A vibration localization method, device, and double-loop through-beam fiber optic vibration interferometer

Abstract

This application discloses a vibration localization method, device, and a double-loop through-beam fiber optic vibration interferometer. The double-loop through-beam fiber optic vibration interferometer includes a first system and a second system, which are structurally independent and symmetrical. The method includes: obtaining first phase information and second phase information demodulated by photodetectors in the first and second systems after a vibration event occurs; translating the first and second phase information by a set translation amount to obtain first intermediate phase information and second intermediate phase information; combining the first phase information, second phase information, first intermediate phase information, and second intermediate phase information, and performing time delay estimation to obtain time delay information related to the vibration location of the vibration event; and determining the vibration location of the vibration event in the fiber optic link based on the time delay information and the length of the fiber optic link.

Description

Technical Field

[0001] This application relates to the field of forward fiber interferometer technology, and in particular to a vibration positioning method, device and double loop through-beam fiber vibration interferometer. Background Technology

[0002] As the backbone of modern information society, fiber optic networks have been widely deployed and applied around the world. They not only bear the heavy responsibility of data transmission, but also, due to their unique physical characteristics, have been used to develop various sensing applications, among which distributed fiber optic vibration sensing technology stands out. This technology fully utilizes existing fiber optic networks to achieve real-time monitoring of vibration events along fiber optic links, providing strong technical support for multiple fields such as traffic monitoring, building health monitoring, earthquake monitoring, and marine hydrological monitoring.

[0003] In forward interferometer structures, distributed fiber optic vibration sensing technology has been extensively studied and applied. This structure uses forward-propagating lasers to carry vibration information along the fiber optic link. As the laser propagates through the fiber, it interacts with vibration events, causing a phase change in the laser. At the receiving end, by demodulating the phase of these vibration-information-carrying lasers, relevant information about the vibration event can be extracted. When using this technology for precise vibration event localization, two opposing lasers are typically needed to sense the same vibration event, and the location is determined by comparing the time difference between their sensing of the vibration. This method, when the link is long or the vibration duration is short, can determine the vibration location by estimating the time delay and comparing the time difference between the two sensing of the vibration.

[0004] However, in most cases, the vibration signals sensed by the opposing laser beams are largely superimposed, rendering time delay estimation methods ineffective. To address this issue, researchers proposed the zero-frequency method for localization. The zero-frequency method attempts to extract localization information by analyzing the frequency characteristics of the vibration signal. However, this method requires the vibration itself to have broad-spectrum characteristics, meaning the frequency components of the vibration signal must be sufficiently rich for effective analysis. In practical applications, many vibration events do not meet this requirement, limiting the localization accuracy of the zero-frequency method. Summary of the Invention

[0005] In view of the above problems, this application provides a vibration positioning method, device, and a double-loop through-beam fiber optic vibration interferometer to improve the accuracy of vibration location positioning. The specific solution is as follows:

[0006] This application provides a vibration localization method based on a double-loop through-beam fiber optic vibration interferometer. The double-loop through-beam fiber optic vibration interferometer includes a first system and a second system, which are structurally independent and symmetrical. Each of the first and second systems includes an optical signal transmitting device, a beam splitting device, a transmission control device, an optical fiber link, and a photodetector. The optical fiber links in both the first and second systems are in a target configuration, and a vibration event is sensed twice by the optical fiber links in both systems. The method includes:

[0007] The first phase information and the second phase information obtained by demodulating the photodetectors in the first system and the second system after the vibration event occurs are obtained.

[0008] Based on a set translation amount, the first phase information and the second phase information are translated respectively to obtain the first intermediate phase information and the second intermediate phase information; the set translation amount is used to change the distribution of the phase values ​​in the first phase information and the second phase information on the time axis;

[0009] By combining the first phase information, the second phase information, the first intermediate phase information, and the second intermediate phase information, and performing time delay estimation, time delay information related to the vibration location of the vibration event is obtained.

[0010] Based on the time delay information and the length of the optical fiber link, the vibration location in the optical fiber link where the vibration event occurred is determined.

[0011] In one possible implementation, the optical fiber link is in a folded state, with the midpoint of the optical fiber link in the first system coinciding with the starting point of the optical fiber link in the second system, and the midpoint of the optical fiber link in the second system coinciding with the starting point of the optical fiber link in the first system.

