Method for collecting cable skin length information based on cable route survey instrument tapping vibration

Abstract

The present application relates to the technical field of optical cable positioning monitoring, in particular to an optical cable skin length information acquisition method based on optical cable route survey instrument knocking vibration, comprising: predicting the position P1 of the next knocking, obtaining the marked point P with the greatest knocking vibration transmission similarity of the waveform signal at P1, the path length of all marked points connected between P1 and P is taken as the path error of P1, the difference between the relative skin length of P1 and P; predicting the position P2 of the next knocking again, when the difference between the distance of P1 and P2 and the path error of P1 is less than th1, taking P1 as the marked point obtained by the current knocking sampling; after updating the value of th1 according to the path error of the marked point obtained in the current knocking sampling process, the updated th1 is used to obtain the marked point in the next knocking sampling process. The present application ensures that the whole information acquisition process is efficient and as accurate as possible.

Description

Technical Field

[0001] This invention relates to the field of data processing technology, specifically to a method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument. Background Technology

[0002] Fiber optic cables are typically laid via direct burial. However, issues such as inaccurate construction data and route relocation can make it difficult to obtain cable routing data and cable sheath length data at different locations. A common method for determining cable routes or geographical coordinates is to manually inspect the cable's entry and exit points, including locations such as shafts or exposed sections. However, this method only provides a rough estimate of the route, and it becomes inaccurate when there are few (or distant) entry and exit points, or when cable identification information is incomplete (e.g., worn-out ID numbers).

[0003] Another method for determining cable routes or geographic coordinates is to tap the ground. When the cable underground is subjected to the vibration, the mechanical strain causes a phase change in Rayleigh scattering light, which in turn generates a vibration response signal. This vibration response signal is used to detect the tapping event and collect cable routes and sheath lengths. While this method can densely collect the cable route coordinates and sheath lengths at different coordinates, achieving a "point-to-point" correspondence between cable sheath lengths and geographic coordinates, the information collection results are affected by ground conditions. For example, soil moisture, sand and gravel composition, soil thickness, and pipeline / road structure can interfere with the propagation of vibration waves. Furthermore, the information collection results also show significant differences and errors when tapping at different locations (or when the tapping location deviates from the cable by different amplitudes). In summary, directly using this method cannot accurately and efficiently collect cable route and sheath length information; or rather, collecting the most accurate cable route and sheath length information requires a significant time investment by staff (e.g., requiring frequent and repeated tapping of the ground), resulting in low information collection efficiency. Summary of the Invention

[0004] To address the aforementioned problem of the inability to accurately and efficiently collect fiber optic cable route length information, this invention provides a method for collecting fiber optic cable length information based on the vibration of a fiber optic cable route survey instrument.

[0005] The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument in this invention adopts the following technical solution:

[0006] One embodiment of the present invention provides a method for collecting optical cable sheath length information based on the tapping vibration of an optical cable route survey instrument. The method includes the following steps:

[0007] Each tap sampling in history yields a marker point; the process of obtaining a marker point during the current tap sampling includes:

[0008] D1: Perform several taps on the ground, record the signal waveform of the optical cable after each tap, and predict the position P1 of the next tap based on the signal strength of the signal waveforms at all tap locations.

[0009] D2: Obtain the similarity of the vibration transmission of the waveform signal after being struck at P1 with the signal waveform of each marker point in history. The marker point with the greatest similarity in vibration transmission is denoted as P. The relative skin length between P and P1 is obtained by using the transmission time difference of the vibration signals of P and P1 in the optical cable. The difference between the length of the path formed by connecting all marker points between P1 and P and the relative skin length is used as the path error of P1.

[0010] D3: Based on the signal strength of the signal waveforms of all striking positions, including P1, predict the position P2 of the next striking. If the difference between the path error of P1 and the distance between P1 and P2 is less than the first preset threshold th1, P1 is used as the marker point obtained by the current striking sample; if it is not less than th1, P2 is regarded as P1 and D2 and D3 are repeated.

[0011] D4: After updating the value of th1 based on the path error of the marker point obtained in the current tapping sampling process, use the updated th1 to obtain the marker point for the next tapping sampling process.

[0012] The fiber optic cable sheath length information was obtained based on the marker points from all the tapping sampling processes.

[0013] Preferably, the specific steps for predicting the next tap position P1 based on the signal strength of the signal waveforms at all tap positions are as follows:

[0014] For all tapping positions in the current tapping sampling process, the signal intensity of the signal waveform at all tapping positions is normalized, and the normalized signal intensity is set as the weight of the tapping position. The weighted sum of all tapping positions is recorded as the predicted tapping position, denoted as P1.

[0015] Preferably, the specific steps for obtaining the similarity of the impact vibration transmission between the waveform signal after being struck at P1 and the signal waveform at each historical marker point are as follows:

[0016] For any two signal waveforms corresponding to P1 and the marker point, perform Fourier transform on the two signal waveforms to obtain two spectral distributions. Each spectral distribution includes all frequencies of the signal waveform and the amplitude corresponding to each frequency. Divide all frequencies of each spectral distribution into several intervals. For any spectral distribution, obtain the mean of all amplitudes in each interval of the spectral distribution, which is denoted as the average amplitude of each interval of the spectral distribution.

[0017] For any interval in any spectral distribution, set the amplitude of all intervals outside that interval to 0 to obtain a new spectral distribution. Use the inverse Fourier transform algorithm to transform the new spectral distribution to obtain the filtered signal waveform of that region. Use the parameters of the polynomial fitted to the filtered signal waveform as the attenuation characteristics of that interval.

[0018] The similarity of the impact vibration transmission is obtained by the similarity of the average amplitude and the similarity of the attenuation characteristics of all intervals in the spectral distribution of any two signal waveforms. The similarity of the impact vibration transmission is positively correlated with the similarity of the average amplitude and the similarity of the attenuation characteristics, respectively.

[0019] Preferably, the specific formula for updating the value of th1 based on the path error of the marker point obtained during the current tapping sampling process is as follows:

[0020]

[0021] Where T1 represents the updated value of th1, and T0 represents the original value of th1; L0 represents the path error of the marker point obtained in the current tap sampling process, and L represents the length of the path of the marker point obtained in the current tap sampling process; th2 represents the second preset threshold.

