Feasibility Engineering Verification Method and System for the Sagnac Effect Time Deviation Correction Model

Abstract

This invention discloses a feasibility engineering verification method and system for a Sagnac effect time deviation correction model. The method includes the following steps: performing fixed-delay calibration on each device in the optical fiber time transfer system at a preset location to obtain the calibrated devices; acquiring laboratory optical fiber test results and field optical fiber test results respectively; based on the laboratory and field optical fiber test results, obtaining the measured Sagnac time deviation values ​​at each site; acquiring the theoretical Sagnac time deviation values ​​at each site; and comparing the measured Sagnac time deviation values ​​with the theoretical Sagnac time deviation values ​​at the same site to verify the Sagnac effect time deviation correction model. This invention can verify the accuracy of the theoretical model for Sagnac effect time deviation correction in long-distance optical fiber time transfer links.

Description

Technical Field

[0001] This invention belongs to the field of time and frequency technology, and relates to the field of long-distance optical fiber time transmission. In particular, it relates to a feasibility engineering verification method and system for a Sagnac effect time deviation correction model. Background Technology

[0002] High-precision time and frequency signals play a crucial role in scientific research, social applications, and national defense. For the construction of high-precision time and frequency systems, fiber optic time transfer, with its advantages of high precision, high reliability, strong resilience, good compatibility with fiber optic communication systems, and long transmission distances, has gradually become the primary method for high-precision time transfer. The prerequisite for high-precision fiber optic time transfer is that the time delay of bidirectional transmission in the fiber optic link is perfectly symmetrical, or that its difference can be accurately measured and compensated. Therefore, the asymmetry of bidirectional transmission delay is a major factor affecting the accuracy and stability of long-distance fiber optic time transfer.

[0003] The Sagnac effect, caused by the Earth's rotation, affects the symmetry of the round-trip transmission delay, and this delay difference cannot be directly measured. Specifically, if two light beams propagate along the same path on a rotating disk, one clockwise and the other counterclockwise, they will complete the loop at different times; this phenomenon is known as the Sagnac effect. In fiber optic time transfer systems, since optical fibers are laid along the Earth's surface, the Sagnac effect caused by the Earth's rotation will similarly cause different propagation delays in the round-trip link, disrupting the symmetry of the link delay and introducing time transfer deviations. Furthermore, in long-distance fiber optic time transfer links, the Sagnac effect can introduce time deviations exceeding nanoseconds. In the subsequent construction of many long-distance fiber optic time transfer links, the time deviation caused by the Sagnac effect cannot be ignored.

[0004] Since large-scale long-distance fiber optic time transfer projects have not yet been carried out globally, there is currently insufficient data available for review, and no actual engineering tests have been conducted. With the construction of a new generation of high-precision fiber optic time transfer systems, the theoretical model for correcting the Sagnac effect time deviation in long-distance fiber optic time transfer links urgently needs to be verified for its accuracy. Therefore, a feasibility engineering verification method for the Sagnac effect time deviation correction model in long-distance fiber optic time transfer is urgently needed. Summary of the Invention

[0005] The purpose of this invention is to provide a feasibility engineering verification method and system for a Sagnac effect time deviation correction model, in order to solve one or more of the aforementioned technical problems. The method or system provided by this invention can verify the accuracy of the theoretical model for Sagnac effect time deviation correction in long-distance optical fiber time transmission links.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a feasibility engineering verification method for a Sagnac effect time deviation correction model, comprising the following steps:

[0008] Perform fixed-delay calibration on each device in the fiber optic time transfer system at a preset location to obtain the calibrated devices;

[0009] Based on the calibrated equipment, laboratory fiber optic test results and field fiber optic test results were obtained respectively.

[0010] Based on laboratory fiber optic test results and field fiber optic test results, the measured Sagnac time deviation values ​​of each site were obtained; based on the Sagnac effect time deviation correction model, the theoretical Sagnac time deviation values ​​of each site were obtained.

[0011] The measured Sagnac time deviation values ​​at the same site are compared with the theoretical Sagnac time deviation values ​​to verify the Sagnac effect time deviation correction model.

