Method and system for frequency drift suppression for phase sensitive optical time domain reflectometry devices

Abstract

This invention relates to the field of fiber optic sensing, specifically providing a method and system for suppressing frequency drift in phase-sensitive optical time-domain reflectometry (OTDR) devices. The suppression method involves dividing an optical cable into several sampling intervals according to a preset length; acquiring the spatial phase difference of each sampling interval; acquiring the spatiotemporal phase difference of each sampling interval; acquiring a target optical cable segment and its frequency drift phase difference; acquiring the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial and spatiotemporal phase differences; and correcting the frequency drift phase difference of the target optical cable segment based on the minimum spatiotemporal phase difference. Compared to existing technologies, this invention extracts the minimum spatiotemporal phase difference from the spatiotemporal phase information. The minimum spatiotemporal phase difference represents the frequency drift of the optical cable at the corresponding pulse time caused solely by the laser's influence. Therefore, the frequency drift phase difference can be corrected based on the minimum spatiotemporal phase difference, ensuring the normal operation of the optical cable.

Description

Technical Field

[0001] This invention relates to the field of fiber optic sensing technology, and more specifically, to a method and system for suppressing frequency drift in phase-sensitive optical time-domain reflectometry (OTDR) devices. Background Technology

[0002] Optical fiber communication technology is a crucial pillar of modern communications, boasting advantages such as high transmission speed, large capacity, strong anti-interference capabilities, and excellent security. With the rapid development of technologies like the Internet, big data, and cloud computing, the construction and application of optical fiber communication networks are becoming increasingly widespread. However, during use, over time, the laser that transmits light into the optical fiber may experience frequency drift due to factors such as equipment aging and the effects of long-term thermal effects. Frequency drift refers to the frequency deviation of the optical signal transmitted in the optical fiber, leading to a decrease in signal transmission quality and, in severe cases, even communication interruption. Summary of the Invention

[0003] The present invention aims to overcome at least one of the defects of the prior art and provide a method and system for suppressing frequency drift in phase-sensitive optical time-domain reflectometry devices, which can effectively suppress frequency drift generated by lasers in optical cables.

[0004] The technical solution adopted in this invention is as follows:

[0005] In a first aspect, the present invention provides a method for suppressing frequency drift in a phase-sensitive optical time-domain reflectometry device, the suppression method comprising:

[0006] The optical cable is divided into several sampling intervals according to the preset length;

[0007] The spatial phase difference of each sampling interval of the optical cable is obtained; the spatial phase difference is the difference in phase value between the start and end points of the corresponding sampling interval within the same pulse time.

[0008] The spatiotemporal phase difference of each sampling interval of the optical cable is obtained; the spatiotemporal phase difference is the difference between the spatial phase difference of the sampling interval at the corresponding pulse time and the previous pulse time.

[0009] Obtain the target optical cable segment on the optical cable and obtain the frequency drift phase difference of the target optical cable segment; the frequency drift phase difference is the difference in phase value between the start position point and the end position point of the target optical cable segment within the frequency drift pulse time.

[0010] Based on the spatial phase difference and the spatiotemporal phase difference, obtain the minimum spatial phase difference corresponding to the frequency drift pulse time;

[0011] The frequency drift phase difference of the target optical cable segment is corrected based on the minimum spatiotemporal phase difference.

[0012] By dividing the optical cable into several sampling intervals of preset length, and then obtaining the corresponding spatial phase difference to obtain the spatial phase information of the optical cable, the spatiotemporal phase difference is obtained based on the spatial phase difference to obtain the temporal phase information of the optical cable, thereby obtaining the spatiotemporal phase information of the optical cable. The minimum spatiotemporal phase difference is extracted from the spatiotemporal phase information. The minimum spatiotemporal phase difference represents the phase difference of the optical cable at the corresponding pulse time that is least affected by external factors. It can be understood that the minimum phase difference only includes the frequency drift generated by the laser that irradiates the optical cable. Then, the frequency drift phase difference of the target optical cable segment at the corresponding pulse time can be corrected according to the minimum spatiotemporal phase difference to ensure the normal operation of the optical cable.

[0013] Furthermore, obtaining the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial phase difference and the spatiotemporal phase difference specifically includes:

[0014] Obtain the spatial phase difference of each of the sampling intervals during the frequency drift pulse time;

[0015] Based on the spatial phase differences, obtain the sampling interval with the smallest spatial phase difference;

[0016] Based on the sampling interval with the smallest spatial phase difference, the spatiotemporal phase difference at the frequency drift pulse time within the sampling interval is obtained as the minimum spatiotemporal phase difference.

[0017] The spatial phase difference represents the amount of spatial phase change. The sampling interval with the smallest spatial phase change is defined as the quiet region. It can be assumed that in the quiet region, the only influence is the frequency drift generated by the laser emitted into the optical cable, and there is no external interference. Furthermore, by acquiring the spatiotemporal phase difference for each pulse time in the quiet region, the frequency drift of each laser pulse time can be obtained. Therefore, based on the minimum spatiotemporal phase difference, phase correction can be performed on the target optical cable segment corresponding to the pulse time, thereby ensuring the normal operation of the optical cable.