[0022] Preferably, the specific steps for obtaining the optical cable sheath length information acquisition result based on the marker points of all tapping sampling processes are as follows:

[0023] Cluster all marker points by utilizing the similarity of the signal waveforms transmitted by the impact vibration between any two marker points to obtain several categories; for any category and the burial point of the optical cable, the marker point closest to the burial point in that category is selected and recorded as the reference point; the distance between the burial point and the reference point plus the sheath length of the burial point is obtained as the sheath length of the reference point.

[0024] For any marker point other than the reference point in this category, obtain the relative skin length between the marker point and the reference point; add the skin length of the reference point to the relative skin length to obtain the marker point;

[0025] The location and length of all marker points are used as the results of optical cable length information collection.

[0026] Preferably, the specific steps for obtaining the relative skin length are as follows:

[0027] For any two markers including P and P1, the time interval between the tapping time and the tapping event reception time of each marker is obtained, and the product of the difference between the time intervals of the two markers and the speed of light is used as the relative skin length of the two markers.

[0028] Preferably, the specific steps for obtaining the similarity of impact vibration transmission based on the similarity of the average amplitude and attenuation characteristics of all intervals in the spectral distribution of any two signal waveforms are as follows:

[0029] The average amplitude of all intervals in any spectral distribution is used to construct a spectral distribution vector; the cosine similarity of the spectral distribution vectors corresponding to the spectral distributions of any two signal waveforms is denoted as the first similarity.

[0030] For the attenuation characteristics of the same interval in the spectral distribution of any two signal waveforms, the cosine similarity of the two attenuation characteristics in the same interval is denoted as the attenuation similarity of the same interval; the mean of the two average amplitudes in the same interval is denoted as the attention weight of the same interval.

[0031] The attention weights of all intervals are normalized, and the attenuation similarity of all intervals is weighted and summed using the normalized attention weights of each interval to obtain the second similarity; the mean of the first similarity and the mean of the second similarity are denoted as the impact vibration transmission similarity.

[0032] Preferably, the specific steps for clustering all marker points using the similarity of the impact vibration transmission of signal waveforms between any two marker points to obtain several classes are as follows:

[0033] Let x be the similarity of the signal waveforms transmitted by the impact vibration between any two marker points, and let exp(-x) be the clustering distance between any two marker points. Based on the clustering distance between all marker points, perform K-Means clustering on all marker points to obtain several categories.

[0034] Preferably, the specific steps for obtaining the signal waveform are as follows:

[0035] In the impact vibration signal generated in the optical cable, a signal segment of a preset time length is extracted starting from the impact time; for two signal segments obtained after two consecutive impacts at the same position; the two signal segments are subjected to Fourier transform to obtain the spectral distribution of each signal segment;

[0036] For the two spectral distributions of the two signal segments, if the amplitudes at the same frequency in the two spectral distributions are not the same, then the amplitudes at the same frequency in the two spectral distributions are set to 0; the average spectral distribution is obtained by averaging the amplitudes at the same frequency in the two spectral distributions, and the signal waveform is obtained by transforming the average spectral distribution using the inverse Fourier transform algorithm.

[0037] Preferably, the insertion and exit points of the optical cable are also regarded as marker points, and the insertion and exit points are tapped to obtain the time interval between the tapping time and the tapping event reception time. The product of the time interval and the speed of light is used as the sheath length of the insertion or exit point.

[0038] The beneficial effects of the technical solution of the present invention are:

[0039] This invention involves performing several taps on the ground during the initial tapping sampling process, recording the signal waveform of the optical cable after each tap, and predicting the next tapping position P1 based on the signal strength of the signal waveforms from all tapping locations. This process, by predicting the tapping position, allows workers to tap at the predicted location, avoiding excessive deviation from the optical cable and initially improving information acquisition efficiency.

[0040] Furthermore, this invention obtains the similarity of the vibration transmission of the waveform signal after being struck at P1 with the signal waveform of each historical marker point. The marker point with the highest vibration transmission similarity is denoted as P. The relative sheath length between P and P1 is obtained by using the time difference in the transmission of the vibration signals of P and P1 within the optical cable. The difference between the length of the path connecting all marker points between P1 and P and the relative sheath length is used as the path error of P1. The process describes the propagation of vibration waves in the soil when striking different locations by using the similarity of the vibration transmission of the signal waveform. This allows the soil at different locations to cancel out the propagation of vibration waves to a certain extent, resulting in higher accuracy of the relative sheath length of the optical cable between different locations. Based on this, reliable error assessment (i.e., the path error of P1) can be performed on local segments of the optical cable (i.e., the path between P1 and P), which helps to collect information accurately and efficiently in the future.

[0041] Based on the above, this invention predicts the next striking position P2 again based on the signal strength of the signal waveforms of all striking positions, including P1. When the difference between the distance between P1 and P2 and the path error of P1 is less than a first preset threshold th1, P1 is used as the marker point obtained from the current striking sampling; when it is not less than th1, P1 in D2 is replaced with P2 and D2 is executed. This process determines whether the current striking sampling process needs to be terminated early by using the acquisition error of the local segment of the optical cable (i.e., the path error of P1) and the distribution of the subsequent striking predicted positions. This allows the current striking sampling process to balance information acquisition efficiency and accuracy. For example, it can ensure the accuracy of the skin length by offsetting the propagation process of vibration waves by soil at different locations, and it can also terminate the current striking sampling process early.

[0042] Furthermore, this invention updates the value of th1 based on the path error of the marker points obtained in the current tapping sampling process, and then uses the updated th1 to obtain the marker points for the next tapping sampling process. This process avoids the problem of large cumulative path errors in subsequent tapping sampling processes while ensuring high information acquisition efficiency. By continuously updating th1, the path error and information acquisition efficiency can be dynamically changed in all subsequent tapping sampling processes. For example, when the path error is large, it can be reduced by sacrificing information acquisition efficiency; when the information acquisition efficiency is low, it can be increased by appropriately increasing the path error. This ensures that all tapping sampling processes (or the entire information acquisition process) are both highly efficient and as accurate as possible. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 The flowchart illustrates the steps of a method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument, as provided in an embodiment of the present invention. Detailed Implementation

[0045] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of the optical cable sheath length information collection method based on the vibration of an optical cable route survey instrument proposed by the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0047] The following description, in conjunction with the accompanying drawings, details the specific scheme of the optical cable sheath length information collection method based on the vibration of an optical cable route survey instrument provided by the present invention.

