CN113532808B - Multichannel monitoring method and system based on vibration-sensitive optical fiber sensing technology - Google Patents
Multichannel monitoring method and system based on vibration-sensitive optical fiber sensing technology Download PDFInfo
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Abstract
The invention relates to a multichannel monitoring method based on vibration sensitive optical fiber sensing technology, based on that one end of each optical fiber to be tested receives the same pulse light at the same time, aiming at the electric signals to be compared corresponding to the superimposed back scattering light signals from each optical fiber to be tested, combining the reference electric signals corresponding to the superimposed back scattering light signals of each optical fiber to be tested in a quiet state, applying a binary tree idea to carry out iterative screening, realizing the confirmation of the vibration disturbance position on each optical fiber to be tested, accelerating the optical fiber monitoring and screening process through the analysis of the superimposed signals in the whole process, and having stable accuracy in practical application; correspondingly, the invention also designs a system for realizing the method, based on the module construction of the designed transmitting light path and receiving light path, the 1xN coupler and the N optical switches are used for forming a multi-channel structure to butt joint each optical fiber to be detected, the application of the designed multi-channel monitoring method can be realized rapidly, and the monitoring efficiency of the multi-optical fiber to be detected is improved effectively.
Description
Technical Field
The invention relates to a multichannel monitoring method and system based on a vibration sensitive type optical fiber sensing technology, and belongs to the technical field of optical fiber sensing.
Background
With the development of optical fiber technology, the arrangement amount of optical fibers is greatly increased, the arrangement environment is more and more complicated and diversified, a large number of optical fiber cables can pass through areas such as deserts, forests, oceans and the like, and the probability of being damaged by the outside is greatly increased, so that the health monitoring of the optical fiber cables is particularly important.
The traditional line monitoring scheme, such as using a wireless vibration sensor, an acoustic emission sensor and the like, is an active sensor, needs independent power supply, and is inconvenient for large-area networking monitoring; further, the unmanned plane, the robot, and the like have problems such as high unit man-hour cost, limited monitoring range, and the like.
By using the distributed optical fiber sensing technology, vibration sensitive distributed optical fiber sensing equipment can be utilized to monitor the state of a single monitoring line in real time and on line for a long time. However, most existing monitoring methods generally use a polling measurement method when monitoring multiple lines, so that other lines cannot be effectively monitored in a polling gap, and as the polling lines increase, the effective measurement duration of each line is shorter.
Disclosure of Invention
The invention aims to solve the technical problem of providing a multichannel monitoring method based on a vibration-sensitive optical fiber sensing technology, which is based on parallel real-time monitoring of a plurality of optical fibers to be monitored and can effectively improve the monitoring efficiency of the optical fibers to be monitored.
The invention adopts the following technical scheme for solving the technical problems: the invention designs a multichannel monitoring method based on a vibration-sensitive optical fiber sensing technology, which is used for simultaneously monitoring the vibration states of N optical fibers to be tested, which are identical in material and known in length, and comprises the following steps:
step A, based on that one end of each optical fiber to be tested receives the same pulse light at the same time, the superimposed back scattering light signals from each optical fiber to be tested are converted into corresponding electric signals to be compared, and the step B is carried out;
b, comparing the electric signals to be compared with the reference electric signals corresponding to the superimposed back scattering light signals obtained in the step A under the quiet state of each optical fiber to be compared, judging whether the electric signals to be compared have abnormal amplitude positions or not, and if so, respectively aiming at each abnormal amplitude position, and entering the step C; otherwise, judging that the optical fibers to be tested do not generate vibration disturbance;
step C, determining the length position of the optical fiber corresponding to the abnormal amplitude position as an abnormal position, selecting each optical fiber to be detected with the length not smaller than the abnormal position as each optical fiber to be analyzed, forming a set to be analyzed, and then entering the step D;
