Method for taming rubidium atomic clock based on beidou and long wave dual-source fusion and related products
By employing a rubidium atomic clock training method that integrates BeiDou and longwave signals, and utilizing an extended Kalman filter model to synchronously update state variables, the high-precision and reliable training of the rubidium atomic clock is achieved by combining the advantages of BeiDou and longwave signals. This solves the problem of insufficient accuracy and reliability of a single time source and improves the training effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NAT TIME SERVICE CENT CHINESE ACAD OF SCI
- Filing Date
- 2026-03-31
- Publication Date
- 2026-06-02
AI Technical Summary
Existing methods for disciplining rubidium atomic clocks suffer from insufficient accuracy and reliability due to the use of a single time source, especially in complex environments where it is difficult to guarantee short-term accuracy and long-term stability.
A rubidium atomic clock training method based on the fusion of BeiDou and longwave signals is adopted. By acquiring the time difference value, an extended Kalman filter model is constructed, the state variables are updated synchronously, and the frequency adjustment is generated to achieve closed-loop control. Combining the short-term accuracy of BeiDou signals and the long-term stability of longwave signals, the training accuracy and reliability are improved.
It achieves high precision and reliable discipline of rubidium atomic clocks in complex environments, improves the short-term synchronization accuracy and long-term stability of rubidium atomic clocks, and solves the shortcomings of single time sources in terms of accuracy and reliability.
Smart Images
Figure CN122131565A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of high-precision time and frequency synchronization technology, specifically to a rubidium atomic clock discipline method and related products based on the fusion of BeiDou and long-wave dual sources. Background Technology
[0002] Rubidium atomic clocks are widely used in fields with extremely high time synchronization accuracy, such as communications, power, and defense, due to their excellent short-term frequency stability and relatively low cost. To ensure that their output time and frequency signals are consistent with Coordinated Universal Time (UTC) or national standard time, rubidium atomic clocks that exhibit frequency drift during free operation must be periodically trained (phase-locked looped).
[0003] Currently, mainstream taming solutions typically rely on a single external reference source; however, these solutions all have inherent limitations: Firstly, when using a single long-wave signal for taming, although the long-wave signal has the advantages of wide coverage, strong anti-interference ability and good long-term stability, its propagation path delay is significantly affected by periodic factors such as day-night changes and seasonal changes, which limits its short-term accuracy and makes it difficult to further improve the short-term stability of the rubidium clock after taming.
[0004] Secondly, when using a single BeiDou Navigation Satellite System (GNSS) signal for training, the BeiDou signal can provide high-precision instantaneous time information and has the advantage of high short-term synchronization accuracy. However, the BeiDou signal is susceptible to environmental factors such as electromagnetic interference, building obstruction, and multipath effects, which can easily lead to signal loss or quality degradation, resulting in the inability to guarantee the continuity of timing and insufficient reliability in complex environments.
[0005] Therefore, overcoming the shortcomings of a single time source in terms of accuracy and reliability has become a technical challenge that urgently needs to be tackled by those skilled in the art. Summary of the Invention
[0006] The purpose of this invention is to provide a rubidium atomic clock discipline method and related products based on the fusion of Beidou and long-wave dual sources, so as to overcome the problem of insufficient accuracy and reliability of existing discipline methods due to the use of a single time source.
[0007] The present invention solves the above-mentioned technical problems through the following technical solution: This invention provides a method for disciplining a rubidium atomic clock based on the fusion of BeiDou and long-wave dual sources, comprising the following steps: Obtain a first time difference value and a second time difference value. The first time difference value is the time difference between the local time signal output by the rubidium atomic clock and the Beidou reference time signal output by the Beidou receiver. The second time difference value is the time difference between the local time signal and the longwave reference time signal output by the longwave receiver. definition The state vector at time t, the The state vector at any given time includes a first type of state variable characterizing the time-frequency characteristics of the rubidium atomic clock itself and a second type of state variable characterizing the time difference between BeiDou and longwave fusion; based on The state vector at time t is used to construct an extended Kalman filter model. The extended Kalman filter model includes a state transition equation and an observation equation. The state transition equation describes the evolution of the state vector over time, and the observation equation describes the mapping relationship between the first time difference, the second time difference, and the state vector. Using the first and second time differences as the observation inputs to the extended Kalman filter model, iterative estimation is performed to simultaneously update the optimal estimates of the first and second class state variables. Based on the optimal estimate, a frequency adjustment amount is generated and the output frequency of the rubidium atomic clock is controlled in a closed loop to achieve taming.
[0008] A further improvement of this invention is that the first type of state variable characterizing the time-frequency characteristics of the rubidium atomic clock itself includes the rubidium clock phase deviation, the rubidium clock frequency deviation, and the rubidium clock frequency drift rate; the second type of state variable characterizing the time difference between BeiDou and longwave fusion is the time difference value after BeiDou and longwave fusion.