[0048] Example 1:

[0049] Please see Figure 1 The diagram illustrates a flowchart of a method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument, according to an embodiment of the present invention. The method includes the following steps:

[0050] Step S101: During the current tapping sampling process, tap the ground several times, and record the signal waveform of the optical cable after each tap.

[0051] Connect any one of the optical fibers of the optical cable whose length information needs to be collected to a vibration signal acquisition device. In this embodiment, the vibration signal acquisition device includes a distributed vibration sensing unit (DVS) to detect the vibration response signal generated when the optical cable is subjected to impact vibration.

[0052] In this embodiment, the optical cable is struck along its possible burial path. The vibration wave from the strike is transmitted to the underground optical cable. When the optical fiber in the cable senses the strike vibration signal, the phase change of Rayleigh scattered light caused by mechanical strain generates a vibration response signal, which is then transmitted along the optical fiber to the vibration signal acquisition device.

[0053] A comparative embodiment is: the time interval between the impact time and the time it takes for the vibration signal acquisition device to receive the vibration response signal (denoted as the impact event reception time) is obtained, and the product of this time interval and the speed of light is used as the observation skin length of the impact position.

[0054] This embodiment involves multiple tapping sampling processes throughout its history. During each tapping sampling process, tapping is performed along the possible burial path of the optical cable to obtain marked points.

[0055] This embodiment takes the current tapping sampling process as an example for detailed description, specifically:

[0056] Workers moved to a location along a possible burial path of the optical cable and tapped it. The tapping time and coordinates were recorded. A vibration signal acquisition device collected the vibration response signal waveform and the reception time of the vibration response signal (i.e., the tapping event reception time), and also obtained the signal strength of the waveform.

[0057] Starting from this position, tap other positions in sequence in the direction of increasing signal strength until the signal strength of the signal waveform in that direction decreases, then stop tapping.

[0058] Each strike corresponds to a signal waveform and its signal strength.

[0059] Step S102: Predict the position P1 of the next strike based on the signal intensity of the signal waveforms at the several strike positions.

[0060] The signal intensity of the signal waveforms at all striking positions is normalized. In this embodiment, the softmax formula is used for normalization. The normalized signal intensity is set as the weight of the striking position. The weighted sum of all striking positions is recorded as the predicted striking position, denoted as P1.

[0061] This step predicts the next tapping location P1 based on the previously tapped location. The predicted tapping location P1 tends to be a location with high signal strength. This process helps staff quickly determine a suitable tapping location, avoiding the problem of staff repeatedly searching for a suitable tapping location and spending a lot of time, thus initially improving the efficiency of optical cable length information acquisition.

[0062] Step S103: The waveform signal after striking P1 is recorded as the target signal. The similarity of the striking vibration transmission between the target signal and the signal waveform of each marker point in history is obtained. The marker point with the greatest similarity in vibration transmission is recorded as P.

[0063] Each marker obtained in history is essentially a striking point, and each also corresponds to a waveform signal.

[0064] In this embodiment, it is considered that after being struck, the vibration wave needs to travel through soil, sand, pipes, etc. to reach the optical cable (this process is the sound wave propagation process). When the optical cable comes into contact with the vibration wave, the phase change of Rayleigh scattered light is generated due to mechanical strain, which in turn generates an optical signal for transmission (transmitted to the vibration signal acquisition device). Since the speed of sound is much less than the speed of light, the method of obtaining the observed skin length of the striking position using the above comparative embodiment has a large error (because the propagation process of the vibration wave is ignored).

[0065] In one embodiment, the method for reducing interference during the propagation of vibration waves is as follows: the fiber optic cable sheath length is calculated using the finite difference method. Specifically, the observed sheath lengths at any two striking positions are obtained using the comparative embodiment described above, and the absolute value of the difference between the observed sheath lengths at these two striking positions can accurately represent the sheath length of the fiber optic cable between any two striking positions.

[0066] However, a problem remains: considering that soil conditions may vary at different impact locations (e.g., soil moisture, sand and gravel composition, soil thickness, pipeline and road structure), the propagation of vibration waves (e.g., propagation speed, scattering, absorption, echo) will also differ. In this case, when using the finite difference method to calculate the cable sheath length, the propagation processes of vibration waves at the two locations cannot cancel each other out, resulting in the cable sheath length between any two impact locations still not being accurately obtained. This is especially true for two locations far from the cable (where the soil layer has a greater interference and influence on the propagation of vibration waves during their propagation to the cable), where the difference in soil conditions has a greater impact on the calculated cable sheath length.

[0067] In this embodiment, it is considered that after each impact, the vibration wave will be affected by the vibration wave at multiple locations on the optical cable after propagating through the soil. The vibration impact received at different locations on the optical cable is different (e.g., the reception time of the impact event, the vibration intensity, etc. are different), resulting in the signal waveform at the impact location having certain characteristics (e.g., having a certain frequency distribution and attenuation). The signal waveform has different characteristics under different soil conditions, such as different frequency components and attenuation; the signal waveform under the same soil conditions has the same or similar characteristics.

[0068] Therefore, this embodiment uses the similarity of the impact vibration transmission between any two signal waveforms to evaluate the similarity of soil conditions at any two impact locations. The greater the similarity of the impact vibration transmission, the more similar the soil conditions at any two impact locations are (the more the vibration waves at the two impact locations can differentially cancel each other out in the soil); the smaller the similarity of the impact vibration transmission, the more dissimilar the soil conditions at any two impact locations are (the more the vibration waves at the two impact locations cannot cancel each other out in the soil).

[0069] Furthermore, in this embodiment, the similarity of the impact vibration transmission between the target signal and the signal waveform of each marker point in the history is obtained, and the marker point with the greatest similarity in vibration transmission is denoted as P. Among them, P and P1 have the same or similar soil conditions.

[0070] In this embodiment, the time interval between the tapping time of P and the tapping event reception time is denoted as the first interval, and the time interval between the tapping time of P1 and the tapping event reception time is denoted as the second interval. The absolute value of the difference between the first interval and the second interval represents the transmission time difference of the vibration signals of P and P1 in the optical cable. The product of this time difference and the speed of light is used as the relative skin length between P and P1.

[0071] It should be noted that the relative skin length between P and P1 is also equal to the absolute value of the difference between the observed skin length of P and the observed skin length of P1. The method for obtaining the observed skin length is detailed in the comparative embodiment.

[0072] Step S104: The difference between the path length and the skin length of the path formed by connecting all the marked points between P1 and P is taken as the path error of P1.