[0012] Obtaining the first phase information and the second phase information demodulated by the photodetectors in the first system and the second system after the vibration event occurs includes:

[0013] Through the first demodulation formula Φ left The first phase information is obtained by demodulating the photodetector in the first system after the vibration event occurs; where Φleft(t) represents the first phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the first system. In the first system, the phase waveform of the outgoing optical signal after sensing the vibration event propagates to the photodetector in the first system is represented; t represents the moment when the optical fiber link in the first system senses the phase information φ; l1 represents the distance between the vibration location and the optical signal transmitting device in the first system; l2 represents the distance between the vibration location and the midpoint of the optical fiber link in the first system; and v represents the propagation speed of the optical signal.

[0014] Through the second demodulation formula Φ right The second phase information is obtained by demodulating the photodetector in the second system after the vibration event occurs; where Φright(t) represents the second phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the second system. In the second system, t represents the phase waveform when the outgoing optical signal senses the vibration event and propagates to the photodetector in the second system; t represents the moment when the optical fiber link in the second system senses the phase information φ; l1 represents the distance between the vibration location and the midpoint of the optical fiber link in the second system; l2 represents the distance between the vibration location and the optical signal transmitting device in the second system; and v represents the optical signal propagation speed.

[0015] In one possible implementation, based on a set translation amount, the first phase information and the second phase information are translated respectively to obtain first intermediate phase information and second intermediate phase information, including:

[0016] Will Substituting into the first demodulation formula, we get This indicates the set translation amount, and Φ′left(t) represents the first intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation;

[0017] The Substituting into the second demodulation formula, we get Φ′right(t) represents the second intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation.

[0018] In one possible implementation, time delay information related to the vibration location of the vibration event is obtained by combining the first phase information, the second phase information, the first intermediate phase information, and the second intermediate phase information, and performing time delay estimation, including:

[0019] By cross-combining the Φleft(t), the Φright(t), the Φ′left(t), and the Φ′right(t), we obtain Φ1(t) represents the difference between Φ′left(t) and Φright(t), and Φ2(t) represents the difference between Φ′right(t) and Φleft(t).

[0020] Time delay is estimated for Φ1(t) and Φ2(t) to obtain time delay information.

[0021] Another aspect of this application provides a vibration positioning device based on a double-loop through-beam fiber optic vibration interferometer. The double-loop through-beam fiber optic vibration interferometer includes a first system and a second system, which are structurally independent and symmetrical. Both the first and second systems include an optical signal transmitting device, a beam splitting device, a transmission control device, an optical fiber link, and a photodetector. The optical fiber links in both the first and second systems are in a target configuration, and a vibration event is sensed twice by the optical fiber links in both systems in the target configuration. The device includes:

[0022] The module is used to obtain the first phase information and the second phase information obtained by demodulating the photodetectors in the first system and the second system after the vibration event occurs.

[0023] A translation module is used to translate the first phase information and the second phase information respectively based on a set translation amount to obtain first intermediate phase information and second intermediate phase information; the set translation amount is used to change the distribution of phase values ​​in the first phase information and the second phase information on the time axis;

[0024] The first determining module is used to obtain time delay information related to the vibration position of the vibration event by combining the first phase information, the second phase information, the first intermediate phase information, and the second intermediate phase information.

[0025] The second determining module is used to determine the vibration location in the optical fiber link where the vibration event occurs, based on the time delay information and the length of the optical fiber link.

[0026] In one possible implementation, the optical fiber link is in a folded state, with the midpoint of the optical fiber link in the first system coinciding with the starting point of the optical fiber link in the second system, and the midpoint of the optical fiber link in the second system coinciding with the starting point of the optical fiber link in the first system.

[0027] The obtaining module is specifically used for:

[0028] Through the first demodulation formula The first phase information is obtained by demodulating the photodetector in the first system after the vibration event occurs; where Φleft(t) represents the first phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the first system. In the first system, the phase waveform of the outgoing optical signal when it senses a vibration event and propagates to the photodetector in the first system is represented by t, which represents the moment when the optical fiber link in the first system senses the phase information φ, l1 represents the distance between the vibration location and the optical signal transmitting device in the first system, l2 represents the distance between the vibration location and the midpoint of the optical fiber link in the first system, and v represents the propagation speed of the optical signal.

[0029] Through the second demodulation formula The second phase information is obtained by demodulating the photodetector in the second system after the vibration event occurs; where Φright(t) represents the second phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the second system. In the second system, t represents the phase waveform when the outgoing optical signal senses the vibration event and propagates to the photodetector in the second system; t represents the moment when the optical fiber link in the second system senses the phase information φ; l1 represents the distance between the vibration location and the midpoint of the optical fiber link in the second system; l2 represents the distance between the vibration location and the optical signal transmitting device in the second system; and v represents the optical signal propagation speed.