[0018] Furthermore, the step of correcting the frequency drift phase difference of the target optical cable segment based on the minimum spatiotemporal phase difference specifically includes:

[0019] The unit frequency drift value of the optical cable is obtained based on the minimum spatiotemporal phase difference and the preset length.

[0020] Based on the unit frequency drift value and the length of the target optical cable segment, the fixed frequency drift value of the target optical cable segment is obtained; the optical cable distance is the distance from the midpoint of the target optical cable segment to the laser emission point of the optical cable.

[0021] The frequency drift correction is achieved by subtracting the fixed frequency drift value from the frequency drift phase difference of the target optical cable segment.

[0022] The minimum spatiotemporal phase difference represents the phase change of the sampling interval within one pulse time, which is a range quantity. In order to obtain the frequency drift at each position point on the optical cable, it is necessary to obtain the unit frequency drift value within the sampling interval according to the preset length. Then, by obtaining the optical cable distance at any position point on the optical cable, the frequency drift at that arbitrary position point can be obtained, thereby effectively realizing the correction of each position point on the optical cable.

[0023] Furthermore, the unit frequency drift value of the optical cable is obtained based on the minimum spatiotemporal phase difference and the preset length, and is expressed as:

[0024] Φ1={Φ0} tn / N

[0025] In the formula, t n The frequency drift pulse time is represented by Φ1, and the unit frequency drift value is represented by {Φ0}. tn The minimum spatiotemporal phase difference corresponding to the frequency drift pulse time is represented by N, and the preset length is represented by N.

[0026] Furthermore, the fixed frequency drift value of the target optical cable segment, obtained based on the unit frequency drift value and the length of the target optical cable segment, is expressed as:

[0027] Φ2=Φ1*M

[0028] In the formula, Φ1 represents the unit frequency drift value, M represents the length of the target optical cable segment, and Φ2 represents the fixed frequency drift value of the target optical cable segment.

[0029] Furthermore, the phase value is calculated according to the phase formula atan(Q / I);

[0030] In the formula, Q represents the component of the complex number of signal states at the corresponding position that is in phase with the reference signal; I represents the component of the complex number of signal states at the corresponding position that is orthogonal to the reference signal.

[0031] Furthermore, prior to the step of obtaining the target optical cable segment on the optical cable, the method further includes:

[0032] Based on the target optical cable length and laser pulse width, the optical cable is divided into several defense zones.

[0033] By setting up the defense zones on the optical cable, the data of the optical cable can be sampled and located through the defense zones on the optical cable, and the target optical cable segment can be obtained quickly and accurately.

[0034] Furthermore, the length of the target optical cable segment does not exceed a preset threshold.

[0035] The preset threshold is set according to the length of the optical cable, and the length of the target optical cable segment is set to not exceed the preset threshold, so that the target optical cable segment can be regarded as a position point relative to the entire optical cable. This can ensure that the frequency drift phase difference of the target optical cable segment is effectively obtained, and the frequency drift correction of the target optical cable segment can be well achieved.

[0036] Furthermore, the laser in the optical cable is emitted through a phase-sensitive optical time-domain reflectometry device; the phase-sensitive optical time-domain reflectometry device is connected to the optical cable.

[0037] The phase-sensitive optical time-domain reflectometry device is more sensitive to interference with the optical cable, and thus can better correct the optical cable based on the minimum spatiotemporal phase difference.

[0038] In a second aspect, the present invention provides a frequency drift suppression system for a phase-sensitive optical time-domain reflectometry device, the suppression system comprising:

[0039] The optical cable segmentation module is used to divide the optical cable into several sampling intervals according to a preset length;

[0040] A spatial phase calculation module is used to obtain the spatial phase difference of each sampling interval of the optical cable; the spatial phase difference is the difference in phase values ​​between the start and end points of the corresponding sampling interval within the same pulse time.

[0041] The time-domain phase calculation module is used to obtain the spatiotemporal phase difference of each sampling interval of the optical cable; the spatiotemporal phase difference is the difference between the spatial phase difference of the sampling interval at the corresponding pulse time and the previous pulse time.

[0042] The frequency drift phase calculation module is used to obtain the target optical cable segment on the optical cable and obtain the frequency drift phase difference of the target optical cable segment; the frequency drift phase difference is the difference between the phase values ​​of the starting position point and the ending position point of the target optical cable segment within the frequency drift pulse time.

[0043] The correction phase calculation module is used to obtain the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial phase difference and the spatiotemporal phase difference.

[0044] The frequency drift correction module is used to correct the frequency drift phase difference of the target optical cable segment based on the minimum spatiotemporal phase difference.

[0045] In a third aspect, the present invention provides an electronic device, including a memory and a processor, wherein the memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device described in the first aspect.