[0073] Obtain all marked points between P1 and P (including P1 and P), and denote them as reference positions. Connect these reference positions to form a path (i.e., the shortest path with P and P1 as endpoints). This path represents the route of a section of underground optical cable marked on the ground. Obtain the Euclidean distance between any two adjacent reference positions on this path. The sum of the Euclidean distances of all adjacent reference positions on this path is taken as the length of the path. The length represented by this path is denoted as the estimated sheath length of the optical cable. In this embodiment, this path is denoted as the reference path of P.

[0074] The relative length of the optical cable between P and P1 obtained in the above steps is denoted as L(P, P1), and the absolute value of the difference between the estimated length and L(P, P1) is denoted as the path error of P1.

[0075] The larger the path error at P1, the greater the difference between the predicted path and the actual burial path of the optical cable; in other words, the more likely the location of P1 is to deviate from the optical cable. In short, the less reliable the predicted impact location P1 is, or the less reliable the optical cable sheath length data collection at P1 is. Conversely, the smaller the path error at P1, the more likely the marker points on that path (including P1) are to be close to the actual burial path of the optical cable; in short, the more reliable the predicted impact location P1 is, or the more reliable the optical cable sheath length data collection at P1 is.

[0076] Step S105: Based on the signal strength of the signal waveforms at all positions including P1, predict the position of the next tap again, and obtain the marker point obtained from the current tap sampling.

[0077] The signal intensity of the signal waveforms at all impact positions (including P1) during the current impact sampling process is obtained. These signal intensities are then normalized using the softmax formula in this embodiment. The normalized signal intensities are then used as the weights for each impact position. All impact positions (including P1) are then weighted and summed again, and the result is denoted as the predicted impact position, P2. P2 is closer to the optical cable than P1.

[0078] Obtain the Euclidean distance between P1 and P2, denoted as L1. The larger L1 is, the more necessary it is to continue changing the tapping position (i.e., the more necessary it is to tap at P2) to further reduce the path marking error (i.e., the path error of P1). The smaller L1 is, the less necessary it is to continue changing the tapping position to further reduce the path marking error (i.e., the path error of P1).

[0079] Based on this, the path error of P1 is denoted as L2, and in this embodiment, (L2-L1) / (L1+L2) is denoted as the necessity of P2's acquisition. The denominator L1+L2 is used to remove the dimension of (L2-L1).

[0080] In some embodiments, L2-L1 may also be denoted as the acquisition necessity of P2.

[0081] The greater the necessity of this data collection, the larger the path error at P1 and the smaller the distance between P1 and P2. In this case, further reduction of the path error is needed. Specifically, this can be achieved by continuing to tap at P2. Furthermore, since the distance between P1 and P2 is small, tapping at P2 is also highly efficient (e.g., it easily finds a position that doesn't deviate from the fiber optic cable and collects the signal waveform). In summary, a greater necessity for data collection indicates both higher information collection efficiency and reduced path error, ensuring the path identification aligns with the fiber optic cable's route.

[0082] The less necessary the data acquisition, the smaller the path error at P1 and the larger the distance between P1 and P2. In this case, there's no need to further reduce the path error; specifically, there's no need to continue tapping at P2 to further reduce the error. Furthermore, due to the large distance between P1 and P2, tapping at P2 might be less efficient (for example, it might be difficult to acquire a signal waveform without deviating from the fiber optic cable, or it might require multiple, wide-area tapping tests to obtain a position without deviation from the cable). In summary, the less necessary the data acquisition, the less necessary it is to reduce the path error. Continuing to tap at other locations to reduce the path error would actually result in lower information acquisition efficiency.

[0083] Based on the above, when the necessity of data acquisition is less than the first preset threshold th1, P1 is taken as the marker point obtained in the current tap sampling, and the current tap sampling process ends. The tapping time, tapping event reception time, location, and signal waveform of this marker point are used as the information acquired for that marker point. It should be noted that the time used in the current tap sampling process can be used to represent the information efficiency of the marker point.

[0084] When the necessity of data collection is not less than the first preset threshold th1, P2 in this step is regarded as P1 in step S103, and steps S103 to S105 are repeated until the current tapping sampling process ends. Specifically, the current tapping sampling process also ends when the number of times steps S103 to S105 are repeated is greater than 15.

[0085] Step S106: After updating the value of th1 based on the path error of P1, use the updated th1 to obtain the marker point for the next tapping sampling. Obtain the optical cable sheath length information acquisition result based on the marker points of all tapping sampling processes.

[0086] The above completes the current tapping sampling process and obtains the current marker point. This marker point corresponds to a path error, which is used to describe the difference between the path where the marker point is located (i.e., the reference path of the marker point) and the actual burial path of the optical cable.

[0087] Before the next tapping sampling process, the value of th1 needs to be updated based on the path error of P1. The purpose is to ensure that the path formed by the marker point has a suitable path error while maintaining high information acquisition efficiency, rather than excessively sacrificing acquisition efficiency to significantly reduce path error. However, as mentioned above, due to the influence of soil conditions on vibration waves, the offset of the marker point (or tapping position) has a significant impact on the fiber optic cable sheath length. In this embodiment, to avoid the problem of a large cumulative path error in subsequent tapping sampling processes while maintaining high information acquisition efficiency, th1 needs to be continuously updated. This allows the path error and information acquisition efficiency to change dynamically in all subsequent tapping sampling processes. For example, when the path error is large, it can be reduced by sacrificing information acquisition efficiency; when the information acquisition efficiency is low, it can be increased by appropriately increasing the path error. This ensures that all tapping sampling processes are both highly efficient and have low path error overall.

[0088] As an example, the specific implementation method for updating the value of th1 based on the path error of P1 is as follows:

[0089]

[0090] T1 represents the updated value of th1, and T0 represents the original value of th1. L0 represents the path error of the marker obtained in the current tap sampling process; L represents the length of the aforementioned path (the reference path of the marker) where the marker obtained in the previous tap sampling process is located, used to remove the dimensions and orders of magnitude of L0 and th2;

[0091] th2 represents a second preset threshold. In this embodiment, th2 is set to 1 meter. In other embodiments, th2 can be set to other values, preferably within the range of [0.5 meters, 2 meters]. In another embodiment, the length of the optical cable is 10 kilometers. When L is less than 10% of the length of the optical cable, th2 = 0.5 meters; when L is less than 50% of the length of the optical cable, th2 = 1 meter; when L is greater than or equal to 50% of the length of the optical cable, th2 = 2 meters.

