Frequency drift suppression method and system for phase-sensitive optical time domain reflection equipment

Abstract

The invention relates to the field of optical fiber sensing, and particularly provides a frequency drift suppression method and system for phase-sensitive optical time domain reflection equipment, and the method comprises the steps: dividing an optical cable into a plurality of sampling intervals according to a preset length; obtaining a spatial phase difference of each sampling interval of the optical cable; obtaining a space-time phase difference of each sampling interval of the optical cable; obtaining a target optical cable section on the optical cable, and obtaining a frequency drift phase difference of the target optical cable section; obtaining the minimum space-time phase difference corresponding to the frequency drift pulse time according to the space phase difference and the space-time phase difference; and correcting the frequency drift phase difference of the target optical cable section according to the minimum space-time phase difference. Compared with the prior art, the method has the advantages that the minimum space-time phase difference is extracted from the space-time phase information, the minimum space-time phase difference represents the frequency drift generated by the optical cable in the corresponding pulse time and only influenced by the laser, the frequency drift phase difference can be corrected according to the minimum space-time phase difference, and normal operation of the optical cable is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of optical fiber sensing technology, and more specifically, to a frequency drift suppression method and system for a phase-sensitive optical time domain reflectometry device. Background Art

[0002] Optical cable communication technology is an important pillar in the field of modern communications. It has the advantages of high transmission rate, large capacity, strong anti-interference ability, and good confidentiality. With the rapid development of technologies such as the Internet, big data, and cloud computing, the construction and application of optical cable communication networks are becoming more and more extensive. However, during the use of optical cables, as time goes by, the laser that injects laser light into the optical cable may experience frequency drift due to factors such as equipment aging and thermal effects of long-term use. Frequency drift refers to the frequency deviation of the optical signal transmitted in the optical cable, which leads to a decrease in signal transmission quality and may even cause communication interruption in severe cases. Summary of the invention

[0003] The present invention aims to overcome at least one defect of the above-mentioned prior art and provides a method and system for suppressing frequency drift for phase-sensitive optical time domain reflectometry equipment, which is used to effectively suppress the frequency drift generated by the laser in the optical cable.

[0004] The technical solution adopted by the present invention is:

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

[0006] Divide the optical cable into several sampling intervals according to the preset length;

[0007] Obtaining the spatial phase difference of each sampling interval of the optical cable; the spatial phase difference is the difference between the phase values ​​of the starting position point and the ending position point of the corresponding sampling interval within the same pulse time;

[0008] Obtaining the space-time phase difference of each sampling interval of the optical cable; the space-time phase difference is the difference between the space phase difference of the sampling interval at the corresponding pulse time and the previous pulse time;

[0009] Obtaining a target optical cable segment on the optical cable, and obtaining a frequency drift phase difference of the target optical cable segment; the frequency drift phase difference is a difference in phase values ​​between a starting position point and an ending position point of the target optical cable segment within a frequency drift pulse time;

[0010] According to the spatial phase difference and the spatiotemporal phase difference, obtaining a minimum spatiotemporal phase difference corresponding to the frequency drift pulse time;

[0011] The frequency drift phase difference of the target optical cable segment is corrected according to the minimum space-time phase difference.

[0012] The spatial phase information of the optical cable is obtained by evenly dividing the optical cable into several sampling intervals of preset lengths, and then obtaining the corresponding spatial phase difference. The time-domain phase information of the optical cable is obtained by obtaining the space-time phase difference based on the spatial phase difference, and then the space-time phase information of the optical cable can be obtained. The minimum space-time phase difference is extracted from the space-time phase information. The minimum space-time phase difference represents the phase difference of the optical cable at the corresponding pulse time that is least affected by the external environment. It can be understood that the minimum phase difference only includes the frequency drift generated by the laser that emits laser light into the optical cable. The frequency drift phase difference of the target optical cable segment corresponding to the pulse time can be corrected according to the minimum space-time phase difference to ensure the normal operation of the optical cable.

[0013] Further, obtaining the minimum space-time phase difference corresponding to the frequency drift pulse time according to the spatial phase difference and the space-time phase difference specifically includes:

[0014] Acquire the spatial phase difference of each sampling interval in the frequency drift pulse time;

[0015] According to each of the spatial phase differences, acquiring the sampling interval in which the spatial phase difference is the smallest;

[0016] According to 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.