[0046] In a fourth aspect, the present invention provides a computer storage medium storing computer-readable instructions thereon, wherein when the computer-readable instructions are executed, the frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device described in the first aspect is implemented.

[0047] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0048] This invention obtains the spatial phase information of the optical cable by dividing the optical cable into several sampling intervals of preset length, and then acquiring the corresponding spatial phase difference. Based on the spatial phase difference, the temporal phase difference is obtained to obtain the temporal phase information of the optical cable, thereby acquiring the temporal phase information of the optical cable. The minimum temporal phase difference is extracted from the temporal phase information. The minimum temporal phase difference represents the phase difference of the optical cable at the corresponding pulse time that is least affected by external factors. It can be understood that the minimum phase difference only includes the frequency drift generated by the laser that irradiates the optical cable. Based on the minimum temporal phase difference, the frequency drift phase difference of the target optical cable segment at the corresponding pulse time can be corrected to ensure the normal operation of the optical cable. Attached Figure Description

[0049] Figure 1 This is a flowchart of the suppression method of the present invention.

[0050] Figure 2 This is a system structure diagram of the suppression system of the present invention.

[0051] Figure 3 This is a structural diagram of the electronic device of the present invention.

[0052] Figure captions: 11 Optical cable segmentation module, 12 Spatial phase calculation module, 13 Temporal phase calculation module, 14 Frequency drift phase calculation module, 15 Correction phase calculation module, 16 Frequency drift correction module, 21 Memory, 22 Processor, 23 Bus, 24 Communication interface. Detailed Implementation

[0053] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the invention. To better illustrate the following embodiments, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions; it is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0054] Example 1

[0055] Optical fiber communication technology is a crucial pillar of modern communications, boasting advantages such as high transmission rates, large capacity, strong anti-interference capabilities, and excellent security. With the rapid development of technologies like the Internet, big data, and cloud computing, the construction and application of optical fiber communication networks are becoming increasingly widespread. During operation, optical fibers are susceptible to frequency drift due to both internal and external factors. Frequency drift refers to the frequency deviation of the transmitted optical signal within the fiber, leading to a decrease in signal transmission quality and, in severe cases, even communication interruption. External factors primarily include external interference such as temperature, vibration, stress, and electromagnetic waves. Because these external factors are numerous and complex, frequency drift caused by them is difficult to suppress. However, the effects of external factors are usually short-lived, and their overall impact on the optical fiber's operation is relatively small.

[0056] In contrast, the internal factors causing frequency drift in optical cables are mainly generated by the lasers in the optical cable access equipment. During the operation of the optical cable, over time, the lasers may experience frequency drift due to factors such as equipment aging and the effects of long-term thermal effects. Compared to external factors, frequency drift caused by internal factors accumulates over time, continuously affecting the optical cable and leading to a decline in communication quality. Therefore, there is an urgent need for a method to effectively suppress frequency drift caused by internal factors.

[0057] This embodiment provides a technical solution that can solve the above problems. The technical solution of this embodiment will be described below with reference to the accompanying drawings.

[0058] like Figure 1 As shown, this embodiment provides a frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device, the suppression method specifically including:

[0059] S1: Divide the optical cable into several sampling intervals according to the preset length;

[0060] In this embodiment, the optical cable is connected to a phase-sensitive optical time-domain reflectometry (OTDR) device. The OTDR device is equipped with a φ-OTDR system and possesses advantages such as electromagnetic interference resistance, corrosion resistance, and long-distance distributed measurement, enabling simultaneous detection of multiple locations on the optical cable with high sensitivity. The location points are set according to the length of the optical cable and the monitoring accuracy of the OTDR device. The monitoring accuracy of the OTDR device mainly includes spatial resolution, detection sensitivity, and signal processing capabilities.

[0061] Specifically, the phase-sensitive optical time-domain reflectometry device is equipped with a laser. The laser emits a laser with a pulse signal into the optical cable and receives the optical signal returned by the optical cable. After converting the optical signal into an electrical signal, the electrical signal is analyzed to obtain information about various locations on the optical cable.

[0062] Understandably, since the sampling interval is required to collect information from the optical cable, and in order to facilitate better acquisition of the phase difference of the sampling interval later, in this embodiment, the preset length needs to be set according to the interval of the position points, so that the sampling interval contains at least two position points of the optical cable, which serve as the starting position point and the ending position point of the sampling interval, respectively.

[0063] In one specific implementation of this embodiment, the sampling interval starts at a given location point and ends at the next location point after that starting location point, or ends at the (n+1)th location point after an interval of n (n≥1) location points; the next sampling interval starts at the end point of the previous sampling interval and ends at the next location point after that starting location point, or ends at the (n+1)th location point after an interval of n (n≥1) location points; and so on.

[0064] The optical cable is divided according to the preset length, and the optical cable is divided into several sampling intervals on an average basis, so that the theoretical phase difference of each sampling interval is the same, which facilitates subsequent phase calculation.