[0012] A further improvement of the present invention is that the fixed delay calibration of each device in the fiber optic time transfer system at a preset location to obtain the calibrated device specifically includes:

[0013] Fixed delay calibration is performed on each device in the fiber optic time transfer system at a preset location. The time deviation center value between each remote end device and the local end device is adjusted to be within a preset range close to 0, and the calibrated device is obtained.

[0014] A further improvement of the present invention is that, based on the calibrated device, the laboratory fiber optic test results and the field fiber optic test results are obtained respectively.

[0015] When obtaining laboratory fiber optic test results, laboratory fiber optic coils are used to simulate the actual field fiber optic link, based on the actual test link conditions. The local end device, remote end 1 device, remote end 2 device, ..., remote end m device, ..., remote end n device are connected in series by fiber optic coils, and the length of the fiber optic coils between each device is the same as the length of the fiber optic link between each device in the actual field fiber optic link.

[0016] When obtaining the results of the actual fiber optic test, ensure that the equipment at each site is the same as the equipment at the corresponding position in the laboratory fiber optic simulation during the actual link test. Connect the local end device, remote end 1 device, remote end 2 device, ..., remote end m device, ..., remote end n device in series through the actual link.

[0017] A further improvement of this invention lies in the process of obtaining the measured Sagnac time deviation values ​​for each site based on laboratory fiber optic test results and field fiber optic test results; and in the process of obtaining the theoretical Sagnac time deviation values ​​for each site based on the Sagnac effect time deviation correction model.

[0018] For station n, the measured Sagnac time synchronization deviation is 1 / 2 (T n '-T n ); where T n T represents the center value of the time deviation between the local device and the remote terminal n device after transmission through remote terminal n1, ..., remote terminal n-1 devices during laboratory fiber optic simulation; n 'This is the center value of the time deviation between the remote end n device and the local end device after transmission through remote end n device 1, ..., remote end n-1 devices during on-site fiber optic testing;

[0019] For station n, the theoretical Sagnac timing deviation is T. 0n It is calculated based on the actual fiber optic link route and the latitude and longitude of site n, according to the model to be verified.

[0020] This invention provides a feasibility engineering verification system for a Sagnac effect time deviation correction model, comprising:

[0021] The calibration module is used to perform fixed-delay calibration on each device in the fiber optic time transfer system at a preset location to obtain the calibrated device.

[0022] The test result acquisition module acquires laboratory fiber optic test results and field fiber optic test results based on the calibrated equipment.

[0023] The Sagnac time deviation value acquisition module is used to obtain the measured Sagnac time deviation value of each site based on laboratory fiber optic test results and field fiber optic test results; and to obtain the theoretical Sagnac time deviation value of each site based on the Sagnac effect time deviation correction model.

[0024] The verification module is used to compare the measured Sagnac time deviation values ​​with the theoretical Sagnac time deviation values ​​at the same site, thereby verifying the Sagnac effect time deviation correction model.

[0025] A further improvement of the present invention is that the fixed delay calibration of each device in the fiber optic time transfer system at a preset location to obtain the calibrated device specifically includes:

[0026] Fixed delay calibration is performed on each device in the fiber optic time transfer system at a preset location. The time deviation center value between each remote end device and the local end device is adjusted to be within a preset range close to 0, and the calibrated device is obtained.

[0027] A further improvement of the present invention is that, in the process of acquiring laboratory fiber optic test results and field fiber optic test results based on the calibrated equipment,

[0028] When obtaining laboratory fiber optic test results, laboratory fiber optic coils are used to simulate the actual field fiber optic link, based on the actual test link conditions. The local end device, remote end 1 device, remote end 2 device, ..., remote end m device, ..., remote end n device are connected in series by fiber optic coils, and the length of the fiber optic coils between each device is the same as the length of the fiber optic link between each device in the actual field fiber optic link.

[0029] When obtaining the results of the actual fiber optic test, ensure that the equipment at each site is the same as the equipment at the corresponding position in the laboratory fiber optic simulation during the actual link test. Connect the local end device, remote end 1 device, remote end 2 device, ..., remote end m device, ..., remote end n device in series through the actual link.

[0030] A further improvement of this invention lies in the process of obtaining the measured Sagnac time deviation values ​​for each site based on laboratory fiber optic test results and field fiber optic test results; and in the process of obtaining the theoretical Sagnac time deviation values ​​for each site based on the Sagnac effect time deviation correction model.