[0017] The spatial phase difference represents the amount of spatial phase change, and the sampling interval with the smallest amount of spatial phase change is identified as a quiet area. It can be considered that in the quiet area, only the frequency drift generated by the laser that emits laser light into the optical cable is affected, and there is no external interference information. Then, by further obtaining the spatiotemporal phase difference of each pulse time in the quiet area, the frequency drift of each pulse time of the laser can be obtained, and then the phase of the target optical cable segment corresponding to the pulse time can be corrected according to the minimum spatiotemporal phase difference, thereby ensuring the normal operation of the optical cable.

[0018] Further, the correcting the frequency drift phase difference of the target optical cable segment according to the minimum space-time phase difference specifically includes:

[0019] Acquire a unit frequency drift value of the optical cable according to the minimum space-time phase difference and the preset length;

[0020] According to the unit frequency drift value and the length of the target optical cable segment, a 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 space-time phase difference represents the phase change of the sampling interval within a 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, and then the frequency drift of any position point on the optical cable can be obtained by obtaining the optical cable distance, thereby effectively realizing the correction of each position point of the optical cable.

[0023] Further, the unit frequency drift value of the optical cable is obtained according to the minimum space-time phase difference and the preset length, which is expressed as:

[0024] Φ1={Φ0} tn / N

[0025] Where, t n represents the frequency drift pulse time, Φ1 represents the unit frequency drift value, {Φ0} tn represents the minimum spatiotemporal phase difference corresponding to the frequency drift pulse time, and N represents the preset length.

[0026] Further, the fixed frequency drift value of the target optical cable segment is obtained according to the unit frequency drift value and the length of the target optical cable segment, which 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] Further, the phase value is calculated according to the phase formula atan(Q / I);

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

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

[0032] The optical cable is divided into several defense zones according to the target optical cable length and laser pulse width.

[0033] By dividing 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 quickly and accurately acquired.

[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 not to exceed the preset threshold, so that the target optical cable segment can be regarded as a position point relative to the entire optical cable, which can not only ensure that the frequency drift phase difference of the target optical cable segment is effectively obtained, but also can well realize the frequency drift correction of the target optical cable segment.

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

[0037] The phase-sensitive optical time domain reflectometer is more sensitive to interference with the optical cable, and can thus better correct the optical cable according to the minimum space-time 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] An optical cable division module, used to divide the optical cable into several sampling intervals according to preset lengths;

[0040] A spatial phase calculation module, used to obtain the spatial phase difference of each sampling interval of the optical cable; the spatial phase difference is the difference between the phase values ​​of the starting position point and the ending position point of the corresponding sampling interval within the same pulse time;

[0041] A time domain phase calculation module, used to obtain the time and space phase difference of each sampling interval of the optical cable; the time and space 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] A frequency drift phase calculation module, used to obtain a target optical cable segment on the optical cable, and obtain a frequency drift phase difference of the target optical cable segment; the frequency drift phase difference is a difference in phase values ​​between a starting position point and an ending position point of the target optical cable segment within a frequency drift pulse time;

[0043] A correction phase calculation module, used to obtain the minimum space-time phase difference corresponding to the frequency drift pulse time according to the spatial phase difference and the space-time phase difference;

[0044] A frequency drift correction module is used to correct the frequency drift phase difference of the target optical cable segment according to the minimum space-time phase difference.

[0045] According to a third aspect of the present invention, there is provided an electronic device, comprising 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 reflectometer device as described in the first aspect.

[0046] According to a fourth aspect of the present invention, a computer storage medium is provided, on which computer-readable instructions are stored. When the computer-readable instructions are executed, the frequency drift suppression method for the phase-sensitive optical time-domain reflectometer device described in the first aspect is implemented.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The present invention obtains the spatial phase information of the optical cable by evenly dividing the optical cable into a number of sampling intervals of preset lengths, and then obtains the corresponding spatial phase difference, and obtains the time-domain phase information of the optical cable by obtaining the time-space phase difference based on the spatial phase difference, thereby obtaining the time-space phase information of the optical cable, and extracts the minimum time-space phase difference from the time-space phase information. The minimum time-space phase difference indicates the phase difference of the optical cable at the corresponding pulse time that is least affected by the external environment. It can be understood that the minimum phase difference only includes the frequency drift generated by the laser that injects laser light into the optical cable. The frequency drift phase difference of the target optical cable segment corresponding to the pulse time can be corrected according to the minimum time-space phase difference to ensure the normal operation of the optical cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The present invention is a flowchart of the steps of the inhibition method.