[0009] A further improvement of this invention lies in generating a frequency adjustment amount based on the optimal estimate and performing closed-loop control on the output frequency of the rubidium atomic clock to achieve taming, specifically including the following steps: Determine whether the absolute value of the optimal estimate of the rubidium clock phase deviation is greater than a preset threshold. If the determination result is yes, then generate the adjustment amount of the rubidium clock frequency deviation and the adjustment amount of the rubidium clock phase deviation based on the optimal estimates of the rubidium clock frequency deviation and the rubidium clock phase deviation, so as to quickly eliminate large disturbances. Adjustment amount for rubidium clock frequency deviation Specifically:
[0010] in, This is the optimal estimate of the rubidium clock frequency deviation; Adjustment amount of rubidium clock phase deviation Specifically:
[0011] in, This is the optimal estimate of the rubidium clock phase deviation; Adjust the duration of the rubidium clock; If the judgment result is negative, then the predicted clock error is calculated based on the optimal estimates of the rubidium clock phase deviation, rubidium clock frequency deviation, and rubidium clock frequency drift rate; a frequency adjustment is generated based on the optimal estimate of the rubidium clock frequency deviation and the predicted clock error to dynamically maintain synchronization accuracy, specifically: When the predicted clock error is greater than the first threshold and the optimal estimate of the rubidium clock frequency deviation is greater than the second threshold, or when the predicted clock error is less than the negative first threshold and the optimal estimate of the rubidium clock frequency deviation is less than the negative second threshold, the frequency adjustment amount is:
[0012] in, This is the adjustment amount for the rubidium clock frequency; Adjusting the duration of the rubidium clock Predicted phase deviation in the last second; When the absolute value of the predicted clock error is less than or equal to the first threshold and the absolute value of the optimal estimate of the rubidium clock frequency deviation is greater than the second threshold, the frequency adjustment amount is:
[0013] The frequency adjustment is 0 when the absolute value of the predicted clock error is less than or equal to the first threshold and the absolute value of the best estimate of the rubidium clock frequency deviation is less than or equal to the second threshold.
[0014] A further improvement of the present invention is that, The state vector at time step is specifically:
[0015] in, for The state vector at any given time; This is due to the phase deviation of the rubidium clock; This is due to the frequency deviation of the rubidium clock; This refers to the frequency drift rate of the rubidium clock. This is the time difference value after the fusion of Beidou and long-wave.
[0016] A further improvement of this invention is that the state transition equation is specifically as follows:
[0017] in, for The state vector at any given time; for The state vector at any given time; This is the state transition matrix; This is process noise; State transition matrix Specifically:
[0018] in, The sampling interval is denoted as .
[0019] A further improvement of this invention is that the observation equation is specifically as follows:
[0020] in, For BeiDou observation matrix, For long-wavelength observation matrices, and , This refers to the data sampling time. This is the first time difference value; for The state vector at any given time; Noise from BeiDou observations; This is the second time difference value; This is noise from long-wavelength observations.
[0021] This invention also provides a rubidium atomic clock discipline system based on the fusion of BeiDou and longwave dual sources, comprising: The first module is used to obtain a first time difference value and a second time difference value. The first time difference value is the time difference between the local time signal output by the rubidium atomic clock and the Beidou reference time signal output by the Beidou receiver. The second time difference value is the time difference between the local time signal and the long-wave reference time signal output by the long-wave receiver. The second module is used to define the state vector, which includes a first type of state variable characterizing the time-frequency characteristics of the rubidium atomic clock itself and a second type of state variable characterizing the time difference between BeiDou and longwave fusion. Based on the state vector, an extended Kalman filter model is constructed. The extended Kalman filter model includes a state transition equation and an observation equation. The state transition equation is used to describe the evolution of the state vector over time, and the observation equation is used to describe the mapping relationship between the first time difference value, the second time difference value and the state vector. The third module is used to perform iterative estimation using the first time difference and the second time difference as the observation input of the extended Kalman filter model, and to synchronously update the optimal estimates of the first and second type of state variables. The fourth module is used to generate frequency adjustment based on the optimal estimate and to perform closed-loop control on the output frequency of the rubidium atomic clock to achieve taming.
[0022] The present invention also provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of the rubidium atomic clock discipline method based on the above-described fusion of Beidou and long-wave dual sources.
[0023] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the rubidium atomic clock discipline method based on the above-described fusion of BeiDou and long-wave dual sources.
[0024] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the rubidium atomic clock discipline method based on the above-described fusion of BeiDou and long-wave dual sources.