[0030] In one possible implementation, the translation module is specifically used for:

[0031] Will Substituting into the first demodulation formula, we get This indicates the set translation amount, and Φ′left(t) represents the first intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation;

[0032] The Substituting into the second demodulation formula, we get Φ′right(t) represents the second intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation.

[0033] In one possible implementation, the first determining module is specifically used for:

[0034] By cross-combining the Φleft(t), the Φright(t), the Φ′left(t), and the Φ′right(t), we obtain Φ1(t) represents the difference between Φ′left(t) and Φright(t), and Φ2(t) represents the difference between Φ′right(t) and Φleft(t).

[0035] Time delay is estimated for Φ1(t) and Φ2(t) to obtain time delay information.

[0036] A third aspect of this application provides a double-loop through-beam fiber optic vibration interferometer, comprising:

[0037] The first system and the second system are structurally independent and symmetrical. Both the first system and the second system include: an optical signal transmitting device, a beam splitting device, a transmission control device, an optical fiber link, and a photodetector. The optical fiber links in both the first system and the second system are in the target state. A vibration event will be sensed twice by the optical fiber links in the first system and the second system in the target state, respectively.

[0038] The optical signal transmitting device is used to generate optical signals;

[0039] The beam splitter is used to split the generated optical signal into two beams, one as a reference optical signal and the other as a probe optical signal.

[0040] The transmission control device is used to send the detection optical signal into the optical fiber link and guide the optical signal returned by the vibration event in the optical fiber link to the photodetector.

[0041] The photodetector is used to coherently detect the reference optical signal and the optical signal returned by the vibration event in the optical fiber link to obtain phase information.

[0042] In one possible implementation, the optical signal transmitting device includes a laser; the transmission control device includes a circulator.

[0043] In this application, in the dual-loop through-beam fiber optic vibration interferometer, the first system and the second system are structurally independent and symmetrical, and the fiber optic links in each system are in the target configuration. A vibration event is sensed twice by the fiber optic links in the first and second systems, respectively, meaning the same vibration event is sensed four times. The same vibration event is recorded four times using first and second phase information. Based on this, the first and second phase information are translated by a set translation amount to obtain first and second intermediate phase information. By combining the first, second, first, and second intermediate phase information and performing time delay estimation, time delay information related to the vibration location of the vibration event is obtained. Based on the time delay information and the length of the fiber optic link, the vibration location of the vibration event in the fiber optic link is determined. This avoids the inaccurate positioning problem that may be caused by frequency resolution limitations in the zero-frequency method, thus improving positioning accuracy. Attached Figure Description

[0044] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0045] Figure 1 A schematic diagram of a double-loop through-beam fiber optic vibration interferometer provided in this application;

[0046] Figure 2 This is a schematic flowchart of a vibration positioning method provided in Embodiment 1 of this application;

[0047] Figure 3 This is a schematic diagram of an implementation scenario of the vibration positioning method provided in this application;

[0048] Figure 4 A schematic diagram illustrating another implementation scenario of the vibration positioning method provided in this application;

[0049] Figure 5 A schematic diagram illustrating another implementation scenario of the vibration positioning method provided in this application;

[0050] Figure 6 This is a structural schematic diagram of a vibration positioning device provided in this application. Detailed Implementation

[0051] The embodiments of this application are described below with reference to the accompanying drawings. The terminology used in the implementation section of this application is for explaining specific embodiments only and is not intended to limit the scope of this application.

[0052] The embodiments of this application will now be described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0053] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0054] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] The vibration localization method provided in this application is based on a double-loop through-beam fiber optic vibration interferometer, which includes a first system and a second system. The first system and the second system are structurally independent and symmetrical. Both the first system and the second system include an optical signal transmitting device, a beam splitting device, a transmission control device, an optical fiber link, and a photodetector. The optical fiber links in both the first system and the second system are in the target configuration. A vibration event will be sensed twice by the optical fiber links in the first system and the second system, respectively, in the target configuration.

[0056] An optical signal transmitting device can be used to generate optical signals.

[0057] A beam splitter can be used to split the generated optical signal into two beams, one as a reference optical signal and the other as a probe optical signal.