[0050] Figure 2 4 is a system structure diagram of the suppression system of the present invention.

[0051] Figure 3 It is a device structure diagram of the electronic device of the present invention.

[0052] The accompanying drawings are marked with: optical cable division module 11, spatial phase calculation module 12, time domain phase calculation module 13, frequency drift phase calculation module 14, correction phase calculation module 15, frequency drift correction module 16, memory 21, processor 22, bus 23, and communication interface 24. DETAILED DESCRIPTION

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

[0054] Example 1

[0055] Optical cable communication technology is an important pillar in the field of modern communications. It has the advantages of high transmission rate, large capacity, strong anti-interference ability and good confidentiality. With the rapid development of technologies such as the Internet, big data, and cloud computing, the construction and application of optical cable communication networks are becoming more and more extensive. During the use of optical cables, they will be affected by internal and external factors and experience frequency drift. Frequency drift refers to the frequency deviation of the optical signal transmitted in the optical cable, which leads to a decrease in signal transmission quality and even causes communication interruption in severe cases. Among them, external factors mainly include external interference such as temperature, vibration, stress, and electromagnetic waves. These external factors are difficult to suppress because they contain many and complex factors. However, the impact of external factors is usually short-lived and has relatively little impact on the overall operation of the optical cable.

[0056] In contrast, the internal factors that cause frequency drift in optical cables are mainly generated by the laser of the optical cable access equipment. During the operation of the optical cable, over time, the laser may drift due to factors such as equipment aging and thermal effects from long-term use. Compared with external factors, the frequency drift caused by internal factors will continue to accumulate over time, and then continue to affect the optical cable, resulting in a decrease in the communication quality of the optical cable. Therefore, a method that can effectively suppress the frequency drift caused by internal factors is urgently needed.

[0057] This embodiment provides a technical solution that can solve the above-mentioned problem. The technical solution of this embodiment is 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, and the suppression method may specifically include:

[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 reflectometer; the phase-sensitive optical time domain reflectometer is equipped with a φ-OTDR system, and the phase-sensitive optical time domain reflectometer has the advantages of anti-electromagnetic interference, anti-corrosion, and long-distance distributed measurement, and can achieve simultaneous detection and high sensitivity of multiple position points on the optical cable. The setting of the position points is set according to the length of the optical cable and the monitoring accuracy of the phase-sensitive optical time domain reflectometer; the monitoring accuracy of the phase-sensitive optical time domain reflectometer mainly includes spatial resolution, detection sensitivity, and signal processing capability.

[0061] Specifically, the phase-sensitive optical time-domain reflectometer is provided with a laser, which emits a laser with a pulse signal into the optical cable, receives an optical signal returned by the optical cable, converts the optical signal into an electrical signal, and then analyzes the electrical signal to obtain information of each position point on the optical cable.

[0062] It is understandable that since the sampling interval needs to realize the collection of information of the optical cable, and at the same time, in order to facilitate the subsequent better acquisition of the phase difference of the sampling interval, 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 end position point of the sampling interval respectively.

[0063] In a specific implementation manner of this embodiment, the sampling interval takes a position point as its starting position point and the position point next to its starting position point as its ending position point, or after an interval of n (n≥1) position points, takes the n+1th position point as its ending position point; the next sampling interval takes the ending position point of the previous sampling interval as its starting position point and the position point next to its starting position point as its ending position point, or after an interval of n (n≥1) position points, takes the n+1th position point as its ending position point; and so on.

[0064] According to the preset length, the optical cable is divided into a number of sampling intervals on average, so that the theoretical phase difference of each sampling interval is the same, which is convenient for subsequent phase calculation.

[0065] S2: Obtaining 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 starting position point and the ending position point of the corresponding sampling interval within the same pulse time; the phase value can be calculated by the phase calculation formula atan(Q / I), wherein Q represents the component of the signal state complex number at the corresponding position that is in phase with the reference signal; I represents the component of the signal state complex number at the corresponding position that is orthogonal to the reference signal.