[0092] When L2 is greater than th2, it indicates that the path error is large. In this case, it is equivalent to reducing the value of th1, so that the predicted position can be obtained more times in the subsequent (next) tapping sampling process and tapping can be performed at the predicted position. By reducing efficiency, it is ensured that the marker point obtained next time does not deviate from the optical cable.

[0093] When L2 is less than th2, it indicates that the path error is large. In this case, it is equivalent to increasing the value of th1 so that the predicted position can be obtained and the tapping can be performed at the predicted position more quickly in the subsequent (next) tapping sampling process. By discarding a certain path error, the efficiency of information collection is guaranteed.

[0094] This concludes the example.

[0095] In summary, this embodiment involves several taps on the ground during the initial tapping sampling process. After each tap, the signal waveform of the optical cable is recorded. Based on the signal strength of the signal waveforms from all tapping locations, the location P1 of the next tap is predicted. This process, by predicting the tapping location, allows workers to tap at the predicted location, avoiding excessive deviation from the optical cable and initially improving the efficiency of information acquisition.

[0096] Furthermore, this embodiment obtains the similarity of the vibration transmission of the waveform signal after being struck at P1 with the signal waveform of each historical marker point. The marker point with the highest vibration transmission similarity is denoted as P. The relative sheath length between P and P1 is obtained by using the time difference in the transmission of the vibration signals of P and P1 within the optical cable. The difference between the length of the path connecting all marker points between P1 and P and the relative sheath length is used as the path error of P1. The process describes the propagation of vibration waves in the soil when striking different locations by using the similarity of the vibration transmission of the signal waveform. This allows the soil at different locations to cancel out the propagation of vibration waves to a certain extent, resulting in higher accuracy of the relative sheath length of the optical cable between different locations. Based on this, a reliable error assessment (i.e., the path error of P1) can be performed on local segments of the optical cable (i.e., the path between P1 and P), which helps to collect information accurately and efficiently in the future.

[0097] Based on the above, this embodiment predicts the next striking position P2 again based on the signal strength of the signal waveforms of all striking positions, including P1. When the difference between the distance between P1 and P2 and the path error of P1 is less than a first preset threshold th1, P1 is used as the marker point obtained from the current striking sampling; when it is not less than th1, P1 in D2 is replaced with P2 and D2 is executed. This process determines whether the current striking sampling process needs to be terminated early by using the acquisition error of the local segment of the optical cable (i.e., the path error of P1) and the distribution of the subsequent striking predicted positions. This allows the current striking sampling process to balance information acquisition efficiency and accuracy. For example, it can ensure the accuracy of the skin length by offsetting the propagation process of vibration waves by soil at different locations, and it can also terminate the current striking sampling process early.

[0098] Furthermore, in this embodiment, after updating the value of th1 based on the path error of the marker points obtained in the current tapping sampling process, the updated th1 is used to obtain the marker points for the next tapping sampling process. This process avoids the problem of a large cumulative value of path error in subsequent tapping sampling processes while ensuring high information acquisition efficiency. By continuously updating th1, the path error and information acquisition efficiency can be dynamically changed in all subsequent tapping sampling processes. For example, when the path error is large, the path error is reduced by sacrificing information acquisition efficiency; when the information acquisition efficiency is low, the path error is appropriately increased to increase information acquisition efficiency. This ensures that all tapping sampling processes (or the entire information acquisition process) are both efficient and as accurate as possible overall.

[0099] Example 2:

[0100] As an example, the possible burial paths of optical cables can be obtained as follows:

[0101] For some optical cables equipped with positioning devices (such as Beidou positioning devices), obtain the coordinate positions of all positioning devices on each optical cable, and the line connecting all coordinate positions is used as the possible burial path of the optical cable.

[0102] As another example, the possible burial paths of optical cables can be obtained as follows:

[0103] The location where the optical cable emerges from the ground or the location of the shaft through which the optical cable passes is used to determine the possible burial path of the optical cable.

[0104] As another example, the possible burial paths of optical cables can be obtained as follows:

[0105] Based on the drawings obtained during the construction of the optical cable, the possible burial path of the optical cable is determined according to the route of the optical cable in the drawings.

[0106] In some other examples, based on the above examples, staff manually draw possible burial paths for optical cables according to urban roads or geographical environment.

[0107] As an example, workers move to a location along a possible burial path of the fiber optic cable, tap on it, and record the tapping time and coordinates. Specifically, this includes:

[0108] The work begins arbitrarily from the nearest marker point, moves at least 100 meters along the possible burial path of the optical cable to select a location, and taps at that location. In this embodiment, the same tapping force is used for all taps.

[0109] For example, a rubber hammer is used to strike the ground. To ensure the same striking force each time, the striking device in this embodiment includes a cube-shaped rubber hammer, four metal guide rails, and springs. Metal sliders are fixed around the hammer and slidably connected to each guide rail. A spring is installed on the back of the hammer (the side away from the ground), and its upper end is fixed to a cover plate above the guide rails (the cover plate is welded to the top of the four metal guide rails). By compressing the spring vertically upwards and then releasing it, the spring drives the hammer to strike the ground vertically downwards along the guide rails, thus completing one strike. In this embodiment, ensuring the same spring compression for each strike achieves the same striking force.

[0110] Other methods can also be used to achieve the same striking force in other embodiments, such as striking with a handheld rubber hammer with the same force. This embodiment does not specifically limit or elaborate on the striking method and striking device.

[0111] In addition, in this embodiment, a pressure sensor is installed inside the side of the hammer head that contacts the ground, and a positioning device (such as a Beidou positioning device) is installed on the striking device. When the pressure value read by the pressure sensor is greater than the preset pressure threshold (such as 500 Newtons), the time (i.e., the striking time) and positioning coordinates (the coordinates of the striking position) are recorded. In this embodiment, a high-precision quartz oscillator is used for timing, with a timing accuracy of 200 nanoseconds.

[0112] The tapping time and positioning coordinates are transmitted to the worker's handheld terminal (such as a mobile phone) via Bluetooth.

[0113] It should be noted that in this embodiment, the positioning coordinates obtained by the positioning device are all mapped to plane coordinate positions using the Mercator projection method.