[0058] A transmission control device is used to send the detection optical signal into the optical fiber link and guide the optical signal returned by the vibration event in the optical fiber link to the photodetector.

[0059] Photodetectors are used to coherently detect reference optical signals and optical signals returned from fiber optic links due to vibration events, thereby obtaining phase information.

[0060] In this application, as Figure 1 As shown, the optical signal transmitting device may include a laser, and the transmission control device may include a circulator. The optical fiber link is in a folded state. The midpoint of the optical fiber link in the first system coincides with the starting point of the optical fiber link in the second system, and the midpoint of the optical fiber link in the second system coincides with the starting point of the optical fiber link in the first system.

[0061] Of course, the transmission control device can also be: a beam splitter and a mirror in a Mach-Zehnder interferometer; or a semi-transparent mirror in a Michelson interferometer; or a ring optical path in a Sagnac interferometer.

[0062] Reference Figure 2 This is a flowchart illustrating a vibration positioning method provided in Embodiment 1 of this application. Figure 2 As shown, the method may include, but is not limited to, the following steps:

[0063] Step S101: Obtain the first phase information and the second phase information obtained by demodulating the photodetectors in the first system and the second system after the vibration event occurs.

[0064] In the first system, the optical fiber link is in the target mode. In the target mode, a vibration event will be sensed twice by the optical fiber link. Accordingly, the vibration event can be recorded twice through the first phase information.

[0065] In the second system, the optical fiber link is in the target mode. In the target mode, a vibration event will be sensed twice by the optical fiber link. Accordingly, the vibration event can be recorded twice through the second phase information.

[0066] Since the first system records the vibration event twice, and the second system also records the vibration event twice, the vibration event can be recorded four times.

[0067] Step S102: Based on the set translation amount, translate the first phase information and the second phase information respectively to obtain the first intermediate phase information and the second intermediate phase information.

[0068] The set translation amount can be used to change the distribution of phase values ​​in the first phase information and the second phase information on the time axis.

[0069] The specified translation amount can be set as needed and is not limited in this application.

[0070] In this embodiment, the directions in which the first phase information and the second phase information are translated can be the same or different.

[0071] Step S103: By combining the first phase information, the second phase information, the first intermediate phase information, and the second intermediate phase information, and performing time delay estimation, time delay information related to the vibration location of the vibration event is obtained.

[0072] In this embodiment, the first intermediate phase information and the second phase information can be combined to obtain a first combined phase information, and the first phase information and the second intermediate phase information can be combined to obtain a second combined phase information.

[0073] By estimating the time delay of the first combined phase information and the second combined phase information, time delay information related to the vibration location of the vibration event is obtained. For example, assuming the length of the optical fiber link is 2L, and the vibration event occurs at a distance l1 from the start of the optical fiber link, and the vibration location is at a distance l2 from the midpoint of the optical fiber link, the time delay information related to the vibration location of the vibration event can be correlated with l1, l2, and v, where v is the propagation speed of the optical signal.

[0074] Step S104: Based on the time delay information and the length of the optical fiber link, determine the vibration location in the optical fiber link where the vibration event occurred.

[0075] When the length of the optical fiber link is known, the vibration location in the optical fiber link where the vibration event occurs can be determined based on the time delay information and the length of the optical fiber link. For example, as in step S103, when 2L is known, l1 can be calculated based on the time delay information related to l1, l2, and v, thereby determining the vibration location in the optical fiber link where the vibration event occurs.

[0076] In this embodiment, in the dual-loop through-beam fiber optic vibration interferometer, the first system and the second system are structurally independent and symmetrical, and the fiber optic links in each system are in the target configuration. A vibration event will be sensed twice by the fiber optic links in the first and second systems respectively, meaning the same vibration event will be sensed four times. The same vibration event is recorded four times using first and second phase information. Based on this, the first and second phase information are translated by a set translation amount to obtain first and second intermediate phase information. By combining the first, second, first, and second intermediate phase information and performing time delay estimation, time delay information related to the vibration location of the vibration event is obtained. Based on the time delay information and the length of the fiber optic link, the vibration location of the vibration event in the fiber optic link is determined. This avoids the inaccurate positioning problem that may be caused by frequency resolution limitations in the zero-frequency method, thus improving positioning accuracy.