[0031] For station n, the measured Sagnac time synchronization deviation is 1 / 2 (T n '-T n ); where T n T represents the center value of the time deviation between the local device and the remote terminal n device after transmission through remote terminal n1, ..., remote terminal n-1 devices during laboratory fiber optic simulation; n 'This is the center value of the time deviation between the remote end n device and the local end device after transmission through remote end n device 1, ..., remote end n-1 devices during on-site fiber optic testing;

[0032] For station n, the theoretical Sagnac timing deviation is T. 0n It is calculated based on the actual fiber optic link route and the latitude and longitude of site n, according to the model to be verified.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] Due to the Earth's rotation, time transmission in optical fibers suffers from timing deviations, but there is no method to measure these deviations, making it impossible to verify the accuracy of theoretical models. The method provided by this invention can verify the accuracy of the theoretical model for correcting Sagnac effect time deviations in long-distance optical fiber time transmission links. More specifically, the timing deviation introduced by the Sagnac effect due to the Earth's rotation is determined by the latitude and longitude of the optical fiber link's location. Once the location information of the optical fiber link and the optical fiber timing equipment is determined, this deviation value is fixed and can be compensated for with high precision. By comparing the theoretical and measured values ​​of Sagnac time deviations at each site, this invention can verify the accuracy and completeness of the Sagnac effect time deviation correction model in long-distance optical fiber time transmission. This allows for continuous optimization of the model algorithm, improvement of the model, and enhancement of the theoretical model's engineering adaptability in practical applications. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art are briefly introduced below; obviously, the drawings described below are some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0036] Figure 1 This is a flowchart illustrating the feasibility engineering verification method for a Sagnac effect time deviation correction model provided in an embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram of the laboratory fiber optic testing scheme provided in an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the field optical fiber testing scheme provided in an embodiment of the present invention. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0041] The present invention will now be described in further detail with reference to the accompanying drawings:

[0042] Please see Figure 1 This invention provides a feasibility engineering verification method for a Sagnac effect time deviation correction model, used for the feasibility engineering verification of a long-distance optical fiber time transfer Sagnac effect time deviation correction model, comprising the following steps:

[0043] All devices and fiber optic links in the fiber optic time transfer system are placed in the same location, and the fixed time delay of each device is calibrated.

[0044] Based on the calibrated equipment, laboratory fiber optic test results and field fiber optic test results were obtained respectively.

[0045] Based on laboratory fiber optic test results and field fiber optic test results, the measured Sagnac time deviation values ​​of each site were obtained; based on the Sagnac effect time deviation correction model, the theoretical Sagnac time deviation values ​​of each site were obtained.

[0046] The Sagnac effect time deviation correction model is validated by comparing the measured Sagnac time deviation values ​​with the theoretical Sagnac time deviation values ​​at the same site.

[0047] In the method provided by the embodiments of the present invention, the accuracy and completeness of the Sagnac effect time deviation correction model in long-distance optical fiber time transfer can be verified by comparing the theoretical value and the measured value of the Sagnac time deviation at each site. This can help optimize the model algorithm, improve the model, and enhance the engineering adaptability of the theoretical model in practical applications.

[0048] Please see Figures 1 to 3Based on existing theoretical models analyzing the impact of the Sagnac effect on optical fiber time transfer accuracy, this invention proposes a feasibility engineering verification method for a long-distance optical fiber time transfer Sagnac effect time deviation correction model, implemented through the following steps:

[0049] Step 1: Place all devices and fiber optic links in the long-distance fiber optic time transfer system in the same location. Then, the time deviation introduced by the Sagnac effect caused by the Earth's rotation can be ignored. Calibrate the fixed time delay of each device to reduce the difference between devices. Adjust the center value of the time deviation between each remote end device and the local end device to be as close to 0 as possible.

[0050] Step 2: Based on the actual test link conditions, use laboratory fiber optic cable conduits to simulate the real-world fiber optic link, ensuring that the fiber optic link lengths between devices are the same as in the actual fiber optic link. Figure 2 Connect the laboratory fiber optic testing solution and record the test results in Table I.