[0114] As an optional example, the method for obtaining the signal waveform is as follows:

[0115] In this embodiment, the vibration signal acquisition device continuously acquires the impact vibration signal from the optical cable using pulses with a width of 1 microsecond. When the hammer strikes the ground and the handheld terminal receives the impact time, the handheld terminal sends the impact time to the vibration signal acquisition device via a wireless network (e.g., 5G network). The vibration signal acquisition device uses the impact time as the starting point and extracts a signal segment of a preset time length (e.g., 20 milliseconds) from the acquired impact vibration signal, using this signal segment as the signal waveform.

[0116] As a preferred example, the method for obtaining the signal waveform is as follows:

[0117] Considering that there may be interference when capturing signal waveforms for a preset time length (such as interference from vehicle and construction vibrations), this example involves striking the same location twice consecutively. Using the comparison example above, two signal waveforms are obtained. Fourier transforms are then performed on these two signal waveforms to obtain the spectral distribution of each signal waveform. Each spectral distribution includes all frequencies of the signal waveform and the amplitude corresponding to each frequency. The larger the amplitude, the stronger the response of the corresponding frequency; the smaller the amplitude, the weaker the response of the corresponding frequency; and an amplitude of 0 indicates that there is no response at the corresponding frequency.

[0118] For two spectral distributions of two signal waveforms, if the amplitudes at the same frequency in the two spectral distributions are not the same, then the amplitudes at the same frequency in the two spectral distributions are set to 0.

[0119] It should be noted that in this embodiment, if the ratio of the absolute value of the difference between the two amplitudes to the average of the two amplitudes is greater than 0.1, then the two amplitudes are determined to be different; otherwise, they are determined to be the same.

[0120] In this embodiment, the average spectral distribution is obtained by averaging the amplitudes at the same frequency in the two spectral distributions. The average spectral distribution is then transformed using the inverse Fourier transform algorithm to obtain the signal waveform obtained in this preferred example.

[0121] Note that, for ease of description, after two consecutive taps, the description will focus on the last tap.

[0122] It should be noted that the signal waveform obtained in the preferred example has less interference compared to the signal waveform obtained in the optional example.

[0123] As an optional example, the method for obtaining the tap event reception time is as follows:

[0124] In the impact vibration signal acquired by the vibration signal acquisition device, the signal segment with a preset time length (i.e., 20 milliseconds) before (including) the impact time is recorded as the noise signal waveform. The noise signal waveform is subjected to Fourier transform to obtain the noise spectrum. The noise spectrum contains the amplitude of each frequency. The maximum value of the amplitude is obtained and recorded as the noise threshold.

[0125] The spectral distribution obtained by performing a Fourier transform on the signal waveform is used to identify frequencies whose amplitudes are less than or equal to the noise threshold. The amplitudes of these frequencies are then set to 0. The inverse Fourier transform algorithm is then used to transform the spectral distribution to obtain a noise-filtered signal. The time corresponding to the first maximum point in the noise-filtered signal is recorded as the tap event reception time. In some embodiments, the obtained noise-filtered signal waveform can also be used as the signal waveform described in the subsequent steps of Embodiment 1.

[0126] As an example, the method for obtaining the signal strength of a signal waveform is as follows:

[0127] After the signal waveform is subjected to Fourier transform, the maximum value of the amplitude of all frequencies in the spectrum distribution is taken as the signal strength.

[0128] In other examples, the mean of the amplitudes of all frequencies in the spectral distribution can be used as the signal strength.

[0129] It should be noted that the vibration signal acquisition device acquires the signal waveform and transmits it to the worker's handheld terminal, and the signal strength of the signal waveform is obtained on the handheld terminal. In addition, steps S102 to S106 in Embodiment 1 are all executed on the handheld terminal, and all striking positions (including predicted striking positions and marker points) are displayed on the handheld terminal.

[0130] As an example, in step S101, starting from that position, other positions are tapped sequentially in a direction of increasing signal strength until the signal strength of the signal waveform in that direction decreases, at which point the tapping stops. This includes the following method:

[0131] Centered on this location, four tapping positions are randomly and evenly selected on a 2-meter radius circle. Each tapping position is tapped to obtain the signal strength. Among these four positions, the two positions with the largest signal strength difference are selected. The direction from the position with the smallest signal strength to the position with the largest signal strength is used as the movement direction (i.e., the direction of increasing signal strength). The staff selects a tapping position every 2 meters along this direction. When the signal strength of the current tapping position is less than that of the previous tapping position, the selection of a tapping position is stopped.

[0132] Specifically, when all signal strengths are 0, four striking positions are evenly selected on a circle with a radius of 2 meters, centered on the current striking position, and then the above process is repeated.

[0133] As another example, in step S101, starting from that position, other positions are tapped sequentially in the direction of increasing signal strength until the signal strength of the signal waveform in that direction decreases, at which point the tapping stops. This includes the following method:

[0134] Workers manually select a tapping location based on terrain or building obstacles, and then select a tapping location along the direction of increasing signal strength. If the signal strength at the current tapping location is less than that at the previous tapping location, the selection of a tapping location is stopped.

[0135] As an optional example, the method for obtaining the similarity of the impact vibration transmission of any two signal waveforms in step S103 is as follows:

[0136] The cosine similarity between any two signal waveforms is used as the similarity of the impact vibration transmission.

[0137] As a preferred example, the method for obtaining the similarity of the impact vibration transmission of any two signal waveforms in step S103 is as follows:

[0138] This embodiment takes into account that different soil conditions (such as soil moisture, thickness, sand and gravel conditions, etc.) result in different signal waveforms. For example, dry soil has a faster vibration transmission speed, more high-frequency components, and faster signal attenuation; moist soil has a slower transmission speed, fewer high-frequency components, and slower signal attenuation; rocky soil has a faster transmission speed, more high-frequency components, and very slow signal attenuation.

[0139] Performing Fourier transforms on any two signal waveforms yields two spectral distributions, each of which includes all frequencies of the signal waveform and the amplitude corresponding to each frequency.

[0140] In this embodiment, all frequencies are divided into N equal intervals. For any spectral distribution, the mean of all amplitudes in each interval of the spectral distribution is obtained and recorded as the average amplitude of each interval in any spectral distribution.

[0141] For any interval in any spectral distribution, set the amplitude of all intervals outside that interval to 0 to obtain a new spectral distribution. Use the inverse Fourier transform algorithm to transform the new spectral distribution to obtain the filtered signal waveform of that region. Use the least squares method to fit the filtered signal waveform into a polynomial (e.g., a 3rd degree polynomial). Use the parameters of the polynomial as the attenuation characteristics of that interval.