[0025] Compared with the prior art, the positive and progressive effects of the present invention are as follows: This invention provides a method for training a rubidium atomic clock based on the fusion of BeiDou and longwave dual-source signals. By fusing BeiDou and longwave dual-source signals, and utilizing an extended Kalman filter model, the method simultaneously estimates the state variables and fusion time difference of the rubidium atomic clock, achieving high-precision and reliable training of the rubidium atomic clock. Specifically, in the steps of obtaining the first and second time difference values, the time difference between the rubidium atomic clock and both the BeiDou and longwave reference time signals is measured simultaneously. This combines the short-term accuracy advantage of the BeiDou signal and the long-term stability advantage of the longwave signal, overcoming the shortcomings in accuracy or reliability of a single time source. In the steps of defining the state vector at a given time and constructing the extended Kalman filter model, the state vector is designed to include a first type of state variable representing the time-frequency characteristics of the rubidium atomic clock itself and a second type of state variable representing the fusion time difference between BeiDou and longwave. This allows the model to simultaneously track the internal drift of the rubidium atomic clock and the dynamic changes of the external reference reference, thus solving the problem that a single state variable cannot fully reflect the system state. When constructing the extended Kalman filter model based on the state vector, a state transition equation is used to describe the state. The evolution of the state vector over time, and the observation equation describing the mapping relationship between the first and second time differences and the state vector, handle the uncertainties and noise of nonlinear systems, and improve the model's adaptability in dynamic environments. In the step of performing iterative estimation with the time difference as the observation input, the first and second time differences are input into the extended Kalman filter model for iterative calculation, and the optimal estimates of the first and second type of state variables are updated synchronously. Dual-source information is fused to enhance the accuracy and robustness of the estimation. In the step of generating frequency adjustment based on the optimal estimate and performing closed-loop control, the frequency adjustment is dynamically generated according to the optimal estimate, and closed-loop control is implemented on the output frequency of the rubidium atomic clock to achieve adaptive adjustment, ensuring that the taming process maintains high accuracy and stability in both the short and long term. Attached Figure Description
[0026] The accompanying drawings are provided to further understand the invention and constitute a part of this invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0027] Figure 1 This is a flowchart of a rubidium atomic clock discipline method based on the fusion of Beidou and long-wave dual sources according to the present invention; Figure 2 This is a schematic diagram of the hardware connection of a rubidium atomic clock discipline system based on the fusion of Beidou and long-wave dual sources according to the present invention. Figure 3 This is a schematic diagram of the clock difference curve between the Beidou and long-wave fusion clock-trained rubidium atomic clock and UTC (NTSC) of this invention; Figure 4 A comparison chart of the stability of the breccia atomic clock trained by the BeiDou and long-wave fusion clock. Detailed Implementation
[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0029] In the description of this invention, it should be understood that the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.
[0030] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.
[0031] It should be understood that although terms such as first, second, third, etc., may be used in the embodiments of the present invention to describe the preset range, these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from one another. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.
[0032] Depending on the context, the word "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection." Similarly, depending on the context, the phrase "if determination" or "if detection (of the stated condition or event)" can be interpreted as "when determination," "in response to determination," "when detection (of the stated condition or event)," or "in response to detection (of the stated condition or event)."
[0033] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This is an explanation of the present invention and not a limitation thereof.
[0034] See Figure 1This invention provides a method for taming a rubidium atomic clock based on the fusion of BeiDou and long-wave dual sources, comprising the following steps: Obtain a first time difference value and a second time difference value. The first time difference value is the time difference between the local time signal output by the rubidium atomic clock and the Beidou reference time signal output by the Beidou receiver. The second time difference value is the time difference between the local time signal and the longwave reference time signal output by the longwave receiver. definition The state vector at time t, the The state vector at any given time includes a first type of state variable characterizing the time-frequency characteristics of the rubidium atomic clock itself and a second type of state variable characterizing the time difference between BeiDou and longwave fusion; based on The state vector at time t is used to construct an extended Kalman filter model. The extended Kalman filter model includes a state transition equation and an observation equation. The state transition equation describes the evolution of the state vector over time, and the observation equation describes the mapping relationship between the first time difference, the second time difference, and the state vector. Using the first and second time differences as the observation inputs to the extended Kalman filter model, iterative estimation is performed to simultaneously update the optimal estimates of the first and second class state variables. Based on the optimal estimate, a frequency adjustment amount is generated and the output frequency of the rubidium atomic clock is controlled in a closed loop to achieve taming.
[0035] This invention provides a method for training a rubidium atomic clock based on the fusion of BeiDou and longwave dual-source signals. By fusing BeiDou and longwave dual-source signals, and utilizing an extended Kalman filter model, the method simultaneously estimates the state variables and fusion time difference of the rubidium atomic clock, achieving high-precision and reliable training of the rubidium atomic clock. Specifically, in the steps of obtaining the first and second time difference values, the time difference between the rubidium atomic clock and both the BeiDou and longwave reference time signals is measured simultaneously. This combines the short-term accuracy advantage of the BeiDou signal and the long-term stability advantage of the longwave signal, overcoming the shortcomings in accuracy or reliability of a single time source. In the steps of defining the state vector at a given time and constructing the extended Kalman filter model, the state vector is designed to include a first type of state variable representing the time-frequency characteristics of the rubidium atomic clock itself and a second type of state variable representing the fusion time difference between BeiDou and longwave. This allows the model to simultaneously track the internal drift of the rubidium atomic clock and the dynamic changes of the external reference reference, thus solving the problem that a single state variable cannot fully reflect the system state. When constructing the extended Kalman filter model based on the state vector, a state transition equation is used to describe the state. The evolution of the state vector over time, and the observation equation describing the mapping relationship between the first and second time differences and the state vector, handle the uncertainties and noise of nonlinear systems, and improve the model's adaptability in dynamic environments. In the step of performing iterative estimation with the time difference as the observation input, the first and second time differences are input into the extended Kalman filter model for iterative calculation, and the optimal estimates of the first and second type of state variables are updated synchronously. Dual-source information is fused to enhance the accuracy and robustness of the estimation. In the step of generating frequency adjustment based on the optimal estimate and performing closed-loop control, the frequency adjustment is dynamically generated according to the optimal estimate, and closed-loop control is implemented on the output frequency of the rubidium atomic clock to achieve adaptive adjustment, ensuring that the taming process maintains high accuracy and stability in both the short and long term.