[0067] It can be understood that the spatial phase difference represents the phase difference caused by the influence of external factors and lasers in the corresponding sampling interval. Assuming that in an ideal state, the influence of external factors and lasers is not considered, and the length of each sampling interval is the same, the spatial phase difference should be a fixed value; however, under the influence of external factors and lasers, frequency drift occurs in the optical cable, which increases the spatial phase difference of each sampling interval on the basis of the ideal fixed value; the frequency drift generated by the laser is more stable than the frequency drift generated by the influence of external factors, and the influence on the optical cable is continuous and stable, so the frequency drift generated by the laser can also be regarded as a fixed value in the short term, so it can be understood that within the same pulse time, the sampling interval with the smallest spatial phase difference is least disturbed by external factors and can be ignored, then the sampling interval with the smallest spatial phase difference can be identified as a quiet area, in which it is only affected by the frequency drift generated by the laser that emits laser light into the optical cable, and there is no external interference information.

[0068] S3: Obtaining the time and space phase difference of each sampling interval of the optical cable;

[0069] In this embodiment, the space-time phase difference is the difference between the space 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 will continue to increase with the passage of time, in addition to calculating the spatial phase difference of each sampling interval of the optical cable, it is also necessary to obtain the time domain 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: obtaining a target optical cable segment on the optical cable, and obtaining a frequency drift phase difference of the target optical cable segment;

[0073] In this embodiment, the frequency drift phase difference is the difference in phase value between the starting position and the ending position 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 understandable that the frequency drift pulse time does not specifically refer to a specific pulse time, and 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, so as to realize the real-time correction of the 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] The optical cable is divided into several defense zones according to the target optical cable length and laser pulse width.

[0076] The defense zones are several relatively independent areas formed by dividing the optical cable according to certain rules and standards in order to improve the safety, reliability and management efficiency of the optical cable. Therefore, in this embodiment, the optical cable is divided into several defense zones, and the position of the target optical cable segment can be quickly and accurately determined according to the set 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 value, so that the target optical cable segment can be regarded as a "position point" relative to the entire optical cable, which can not only ensure that the frequency drift phase difference of the target optical cable segment is effectively obtained, but also can well realize the frequency drift correction of the target optical cable segment.

[0078] S5: acquiring a minimum space-time phase difference corresponding to the frequency drift pulse time according to the spatial phase difference and the space-time phase difference;

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

[0080] Acquire the spatial phase difference of each sampling interval in the frequency drift pulse time;

[0081] According to each of the spatial phase differences, acquiring the sampling interval in which the spatial phase difference is the smallest;

[0082] As mentioned above, within the same pulse time, when the spatial phase difference of the sampling interval is the smallest, 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; so 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] Then, according to 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: Correcting the frequency drift phase difference of the target optical cable segment according to the minimum space-time phase difference.

[0085] As described above, the minimum space-time phase difference represents the spatial phase change and time phase change caused by the optical cable being only affected by the laser itself at the frequency drift pulse time, so the frequency drift phase difference can be corrected by the minimum space-time phase difference, which may specifically include:

[0086] Acquire a unit frequency drift value of the optical cable according to the minimum space-time phase difference and the preset length;

[0087] Specifically, it can be expressed as:

[0088] Φ1={Φ0} tn / N

[0089] Where, t n represents the frequency drift pulse time, Φ1 represents the unit frequency drift value, {Φ0} tn represents the minimum spatiotemporal phase difference corresponding to the frequency drift pulse time, and N represents the preset length.

[0090] According to the unit frequency drift value and the length of the target optical cable segment, a 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] It is understandable that the target optical cable segment should actually be a target position point on the optical cable, but because the phase is obtained based on two positions, a certain length is assigned to the target position point, thereby obtaining the target optical cable segment. Therefore, when performing frequency drift correction on the target optical cable segment, it is necessary to average the impact on the entire sampling interval to each point in the sampling interval, obtain the frequency drift impact per unit length in the sampling interval, that is, the unit frequency drift value, and thereby realize frequency drift correction for each position point on the optical cable.

[0096] In a preferred implementation of the present embodiment, the frequency drift pulse time is set to the pulse time at the current moment. In the present embodiment, 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 space-time phase difference, and finally frequency drift correction is performed according to the minimum space-time phase difference to suppress the frequency drift at the current moment; then at the next pulse time, the frequency drift pulse time is reset, and the above operation is repeated to suppress the frequency drift in the optical cable in real time.