[0077] As another optional embodiment of this application, a vibration positioning method is provided in Embodiment 2 of this application. This embodiment is mainly an implementation of step S101 in Embodiment 1 above. In this embodiment, the optical fiber link is in a folded state, the midpoint of the optical fiber link in the first system coincides with the starting point of the optical fiber link in the second system, and the midpoint of the optical fiber link in the second system coincides with the starting point of the optical fiber link in the first system. Step S101 may include, but is not limited to, the following steps:

[0078] Step S1011: Using the first demodulation formula The first phase information obtained by demodulating the photodetector in the first system after the vibration event occurs is obtained.

[0079] Wherein, Φleft(t) represents the first phase information.

[0080] t can represent the moment when the optical fiber link in the first system senses the phase information φ. l1 represents the distance between the vibration location and the optical signal transmitting device in the first system, l2 represents the distance between the vibration location and the midpoint of the optical fiber link in the first system, and v represents the propagation speed of the optical signal.

[0081] like Figure 3 As shown, in the first system, the outgoing optical signal first passes through the vibration point (assuming the vibration event occurs at l1 of the fiber optic link) and generates a phase change. This phase change propagates to the photodetector as the outgoing optical signal propagates.

[0082] Subsequently, the return light needs to reach the midpoint of the fiber optic link before returning. The return light signal will also pass through the same vibration point (on the return path) and undergo a phase change again.

[0083] Therefore, when the photodetector in the first system receives the optical signal, it will first receive the phase change of the outgoing optical signal (i.e., time backtracking). Only after the phase change of the return optical signal (i.e., time rewind) is received (part of the process). (part of it). Therefore, This can be represented as the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the first system. This represents the phase waveform of the outgoing optical signal when it senses a vibration event and propagates to the photodetector in the first system.

[0084] Step S1012: Using the second demodulation formula The second phase information obtained by demodulating the photodetector in the second system after the vibration event occurs is obtained.

[0085] Wherein, Φright(t) represents the second phase information.

[0086] t represents the moment when the photodetector in the second system receives the optical signal, l1 represents the distance between the vibration location and the midpoint of the optical fiber link in the second system, l2 represents the distance between the vibration location and the optical signal transmitting device in the second system, and v represents the propagation speed of the optical signal.

[0087] like Figure 3 As shown, in the second system, the outgoing optical signal first passes through the vibration point (assuming the vibration event occurs at l1 of the fiber optic link) and undergoes a phase change. This phase change propagates to the photodetector as the outgoing optical signal propagates.

[0088] Subsequently, the return light needs to reach the midpoint of the fiber optic link before returning. The return light signal will also pass through the same vibration point (on the return path) and undergo a phase change again.

[0089] Therefore, when the photodetector in the second system receives the optical signal, it will first receive the phase change of the outgoing optical signal (i.e., time backtracking). Only after the phase change of the return optical signal (i.e., time rewind) is received (part of the process). (part of it). Therefore, This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the second system. This represents the phase waveform of the outgoing optical signal when it senses a vibration event and propagates to the photodetector in the second system.

[0090] As another optional embodiment of this application, a vibration positioning method is provided in Embodiment 3 of this application. This embodiment is mainly an implementation of step S102 in Embodiment 2 above. Step S102 may include, but is not limited to, the following steps:

[0091] Step S1021, to Substituting into the first demodulation formula, we get

[0092] This can represent the set translation amount, where Φ′left(t) represents the first intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation.

[0093] Step S1022, the... Substituting into the second demodulation formula, we get

[0094] Φ′right(t) represents the second intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation.

[0095] After the translation, the relationship diagram of Φleft(t), Φright(t), Φ′left(t), and Φ′right(t) can be found in [reference needed]. Figure 4 ,like Figure 4 As shown, Φ′left(t) and Φright(t) Can cancel each other out and Φ′right(t) and Φ′left(t) in the middle They can cancel each other out.

[0096] As another optional embodiment of this application, a vibration positioning method is provided in Embodiment 4 of this application. This embodiment is mainly an implementation of step S103 in Embodiment 3 above. Step S103 may include, but is not limited to, the following steps:

[0097] Step S1031: Perform cross-combinations on Φleft(t), Φright(t), Φ′left(t), and Φ′right(t) to obtain

[0098] Φ1(t) represents the difference between Φ′left(t) and Φright(t), and Φ2(t) represents the difference between Φ′right(t) and Φleft(t).

[0099] right By organizing, we can obtain

[0100]

[0101] pass It can be determined that, such as Figure 5 As shown, Φ1(t) and Φ2(t) differ only in time delay.

[0102] Step S1032: Estimate the time delay of Φ1(t) and Φ2(t) to obtain time delay information.