[0036] Specifically, the first type of state variables characterizing the time and frequency characteristics of the rubidium atomic clock itself includes the rubidium clock phase deviation, the rubidium clock frequency deviation, and the rubidium clock frequency drift rate. The second type of state variable characterizing the time difference between BeiDou and longwave fusion is the time difference value after BeiDou and longwave fusion.
[0037] The first type of state variables includes rubidium clock phase deviation, rubidium clock frequency deviation, and rubidium clock frequency drift rate. These help to accurately capture the phase changes, frequency shifts, and long-term drift characteristics of the rubidium atomic clock in the state transition equation, thereby more realistically simulating its dynamic evolution process and avoiding estimation bias caused by missing dependent variables. The second type of state variable is defined as the time difference value after the fusion of BeiDou and longwave, effectively integrating the advantages of dual sources, improving the stability and reliability of the reference, more efficiently synchronizing and updating state variables, and enhancing the overall accuracy and adaptability of the training.
[0038] Specifically, based on the optimal estimate, a frequency adjustment is generated and the output frequency of the rubidium atomic clock is controlled in a closed loop to achieve taming. This includes the following steps: Determine whether the absolute value of the optimal estimate of the rubidium clock phase deviation is greater than a preset threshold. If the determination result is yes, then generate the adjustment amount of the rubidium clock frequency deviation and the adjustment amount of the rubidium clock phase deviation based on the optimal estimates of the rubidium clock frequency deviation and the rubidium clock phase deviation, so as to quickly eliminate large disturbances. Adjustment amount for rubidium clock frequency deviation Specifically:
[0039] in, This is the optimal estimate of the rubidium clock frequency deviation; Adjustment amount of rubidium clock phase deviation Specifically:
[0040] in, This is the optimal estimate of the rubidium clock phase deviation; Adjust the duration of the rubidium clock; If the judgment result is negative, then the predicted clock error is calculated based on the optimal estimates of the rubidium clock phase deviation, rubidium clock frequency deviation, and rubidium clock frequency drift rate; a frequency adjustment is generated based on the optimal estimate of the rubidium clock frequency deviation and the predicted clock error to dynamically maintain synchronization accuracy, specifically: When the predicted clock error is greater than the first threshold and the optimal estimate of the rubidium clock frequency deviation is greater than the second threshold, or when the predicted clock error is less than the negative first threshold and the optimal estimate of the rubidium clock frequency deviation is less than the negative second threshold, the frequency adjustment amount is:
[0041] in, This is the adjustment amount for the rubidium clock frequency; Adjusting the duration of the rubidium clock Predicted phase deviation in the last second; When the absolute value of the predicted clock error is less than or equal to the first threshold and the absolute value of the optimal estimate of the rubidium clock frequency deviation is greater than the second threshold, the frequency adjustment amount is:
[0042] The frequency adjustment is 0 when the absolute value of the predicted clock error is less than or equal to the first threshold and the absolute value of the best estimate of the rubidium clock frequency deviation is less than or equal to the second threshold.
[0043] By introducing an adaptive control mechanism, the problems of rapidly eliminating disturbances and accurately maintaining synchronization accuracy are solved by distinguishing between large disturbances and normal states. Specifically, the absolute value of the optimal estimate of the rubidium clock phase deviation is determined to detect the degree of disturbance. The control strategy is determined based on the magnitude of the phase deviation to ensure priority handling when disturbances occur. If the determination result is yes, an adjustment amount is generated based on the optimal estimates of the rubidium clock frequency deviation and phase deviation. The frequency deviation adjustment amount is directly generated based on the optimal estimate of the frequency deviation, which can quickly correct the frequency offset. At the same time, the phase deviation adjustment amount is generated based on the optimal estimate of the phase deviation and the adjustment duration. Combined with the adjustment duration parameter, the phase deviation is compensated in real time, thereby efficiently eliminating large disturbances. If the judgment result is negative, the predicted clock error is calculated based on the optimal estimates of the rubidium clock phase deviation, frequency deviation, and frequency drift rate. Under normal conditions, the frequency drift rate variable is introduced to predict future clock error changes and improve the foresight of the control. Then, the frequency adjustment amount is generated based on the optimal estimate of the frequency deviation and the predicted clock error. Fine control is achieved through condition judgment to avoid unnecessary intervention, thereby dynamically maintaining high-precision synchronization and optimizing the control response speed and accuracy.
[0044] Specifically, The state vector at time step is specifically:
[0045] in, for The state vector at any given time; This is due to the phase deviation of the rubidium clock; This is due to the frequency deviation of the rubidium clock; This refers to the frequency drift rate of the rubidium clock. This is the time difference value after the fusion of Beidou and long-wave.