[0097] Example 2

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

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

[0100] In this embodiment, the optical cable is connected to a phase-sensitive optical time domain reflectometer; the phase-sensitive optical time domain reflectometer is equipped with a φ-OTDR system, and the phase-sensitive optical time domain reflectometer has the advantages of anti-electromagnetic interference, anti-corrosion, and long-distance distributed measurement, and can achieve simultaneous detection and high sensitivity of multiple position points on the optical cable. The setting of the position points is set according to the length of the optical cable and the monitoring accuracy of the phase-sensitive optical time domain reflectometer; the monitoring accuracy of the phase-sensitive optical time domain reflectometer mainly includes spatial resolution, detection sensitivity, and signal processing capability.

[0101] Specifically, the phase-sensitive optical time-domain reflectometer is provided with a laser, which emits a laser with a pulse signal into the optical cable, receives an optical signal returned by the optical cable, converts the optical signal into an electrical signal, and then analyzes the electrical signal to obtain information of each position point on the optical cable.

[0102] It is understandable that since the sampling interval needs to realize the collection of information of the optical cable, and at the same time, in order to facilitate the subsequent better acquisition of the phase difference of the sampling interval, 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 end position point of the sampling interval respectively.

[0103] In a specific implementation manner of this embodiment, the sampling interval takes a position point as its starting position point and the position point next to its starting position point as its ending position point, or after an interval of n (n≥1) position points, takes the n+1th position point as its ending position point; the next sampling interval takes the ending position point of the previous sampling interval as its starting position point and the position point next to its starting position point as its ending position point, or after an interval of n (n≥1) position points, takes the n+1th position point as its ending position point; and so on.

[0104] According to the preset length, the optical cable is divided into a number of sampling intervals on average, so that the theoretical phase difference of each sampling interval is the same, which is convenient for 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 between the phase values ​​of the starting position point and the ending 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 starting position point and the ending position point of the corresponding sampling interval within the same pulse time; the phase value can be calculated by the phase calculation formula atan(Q / I), wherein Q represents the component of the signal state complex number at the corresponding position that is in phase with the reference signal; I represents the component of the signal state complex number at the corresponding position that is orthogonal to the reference signal.

[0107] It can be understood that the spatial phase difference represents the phase difference caused by the influence of external factors and lasers in the corresponding sampling interval. Assuming that in an ideal state, the influence of external factors and lasers is not considered, and the length of each sampling interval is the same, the spatial phase difference should be a fixed value; however, under the influence of external factors and lasers, frequency drift occurs in the optical cable, which increases the spatial phase difference of each sampling interval on the basis of the ideal fixed value; the frequency drift generated by the laser is more stable than the frequency drift generated by the influence of external factors, and the influence on the optical cable is continuous and stable, so the frequency drift generated by the laser can also be regarded as a fixed value in the short term, so it can be understood that within the same pulse time, the sampling interval with the smallest spatial phase difference is least disturbed by external factors and can be ignored, then the sampling interval with the smallest spatial phase difference can be identified as a quiet area, in which it is only affected by the frequency drift generated by the laser that emits laser light into the optical cable, and there is no external interference information.

[0108] The time domain phase calculation module 13 is used to obtain the time and space phase difference of each sampling interval of the optical cable; the time and space 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 space-time phase difference is the difference between the space 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 will continue to increase with the passage of time, in addition to calculating the spatial phase difference of each sampling interval of the optical cable, it is also necessary to obtain the time domain 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 value between the starting position and the ending position 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 understandable that the frequency drift pulse time does not specifically refer to a specific pulse time, and 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, so as to realize the real-time correction of the 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] The optical cable is divided into several defense zones according to the target optical cable length and laser pulse width.

[0116] The defense zones are several relatively independent areas formed by dividing the optical cable according to certain rules and standards in order to improve the safety, reliability and management efficiency of the optical cable. Therefore, in this embodiment, the optical cable is divided into several defense zones, and the position of the target optical cable segment can be quickly and accurately determined according to the set 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 value, so that the target optical cable segment can be regarded as a "position point" relative to the entire optical cable, which can not only ensure that the frequency drift phase difference of the target optical cable segment is effectively obtained, but also can well realize the frequency drift correction of the target optical cable segment.