step D, obtaining a difference value between the signal amplitude of the electric signal to be compared corresponding to the abnormal amplitude position and the signal amplitude of the reference electric signal corresponding to the abnormal amplitude position, combining the preset single fiber vibration light amplitude variation quantity, confirming the number of target disturbance fibers corresponding to the set to be analyzed, assigning the number to M, and then entering the step E;
step E, randomly selecting half of optical fibers to be analyzed from a set to be analyzed, executing the step A to the step B, judging whether the signal amplitude of the electric signal to be compared corresponding to each optical fiber to be analyzed at the position of the abnormal amplitude is abnormal compared with that of a reference electric signal, if so, obtaining the difference value between the two corresponding to the abnormality, combining the preset vibration light amplitude variation quantity of a single optical fiber, determining the number of target disturbance optical fibers corresponding to the optical fibers to be analyzed, and then entering the step G, otherwise, entering the step F;
step F, combining the optical fibers to be analyzed which are not selected in the set to be analyzed in the adjacent previous step E into one set to be analyzed, updating the optical fibers to be analyzed selected in the adjacent previous step E into the optical fibers to be analyzed, and returning to the step E according to the set to be analyzed obtained in the step;
step G, judging whether the number of the target disturbance fibers corresponding to the selected optical fibers to be analyzed in the adjacent previous step E to be analyzed is equal to the number of the target disturbance fibers corresponding to the belonging to the to-be-analyzed set, if so, combining the selected optical fibers to be analyzed into one to-be-analyzed set, determining that the number of the target disturbance fibers corresponding to the to-be-analyzed set is the number of the target disturbance fibers corresponding to the selected optical fibers to be analyzed, updating the unselected optical fibers in the adjacent previous step E to be non-to-be-analyzed, and then entering the step H aiming at the to-be-analyzed set obtained in the step;
otherwise, combining the optical fibers to be analyzed selected in the adjacent previous step E to form a to-be-analyzed set, determining the number of the target disturbance optical fibers corresponding to the to-be-analyzed set to be the number of the target disturbance optical fibers corresponding to the optical fibers to be analyzed selected in the adjacent previous step E to be-analyzed set, combining the optical fibers not selected in the adjacent previous step E to be-analyzed set to form a to-be-analyzed set, determining the number of the target disturbance optical fibers corresponding to the to-be-analyzed set to be the difference value between the number of the target disturbance optical fibers corresponding to the adjacent previous step E to be-analyzed set and the number of the target disturbance optical fibers corresponding to the selected to-be-analyzed optical fibers, and then respectively aiming at each to-be-analyzed set obtained in the step to enter the step H;
step H, judging whether the number of the optical fibers to be analyzed in the set to be analyzed is equal to the number of the target disturbance optical fibers corresponding to the set to be analyzed, if so, updating each optical fiber to be analyzed in the set to be each vibration disturbance optical fiber corresponding to the position of the abnormal amplitude, otherwise, returning to the step E for the set to be analyzed;
and C, executing the step C to the step H aiming at the abnormal amplitude position, and ending the operation of searching the vibration disturbance optical fibers aiming at the abnormal amplitude position when the number of the vibration disturbance optical fibers corresponding to the abnormal amplitude position is equal to M.
As a preferred technical scheme of the invention: and in the step E, half optical fibers to be analyzed, which are adjacent to each other in position, are randomly selected from the set to be analyzed, and the steps A to B are executed.
In view of the foregoing, the present invention further provides a system for implementing a multi-channel monitoring method based on a vibration-sensitive optical fiber sensing technology, which combines connection of multiple switches to each optical fiber to be tested based on each designed module, and applies the designed multi-channel monitoring method to monitor multiple optical fibers to be tested in parallel and in real time, so as to effectively improve the monitoring efficiency of the multiple optical fibers to be tested.
The invention adopts the following technical scheme for solving the technical problems: the invention designs a multichannel monitoring method system based on vibration sensitive optical fiber sensing technology, which comprises a 1xN coupler and N optical switches, wherein N paths of interfaces on one side of the 1xN coupler are respectively connected with one end of each optical fiber to be tested through the optical switches, and a single path of interfaces on the other side of the 1xN coupler are used for transmitting the same pulse light to each optical fiber to be tested and receiving superimposed back scattering light signals from each optical fiber to be tested.