[0046] Specifically, the state transition equation is as follows:
[0047] in, for The state vector at any given time; for The state vector at any given time; This is the state transition matrix; This is process noise; State transition matrix Specifically:
[0048] in, The sampling interval is denoted as .
[0049] Specifically, the observation equation is as follows:
[0050] in, For BeiDou observation matrix, For long-wavelength observation matrices, and , This refers to the data sampling time. This is the first time difference value; for The state vector at any given time; Noise from BeiDou observations; This is the second time difference value; This is noise from long-wavelength observations.
[0051] Based on the same inventive concept, this invention also provides a rubidium atomic clock discipline system based on the fusion of BeiDou and long-wave dual sources, comprising: The first module is used to obtain a first time difference value and a second time difference value. The first time difference value is the time difference between the local time signal output by the rubidium atomic clock and the Beidou reference time signal output by the Beidou receiver. The second time difference value is the time difference between the local time signal and the long-wave reference time signal output by the long-wave receiver. The second module is used to define the state vector, which includes a first type of state variable characterizing the time-frequency characteristics of the rubidium atomic clock itself and a second type of state variable characterizing the time difference between BeiDou and longwave fusion. Based on the state vector, an extended Kalman filter model is constructed. The extended Kalman filter model includes a state transition equation and an observation equation. The state transition equation is used to describe the evolution of the state vector over time, and the observation equation is used to describe the mapping relationship between the first time difference value, the second time difference value and the state vector. The third module is used to perform iterative estimation using the first time difference and the second time difference as the observation input of the extended Kalman filter model, and to synchronously update the optimal estimates of the first and second type of state variables. The fourth module is used to generate frequency adjustment based on the optimal estimate and to perform closed-loop control on the output frequency of the rubidium atomic clock to achieve taming.
[0052] This system effectively addresses the shortcomings of a single time source in terms of short-term accuracy and long-term reliability by fusing BeiDou and long-wave dual-source signals to construct a closed-loop control system. Specifically, the first module acquires the first and second time difference values. By simultaneously measuring the difference between the local time and both the BeiDou and long-wave reference times, it combines the high short-term accuracy of the BeiDou signal with the anti-interference capability and long-term stability of the long-wave signal, thus compensating for the shortcomings of a single source at the data source level, which is susceptible to environmental interference or has limited accuracy. The second module defines a state vector and constructs an extended Kalman filter model. The state vector includes a first type of state variable representing the time-frequency characteristics of the rubidium atomic clock itself and a second type of state variable representing the fused time difference, integrating the clock's internal dynamics with the external reference into a whole. The state transition equation describes the evolution of the state vector over time, and the observation equation describes the mapping relationship between the first and second time difference values and the state vector. This allows the model to simultaneously handle clock drift and the fusion of dual-source references, avoiding the problem that a single-source model cannot simultaneously address short-term fluctuations and long-term stability. The third module uses the first and second time differences as observation inputs to perform iterative estimation. By inputting dual-source data in real time, it synchronously updates the optimal estimates of the first and second type of state variables, ensuring continuous optimization of the estimation results in a dynamic environment and improving the robustness and continuity of the system. The fourth module generates a frequency adjustment based on the optimal estimate and performs closed-loop control on the output frequency of the rubidium atomic clock. By directly using the optimal estimate to dynamically adjust the frequency, it achieves precise closed-loop control, thereby efficiently taming the rubidium clock and comprehensively improving the overall time synchronization performance.
[0053] In a specific embodiment of the present invention, a method for taming a rubidium atomic clock based on the fusion of BeiDou and long-wave dual sources is provided, comprising the following steps: 1. Hardware preparation and data acquisition: Setting up the hardware system: See Figure 2 It includes a rubidium atomic clock, a Beidou receiver, a long-wave receiver, and a multi-channel time interval counter. The rubidium atomic clock outputs a 1PPS (pulses per second) signal; after locking onto their respective signals, the Beidou receiver and the long-wave receiver output a 1PPS reference signal synchronized with their respective system time; the multi-channel time interval counter is used to accurately measure the time interval.
[0054] Time difference data acquisition: Simultaneous measurement and recording via a time interval counter. The following two sets of time difference values are as follows: The time difference between the 1PPS pulse output by the rubidium atomic clock and the 1PPS pulse output by the BeiDou receiver The time difference between the 1PPS pulse output by the rubidium atomic clock and the 1PPS pulse output by the longwave receiver These two time difference sequences constitute dual-source observation data.
[0055] 2. Construct the Extended Kalman Filter (EKF) model: State vector definition: definition The state vector at time t is: The physical properties of each element are as follows: Rubidium clock phase deviation (unit: ns) reflects the absolute time synchronization error at the current moment; Rubidium clock frequency deviation (unit: Hz) determines the rate at which clock error accumulates over time; : Rubidium clock frequency drift rate (unit: Hz / s), characterizing the aging characteristics of a rubidium clock during long-term operation; Time difference data after BeiDou and longwave fusion (unit: ns).