[0065] S2: Obtain the spatial phase difference of each sampling interval of the optical cable;

[0066] Specifically, in this embodiment, the spatial phase difference is the difference in phase values ​​between the start and end points of the corresponding sampling interval within the same pulse time. The phase value can be calculated using the phase calculation formula atan(Q / I), where Q represents the component in phase with the reference signal in the complex number of the signal state at the corresponding position, and I represents the component in the complex number of the signal state at the corresponding position that is orthogonal to the reference signal.

[0067] Understandably, the spatial phase difference represents the phase difference of the corresponding sampling interval under the influence of external factors and the laser. Assuming an ideal state, disregarding the influence of external factors and the laser, and assuming that the lengths of all sampling intervals are the same, the spatial phase difference should be a fixed value. However, under the influence of external factors and the laser, frequency drift occurs in the optical cable, increasing the spatial phase difference of each sampling interval beyond the ideal fixed value. The frequency drift generated by the laser is more stable than the frequency drift caused by external factors, and its influence on the optical cable is continuous and stable. Therefore, the frequency drift generated by the laser can be considered a fixed value in the short term. It can be understood that within the same pulse time, the sampling interval with the smallest spatial phase difference experiences the least interference from external factors, which can be ignored. Thus, the sampling interval with the smallest spatial phase difference can be considered a quiet region, where it is only affected by the frequency drift generated by the laser emitted into the optical cable, without external interference.

[0068] S3: Obtain the spatiotemporal phase difference of each sampling interval of the optical cable;

[0069] In this embodiment, the spatiotemporal phase difference is the difference between the spatial phase difference of the sampling interval at the corresponding pulse time and the previous pulse time;

[0070] As described above, since the influence of the laser on the optical cable increases over time, in addition to calculating the spatial phase difference of each sampling interval of the optical cable, it is also necessary to obtain the temporal phase change of each sampling interval to obtain the spatiotemporal phase difference of the sampling interval.

[0071] The spatiotemporal phase difference reflects how the phase of the corresponding sampling interval changes with the pulse time.

[0072] S4: Obtain the target optical cable segment on the optical cable and obtain the frequency drift phase difference of the target optical cable segment;

[0073] In this embodiment, the frequency drift phase difference is the difference in phase values ​​between the start and end points of the target optical cable segment within the frequency drift pulse time. It should be noted that the frequency drift pulse time is the pulse time corresponding to the obtained frequency drift phase difference of the target optical cable segment. It is understood that the frequency drift pulse time does not specifically refer to a particular pulse time; it can be the pulse time at the current moment or the pulse time at a historical moment. Preferably, the frequency drift pulse time can be set to the pulse time at the current moment, enabling real-time correction of frequency drift.

[0074] In this embodiment, before the step of obtaining the target optical cable segment on the optical cable, the method further includes:

[0075] Based on the target optical cable length and laser pulse width, the optical cable is divided into several defense zones.

[0076] The defense zone is defined as several relatively independent areas formed by dividing the optical cable according to certain rules and standards in order to improve the security, reliability, and management efficiency of the optical cable. Therefore, in this embodiment, dividing the optical cable into several defense zones allows for the rapid and accurate determination of the location of the target optical cable segment based on the established defense zones.

[0077] It should be noted that in this embodiment, the length of the target optical cable segment does not exceed a preset threshold, so that the target optical cable segment can be regarded as a "position point" relative to the entire optical cable. This ensures that the frequency drift phase difference of the target optical cable segment can be effectively obtained, while also achieving good frequency drift correction of the target optical cable segment.

[0078] S5: Based on the spatial phase difference and the spatiotemporal phase difference, obtain the minimum spatial phase difference corresponding to the frequency drift pulse time;

[0079] Specifically, in this embodiment, obtaining the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial phase difference and the spatiotemporal phase difference specifically includes:

[0080] Obtain the spatial phase difference of each of the sampling intervals during the frequency drift pulse time;

[0081] Based on the spatial phase differences, obtain the sampling interval with the smallest spatial phase difference;

[0082] As described above, when the spatial phase difference of the sampling interval is the smallest within the same pulse time, it means that the influence of external factors on the sampling interval can be ignored, that is, it is only affected by the laser itself; therefore, in order to obtain the minimum spatiotemporal phase difference of the frequency drift pulse time, it is necessary to find the sampling interval with the smallest spatial phase difference within the frequency drift pulse time.

[0083] Next, based on the sampling interval with the smallest spatial phase difference, the spatiotemporal phase difference at the frequency drift pulse time in the sampling interval is obtained as the minimum spatiotemporal phase difference.

[0084] S6: Correct the frequency drift phase difference of the target optical cable segment based on the minimum spatiotemporal phase difference.

[0085] As described above, the minimum spatiotemporal phase difference represents the spatial and temporal phase changes of the optical cable caused only by the laser itself during the frequency drift pulse time. Therefore, the frequency drift phase difference can be corrected using the minimum spatiotemporal phase difference, specifically including:

[0086] The unit frequency drift value of the optical cable is obtained based on the minimum spatiotemporal phase difference and the preset length.