As a preferred technical scheme of the invention: the device comprises a laser, an AOM acousto-optic crystal, an erbium-doped fiber amplifier, a fiber loop device and a photoelectric detector, wherein the output end of the laser is connected with the input end of the AOM acousto-optic crystal in a butt joint mode, the AOM acousto-optic crystal is used for modulating laser from the laser into a pulse detection optical signal, the output end of the AOM acousto-optic crystal is connected with the input end of the erbium-doped fiber amplifier in a butt joint mode, the output end of the AOM acousto-optic crystal is used for conveying the pulse detection optical signal to the erbium-doped fiber amplifier, and the erbium-doped fiber amplifier amplifies the pulse detection optical signal according to a preset proportion;
the output end of the erbium-doped optical fiber amplifier is connected with the input end of the optical fiber circulator, the optical fiber circulator receives the pulse detection optical signals from the erbium-doped optical fiber amplifier, one end of the optical fiber circulator is connected with a single-path interface on the 1xN coupler in a butt joint mode, the pulse detection optical signals are transmitted to each optical fiber to be detected, the power of the pulse detection optical signals received by each optical fiber to be detected is fixed, the end of the optical fiber circulator receives the superimposed back scattering optical signals from each optical fiber to be detected, the output end of the optical fiber circulator is connected with the input end of the photoelectric detector, and the photoelectric detector converts the superimposed back scattering optical signals into corresponding electric signals.
Compared with the prior art, the multichannel monitoring method based on the vibration-sensitive optical fiber sensing technology has the following technical effects:
the invention designs a multichannel monitoring method based on vibration sensitive optical fiber sensing technology, which is based on that one end of each optical fiber to be tested receives the same pulse light at the same time, and aims at the electric signals to be compared corresponding to the superimposed back scattering light signals from each optical fiber to be tested, combines the reference electric signals corresponding to the superimposed back scattering light signals of each optical fiber to be tested in a quiet state, applies a binary tree idea to carry out iterative screening, realizes the confirmation of the vibration disturbance position on each optical fiber to be tested, and accelerates the optical fiber monitoring and screening process through the analysis of the superimposed signals in the whole process, and has stable accuracy in practical application; correspondingly, the invention also designs a system for realizing the method, based on the module construction of the designed transmitting light path and receiving light path, the 1xN coupler and the N optical switches are used for forming a multi-channel structure to butt joint each optical fiber to be detected, the application of the designed multi-channel monitoring method can be realized rapidly, and the monitoring efficiency of the multi-optical fiber to be detected is improved effectively.
Drawings
FIG. 1 is a schematic diagram of a system architecture of a multi-channel monitoring method based on vibration-sensitive fiber sensing technology according to the present invention;
FIG. 2 is a schematic diagram of an optical switch in accordance with the present invention;
FIG. 3 is a schematic diagram of signals when the optical fiber is undisturbed in an embodiment of the invention;
FIG. 4 is a schematic diagram of disturbance signals generated at 1000m to 2000m locations on an optical fiber in an embodiment of the present invention;
FIG. 5 is a graph of a superposition of measurements of a length of 5000m fiber and a length of 15000m fiber in an example of a contemplated application of the present invention;
FIG. 6 is a schematic diagram of a disturbance signal generated at a position of 1000m to 2000m for a 5000m optical fiber in an embodiment of the invention;
fig. 7 is a schematic diagram of the turn-off of an optical switch control circuit in a designed application of the present invention.
Detailed Description
The following describes the embodiments of the present invention in further detail with reference to the drawings.
The invention designs a multichannel monitoring method and a multichannel monitoring system based on a vibration sensitive optical fiber sensing technology, which are used for realizing simultaneous monitoring of vibration states of N optical fibers to be tested, which are identical in material and known in length, based on the construction of the designed system in practical application, wherein the designed system specifically comprises a laser, an AOM acousto-optic crystal, an erbium-doped optical fiber amplifier, an optical fiber circulator, a photoelectric detector, a 1xN coupler and N optical switches as shown in fig. 1; the output end of the AOM acousto-optic crystal is connected with the input end of the erbium-doped optical fiber amplifier in a butt joint mode, and the output end of the AOM acousto-optic crystal is used for amplifying the pulse detection optical signal according to a preset proportion.