[0056] State vector through The time difference results of dual-source observation fusion were obtained, and at the same time, through , , By directly capturing the dynamic characteristics of the rubidium clock, EKF can simultaneously complete the time difference fusion of the two sources and the estimation of the rubidium clock adjustment parameters during the iteration process.
[0057] Construction of state transition equations: Based on the mathematical model of rubidium clock time difference, the state transition equation is established as follows: Wherein, the state transition matrix : Sampling interval; State transition matrix middle, and Coupling terms ( This reflects the cumulative effect of frequency drift on frequency deviation. ),and and The independence reflects the decoupling characteristics of phase deviation and dual-source fusion time difference.
[0058] Process noise , The covariance matrix of the process noise is a diagonal matrix with the following initial values: , , , Its elements are dynamically adjusted based on the quality of the dual-source data: When BeiDou signal is available, , , , To enhance stability, noise weights for fusion time differences are reduced. When long waves dominate (BeiDou is interfered with), increase It is compatible with periodic fluctuations in long-wave propagation delay; When the rubidium clock is first started: Increase , To accelerate parameter convergence; after stable operation, adjust to , .
[0059] Construction of observation equations: The observed values are the time difference data between BeiDou and longwave ( , Its mapping relationship with the state vector is as follows: in, This is the BeiDou observation matrix; for The state vector at any given time; Noise from BeiDou observations; This is the long-wavelength observation matrix; This is for long-wavelength observation noise; Observation matrix , The physical meaning of the data sampling time is: BeiDou observation time difference = rubidium clock's own time difference ( ) - Fusion time difference ( ) + observation noise ( Long-wave observation time difference = rubidium clock's own time difference ( ) - Fusion time difference ( ) + observation noise ( ); Among them, the fusion time difference At any moment The fusion value is a weighted average of BeiDou and longwave observations: and The weights for BeiDou and longwave can be expressed as:
[0060] Observation noise covariance Sliding window estimation is used: in, for Real-time BeiDou observation noise covariance; for BeiDou predicts the value at any given time; for Real-time BeiDou observation values; To adjust the sliding window size; This refers to the data sampling time. This refers to the data sampling time. for Time-varying long-wavelength observation noise covariance; for Longwave observations at specific times; for Long-wave prediction value at time; In one specific embodiment of the present invention, N=300.
[0061] 3. Perform EKF iterative estimation: Based on the optimal estimate from the previous moment and its error covariance matrix Predict the state at the current moment. and .
[0062] State prediction: Covariance prediction: in, Let be the process noise covariance matrix.
[0063] renew: Calculation of observation residuals: in, For BeiDou observation matrix, For long-wavelength observation matrix, for BeiDou observation residuals for BeiDou observation residuals, residuals and These reflect the deviation between the observed and predicted values. The larger the absolute value, the more significant the deviation between the current prediction and the actual data, requiring further correction through subsequent steps.
[0064] Kalman gain calculation: in, This is an observation matrix for both BeiDou and longwave data. Gain matrix The size of the elements determines the weight of the observed data on the state correction: if the noise of a certain data source... When the gain is smaller (e.g., when BeiDou is not interfered with), the corresponding gain component increases, strengthening its contribution to state estimation.
[0065] State and covariance updates: Updated That is, to include , , , The optimal estimate, where, and It serves as the core basis for adjusting the frequency of the rubidium clock.
[0066] Based on real-time output , , A two-stage mechanism of coarse synchronization and fine control is adopted to tame the rubidium clock through fine frequency adjustments. The specific steps include: Coarse synchronization stage: Quickly eliminate initial deviations When the system starts up or the rubidium clock experiences a large disturbance ( When ), initiate coarse synchronization: Frequency deviation correction: applied directly This pulls the rubidium clock frequency back to near the reference, suppressing the rapid accumulation of clock bias; phase compensation: through continuous... The frequency transient adjustment compensates for the phase deviation, and the adjustment amount is... ,in, This is the optimal estimate of the rubidium clock phase deviation; Adjust the duration of the rubidium clock (1 hour is equivalent to 3600 seconds).
[0067] For example, if ,but Phase deviation is gradually eliminated through continuous adjustment over 3600 seconds, avoiding instantaneous jumps.
[0068] Fine-tuning phase: Dynamically maintaining synchronization accuracy After coarse synchronization is completed ( ), enter fine-tuning mode, based on With predicted clock bias (t is the prediction duration, taken as...) Dynamic adjustment: Scene 1: and (Large clock bias and positive frequency deviation): Adjustment amount By combining the predictive clock bias allocation strategy with the frequency deviation correction strategy, we can both suppress the current deviation and prevent its future accumulation.
[0069] Scene 2: and (Small clock bias and negative frequency bias): Adjustment amount Similarly, bidirectional deviation compensation can be achieved.
[0070] Scene 3: but (Clock bias is acceptable, but frequency deviation exceeds limits): Adjustment amount Only frequency deviations are corrected to maintain long-term stability.
[0071] Scene 4: and (Both parameters meet the standards): Adjustment amount To avoid over-adjustment that introduces additional noise.
[0072] The above thresholds (20ns and 5e-12 are in scientific notation) are mainly set according to the indicator requirements of different projects.