[0087] Specifically, it can be expressed as:

[0088] Φ1={Φ0} tn / N

[0089] In the formula, t n The frequency drift pulse time is represented by Φ1, and the unit frequency drift value is represented by {Φ0}. tn The minimum spatiotemporal phase difference corresponding to the frequency drift pulse time is represented by N, and the preset length is represented by N.

[0090] Based on the unit frequency drift value and the length of the target optical cable segment, the fixed frequency drift value of the target optical cable segment is obtained; the optical cable distance is the distance from the midpoint of the target optical cable segment to the laser emission point of the optical cable.

[0091] Specifically, it can be expressed as:

[0092] Φ2=Φ1*M

[0093] In the formula, Φ1 represents the unit frequency drift value, M represents the length of the target optical cable segment, and Φ2 represents the fixed frequency drift value of the target optical cable segment.

[0094] The frequency drift correction is achieved by subtracting the fixed frequency drift value from the frequency drift phase difference of the target optical cable segment.

[0095] Understandably, the target optical cable segment should actually be a target location point on the optical cable. However, since the phase is obtained based on two locations, a certain length is assigned to the target location point, thus obtaining the target optical cable segment. Therefore, when performing frequency drift correction on the target optical cable segment, it is necessary to average the influence on the entire sampling interval to each point in the sampling interval, obtaining the frequency drift influence per unit length in the sampling interval, i.e., the unit frequency drift value, thereby enabling frequency drift correction at each location point on the optical cable.

[0096] In a preferred embodiment of this example, the frequency drift pulse time is set to the pulse time at the current moment. In this example, the sampling interval with the smallest spatial phase difference in the pulse time at the current moment is obtained; then, the difference between the pulse time at the current moment in the sampling interval and the spatial phase difference of the previous pulse time is calculated to obtain the minimum spatiotemporal phase difference. Finally, frequency drift correction is performed based on the minimum spatiotemporal phase difference to suppress frequency drift at the current moment; then, in the next pulse time, the frequency drift pulse time is reset, and the above operation is repeated to suppress frequency drift in the optical cable in real time.

[0097] Example 2

[0098] Based on the same inventive concept as Embodiment 1, such as Figure 2 As shown, this embodiment provides a frequency drift suppression system for a phase-sensitive optical time-domain reflectometry device. The suppression system may specifically include:

[0099] The optical cable segmentation module 11 is used to divide the optical cable into several sampling intervals according to a preset length;

[0100] In this embodiment, the optical cable is connected to a phase-sensitive optical time-domain reflectometry (OTDR) device. The OTDR device is equipped with a φ-OTDR system and possesses advantages such as electromagnetic interference resistance, corrosion resistance, and long-distance distributed measurement, enabling simultaneous detection of multiple locations on the optical cable with high sensitivity. The location points are set according to the length of the optical cable and the monitoring accuracy of the OTDR device. The monitoring accuracy of the OTDR device mainly includes spatial resolution, detection sensitivity, and signal processing capabilities.

[0101] Specifically, the phase-sensitive optical time-domain reflectometry device is equipped with a laser. The laser emits a laser with a pulse signal into the optical cable and receives the optical signal returned by the optical cable. After converting the optical signal into an electrical signal, the electrical signal is analyzed to obtain information about various locations on the optical cable.

[0102] Understandably, since the sampling interval is required to collect information from the optical cable, and in order to facilitate better acquisition of the phase difference of the sampling interval later, in this embodiment, the preset length needs to be set according to the interval of the position points, so that the sampling interval contains at least two position points of the optical cable, which serve as the starting position point and the ending position point of the sampling interval, respectively.

[0103] In one specific implementation of this embodiment, the sampling interval starts at a given location point and ends at the next location point after that starting location point, or ends at the (n+1)th location point after an interval of n (n≥1) location points; the next sampling interval starts at the end point of the previous sampling interval and ends at the next location point after that starting location point, or ends at the (n+1)th location point after an interval of n (n≥1) location points; and so on.

[0104] The optical cable is divided according to the preset length, and the optical cable is divided into several sampling intervals on an average basis, so that the theoretical phase difference of each sampling interval is the same, which facilitates subsequent phase calculation.

[0105] The spatial phase calculation module 12 is used to obtain the spatial phase difference of each sampling interval of the optical cable; the spatial phase difference is the difference in phase value between the start position point and the end position point of the corresponding sampling interval within the same pulse time.

[0106] Specifically, in this embodiment, the spatial phase difference is the difference in phase values ​​between the start and end points of the corresponding sampling interval within the same pulse time. The phase value can be calculated using the phase calculation formula atan(Q / I), where Q represents the component in phase with the reference signal in the complex number of the signal state at the corresponding position, and I represents the component in the complex number of the signal state at the corresponding position that is orthogonal to the reference signal.