[0103] In this embodiment, a time delay estimation algorithm can be used to estimate the time delay of Φ1(t) and Φ2(t). The time delay estimation algorithm can be selected as needed and is not limited in this application. For example, the time delay estimation algorithm may include the cross-correlation method, which calculates the correlation function of Φ1(t) and Φ2(t), and the time delay corresponding to the peak value is the time delay.

[0104] Accordingly, step S104 may include, but is not limited to:

[0105] Step S1041, Given Given the speed of light propagation v, the distance difference l1-l2 can be calculated.

[0106] Step S1042: Given l1+l2=L, l1 can be calculated based on the distance difference l1-l2 and l1+l2=L.

[0107] The vibration positioning device provided in this application will be described below. The vibration positioning device described below can be referred to in correspondence with the vibration positioning method described above.

[0108] like Figure 6 As shown, the vibration positioning device includes: a obtaining module 100, a translation module 200, a first determining module 300, and a second determining module 400.

[0109] A vibration positioning device is based on a double-loop through-beam fiber optic vibration interferometer, which includes a first system and a second system. The first system and the second system are structurally independent and symmetrical. Each of the first system and the second system includes an optical signal transmitting device, a beam splitting device, a transmission control device, an optical fiber link, and a photodetector. The optical fiber links in both the first system and the second system are in the target configuration. A vibration event will be sensed twice by the optical fiber links in the first system and the second system, respectively, in the target configuration.

[0110] The module 100 is used to obtain the first phase information and the second phase information obtained by demodulating the photodetectors in the first system and the second system after the vibration event occurs.

[0111] The translation module 200 is used to translate the first phase information and the second phase information respectively based on a set translation amount to obtain the first intermediate phase information and the second intermediate phase information; the set translation amount is used to change the distribution of the phase values ​​in the first phase information and the second phase information on the time axis.

[0112] The first determining module 300 is used to obtain time delay information related to the vibration position of the vibration event by combining the first phase information, the second phase information, the first intermediate phase information and the second intermediate phase information.

[0113] The second determining module 400 is used to determine the vibration location in the optical fiber link where the vibration event occurs, based on the time delay information and the length of the optical fiber link.

[0114] The optical fiber link is in a folded state, the midpoint of the optical fiber link in the first system coincides with the starting point of the optical fiber link in the second system, and the midpoint of the optical fiber link in the second system coincides with the starting point of the optical fiber link in the first system.

[0115] The obtaining module 100 is specifically used for:

[0116] Through the first demodulation formula The first phase information is obtained by demodulating the photodetector in the first system after the vibration event occurs; where Φleft(t) represents the first phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the first system. In the first system, the phase waveform of the outgoing optical signal when it senses a vibration event and propagates to the photodetector in the first system is represented by t, which represents the moment when the optical fiber link in the first system senses the phase information φ, l1 represents the distance between the vibration location and the optical signal transmitting device in the first system, l2 represents the distance between the vibration location and the midpoint of the optical fiber link in the first system, and v represents the propagation speed of the optical signal.

[0117] Through the second demodulation formula The second phase information is obtained by demodulating the photodetector in the second system after the vibration event occurs; where Φright(t) represents the second phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the second system. In the second system, t represents the phase waveform when the outgoing optical signal senses the vibration event and propagates to the photodetector in the second system; t represents the moment when the optical fiber link in the second system senses the phase information φ; l1 represents the distance between the vibration location and the midpoint of the optical fiber link in the second system; l2 represents the distance between the vibration location and the optical signal transmitting device in the second system; and v represents the optical signal propagation speed.

[0118] The translation module 200 can be specifically used for:

[0119] Will Substituting into the first demodulation formula, we get This indicates the set translation amount, and Φ′left(t) represents the first intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation;

[0120] The Substituting into the second demodulation formula, we get Φ′right(t) represents the second intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation.

[0121] The first determining module 300 is specifically used for:

[0122] By cross-combining the Φleft(t), the Φright(t), the Φ′left(t), and the Φ′right(t), we obtain Φ1(t) represents the difference between Φ′left(t) and Φright(t), and Φ2(t) represents the difference between Φ′right(t) and Φleft(t).

[0123] Time delay is estimated for Φ1(t) and Φ2(t) to obtain time delay information.

[0124] It should also be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. In addition, in the device embodiment drawings provided in this application, the connection relationship between modules indicates that they have a communication connection, which can be implemented as one or more communication buses or signal lines.