[0051]

[0052] In Table I, L1 is the length of fiber optic coil 1; T1 is the center value of the time deviation between the time signal transmitted from the local end and the time signal output by the time frequency source after being received by the local end device after being transmitted through remote end device 1; L2 is the sum of the lengths of fiber optic coil 1 and fiber optic coil 2; T2 is the center value of the time deviation between the time signal transmitted from the local end and the time signal output by the time frequency source after being received by the local end device after being transmitted through remote end device 1 and remote end device 2; ...; L n T is the sum of the lengths of fiber 1, fiber 2, ..., fiber n. n The time signal sent from the local end is transmitted through remote end device 1, ..., remote end device n, and the center value of the time deviation between the received local end device and the time signal output by the time frequency source is denoted as n; where n is the number of devices.

[0053] Step 3: In actual link testing, ensure that the equipment at each site is the same as the corresponding equipment in the laboratory test, and follow the instructions. Figure 3 Connect the fiber optic test plan in the field and record the results in Table II.

[0054]

[0055] In Table II, L1' is the length of real link 1, T1' is the center value of the time deviation between the time signal transmitted from the local end, transmitted through remote end 1, and the time signal output by the time frequency source after being received by the local end; L2' is the sum of the lengths of real link 1 and real link 2, T2' is the center value of the time deviation between the time signal transmitted from the local end, transmitted through remote end 1 and remote end 2, and the time signal output by the time frequency source after being received by the local end; ...; L n 'T' represents the sum of the lengths of real link 1, real link 2, ..., real link n, and T n The time signal sent from the local end is transmitted through remote end device 1...remote end device n, and the local end device receives it and compares it with the center value of the time deviation from the time signal output by the time frequency source;

[0056] Step 4: Based on the actual fiber optic link route and the latitude and longitude of each station, calculate the theoretical Sagnac time deviation value and the measured Sagnac time deviation value of each station according to the theoretical model, as shown in Table III.

[0057]

[0058] In this embodiment of the invention, the time synchronization deviation introduced by the Sagnac effect caused by the Earth's rotation is determined by latitude and longitude location information. Each device at each station can transmit latitude and longitude data back to its local end via a fiber optic link, based on the positioning module. The local end device's computing and control unit calculates the theoretical Sagnac time synchronization deviation for each station. Since the optical signal travels back and forth in the fiber optic link, the measured Sagnac time synchronization deviation transmitted one way to each remote station is 1 / 2 (T). i '-T i ), where 1≤i≤n. σ is the total uncertainty deviation introduced by other error quantities. Based on the existing research results of fiber optic time transfer from major research institutions and on-site link verification, various delay quantities affecting the accuracy of fiber optic time transfer are analyzed.

[0059] The present invention includes the following: σ is determined by the time delay temperature drift of each device. DT Time difference measurement error u TIM Laser wavelength error uΔ λ Fiber dispersion coefficient measurement error u in the link Derr Fiber dispersion coefficient temperature drift error uΔ D The summation is expressed as follows:

[0060] In the formula, u DTj The time delay temperature drift of each remote terminal device, where j takes values ​​ranging from 1 to j to i and j is a positive integer, u DT0 This refers to the temperature drift due to delay on the local device.

[0061] Analysis of existing time transfer tests on kilometer-scale fiber optic links shows that the uncertainty deviation of σ is on the order of tens of ps, while kilometer-scale fiber optic links can introduce errors on the order of nanoseconds or higher. Therefore, the method described in this invention can effectively verify its theoretical model. In summary, the fiber optic time transfer time signal in this embodiment is a 1 PPS signal, and the reference frequency signal is a 10 MHz signal. By comparing the theoretical and measured values ​​of the Sagnac time deviation at each site, this invention can verify the accuracy and completeness of the Sagnac effect time deviation correction model in long-distance fiber optic time transfer. Furthermore, the model algorithm can be continuously optimized and improved, enhancing the engineering adaptability of the theoretical model in practical applications.

[0062] The following are embodiments of the apparatus of the present invention, which can be used to execute embodiments of the method of the present invention. For details not omitted in the apparatus embodiments, please refer to the embodiments of the method of the present invention.

[0063] In another embodiment of the present invention, a feasibility engineering verification system for a Sagnac effect time deviation correction model is provided, comprising:

[0064] The calibration module is used to perform fixed-delay calibration on each device in the fiber optic time transfer system at a preset location to obtain the calibrated device.