[0107] Understandably, the spatial phase difference represents the phase difference of the corresponding sampling interval under the influence of external factors and the laser. Assuming an ideal state, disregarding the influence of external factors and the laser, and assuming that the lengths of all sampling intervals are the same, the spatial phase difference should be a fixed value. However, under the influence of external factors and the laser, frequency drift occurs in the optical cable, increasing the spatial phase difference of each sampling interval beyond the ideal fixed value. The frequency drift generated by the laser is more stable than the frequency drift caused by external factors, and its influence on the optical cable is continuous and stable. Therefore, the frequency drift generated by the laser can be considered a fixed value in the short term. It can be understood that within the same pulse time, the sampling interval with the smallest spatial phase difference experiences the least interference from external factors, which can be ignored. Thus, the sampling interval with the smallest spatial phase difference can be considered a quiet region, where it is only affected by the frequency drift generated by the laser emitted into the optical cable, without external interference.

[0108] The time-domain phase calculation module 13 is used to obtain the spatiotemporal phase difference of each sampling interval of the optical cable; the spatiotemporal phase difference is the difference between the spatial phase difference of the sampling interval at the corresponding pulse time and the previous pulse time.

[0109] In this embodiment, the spatiotemporal phase difference is the difference between the spatial phase difference of the sampling interval at the corresponding pulse time and the previous pulse time;

[0110] As described above, since the influence of the laser on the optical cable increases over time, in addition to calculating the spatial phase difference of each sampling interval of the optical cable, it is also necessary to obtain the temporal phase change of each sampling interval to obtain the spatiotemporal phase difference of the sampling interval.

[0111] The spatiotemporal phase difference reflects how the phase of the corresponding sampling interval changes with the pulse time.

[0112] The frequency drift phase calculation module 14 is used to obtain the target optical cable segment on the optical cable and obtain the frequency drift phase difference of the target optical cable segment; the frequency drift phase difference is the difference between the phase values ​​of the starting position point and the ending position point of the target optical cable segment within the frequency drift pulse time.

[0113] In this embodiment, the frequency drift phase difference is the difference in phase values ​​between the start and end points of the target optical cable segment within the frequency drift pulse time. It should be noted that the frequency drift pulse time is the pulse time corresponding to the obtained frequency drift phase difference of the target optical cable segment. It is understood that the frequency drift pulse time does not specifically refer to a particular pulse time; it can be the pulse time at the current moment or the pulse time at a historical moment. Preferably, the frequency drift pulse time can be set to the pulse time at the current moment, enabling real-time correction of frequency drift.

[0114] In this embodiment, before the step of obtaining the target optical cable segment on the optical cable, the method further includes:

[0115] Based on the target optical cable length and laser pulse width, the optical cable is divided into several defense zones.

[0116] The defense zone is defined as several relatively independent areas formed by dividing the optical cable according to certain rules and standards in order to improve the security, reliability, and management efficiency of the optical cable. Therefore, in this embodiment, dividing the optical cable into several defense zones allows for the rapid and accurate determination of the location of the target optical cable segment based on the established defense zones.

[0117] It should be noted that in this embodiment, the length of the target optical cable segment does not exceed a preset threshold, so that the target optical cable segment can be regarded as a "position point" relative to the entire optical cable. This ensures that the frequency drift phase difference of the target optical cable segment can be effectively obtained, while also achieving good frequency drift correction of the target optical cable segment.

[0118] The phase correction calculation module 15 is used to obtain the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial phase difference and the spatiotemporal phase difference.

[0119] Specifically, in this embodiment, obtaining the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial phase difference and the spatiotemporal phase difference specifically includes:

[0120] Obtain the spatial phase difference of each of the sampling intervals during the frequency drift pulse time;

[0121] Based on the spatial phase differences, obtain the sampling interval with the smallest spatial phase difference;

[0122] As described above, when the spatial phase difference of the sampling interval is the smallest within the same pulse time, it means that the influence of external factors on the sampling interval can be ignored, that is, it is only affected by the laser itself; therefore, in order to obtain the minimum spatiotemporal phase difference of the frequency drift pulse time, it is necessary to find the sampling interval with the smallest spatial phase difference within the frequency drift pulse time.

[0123] Next, based on the sampling interval with the smallest spatial phase difference, the spatiotemporal phase difference at the frequency drift pulse time in the sampling interval is obtained as the minimum spatiotemporal phase difference.

[0124] Frequency drift correction module 16 is used to correct the frequency drift phase difference of the target optical cable segment based on the minimum spatiotemporal phase difference.

[0125] As described above, the minimum spatiotemporal phase difference represents the spatial and temporal phase changes of the optical cable caused only by the laser itself during the frequency drift pulse time. Therefore, the frequency drift phase difference can be corrected using the minimum spatiotemporal phase difference, specifically including:

[0126] The unit frequency drift value of the optical cable is obtained based on the minimum spatiotemporal phase difference and the preset length.

[0127] Specifically, it can be expressed as:

[0128] Φ1={Φ0} tn / N

[0129] In the formula, t nThe frequency drift pulse time is represented by Φ1, and the unit frequency drift value is represented by {Φ0}. tn The minimum spatiotemporal phase difference corresponding to the frequency drift pulse time is represented by N, and the preset length is represented by N.