The output end of the erbium-doped optical fiber amplifier is connected with the input end of the optical fiber circulator, the optical fiber circulator receives the pulse detection optical signal from the erbium-doped optical fiber amplifier, one end of the optical fiber circulator is connected with a one-way interface on the 1xN coupler, the other side of the 1xN coupler is connected with one end of each optical fiber to be tested through an optical switch, and the structure of the N optical switches is shown in figure 2; and transmitting the pulse detection optical signals to the connected optical fibers to be detected, wherein the power of the pulse detection optical signals received by the optical fibers to be detected is fixed, the superimposed back scattering optical signals from the connected optical fibers to be detected are received by the end of the optical fiber circulator, the output end of the optical fiber circulator is connected with the input end of the photoelectric detector, and the photoelectric detector converts the superimposed back scattering optical signals into corresponding electric signals.
Based on the construction of the designed system, the optical fibers to be detected are arranged adjacently and side by side according to the length increment or decrement, are respectively connected into an N-way interface on the other side of the 1xN coupler through the optical switch, and are designed according to the following steps, so that the vibration states of N optical fibers to be detected with the same material and known length are monitored simultaneously.
And A, based on that one end of each optical fiber to be tested receives the same pulse light at the same time, converting the superimposed back scattering light signals from each optical fiber to be tested into corresponding electric signals to be compared, and entering the step B.
B, comparing the electric signals to be compared with the reference electric signals corresponding to the superimposed back scattering light signals obtained in the step A under the quiet state of each optical fiber to be compared, judging whether the electric signals to be compared have abnormal amplitude positions or not, and if so, respectively aiming at each abnormal amplitude position, and entering the step C; otherwise, judging that the optical fibers to be tested do not generate vibration disturbance; here, the abnormal amplitude refers to an abnormality in which the variance value corresponding to the amplitude within a unit time varies, and the specific discrimination value is the amplitude variance.
In practical applications, as shown in fig. 3, the reference electrical signal corresponding to the superimposed back-scattered light signal obtained in the step a is performed by each optical fiber to be measured in a quiet state, and when each optical fiber to be measured is in a quiet state, the amplitude of the demodulated signal is approximately consistent with the distance, but in practical measurement due to the attenuation of light in the optical fiber, the amplitude of the demodulated signal is attenuated linearly with the distance.
And C, determining the length position of the optical fiber corresponding to the abnormal amplitude position as an abnormal position, selecting each optical fiber to be detected with the length not smaller than the abnormal position as each optical fiber to be analyzed, forming a set to be analyzed, and then entering the step D.
And D, obtaining a difference value between the signal amplitude of the electric signal to be compared corresponding to the abnormal amplitude position and the signal amplitude of the reference electric signal corresponding to the abnormal amplitude position, combining the preset single fiber vibration light amplitude variation quantity, confirming the number of the target disturbance fibers corresponding to the set to be analyzed, assigning the number to M, and then entering the step E.
And E, randomly selecting half of the optical fibers to be analyzed from the set to be analyzed, executing the steps A to B, judging whether the signal amplitude of the electric signal to be compared corresponding to each optical fiber to be analyzed at the position of the abnormal amplitude is abnormal compared with that of the reference electric signal, if so, obtaining the difference value between the two corresponding to the abnormality, combining the preset vibration light amplitude variation quantity of a single optical fiber, determining the number of the target disturbance optical fibers corresponding to the optical fibers to be analyzed, and then entering the step G, otherwise, entering the step F.
In the practical implementation application of the step E, based on that the optical fibers to be tested are arranged adjacent to each other in parallel in increasing or decreasing length, half of the optical fibers to be analyzed, which are adjacent to each other, are randomly selected from the set to be analyzed, and the steps a to B are executed, so as to further judge whether the signal amplitude of the electrical signal to be compared corresponding to each optical fiber to be analyzed at the position of the abnormal amplitude is abnormal compared with the reference electrical signal, and then make corresponding operation according to different judging results.