[0125] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware, or it can be implemented by special-purpose hardware including application-specific integrated circuits, special-purpose CPUs, special-purpose memory, special-purpose components, etc. Generally, any function performed by a computer program can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be diverse, such as analog circuits, digital circuits, or special-purpose circuits. However, for this application, software program implementation is more often the preferred implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a computer floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk, or optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, training equipment, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0126] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product.

[0127] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

Claims

1. A vibration positioning method, characterized in that, Based on a double-loop through-beam fiber optic vibration interferometer, the double-loop through-beam fiber optic vibration interferometer includes: a first system and a second system, the first system and the second system being structurally independent and symmetrical. Both the first system and the second system include: an optical signal transmitting device, a beam splitting device, a transmission control device, an optical fiber link, and a photodetector. The optical fiber links in both the first system and the second system are in a target configuration, and a vibration event is sensed twice by the optical fiber links in the target configuration of the first system and the second system, respectively. The optical fiber links are in a folded state, with the midpoint of the optical fiber link in the first system coinciding with the starting point of the optical fiber link in the second system, and the midpoint of the optical fiber link in the second system coinciding with the starting point of the optical fiber link in the first system. The method includes: The first phase information and the second phase information obtained by demodulation of the photodetectors in the first system and the second system after the vibration event occurs are obtained. Based on a set translation amount, the first phase information and the second phase information are translated respectively to obtain the first intermediate phase information and the second intermediate phase information; the set translation amount is used to change the distribution of the phase values ​​in the first phase information and the second phase information on the time axis; Time delay is estimated based on the difference between the first phase information and the second intermediate phase information and the difference between the second phase information and the first intermediate phase information to obtain time delay information related to the vibration location of the vibration event; Based on the time delay information and the length of the optical fiber link, the vibration location in the optical fiber link where the vibration event occurred is determined.

2. The vibration positioning method according to claim 1, characterized in that, Obtaining the first phase information and the second phase information demodulated by the photodetectors in the first system and the second system after the vibration event occurs includes: Through the first demodulation formula The first phase information is obtained by demodulating the photodetector in the first system after the vibration event occurs; where Φleft(t) represents the first phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the first system. In the first system, the phase waveform of the outgoing optical signal when it senses a vibration event and propagates to the photodetector in the first system is represented by t, where t represents the moment when the optical fiber link senses the phase information φ, l1 represents the distance between the vibration location and the optical signal transmitting device in the first system, l2 represents the distance between the vibration location and the midpoint of the optical fiber link in the first system, and v represents the propagation speed of the optical signal. Through the second demodulation formula The second phase information is obtained by demodulating the photodetector in the second system after the vibration event occurs; where Φright(t) represents the second phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the second system. In the second system, t represents the phase waveform when the outgoing optical signal senses the vibration event and propagates to the photodetector in the second system; t represents the moment when the optical fiber link in the second system senses the phase information φ; l1 represents the distance between the vibration location and the midpoint of the optical fiber link in the second system; l2 represents the distance between the vibration location and the optical signal transmitting device in the second system; and v represents the optical signal propagation speed.

3. The vibration positioning method according to claim 2, characterized in that, Based on a set translation amount, the first phase information and the second phase information are translated respectively to obtain first intermediate phase information and second intermediate phase information, including: Will Substituting into the first demodulation formula, we get This indicates the set translation amount, and Φ′left(t) represents the first intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation; The Substituting into the second demodulation formula, we get Φ′right(t) represents the second intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation.

4. The vibration positioning method according to claim 3, characterized in that, Time delay estimation is performed based on the difference between the first phase information and the second intermediate phase information, and the difference between the second phase information and the first intermediate phase information, to obtain time delay information related to the vibration location of the vibration event, including: By cross-combining the Φleft(t), the Φright(t), the Φ′left(t), and the Φ′right(t), we obtain Φ1(t) represents the difference between Φ′left(t) and Φright(t), and Φ2(t) represents the difference between Φ′right(t) and Φleft(t). Time delay is estimated for Φ1(t) and Φ2(t) to obtain time delay information.