[0142] Thus, each interval in any spectral distribution corresponds to an average amplitude and an attenuation characteristic.

[0143] The average amplitude of all intervals in any spectral distribution is used to construct a spectral distribution vector. The cosine similarity of the spectral distribution vectors corresponding to the spectral distributions of any two signal waveforms is denoted as the first similarity.

[0144] For the attenuation characteristics of the same interval in the spectral distribution of any two signal waveforms, the cosine similarity of the two attenuation characteristics in that interval is denoted as the attenuation similarity of that interval; the mean of the two average amplitudes in that interval is denoted as the attention weight of that interval.

[0145] The attention weights of all intervals are normalized using the softmax formula. The second similarity is obtained by weighted summation of the decay similarity of all intervals using the normalized attention weights of each interval.

[0146] The mean of the first similarity and the mean of the second similarity are denoted as the similarity of the impact vibration transmission.

[0147] This embodiment uses N=20 as an example for description.

[0148] Although the impact vibration transmission similarity obtained by the above optional examples requires less computation, its accuracy or resistance to error interference is not as high as the vibration transmission similarity obtained by the above preferred examples.

[0149] Example 3:

[0150] The difference between this embodiment and Embodiment 1 is that Embodiment 1 describes a process where multiple tapping sampling processes occur throughout the historical process, resulting in multiple marker points, and then uses the current tapping sampling process as an example. This embodiment describes the method for obtaining marker points when the number of tapping sampling processes throughout the historical process is less than N1.

[0151] If no sampling process was performed during the historical process, then starting from the fiber optic cable burial point, move at least 100 meters along the possible burial path of the cable to select a location. Then, following the method described in the example, tap other locations sequentially in the direction of increasing signal strength until the signal strength of the waveform in that direction decreases, at which point stop tapping. Then, continue tapping manually at other locations in the opposite direction until the staff finds the location with the strongest signal strength and marks it as a marker point.

[0152] Then, starting from that marker point, move at least 100 meters along the possible burial path of the optical cable to select a location, and then obtain a marker point according to the method described in this embodiment. Continue in this manner until N1 marker points are obtained. This embodiment uses N1=3 as an example for description.

[0153] After obtaining N1 marker points, the method of Example 1 is used to obtain subsequent marker points. In Example 1, the first preset threshold th1 is continuously updated through the path error mentioned above, ensuring that the path formed by connecting the marker points can relatively accurately fit and represent the optical cable, while achieving high information acquisition efficiency.

[0154] In this embodiment, the initial value of the first preset threshold th1 (that is, the value of th1 when the N1+1th marker point is obtained) is set to 0.1.

[0155] Specifically, the marker point with the highest vibration transmission similarity in step S103 of Embodiment 1 is denoted as P. When the maximum vibration transmission similarity is less than the preset threshold th3 (for example, less than th3=0.6), then the subsequent steps in Embodiment 1 will no longer be executed, and the marker point will be obtained using the method described above in this embodiment during the current tapping sampling process.

[0156] Example 4:

[0157] Following the method in Example 1, as marker points are continuously acquired, when the distance between the marker point and the optical cable burial point is less than or equal to 150 meters, the location of all marker points, the tapping time of the marker points, the tapping event reception time, and the signal waveform are used as the information collection results between the optical cable burial point and the optical cable burial point.

[0158] The lines connecting all the marked points form the route for the underground fiber optic cable.

[0159] Furthermore, in one embodiment, the optical cable sheath length at each marker point is obtained using the comparative embodiment in Embodiment 1.

[0160] In this embodiment, as an optional example, the method for obtaining the optical cable sheath length of each marker point is as follows:

[0161] The location of the fiber optic cable burial point is obtained using a positioning device. The distance between the burial point and each marker point is obtained, and the sum of this distance and the sheath length of the burial point is taken as the sheath length of each marker point.

[0162] As a preferred example, the method for obtaining the fiber optic cable sheath length at each marker point is as follows:

[0163] Let x be the similarity of the impact vibration transmission of the signal waveforms at any two marked points, and let exp(-x) be the cluster distance between the two marked points. The smaller the cluster distance (i.e., the greater the similarity of the impact vibration transmission), the more the vibration waves can cancel each other out in the soil. exp() represents an exponential function with the natural constant as the base.

[0164] Based on the clustering distance between all markers, K-Means clustering is performed on all markers to obtain K1 categories.

[0165] For any category, the marker point in that category that is closest to the embedment point in terms of Euclidean distance is selected and designated as the reference point; the Euclidean distance between the embedment point and the reference point is added to the skin length of the embedment point and used as the skin length of the reference point.

[0166] For any marker point other than the reference point in this category, the time interval between the tapping time and the reception time of the tapping event at that marker point is denoted as M1, and the time interval between the tapping time and the reception time of the tapping event at the reference point is denoted as M2. The product of the absolute value of the difference between M1 and M2 and the speed of light is denoted as the relative skin length between the marker point and the reference point. The calculation process of the relative skin length can cancel out the propagation of vibration waves in the soil. The skin length of the reference point plus the relative skin length is taken as the marker point.

[0167] All categories are processed using the method described above to obtain the skin length of all marked points. This embodiment uses K1=5 as an example for explanation.

[0168] The skin length of the markers obtained in this preferred example is more accurate compared to the comparative and optional examples described above.

[0169] It should be noted that the embedment point and the embedment point are also regarded as marker points. Their positions are recorded and tapped (simply tap with a hammer). The skin length of the embedment point and the embedment point can be accurately obtained by using the comparative example in Example 1.

[0170] At this point, the positions and sheath lengths of all marked points are taken as the final optical cable sheath length information. The vibration signal acquisition device, the tapping device, and the handheld terminal were used as instruments for acquiring the optical cable sheath length information.