[0118] A correction phase calculation module 15, used to obtain the minimum space-time phase difference corresponding to the frequency drift pulse time according to the spatial phase difference and the space-time phase difference;

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

[0120] Acquire the spatial phase difference of each sampling interval in the frequency drift pulse time;

[0121] According to each of the spatial phase differences, acquiring the sampling interval in which the spatial phase difference is the smallest;

[0122] As mentioned above, within the same pulse time, when the spatial phase difference of the sampling interval is the smallest, 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; so 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] Then, according to 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] The frequency drift correction module 16 is used to correct the frequency drift phase difference of the target optical cable segment according to the minimum space-time phase difference.

[0125] As described above, the minimum space-time phase difference represents the spatial phase change and time phase change caused by the optical cable being only affected by the laser itself at the frequency drift pulse time, so the frequency drift phase difference can be corrected by the minimum space-time phase difference, which may specifically include:

[0126] Acquire a unit frequency drift value of the optical cable according to the minimum space-time phase difference and the preset length;

[0127] Specifically, it can be expressed as:

[0128] Φ1={Φ0} tn / N

[0129] Where, t nrepresents the frequency drift pulse time, Φ1 represents the unit frequency drift value, {Φ0} tn represents the minimum spatiotemporal phase difference corresponding to the frequency drift pulse time, and N represents the preset length.

[0130] According to the unit frequency drift value and the length of the target optical cable segment, a 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] It is understandable that the target optical cable segment should actually be a target position point on the optical cable, but because the phase is obtained based on two positions, a certain length is assigned to the target position point, thereby obtaining the target optical cable segment. Therefore, when performing frequency drift correction on the target optical cable segment, it is necessary to average the impact on the entire sampling interval to each point in the sampling interval, obtain the frequency drift impact per unit length in the sampling interval, that is, the unit frequency drift value, and thereby realize frequency drift correction for each position point on the optical cable.

[0136] In a preferred implementation of the present embodiment, the frequency drift pulse time is set to the pulse time at the current moment. In the present embodiment, 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 space-time phase difference, and finally frequency drift correction is performed according to the minimum space-time phase difference to suppress the frequency drift at the current moment; then at the next pulse time, the frequency drift pulse time is reset, and the above operation is repeated to suppress the frequency drift in the optical cable in real time.

[0137] Example 3

[0138] Based on the same inventive concept as in Example 1, Figure 3As shown, this embodiment provides an electronic device, including a memory 21 and a processor 22, wherein the memory 21 stores computer-readable instructions, and the processor 22 executes the computer-readable instructions to implement the frequency drift suppression method for the phase-sensitive optical time domain reflectometer device of 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 via the bus 23 .

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

[0141] The processor 22 may be an integrated circuit chip with signal processing capability. In the specific implementation process, each step in the above method embodiment may be completed by the hardware integrated logic circuit or software instructions in the processor 22. The above processor 22 may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may 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 gates or transistor logic devices, discrete hardware components, which may implement or execute the methods, steps, and logic diagrams disclosed in the embodiments of the present invention. The general-purpose processor may be a microprocessor or the processor 22 may also be any conventional processor 22, etc. The steps of the method disclosed in conjunction with the embodiments of the present invention may be directly embodied as being executed by a hardware decoding processor, or may be executed by a combination of hardware and software modules in a decoding processor. The software module may be located in a storage medium mature in the art, such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory 21, and the processor 22 reads the information in the memory 21 and completes the steps of the method of the above embodiment in combination with its hardware.

[0142] An embodiment of the present invention further provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are called and executed by the processor 22, the computer-executable instructions prompt the processor 22 to implement the above-mentioned frequency drift suppression method for phase-sensitive optical time-domain reflectometry equipment. The specific implementation can be found in the embodiment and will not be repeated here.