[0073] In a specific embodiment of the present invention, the state estimate is updated and the rubidium clock is adjusted in real time using dual-source observation data. The following steps are also included: evaluating taming performance by monitoring indicators such as clock bias changes and Allan variance.
[0074] To verify the effectiveness of the method of the present invention, Figure 3 To calculate the time difference between rubidium atomic clocks and UTC (NTSC) using MATLAB, Figure 4 The Allan variance (a measure of the stability of rubidium atomic clocks) of the time difference data between rubidium atomic clocks and UTC (NTSC) is calculated using MATLAB. Table 1 shows the results. Figure 4 Statistical values of the data.
[0075] See Figure 3 Experiments show that the method of this invention can reduce the standard deviation of the time difference data between the tamed rubidium clock and UTC to approximately 13.73 ns (three days of data), and improve the long-term stability (Allan variance over 100,000 seconds) from 1.86e-12 in the free state of the rubidium clock to the order of 2.91e-13. The results are as follows: Figure 4 As shown in Table 1.
[0076] Table 1. Comparison of stability of rubidium clock in free state and after clock training with BeiDou and longwave fusion.
[0077] The rubidium atomic clock discipline method based on BeiDou and longwave dual-source fusion provided by this invention uses the rubidium clock adjustment parameters and the fusion results of BeiDou and longwave simultaneously as state variables of the EKF for estimation. This achieves coordinated optimization of data fusion and parameter identification, avoids error accumulation and delay of the step-by-step method, and improves estimation accuracy and response speed. It fully leverages the advantages of BeiDou signal's high short-term accuracy and long-term stability and strong anti-interference capability of longwave signal. In complex electromagnetic environments or when a single signal fails, the other signal can still provide a valid reference, improving the reliability and environmental adaptability of the discipline system. The process noise and observation noise covariance can be dynamically adjusted according to signal quality, the Kalman gain automatically balances the weights of different source data, and the frequency control strategy is implemented in different modes, taking into account the requirements of fast convergence, high accuracy maintenance, and avoidance of phase jumps.
[0078] Based on the same inventive concept, this application provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of a rubidium atomic clock discipline method based on BeiDou and long-wave dual-source fusion. The memory may include main memory, such as high-speed random access memory, or it may also include non-volatile memory, such as at least one disk storage device. The processor, network interface, and memory are interconnected via an internal bus, which may be an industry-standard architecture bus, a peripheral component interconnection standard bus, an extended industry-standard architecture bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. The memory stores the program; specifically, the program may include program code, which includes computer operation instructions. The memory may include main memory and non-volatile memory, and provides instructions and data to the processor.
[0079] Based on the same inventive concept, embodiments of this application provide a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the steps of the rubidium atomic clock discipline method based on BeiDou and long-wave dual-source fusion. Specifically, the computer-readable storage medium includes, but is not limited to, volatile memory and / or non-volatile memory. The volatile memory may include RAM (Random Access Memory) and / or cache memory, etc. The non-volatile memory may include ROM (Read-Only Memory), hard disk, flash memory, optical disk, magnetic disk, etc.
[0080] Based on the same inventive concept, this application provides a computer program product, which includes a computer program stored on a computer-readable storage medium. The computer program includes program instructions, which, when executed by a computer device, cause the computer device to perform the steps of the above-described rubidium atomic clock discipline method based on the fusion of BeiDou and long-wave dual sources.
[0081] Those skilled in the art will understand that embodiments of the present invention can be provided as methods or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention 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 (Compact Disc Read-Only Memory), optical storage, etc.) containing computer-usable program code.
[0082] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as 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 apparatus or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0083] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer device 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.
[0084] These computer program instructions may also be loaded onto a computer device or other programmable data processing equipment to cause a series of operational steps to be performed on the computer device or other programmable equipment to produce a process implemented by the computer device, thereby providing instructions that execute on the computer device 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.
[0085] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.
[0086] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A method for disciplining a rubidium atomic clock based on the fusion of BeiDou and long-wave dual sources, characterized in that, Includes the following steps: Obtain a first time difference value and a second time difference value. The first time difference value is the time difference between the local time signal output by the rubidium atomic clock and the Beidou reference time signal output by the Beidou receiver. The second time difference value is the time difference between the local time signal and the longwave reference time signal output by the longwave receiver. definition The state vector at time t, the The state vector at any given time includes a first type of state variable characterizing the time-frequency characteristics of the rubidium atomic clock itself and a second type of state variable characterizing the time difference between BeiDou and longwave fusion; based on The state vector at time t is used to construct an extended Kalman filter model. The extended Kalman filter model includes a state transition equation and an observation equation. The state transition equation describes the evolution of the state vector over time, and the observation equation describes the mapping relationship between the first time difference, the second time difference, and the state vector. Using the first and second time differences as the observation inputs to the extended Kalman filter model, iterative estimation is performed to simultaneously update the optimal estimates of the first and second class state variables. Based on the optimal estimate, a frequency adjustment amount is generated and the output frequency of the rubidium atomic clock is controlled in a closed loop to achieve taming.