[0171] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for collecting optical cable sheath length information based on the tapping vibration of an optical cable route survey instrument, characterized in that, The method includes the following steps: Each tap sampling in history yields a marker point; the process of obtaining a marker point during the current tap sampling includes: D1: Perform several taps on the ground, record the signal waveform of the optical cable after each tap, and predict the position P1 of the next tap based on the signal strength of the signal waveforms at all tap locations. D2: Obtain the similarity of the vibration transmission of the waveform signal after being struck at P1 with the signal waveform of each marker point in history. The marker point with the greatest similarity in vibration transmission is denoted as P. The relative skin length between P and P1 is obtained by using the transmission time difference of the vibration signals of P and P1 in the optical cable. The difference between the length of the path formed by connecting all marker points between P1 and P and the relative skin length is used as the path error of P1. D3: Based on the signal strength of the signal waveforms of all striking positions, including P1, predict the position P2 of the next striking. If the difference between the path error of P1 and the distance between P1 and P2 is less than the first preset threshold th1, P1 is used as the marker point obtained by the current striking sample; if it is not less than th1, P2 is regarded as P1 and D2 and D3 are repeated. D4: After updating the value of th1 based on the path error of the marker point obtained in the current tapping sampling process, use the updated th1 to obtain the marker point for the next tapping sampling process. The fiber optic cable sheath length information was obtained based on the marker points from all the tapping sampling processes.

2. The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument as described in claim 1, characterized in that, The specific steps for predicting the next strike position P1 based on the signal strength of the signal waveforms at all strike positions are as follows: For all tapping positions in the current tapping sampling process, the signal intensity of the signal waveform at all tapping positions is normalized, and the normalized signal intensity is set as the weight of the tapping position. The weighted sum of all tapping positions is recorded as the predicted tapping position, denoted as P1.

3. The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument as described in claim 1, characterized in that, The specific steps for obtaining the similarity of the waveform signal after being struck at P1 with the signal waveform of each marked point in history in terms of the impact vibration transmission are as follows: For any two signal waveforms corresponding to P1 and the marker point, perform Fourier transform on the two signal waveforms to obtain two spectral distributions. Each spectral distribution includes all frequencies of the signal waveform and the amplitude corresponding to each frequency. Divide all frequencies of each spectral distribution into several intervals. For any spectral distribution, obtain the mean of all amplitudes in each interval of the spectral distribution, which is denoted as the average amplitude of each interval of the spectral distribution. For any interval in any spectral distribution, set the amplitude of all intervals outside that interval to 0 to obtain a new spectral distribution. Use the inverse Fourier transform algorithm to transform the new spectral distribution to obtain the filtered signal waveform of that region. Use the parameters of the polynomial fitted to the filtered signal waveform as the attenuation characteristics of that interval. The similarity of the impact vibration transmission is obtained by the similarity of the average amplitude and the similarity of the attenuation characteristics of all intervals in the spectral distribution of any two signal waveforms. The similarity of the impact vibration transmission is positively correlated with the similarity of the average amplitude and the similarity of the attenuation characteristics, respectively.

4. The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument as described in claim 1, characterized in that, The specific formula for updating the value of th1 based on the path error of the marker point obtained during the current tap sampling process is as follows: Where T1 represents the updated value of th1, and T0 represents the original value of th1; L0 represents the path error of the marker point obtained in the current tap sampling process, and L represents the length of the path of the marker point obtained in the current tap sampling process; th2 represents the second preset threshold.

5. The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument according to claim 1, characterized in that, The specific steps for obtaining the optical cable sheath length information based on the marker points of all tapping sampling processes are as follows: Cluster all marker points by utilizing the similarity of the signal waveforms transmitted by the impact vibration between any two marker points to obtain several categories; for any category and the burial point of the optical cable, the marker point closest to the burial point in that category is selected and recorded as the reference point; the distance between the burial point and the reference point plus the sheath length of the burial point is obtained as the sheath length of the reference point. For any marker point other than the reference point in this category, obtain the relative skin length between the marker point and the reference point; add the skin length of the reference point to the relative skin length to obtain the marker point; The location and length of all marker points are used as the results of optical cable length information collection.

6. The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument according to claim 1 or 5, characterized in that, The specific steps for obtaining the relative skin length are as follows: For any two markers including P and P1, the time interval between the tapping time and the tapping event reception time of each marker is obtained, and the product of the difference between the time intervals of the two markers and the speed of light is used as the relative skin length of the two markers.

7. The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument according to claim 3, characterized in that, The specific steps for obtaining the similarity of impact vibration transmission based on the similarity of the average amplitude and attenuation characteristics of all intervals in the spectral distribution of any two signal waveforms are as follows: The average amplitude of all intervals in any spectral distribution is used to construct a spectral distribution vector; the cosine similarity of the spectral distribution vectors corresponding to the spectral distributions of any two signal waveforms is denoted as the first similarity. For the attenuation characteristics of the same interval in the spectral distribution of any two signal waveforms, the cosine similarity of the two attenuation characteristics in the same interval is denoted as the attenuation similarity of the same interval; the mean of the two average amplitudes in the same interval is denoted as the attention weight of the same interval. The attention weights of all intervals are normalized, and the second similarity is obtained by weighted summation of the decay similarity of all intervals using the normalized attention weights of each interval. The mean of the first similarity and the mean of the second similarity are denoted as the similarity of the impact vibration transmission.

8. The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument according to claim 5, characterized in that, The specific steps for clustering all marker points using the similarity of the impact vibration transmission of signal waveforms between any two marker points to obtain several classes are as follows: Let x be the similarity of the signal waveforms transmitted by the impact vibration between any two marker points, and let exp(-x) be the clustering distance between any two marker points. Based on the clustering distance between all marker points, perform K-Means clustering on all marker points to obtain several categories.

9. The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument according to claim 1, characterized in that, The specific steps for obtaining the signal waveform are as follows: In the impact vibration signal generated in the optical cable, a signal segment of a preset time length is extracted starting from the impact time; for two signal segments obtained after two consecutive impacts at the same position; the two signal segments are subjected to Fourier transform to obtain the spectral distribution of each signal segment; For the two spectral distributions of the two signal segments, if the amplitudes at the same frequency in the two spectral distributions are not the same, then the amplitudes at the same frequency in the two spectral distributions are set to 0; the average spectral distribution is obtained by averaging the amplitudes at the same frequency in the two spectral distributions, and the signal waveform is obtained by transforming the average spectral distribution using the inverse Fourier transform algorithm.

10. The method for collecting optical cable sheath length information based on the vibration of an optical cable route survey instrument according to claim 5, characterized in that, The insertion and exit points of the optical cable are also regarded as marker points, and the insertion and exit points are tapped to obtain the time interval between the tapping time and the tapping event reception time. The product of the time interval and the speed of light is used as the sheath length of the insertion or exit point.

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