Here, in the step E, there is an abnormality, that is, when a strong vibration occurs somewhere on the optical fiber to be measured, the vibration causes micro-strain to the optical fiber to cause a refractive index change, so that the intensity of the back-scattered light is affected, and the demodulated signal is shown in fig. 4, for example, when a disturbance occurs at a position of 1000m to 2000m, the amplitude and silence of the signal are significantly changed.
In practical application, when one optical fiber to be detected with the length of 15000m and one optical fiber to be detected with the length of 5000m are monitored simultaneously, the electric signals corresponding to the returned superimposed back scattering signals are in a superimposed state of the two in amplitude, for example, the signal amplitude of the front 5000m is integrally lifted, and the signal amplitude of the rear 10000m is consistent with that when the 15000m signals are measured independently as shown in fig. 5; in practical application, when the optical fiber to be tested with the wavelength of 5000m is disturbed by 1000-2000 m as shown in fig. 6, the optical fiber to be tested is reflected on the whole signal, and the abnormal change of the amplitude of the signal at the position of 1000-2000 m can be seen. Therefore, the characteristics of the electric signals corresponding to the superimposed scattered light signals under the quiet state of the optical fibers to be detected are recorded, then the electric signals to be compared obtained in the period of time are analyzed every other time such as 10 seconds to be compared with the reference electric signals, and whether suspicious disturbance exists on the optical fibers to be detected is judged by judging whether the average value of the amplitude values of the signal amplitude values of the various parts of the comparison circuit in the time segment is consistent with the reference electric signals.
And F, combining the optical fibers to be analyzed which are not selected in the adjacent to-be-analyzed set in the previous step E into one to-be-analyzed set, updating the optical fibers to be analyzed selected in the adjacent to-be-analyzed set in the previous step E into non-to-be-analyzed optical fibers, and returning to the step E according to the to-be-analyzed set obtained in the previous step.
And G, judging whether the number of the target disturbance fibers corresponding to the selected optical fibers to be analyzed in the adjacent previous step E to be analyzed is equal to the number of the target disturbance fibers corresponding to the belonging to the to-be-analyzed set, if so, combining the selected optical fibers to be analyzed into one to-be-analyzed set, determining that the number of the target disturbance fibers corresponding to the to-be-analyzed set is the number of the target disturbance fibers corresponding to the selected optical fibers to be analyzed, updating the unselected optical fibers in the adjacent previous step E to be non-to-be-analyzed, and then entering the step H aiming at the to-be-analyzed set obtained in the step.
Otherwise, combining the optical fibers to be analyzed selected in the adjacent previous step E to form an analysis set, determining the number of the target disturbance optical fibers corresponding to the analysis set to be the number of the target disturbance optical fibers corresponding to the optical fibers to be analyzed selected in the adjacent previous step E to be analyzed, combining the optical fibers not selected in the adjacent previous step E to form an analysis set, determining the number of the target disturbance optical fibers corresponding to the analysis set to be the difference between the number of the target disturbance optical fibers corresponding to the adjacent previous step E to be analyzed and the number of the target disturbance optical fibers corresponding to the optical fibers to be analyzed, and then respectively aiming at each analysis set obtained in the step to enter the step H.
And H, judging whether the number of the optical fibers to be analyzed in the set to be analyzed is equal to the number of the target disturbance optical fibers corresponding to the set to be analyzed, if so, updating each optical fiber to be analyzed in the set to be each vibration disturbance optical fiber corresponding to the position of the abnormal amplitude, otherwise, returning to the step E aiming at the set to be analyzed.
And C, executing the step C to the step H aiming at the abnormal amplitude position, and ending the operation of searching the vibration disturbance optical fibers aiming at the abnormal amplitude position when the number of the vibration disturbance optical fibers corresponding to the abnormal amplitude position is equal to M.