2. The rubidium atomic clock discipline method based on BeiDou and long-wave dual-source fusion as described in claim 1, characterized in that, The first type of state variables characterizing the time-frequency characteristics of the rubidium atomic clock itself includes the rubidium clock phase deviation, the rubidium clock frequency deviation, and the rubidium clock frequency drift rate. The second type of state variable characterizing the time difference between BeiDou and longwave fusion is the time difference value after BeiDou and longwave fusion.
3. The rubidium atomic clock discipline method based on BeiDou and long-wave dual-source fusion according to claim 2, characterized in that, Based on the optimal estimate, a frequency adjustment is generated and the output frequency of the rubidium atomic clock is controlled in a closed loop to achieve taming. The specific steps include: Determine whether the absolute value of the optimal estimate of the rubidium clock phase deviation is greater than a preset threshold. If the determination result is yes, then generate the adjustment amount of the rubidium clock frequency deviation and the adjustment amount of the rubidium clock phase deviation based on the optimal estimates of the rubidium clock frequency deviation and the rubidium clock phase deviation, so as to quickly eliminate large disturbances. Adjustment amount for rubidium clock frequency deviation Specifically: in, This is the optimal estimate of the rubidium clock frequency deviation; Adjustment amount of rubidium clock phase deviation Specifically: in, This is the optimal estimate of the rubidium clock phase deviation; Adjust the duration of the rubidium clock; If the judgment result is negative, then the predicted clock error is calculated based on the optimal estimates of the rubidium clock phase deviation, rubidium clock frequency deviation, and rubidium clock frequency drift rate; a frequency adjustment is generated based on the optimal estimate of the rubidium clock frequency deviation and the predicted clock error to dynamically maintain synchronization accuracy, specifically: When the predicted clock error is greater than the first threshold and the optimal estimate of the rubidium clock frequency deviation is greater than the second threshold, or when the predicted clock error is less than the negative first threshold and the optimal estimate of the rubidium clock frequency deviation is less than the negative second threshold, the frequency adjustment amount is: in, This is the adjustment amount for the rubidium clock frequency; Adjusting the duration of the rubidium clock Predicted phase deviation in the last second; When the absolute value of the predicted clock error is less than or equal to the first threshold and the absolute value of the optimal estimate of the rubidium clock frequency deviation is greater than the second threshold, the frequency adjustment amount is: The frequency adjustment is 0 when the absolute value of the predicted clock error is less than or equal to the first threshold and the absolute value of the best estimate of the rubidium clock frequency deviation is less than or equal to the second threshold.
4. The rubidium atomic clock discipline method based on BeiDou and long-wave dual-source fusion according to claim 2, characterized in that, The state vector at time step is specifically: in, for The state vector at any given time; This is due to the phase deviation of the rubidium clock; This is due to the frequency deviation of the rubidium clock; This refers to the frequency drift rate of the rubidium clock. This is the time difference value after the fusion of Beidou and long-wave.
5. The rubidium atomic clock discipline method based on BeiDou and long-wave dual-source fusion according to claim 2, characterized in that, The state transition equation is as follows: in, for The state vector at any given time; for The state vector at any given time; This is the state transition matrix; This is process noise; State transition matrix Specifically: in, The sampling interval is denoted as .
6. The rubidium atomic clock discipline method based on BeiDou and long-wave dual-source fusion according to claim 2, characterized in that, The specific observation equation is as follows: in, For BeiDou observation matrix, For long-wavelength observation matrices, and , This refers to the data sampling time. This is the first time difference value; for The state vector at any given time; Noise from BeiDou observations; This is the second time difference value; This is noise from long-wavelength observations.
7. A rubidium atomic clock discipline system based on the fusion of BeiDou and long-wave dual sources, characterized in that, include: The first module is used to obtain a first time difference value and a second time difference value. The first time difference value is the time difference between the local time signal output by the rubidium atomic clock and the Beidou reference time signal output by the Beidou receiver. The second time difference value is the time difference between the local time signal and the long-wave reference time signal output by the long-wave receiver. The second module is used to define the state vector, which includes a first type of state variable characterizing the time-frequency characteristics of the rubidium atomic clock itself and a second type of state variable characterizing the time difference between BeiDou and longwave fusion. Based on the state vector, an extended Kalman filter model is constructed. The extended Kalman filter model includes a state transition equation and an observation equation. The state transition equation is used to describe the evolution of the state vector over time, and the observation equation is used to describe the mapping relationship between the first time difference value, the second time difference value and the state vector. The third module is used to perform iterative estimation using the first time difference and the second time difference as the observation input of the extended Kalman filter model, and to synchronously update the optimal estimates of the first and second type of state variables. The fourth module is used to generate frequency adjustment based on the optimal estimate and to perform closed-loop control on the output frequency of the rubidium atomic clock to achieve taming.
8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the steps of the rubidium atomic clock discipline method based on the fusion of Beidou and long-wave dual sources as described in any one of claims 1 to 6.
9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the rubidium atomic clock discipline method based on the fusion of Beidou and long-wave dual sources as described in any one of claims 1 to 6.
10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the rubidium atomic clock discipline method based on the fusion of Beidou and long-wave dual sources as described in any one of claims 1 to 6.