[0065] The test result acquisition module acquires laboratory fiber optic test results and field fiber optic test results based on the calibrated equipment.

[0066] The Sagnac time deviation value acquisition module is used to obtain the measured Sagnac time deviation value of each site based on laboratory fiber optic test results and field fiber optic test results; and to obtain the theoretical Sagnac time deviation value of each site based on the Sagnac effect time deviation correction model.

[0067] The verification module is used to compare the measured Sagnac time deviation values ​​with the theoretical Sagnac time deviation values ​​at the same site, thereby verifying the Sagnac effect time deviation correction model.

[0068] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0069] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0070] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0071] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A feasibility engineering verification method for a Sagnac effect time deviation correction model, characterized in that, Includes the following steps: Fixed delay calibration is performed on each device in the fiber optic time transfer system at a preset location. The time deviation center value between each remote end device and the local end device is adjusted to be within a preset range close to 0, and the calibrated device is obtained. When obtaining laboratory fiber optic test results, a laboratory fiber optic link is simulated using fiber optic coils, based on the actual test link conditions. The local end device, remote end 1 device, remote end 2 device, ..., remote end m device, ..., remote end n device are connected in series via fiber optic coils, with the fiber optic coil length between each device being the same as the fiber optic link length between each device in the actual fiber optic link. When obtaining actual fiber optic test results, the actual link test ensures that each remote end device is the same as the corresponding device in the laboratory fiber optic coil simulation, and the local end device, remote end 1 device, remote end 2 device, ..., remote end m device, ..., remote end n device are connected in series via the actual link. For the remote terminal n device, the measured Sagnac time deviation value is 1 / 2 ( T n ’-T n );in, T n The center value of the time deviation between the remote terminal n device and the local terminal device after transmission through remote terminal n device 1, ..., remote terminal n-1 devices during laboratory fiber optic simulation; T n ’ This represents the center value of the time deviation between the local device and the remote end device (n) after transmission through remote end device 1, ..., remote end device n-1 during on-site fiber optic testing; for remote end device n, the theoretical Sagnac time deviation value is... T 0n It is calculated based on the actual fiber optic link route and the latitude and longitude of the remote terminal n device, according to the model to be verified. The measured Sagnac time deviation value in the same remote terminal device is compared with the theoretical Sagnac time deviation value to verify the Sagnac effect time deviation correction model.

2. A feasibility engineering verification system for a Sagnac effect time deviation correction model, characterized in that, include: The calibration module is configured to perform fixed delay calibration on each device in the fiber optic time transfer system at a preset location, and adjust the center value of the time deviation between each remote end device and the local end device to a preset range close to 0, so as to obtain the calibrated device. The test result acquisition module is configured to simulate a real-world fiber optic link using laboratory fiber optic cable when acquiring laboratory fiber optic test results, based on the actual test link conditions. Specifically, the local end device, remote end 1 device, remote end 2 device, ..., remote end m device, ..., remote end n device are sequentially connected in series via fiber optic cable, with the length of the fiber optic cable between each device being the same as the fiber optic link length between each device in the real-world fiber optic link. When acquiring real-world fiber optic test results, the module ensures that each remote end device is identical to the corresponding device in the laboratory fiber optic cable simulation during the real-world link test, and the local end device, remote end 1 device, remote end 2 device, ..., remote end m device, ..., remote end n device are sequentially connected in series via the real-world link. The Sagnac time deviation value acquisition module is configured to, for remote device n, measure a Sagnac time deviation value of 1 / 2 ( T n ’-T n );in, T n The center value of the time deviation between the remote terminal n device and the local terminal device after transmission through remote terminal n device 1, ..., remote terminal n-1 devices during laboratory fiber optic simulation; T n ’ This represents the center value of the time deviation between the local device and the remote end device (n) after transmission through remote end device 1, ..., remote end device n-1 during on-site fiber optic testing; for remote end device n, the theoretical Sagnac time deviation value is... T 0n It is calculated based on the actual fiber optic link route and the latitude and longitude of the remote terminal n device, according to the model to be verified. The verification module is used to compare the measured Sagnac time deviation value with the theoretical Sagnac time deviation value in the same remote terminal device, so as to verify the Sagnac effect time deviation correction model.

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