The design is applied to practice, for example, the number of the optical fibers to be measured is 4, the lengths of the optical fibers to be measured are Lm, 2Lm, 3Lm and 4Lm, if the undisturbed 4 optical fibers to be measured, namely, the 4 optical fibers to be measured in a quiet state are measured separately, the signal waveforms of the front Lm are similar, and if the signals measured by the undisturbed 4 optical fibers to be measured are overlapped, the signal waveform characteristics of the front Lm are consistent with the measurement results of the front Lm of any single optical fiber to be measured. By analogy, lm to 2Lm signal waveform characteristics in the superposition result of the 4 optical fibers to be tested are consistent with Lm to 2Lm measurement results of the optical fibers 2, 3 and 4 to be tested; the superposition result of 4 optical fibers to be tested is that the waveform characteristics of signals from 2Lm to 3Lm are consistent with the measurement result from 2Lm to 3Lm of the optical fibers to be tested 3 and 4; and 4 optical fibers to be tested are superposed, wherein the waveform characteristics of the signals from 3Lm to 4Lm are consistent with the measurement results from 3Lm to 4Lm of the optical fibers to be tested 4. Therefore, when one optical fiber to be tested is continuously disturbed, the signal waveforms overlapped by a plurality of optical fibers to be tested can clearly reflect corresponding disturbance. When the signal superimposed by the 4 optical fibers to be detected is monitored to have obvious continuous disturbance at a certain position, the occurrence position of the event is preferentially judged. When the vibration event is in the range of 3Lm to 4Lm, the vibration can be directly judged to occur at the position of the optical fiber 4 to be measured, when the vibration event is in the range of 2Lm to 3Lm, the vibration can be directly judged to occur at the position of the optical fiber 3 to be measured or the optical fiber 4 to be measured, and so on. By the method, when N optical fibers to be measured are actually measured, M optical fibers to be measured, which are unlikely to vibrate, can be rapidly distinguished.
In application, each optical fiber to be detected which is eliminated by an algorithm is turned off by controlling N optical switches so as to reduce interference signals, and other parts of optical fibers to be detected are turned off selectively by optimizing an instruction by the algorithm, so that further discrimination of suspected disturbance optical fibers to be detected is realized; in a specific embodiment, the optical switch is controlled to turn off the L optical fibers to be tested, in which vibration is not likely to occur, in the remaining (N-L) optical fibers to be tested, so that in order to conveniently determine the position where a specific disturbance occurs, we directly selectively turn off the remaining one half of the optical fibers to be tested, and when the remaining one half of the optical fibers to be tested are turned off, preferentially select a series of optical fibers to be tested with adjacent positions. As shown in FIG. 7, the broken line represents L fibers to be tested which are unlikely to be disturbed and are eliminated, and the red line represents (N-L)/2 fibers to be tested which are close in geographic position and are ready to be turned off. And (3) referring to the rest (N-L)/2 optical fibers to be measured in the step (2), comparing the obtained signals with the background, judging that the event occurs on the conducted (N-L)/2 optical fibers to be measured if the threatening disturbance event still exists in the measurement, otherwise, on the turned-off (N-L)/2 optical fibers to be measured, turning on the turned-off optical fibers to be measured, and turning off the optical fibers to be measured just measured.
And repeating the application until the specific position of the disturbance on the specific optical fiber to be detected is judged.
In practical applications, when there is a continuous threatening disturbance occurring at the same location of different optical fibers to be tested, the measured signal amplitude will only change at the same location. At the moment, whether one optical fiber to be tested or multiple optical fibers to be tested is affected by disturbance can be judged through the amplitude change. When no disturbance occurs, the average value of the amplitude of N optical fibers to be measured, which are measured in a period of time, superimposed at a certain position is Q, the average value of the amplitude of a single optical fiber to be measured, which is measured in the position in a period of time, is Q/N, when the position of the single optical fiber to be measured generates a certain degree of disturbance, the variation of the amplitude is delta Q, and the disturbance event of a plurality of optical fibers to be measured at the same time at the position is judged by calculating the multiple relation between the variation delta Q of the amplitude of the disturbance position of the total optical fiber signal to be measured and delta Q. The specific optical fibers to be tested with disturbance can be judged one by one according to the judging method.