[0130] Based on the unit frequency drift value and the length of the target optical cable segment, the fixed frequency drift value of the target optical cable segment is obtained; the optical cable distance is the distance from the midpoint of the target optical cable segment to the laser emission point of the optical cable.

[0131] Specifically, it can be expressed as:

[0132] Φ2=Φ1*M

[0133] In the formula, Φ1 represents the unit frequency drift value, M represents the length of the target optical cable segment, and Φ2 represents the fixed frequency drift value of the target optical cable segment.

[0134] The frequency drift correction is achieved by subtracting the fixed frequency drift value from the frequency drift phase difference of the target optical cable segment.

[0135] Understandably, the target optical cable segment should actually be a target location point on the optical cable. However, since the phase is obtained based on two locations, a certain length is assigned to the target location point, thus obtaining the target optical cable segment. Therefore, when performing frequency drift correction on the target optical cable segment, it is necessary to average the influence on the entire sampling interval to each point in the sampling interval, obtaining the frequency drift influence per unit length in the sampling interval, i.e., the unit frequency drift value, thereby enabling frequency drift correction at each location point on the optical cable.

[0136] In a preferred embodiment of this example, the frequency drift pulse time is set to the pulse time at the current moment. In this example, the sampling interval with the smallest spatial phase difference in the pulse time at the current moment is obtained; then, the difference between the pulse time at the current moment in the sampling interval and the spatial phase difference of the previous pulse time is calculated to obtain the minimum spatiotemporal phase difference. Finally, frequency drift correction is performed based on the minimum spatiotemporal phase difference to suppress frequency drift at the current moment; then, in the next pulse time, the frequency drift pulse time is reset, and the above operation is repeated to suppress frequency drift in the optical cable in real time.

[0137] Example 3

[0138] Based on the same inventive concept as Embodiment 1, such as Figure 3As shown, this embodiment provides an electronic device, including a memory 21 and a processor 22. The memory 21 stores computer-readable instructions, and the processor 22 executes the computer-readable instructions to implement the frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device described in this embodiment.

[0139] Preferably, the electronic device further includes a bus 23 and a communication interface 24, and the processor 22, the communication interface 24 and the memory 21 are connected through the bus 23.

[0140] The memory 21 may include high-speed random access memory (RAM), and may also include non-volatile memory, such as at least one disk storage device. Communication between this system network element and at least one other network element is achieved through at least one communication interface 24 (which can be wired or wireless), such as the Internet, wide area network, local area network, metropolitan area network, etc. The bus 23 may be an ISA bus, PCI bus, or EISA bus, etc. The bus 23 can be divided into address bus, data bus, control bus, etc. (not fully shown in the figure).

[0141] The processor 22 can be an integrated circuit chip with signal processing capabilities. In specific implementations, the steps in the embodiments of the above methods can be completed by the integrated logic circuits in the hardware of the processor 22 or by instructions in the form of software. The processor 22 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components, which can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this invention. The general-purpose processor can be a microprocessor, or the processor 22 can be any conventional processor 22, etc. The steps of the methods disclosed in the embodiments of this invention can be directly manifested as being executed by a hardware decoding processor, or being executed by a combination of hardware and software modules in the decoding processor. The software module can reside in a mature storage medium in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory 21, and processor 22 reads information from memory 21 and, in conjunction with its hardware, completes the steps of the method described in the foregoing embodiments.

[0142] This invention also provides a computer-readable storage medium storing computer-executable instructions. When these computer-executable instructions are invoked and executed by a processor 22, they cause the processor 22 to implement the frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device described above. For specific implementation details, please refer to the embodiments described above, which will not be repeated here.

[0143] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, essentially, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0144] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the technical solution of the present invention, and are not intended to limit the specific implementation of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention should be included within the protection scope of the claims of the present invention.

Claims

1. A method for suppressing frequency drift in a phase-sensitive optical time-domain reflectometry device, characterized in that, The suppression method includes: The optical cable is divided into several sampling intervals according to the preset length; The spatial phase difference of each sampling interval of the optical cable is obtained; the spatial phase difference is the difference in phase value between the start and end points of the corresponding sampling interval within the same pulse time. The spatiotemporal phase difference of each sampling interval of the optical cable is obtained; the spatiotemporal phase difference is the difference between the spatial phase difference of the sampling interval at the corresponding pulse time and the previous pulse time. Obtain the target optical cable segment on the optical cable and obtain the frequency drift phase difference of the target optical cable segment; the frequency drift phase difference is the difference in phase value between the start position point and the end position point of the target optical cable segment within the frequency drift pulse time. Based on the spatial phase difference and the spatiotemporal phase difference, obtain the minimum spatial phase difference corresponding to the frequency drift pulse time; The frequency drift phase difference of the target optical cable segment is corrected based on the minimum spatiotemporal phase difference. The step of obtaining the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial phase difference and the spatiotemporal phase difference specifically includes: Obtain the spatial phase difference of each of the sampling intervals during the frequency drift pulse time; Based on the spatial phase differences, obtain the sampling interval with the smallest spatial phase difference; Based on the sampling interval with the smallest spatial phase difference, the spatiotemporal phase difference at the frequency drift pulse time within the sampling interval is obtained as the minimum spatiotemporal phase difference.