5. A vibration positioning device, characterized in that, Based on a double-loop through-beam fiber optic vibration interferometer, the double-loop through-beam fiber optic vibration interferometer includes: a first system and a second system, the first system and the second system being structurally independent and symmetrical. Both the first system and the second system include: an optical signal transmitting device, a beam splitting device, a transmission control device, an optical fiber link, and a photodetector. The optical fiber links in both the first system and the second system are in a target configuration, and a vibration event is sensed twice by the optical fiber links in the target configuration of the first system and the second system, respectively. The optical fiber links are in a folded state, with the midpoint of the optical fiber link in the first system coinciding with the starting point of the optical fiber link in the second system, and the midpoint of the optical fiber link in the second system coinciding with the starting point of the optical fiber link in the first system. The device includes: The module is used to obtain the first phase information and the second phase information obtained by demodulating the photodetectors in the first system and the second system after the vibration event occurs. A translation module is used to translate the first phase information and the second phase information respectively based on a set translation amount to obtain first intermediate phase information and second intermediate phase information; the set translation amount is used to change the distribution of phase values ​​in the first phase information and the second phase information on the time axis; The first determining module is used to perform time delay estimation based on the difference between the first phase information and the second intermediate phase information and the difference between the second phase information and the first intermediate phase information to obtain time delay information related to the vibration location of the vibration event; The second determining module is used to determine the vibration location in the optical fiber link where the vibration event occurs, based on the time delay information and the length of the optical fiber link.

6. The vibration positioning device according to claim 5, characterized in that, The obtaining module is specifically used for: Through the first demodulation formula The first phase information is obtained by demodulating the photodetector in the first system after the vibration event occurs; where Φleft(t) represents the first phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the first system. In the first system, the phase waveform of the outgoing optical signal when it senses a vibration event and propagates to the photodetector in the first system is represented by t, which represents the moment when the optical fiber link in the first system senses the phase information φ, l1 represents the distance between the vibration location and the optical signal transmitting device in the first system, l2 represents the distance between the vibration location and the midpoint of the optical fiber link in the first system, and v represents the propagation speed of the optical signal. Through the second demodulation formula The second phase information is obtained by demodulating the photodetector in the second system after the vibration event occurs; where Φright(t) represents the second phase information. This represents the phase waveform of the return optical signal when it senses a vibration event and propagates to the photodetector in the second system. In the second system, t represents the phase waveform when the outgoing optical signal senses the vibration event and propagates to the photodetector in the second system; t represents the moment when the optical fiber link in the second system senses the phase information φ; l1 represents the distance between the vibration location and the midpoint of the optical fiber link in the second system; l2 represents the distance between the vibration location and the optical signal transmitting device in the second system; and v represents the optical signal propagation speed.

7. The vibration positioning device according to claim 6, characterized in that, The translation module is specifically used for: Will Substituting into the first demodulation formula, we get This indicates the set translation amount, and Φ′left(t) represents the first intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation; The Substituting into the second demodulation formula, we get Φ′right(t) represents the second intermediate phase information. Indicates to The phase waveform after translation Indicates to The phase waveform after translation.

8. The vibration positioning device according to claim 7, characterized in that, The first determining module is specifically used for: By cross-combining the Φleft(t), the Φright(t), the Φ′left(t), and the Φ′right(t), we obtain Φ1(t) represents the difference between Φ′left(t) and Φright(t), and Φ2(t) represents the difference between Φ′right(t) and Φleft(t). Time delay is estimated for Φ1(t) and Φ2(t) to obtain time delay information.

9. A double-loop through-beam fiber optic vibration interferometer applied to the vibration positioning method as described in any one of claims 1-4, characterized in that, include: The first system and the second system are structurally independent and symmetrical. Both the first system and the second system include: an optical signal transmitting device, a beam splitting device, a transmission control device, an optical fiber link, and a photodetector. Both the fiber optic links in the first system and the second system are in the target configuration. A vibration event will be sensed twice by the fiber optic links in the first system and the second system in the target configuration. The fiber optic links are in a folded state. The midpoint of the fiber optic link in the first system coincides with the starting point of the fiber optic link in the second system, and the midpoint of the fiber optic link in the second system coincides with the starting point of the fiber optic link in the first system. The optical signal transmitting device is used to generate optical signals; The beam splitter is used to split the generated optical signal into two beams, one as a reference optical signal and the other as a probe optical signal. The transmission control device is used to send the detection optical signal into the optical fiber link and guide the optical signal returned by the vibration event in the optical fiber link to the photodetector. The photodetector is used to coherently detect the reference optical signal and the optical signal returned by the vibration event in the optical fiber link to obtain phase information.

10. The double-loop through-beam fiber vibration interferometer according to claim 9, characterized in that, The optical signal transmitting device includes a laser; the transmission control device includes a circulator.

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