[0143] If the functions are implemented in the form of 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 the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[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 methods of the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the claims of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A method for suppressing frequency drift of a phase-sensitive optical time-domain reflectometry device, characterized in that: The inhibition method comprises: Divide the optical cable into several sampling intervals according to the preset length; Obtaining the spatial phase difference of each sampling interval of the optical cable; the spatial phase difference is the difference between the phase values ​​of the starting position point and the ending position point of the corresponding sampling interval within the same pulse time; Obtaining the space-time phase difference of each sampling interval of the optical cable; the space-time phase difference is the difference between the space phase difference of the sampling interval at the corresponding pulse time and the previous pulse time; Obtaining a target optical cable segment on the optical cable, and obtaining a frequency drift phase difference of the target optical cable segment; the frequency drift phase difference is a difference in phase values ​​between a starting position point and an ending position point of the target optical cable segment within a frequency drift pulse time; According to the spatial phase difference and the spatiotemporal phase difference, obtaining a minimum spatiotemporal phase difference corresponding to the frequency drift pulse time; The frequency drift phase difference of the target optical cable segment is corrected according to the minimum space-time phase difference.

2. The frequency drift suppression method for phase-sensitive optical time-domain reflectometry device according to claim 1, characterized in that: The obtaining, according to the spatial phase difference and the spatiotemporal phase difference, the minimum spatiotemporal phase difference corresponding to the frequency drift pulse time specifically includes: Acquire the spatial phase difference of each sampling interval in the frequency drift pulse time; According to each of the spatial phase differences, acquiring the sampling interval in which the spatial phase difference is the smallest; According to 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.

3. The frequency drift suppression method for phase-sensitive optical time-domain reflectometry device according to claim 1, characterized in that: The correcting the frequency drift phase difference of the target optical cable segment according to the minimum space-time phase difference specifically includes: Acquire a unit frequency drift value of the optical cable according to the minimum space-time phase difference and the preset length; According to the unit frequency drift value and the length of the target optical cable segment, a 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.

4. The frequency drift suppression method for phase-sensitive optical time-domain reflectometry device according to claim 3, characterized in that: The unit frequency drift value of the optical cable is obtained according to the minimum space-time phase difference and the preset length, which is expressed as: Where, t n represents the frequency drift pulse time, Φ1 represents the unit frequency drift value, represents the minimum spatiotemporal phase difference corresponding to the frequency drift pulse time, and N represents the preset length.

5. The frequency drift suppression method for phase-sensitive optical time-domain reflectometry device according to claim 3, characterized in that: The fixed frequency drift value of the target optical cable segment is obtained according to the unit frequency drift value and the length of the target optical cable segment, which is expressed as: Φ2=Φ1*M 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.

6. The frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device according to any one of claims 1 to 5, characterized in that: The phase value is calculated according to the phase formula atan(Q / I); Wherein, Q represents the component of the signal state complex number at the corresponding position that is in phase with the reference signal; I represents the component of the signal state complex number at the corresponding position that is orthogonal to the reference signal.

7. The frequency drift suppression method for a phase-sensitive optical time-domain reflectometry device according to any one of claims 1 to 5, characterized in that: Before the step of obtaining the target optical cable segment on the optical cable, the method further includes: The optical cable is divided into several defense zones according to the target optical cable length and laser pulse width.

8. A frequency drift suppression system for a phase-sensitive optical time domain reflectometry device, characterized in that: The suppression system comprises: An optical cable division module, used to divide the optical cable into several sampling intervals according to preset lengths; A spatial phase calculation module, used to obtain the spatial phase difference of each sampling interval of the optical cable; the spatial phase difference is the difference between the phase values ​​of the starting position point and the ending position point of the corresponding sampling interval within the same pulse time; A time domain phase calculation module, used to obtain the time and space phase difference of each sampling interval of the optical cable; the time and space phase difference is the difference between the spatial phase difference of the sampling interval at the corresponding pulse time and the previous pulse time; A frequency drift phase calculation module, used to obtain a target optical cable segment on the optical cable, and obtain a frequency drift phase difference of the target optical cable segment; the frequency drift phase difference is a difference in phase values ​​between a starting position point and an ending position point of the target optical cable segment within a frequency drift pulse time; A correction phase calculation module, used to obtain the minimum space-time phase difference corresponding to the frequency drift pulse time according to the spatial phase difference and the space-time phase difference; A frequency drift correction module is used to correct the frequency drift phase difference of the target optical cable segment according to the minimum space-time phase difference.

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 reflectometer device as described in any one of claims 1 to 7.

10. A computer storage medium, characterized in that: Computer-readable instructions are stored thereon, and when the computer-readable instructions are executed, the frequency drift suppression method for a phase-sensitive optical time-domain reflectometer device described in any one of claims 1 to 7 is implemented.

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