2. The frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device according to claim 1, characterized in that, The step of correcting the frequency drift phase difference of the target optical cable segment based on the minimum spatiotemporal phase difference specifically includes: The unit frequency drift value of the optical cable is obtained based on the minimum spatiotemporal phase difference and the preset length. Based on the unit frequency drift value and the length of the target optical cable segment, the fixed frequency drift value of the target optical cable segment is obtained; the optical cable distance is the distance from the midpoint of the target optical cable segment to the laser emission point of the optical cable. The frequency drift correction is achieved by subtracting the fixed frequency drift value from the frequency drift phase difference of the target optical cable segment.

3. The frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device according to claim 2, characterized in that, The unit frequency drift value of the optical cable is obtained based on the minimum spatiotemporal phase difference and the preset length, and is expressed as: In the formula, This indicates the frequency drift pulse duration. This represents the unit frequency drift value. The minimum spatiotemporal phase difference corresponding to the frequency drift pulse time is represented by N, and the preset length is represented by N.

4. The frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device according to claim 2, characterized in that, The fixed frequency drift value of the target optical cable segment is obtained based on the unit frequency drift value and the length of the target optical cable segment, and is expressed as follows: In the formula, The unit frequency drift value is represented by M, and the length of the target optical cable segment is represented by M. This represents the fixed frequency drift value of the target optical cable segment.

5. The frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device according to any one of claims 1-4, characterized in that, The phase value is based on the phase formula. Calculated; In the formula, Q represents the component of the complex number of signal states at the corresponding position that is in phase with the reference signal; I represents the component of the complex number of signal states at the corresponding position that is orthogonal to the reference signal.

6. The frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device according to any one of claims 1-4, characterized in that, Prior to the step of obtaining the target optical cable segment on the optical cable, the method further includes: Based on the target optical cable length and laser pulse width, the optical cable is divided into several defense zones.

7. A frequency drift suppression system for a phase-sensitive optical time-domain reflectometry device, characterized in that, The suppression system includes: The optical cable segmentation module is used to divide the optical cable into several sampling intervals according to a preset length; A spatial phase calculation module is used to obtain the spatial phase difference of each sampling interval of the optical cable; the spatial phase difference is the difference in phase values ​​between the start and end points of the corresponding sampling interval within the same pulse time. The time-domain phase calculation module is used to obtain the spatiotemporal phase difference of each sampling interval of the optical cable; the spatiotemporal phase difference is the difference between the spatial phase difference of the sampling interval at the corresponding pulse time and the previous pulse time. The frequency drift phase calculation module is used to obtain the target optical cable segment on the optical cable and obtain the frequency drift phase difference of the target optical cable segment; the frequency drift phase difference is the difference between the phase values ​​of the starting position point and the ending position point of the target optical cable segment within the frequency drift pulse time. The correction phase calculation module is used to obtain the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial phase difference and the spatiotemporal phase difference. The frequency drift correction module is used to correct the frequency drift phase difference of the target optical cable segment based on the minimum spatiotemporal phase difference. The step of obtaining the minimum spatial phase difference corresponding to the frequency drift pulse time based on the spatial phase difference and the spatiotemporal phase difference specifically includes: Obtain the spatial phase difference of each of the sampling intervals during the frequency drift pulse time; Based on the spatial phase differences, obtain the sampling interval with the smallest spatial phase difference; Based on the sampling interval with the smallest spatial phase difference, the spatiotemporal phase difference at the frequency drift pulse time within the sampling interval is obtained as the minimum spatiotemporal phase difference.

8. The frequency drift suppression system for a phase-sensitive optical time-domain reflectometry device according to claim 7, characterized in that, The step of correcting the frequency drift phase difference of the target optical cable segment based on the minimum spatiotemporal phase difference specifically includes: The unit frequency drift value of the optical cable is obtained based on the minimum spatiotemporal phase difference and the preset length. Based on the unit frequency drift value and the length of the target optical cable segment, the fixed frequency drift value of the target optical cable segment is obtained; the optical cable distance is the distance from the midpoint of the target optical cable segment to the laser emission point of the optical cable. The frequency drift correction is achieved by subtracting the fixed frequency drift value from the frequency drift phase difference of the target optical cable segment.

9. An electronic device comprising a memory and a processor, characterized in that, The memory stores computer-readable instructions, and the processor executes the computer-readable instructions to implement the frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device as described in any one of claims 1-6.

10. A computer storage medium, characterized in that, It stores computer-readable instructions, which, when executed, implement the frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device as described in any one of claims 1-6.

Images