Furthermore, when disturbance that the positions of different optical fibers to be detected are not coincident occurs, the threatening disturbance at a plurality of positions can be judged by comparing the disturbance with the reference electric signal of the optical fiber to be detected in a quiet state, and the specific disturbance optical fiber to be detected is examined from far to near according to the disturbance occurrence position. In addition, in the process of checking, the optical fiber to be checked possibly appearing in other disturbance is marked, and the judging range is greatly reduced when the optical fiber to be checked in which the disturbance in the next position occurs is checked.
According to the multichannel monitoring method based on the vibration sensitive optical fiber sensing technology, based on the fact that one end of each optical fiber to be tested receives the same pulse light at the same time, aiming at the electric signals to be compared corresponding to the superimposed back scattering light signals from each optical fiber to be tested, the reference electric signals corresponding to the superimposed back scattering light signals of each optical fiber to be tested are combined in a quiet state, iterative screening is carried out by applying a binary tree idea, confirmation of vibration disturbance positions on each optical fiber to be tested is achieved, the whole process is through analysis of the superimposed signals, the optical fiber monitoring and screening process is quickened, and the method has stable accuracy in practical application; correspondingly, the invention also designs a system for realizing the method, based on the module construction of the designed transmitting light path and receiving light path, the 1xN coupler and the N optical switches are used for forming a multi-channel structure to butt joint each optical fiber to be detected, the application of the designed multi-channel monitoring method can be realized rapidly, and the monitoring efficiency of the multi-optical fiber to be detected is improved effectively.
The embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present invention.
Claims (4)
1. A multichannel monitoring method based on vibration-sensitive optical fiber sensing technology is characterized in that: the method is used for simultaneously monitoring the vibration states of N optical fibers to be tested which are identical in material and known in length, and comprises the following steps:
step A, based on that one end of each optical fiber to be tested receives the same pulse light at the same time, the superimposed back scattering light signals from each optical fiber to be tested are converted into corresponding electric signals to be compared, and the step B is carried out;
b, comparing the electric signals to be compared with the reference electric signals corresponding to the superimposed back scattering light signals obtained in the step A under the quiet state of each optical fiber to be compared, judging whether the electric signals to be compared have abnormal amplitude positions or not, and if so, respectively aiming at each abnormal amplitude position, and entering the step C; otherwise, judging that the optical fibers to be tested do not generate vibration disturbance;
step C, determining the length position of the optical fiber corresponding to the abnormal amplitude position as an abnormal position, selecting each optical fiber to be detected with the length not smaller than the abnormal position as each optical fiber to be analyzed, forming a set to be analyzed, and then entering the step D;
step D, obtaining a difference value between the signal amplitude of the electric signal to be compared corresponding to the abnormal amplitude position and the signal amplitude of the reference electric signal corresponding to the abnormal amplitude position, combining the preset single fiber vibration light amplitude variation quantity, confirming the number of target disturbance fibers corresponding to the set to be analyzed, assigning the number to M, and then entering the step E;
step E, randomly selecting half of optical fibers to be analyzed from a set to be analyzed, executing the step A to the step B, judging whether the signal amplitude of the electric signal to be compared corresponding to each optical fiber to be analyzed at the position of the abnormal amplitude is abnormal compared with that of a reference electric signal, if so, obtaining the difference value between the two corresponding to the abnormality, combining the preset vibration light amplitude variation quantity of a single optical fiber, determining the number of target disturbance optical fibers corresponding to the optical fibers to be analyzed, and then entering the step G, otherwise, entering the step F;
step F, combining the optical fibers to be analyzed which are not selected in the set to be analyzed in the adjacent previous step E into one set to be analyzed, updating the optical fibers to be analyzed selected in the adjacent previous step E into the optical fibers to be analyzed, and returning to the step E according to the set to be analyzed obtained in the step;
