, denoted as ; Will and The difference is and The difference between and is used to obtain the attenuation speed.

6. The optical cable route survey method based on optical fiber vibration sensing as claimed in claim 5, characterized in that: The tapping feedback includes tapping position feedback and tapping force feedback; The tapping position feedback is specifically as follows: Set the decay speed threshold, denoted as If the decay rate Greater than , then feedback will be given as a prompt to change the tapping position; The tapping force feedback is specifically as follows: Set the minimum threshold of the average amplitude, denoted as ; Set the maximum threshold of the average amplitude, denoted as ; Set the instability threshold, denoted as ; If the average amplitude Less than , and the decay rate No more than , then feedback will be given to increase the tapping force; If the average amplitude Greater than , and the instability Greater than , then the feedback will be a prompt to reduce the tapping force.

7. The optical cable route survey method based on optical fiber vibration sensing as claimed in claim 6, characterized in that: The characteristic parameters of the knocking vibration segment also include a vibration frequency ratio; the vibration frequency ratio is recorded as , the calculation method is as follows: perform spectrum analysis on the knocking vibration segment and extract the peak frequency; the vibration frequency ratio is the average amplitude Ratio to peak frequency; The tapping feedback also includes tapping frequency feedback, which is as follows: Set the minimum threshold of the frequency ratio, denoted as ; Set the maximum threshold of the frequency ratio, denoted as If the frequency ratio Less than , then feedback will be given to reduce the tapping frequency; If the frequency ratio Greater than , then the prompt to increase the tapping frequency will be fed back.

8. The optical cable route survey method based on optical fiber vibration sensing as claimed in claim 7, characterized in that: The method for determining the direction of the optical cable by tapping the optical cable stake point is as follows: Taking the optical cable stake point as the center, select a test point within a radius of R; Tap each test point, and extract the tapping vibration segment corresponding to each test point based on the vibration signal; Calculate the average amplitude and frequency of the knocking vibration segment corresponding to each test point; Calculate the deviation between each test point and the cable stake point based on the average amplitude and frequency of the test point; Mark the test point with the smallest deviation from the optical cable stake point as the routing point; Calculating the length of the optical cable at the routing point and recording the longitude and latitude coordinates of the routing point; The direction of the optical cable at the optical cable point is determined based on the optical cable length at the optical cable point and the optical cable length at the routing point.

9. The optical cable route survey method based on optical fiber vibration sensing as claimed in claim 8, characterized in that: The longitude and latitude coordinates of the optical cable stake point are obtained by a mobile terminal containing a GPS positioning module held by a construction worker; the optical cable length of the optical cable stake point is the length of the optical cable segment between the optical cable stake point and the transmitting end; the transmitting end is the optical cable port where a pulse light source sends an optical pulse to the optical cable; the optical cable length of the routing point is the length of the optical cable segment between the routing point and the transmitting end; The method for determining the direction of the optical cable at the optical cable point based on the optical cable length of the optical cable point and the optical cable length of the routing point is as follows: if the optical cable length of the optical cable point is greater than the optical cable length of the routing point, the optical cable direction of the optical cable point is to extend from the routing point to the optical cable point; if the optical cable length of the optical cable point is less than the optical cable length of the routing point, the optical cable direction of the optical cable point is to extend from the optical cable point to the routing point.

10. An optical cable route survey device based on optical fiber vibration sensing, used to implement an optical cable route survey method based on optical fiber vibration sensing as claimed in any one of claims 1 to 9, characterized in that: It includes a pulse light source, an optical fiber vibration sensor, a data processing module, a data storage module, and an intelligent mobile terminal; wherein: The pulse light source is used to send light pulses to the optical cable; the pulse light source adjusts the pulse width sent to the optical cable based on the adjustment instruction of the data processing module; The optical fiber vibration sensor is used to collect the vibration signal of the optical fiber, identify the knocking event in the vibration signal, and intercept the knocking vibration segment; The data processing module is used to calculate the adjustment amount of the pulse width and send an instruction to adjust the pulse width to the pulse light source; the data processing module is also used to calculate the characteristic parameters of the knocking vibration segment and send a corresponding prompt of the knocking feedback to the mobile intelligent terminal; The data storage module is used to store the relevant information of the optical cable pile point, including the longitude and latitude coordinates, the length of the optical cable, the direction of the optical cable, the number of the optical cable, the type of the pile point, and the name of the pile point; The intelligent mobile terminal is used to remotely control the start of the pulse light source and receive corresponding prompts of tapping feedback; the intelligent mobile terminal is also used to obtain the longitude and latitude coordinates of the optical cable pile points; the intelligent mobile terminal also includes GIS software for drawing and displaying the optical cable routing map.

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