step G, judging whether the number of the target disturbance fibers corresponding to the selected optical fibers to be analyzed in the adjacent previous step E to be analyzed is equal to the number of the target disturbance fibers corresponding to the belonging to the to-be-analyzed set, if so, combining the selected optical fibers to be analyzed into one to-be-analyzed set, determining that the number of the target disturbance fibers corresponding to the to-be-analyzed set is the number of the target disturbance fibers corresponding to the selected optical fibers to be analyzed, updating the unselected optical fibers in the adjacent previous step E to be non-to-be-analyzed, and then entering the step H aiming at the to-be-analyzed set obtained in the step;
otherwise, combining the optical fibers to be analyzed selected in the adjacent previous step E to form a to-be-analyzed set, determining the number of the target disturbance optical fibers corresponding to the to-be-analyzed set to be the number of the target disturbance optical fibers corresponding to the optical fibers to be analyzed selected in the adjacent previous step E to be-analyzed set, combining the optical fibers not selected in the adjacent previous step E to be-analyzed set to form a to-be-analyzed set, determining the number of the target disturbance optical fibers corresponding to the to-be-analyzed set to be the difference value between the number of the target disturbance optical fibers corresponding to the adjacent previous step E to be-analyzed set and the number of the target disturbance optical fibers corresponding to the selected to-be-analyzed optical fibers, and then respectively aiming at each to-be-analyzed set obtained in the step to enter the step H;
step H, judging whether the number of the optical fibers to be analyzed in the set to be analyzed is equal to the number of the target disturbance optical fibers corresponding to the set to be analyzed, if so, updating each optical fiber to be analyzed in the set to be each vibration disturbance optical fiber corresponding to the position of the abnormal amplitude, otherwise, returning to the step E for the set to be analyzed;
and C, executing the step C to the step H aiming at the abnormal amplitude position, and ending the operation of searching the vibration disturbance optical fibers aiming at the abnormal amplitude position when the number of the vibration disturbance optical fibers corresponding to the abnormal amplitude position is equal to M.
2. The method for multi-channel monitoring based on vibration-sensitive optical fiber sensing technology according to claim 1, wherein the method comprises the following steps: and in the step E, half optical fibers to be analyzed, which are adjacent to each other in position, are randomly selected from the set to be analyzed, and the steps A to B are executed.
3. A system for implementing a vibration-sensitive fiber optic sensing technology-based multichannel monitoring method of claim 1 or 2, wherein: the optical fiber detection device comprises a 1xN coupler and N optical switches, wherein N paths of interfaces on one side of the 1xN coupler are respectively connected with one end of each optical fiber to be detected through the optical switches in a butt joint mode, and a single path of interfaces on the other side of the 1xN coupler are used for transmitting the same pulse light to each optical fiber to be detected and receiving superimposed back scattering light signals from each optical fiber to be detected.
4. A system for a vibration-sensitive fiber optic sensing technology based multichannel monitoring method according to claim 3, wherein: the device comprises a laser, an AOM acousto-optic crystal, an erbium-doped fiber amplifier, a fiber loop device and a photoelectric detector, wherein the output end of the laser is connected with the input end of the AOM acousto-optic crystal in a butt joint mode, the AOM acousto-optic crystal is used for modulating laser from the laser into a pulse detection optical signal, the output end of the AOM acousto-optic crystal is connected with the input end of the erbium-doped fiber amplifier in a butt joint mode, the output end of the AOM acousto-optic crystal is used for conveying the pulse detection optical signal to the erbium-doped fiber amplifier, and the erbium-doped fiber amplifier amplifies the pulse detection optical signal according to a preset proportion;
the output end of the erbium-doped optical fiber amplifier is connected with the input end of the optical fiber circulator, the optical fiber circulator receives the pulse detection optical signals from the erbium-doped optical fiber amplifier, one end of the optical fiber circulator is connected with a single-path interface on the 1xN coupler in a butt joint mode, the pulse detection optical signals are transmitted to each optical fiber to be detected, the power of the pulse detection optical signals received by each optical fiber to be detected is fixed, the end of the optical fiber circulator receives the superimposed back scattering optical signals from each optical fiber to be detected, the output end of the optical fiber circulator is connected with the input end of the photoelectric detector, and the photoelectric detector converts the superimposed back scattering optical signals into corresponding electric signals.
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