Reference clock correction method, apparatus, device, storage medium and program product

Abstract

The application discloses a reference clock correction method and device, equipment, storage medium and program product, based on the radio frequency signal output by a GNSS anti-interference antenna, a first detection result of whether a reference clock exists a timing type interference is determined, and a second detection result of whether a GNSS time signal corresponding to the GNSS anti-interference antenna exists an anomaly is determined; when the timing type interference exists or the GNSS time signal exists the anomaly, based on historical effective data, model parameters of an independent operation model of a high-precision atomic clock are fitted, a time difference estimation value is obtained, and the reference clock is corrected based on the time difference estimation value. By adopting the embodiment of the application, GNSS interference can be effectively detected, ePRTC can be prevented from tracking an abnormal timing signal, accurate clock signals can be stably output under GNSS interference, and the reliable operation of a communication network time synchronization system can be maintained.

Description

Technical Field

[0001] This invention relates to the field of communications, and more particularly to a reference clock correction method, apparatus, device, storage medium, and program product. Background Technology

[0002] With the dense development of communication networks, the requirements for time synchronization are becoming increasingly stringent, posing challenges to the accuracy and reliability of the Primary Reference Time Clock (PRTC). To address this, existing technologies have defined an Enhanced Primary Reference Time Clock (ePRTC), which can provide a time accuracy of 30ns when GNSS (Global Navigation Satellite System) one-way time synchronization is effective. The ePRTC uses GNSS as an external high-precision time reference, and during normal operation, it calibrates its own clock by receiving one-way time synchronization signals from GNSS, ensuring that the output time is precisely aligned with Global Standard Time (UTC). Therefore, GNSS is a crucial external support for the ePRTC to achieve ultra-high precision time synchronization. However, current ePRTC technology does not include solutions for GNSS interference. Once GNSS is interfered with, its output timing signal will be distorted, deviated, or even completely fail. If ePRTC continues to track the abnormal GNSS signal, it will directly cause its own output time signal to deviate. Even if it enters autonomous operation mode, the reference stability of the atomic clock will be damaged due to the calibration interference from the abnormal GNSS signal in the early stage, which will eventually cause the ePRTC's time synchronization function to fail, thereby affecting the time synchronization system of the entire communication network and reducing the reliability and security of the communication network. Summary of the Invention

[0003] The purpose of this invention is to provide a reference clock correction method, apparatus, device, storage medium, and program product that can effectively detect GNSS interference, prevent ePRTC from tracking abnormal timing signals, ensure that it still outputs accurate clock signals stably under GNSS interference, and maintain the reliable operation of the communication network time synchronization system.

[0004] To achieve the above objectives, embodiments of the present invention provide a reference clock calibration method, comprising: Acquire the radio frequency signal output by the GNSS anti-jamming antenna; Based on the radio frequency signal, a first detection result is determined to determine whether the reference clock is subject to timing interference. Based on the output time signal of a preset high-precision atomic clock, a second detection result is used to determine whether there is an anomaly in the GNSS time signal corresponding to the GNSS anti-interference antenna. When the first detection result indicates the presence of timing interference, or the second detection result indicates an anomaly in the GNSS time signal, the model parameters of the autonomous operation model of the high-precision atomic clock are fitted based on historical valid data to obtain the time difference estimate. The reference clock is calibrated based on the estimated time difference.

[0005] As an improvement to the above scheme, the GNSS anti-jamming antenna has the same frequency as the GNSS receiver of the reference clock.

[0006] As an improvement to the above scheme, the second detection result for determining whether there is an anomaly in the GNSS time signal corresponding to the GNSS anti-interference antenna based on the output time signal of a preset high-precision atomic clock includes: Acquire the output time signal of a preset high-precision atomic clock, and measure the time difference sample between the GNSS time signal and the output time signal; A first time difference sample set measured during a first set time period is obtained, and a second time difference sample set measured during a second set time period is obtained; wherein, the first set time period is earlier than the second set time period, and is a historical time period without interference or anomalies; The reference frequency of the high-precision atomic clock is obtained by fitting the first time difference sample set, and the current frequency of the high-precision atomic clock is obtained by fitting the second time difference sample set. The frequency difference between the current frequency and the reference frequency is calculated. The frequency difference is compared with a preset anomaly threshold, and a second detection result is determined based on the comparison result to determine whether there is an anomaly in the GNSS time signal.

[0007] As an improvement to the above scheme, the anomaly threshold is obtained based on the root mean square error of the reference frequency.

[0008] As an improvement to the above scheme, the historical valid data refers to historical measurement data in which no timing interference was detected and the GNSS time signal showed no abnormalities.

[0009] As an improvement to the above scheme, the step of fitting the model parameters of the autonomous operation model of the high-precision atomic clock based on historical valid data to obtain the time difference estimate includes: The historical valid data are fitted using the least squares method to obtain the model parameters of the autonomous operation model of the high-precision atomic clock; wherein, the model parameters include the reference frequency and the initial phase; Based on the reference frequency and the initial phase, the estimated time difference between the high-precision atomic clock and the GNSS receiver is calculated using the autonomous operation model.

[0010] To achieve the above objectives, embodiments of the present invention also provide a reference clock correction device, comprising: The radio frequency signal acquisition module is used to acquire the radio frequency signal output by the GNSS anti-interference antenna; The first detection module is used to determine, based on the radio frequency signal, a first detection result indicating whether the reference clock is subject to timing interference. The second detection module is used to determine whether there is an abnormal second detection result in the GNSS time signal corresponding to the GNSS anti-interference antenna, based on the output time signal of a preset high-precision atomic clock. The time difference estimation module is used to obtain a time difference estimate by fitting the model parameters of the autonomous operation model of the high-precision atomic clock based on historical valid data when the first detection result indicates the presence of timing interference or the second detection result indicates an anomaly in the GNSS time signal. The correction module is used to perform clock correction on the reference clock based on the time difference estimate.

[0011] To achieve the above objectives, embodiments of the present invention also provide a reference clock correction device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, it implements the reference clock correction method as described in any of the above embodiments.

[0012] To achieve the above objectives, embodiments of the present invention also provide a computer-readable storage medium, the computer-readable storage medium including a stored computer program, wherein, when the computer program is executed, it controls the device where the computer-readable storage medium is located to perform the reference clock correction method as described in any of the above embodiments.

[0013] To achieve the above objectives, embodiments of the present invention also provide a computer program product, including computer instructions, which, when executed by a processor, implement the reference clock correction method as described in any of the above embodiments.

[0014] Compared to existing technologies, the reference clock correction method, apparatus, device, storage medium, and program products disclosed in this invention address the problems of susceptibility to interference and poor clock synchronization stability in traditional GNSS timing scenarios. Through a dual judgment mechanism of radio frequency interference detection and atomic clock reference anomaly verification, it accurately identifies timing-related interference or GNSS time signal anomalies. Upon anomaly triggering, it calculates a high-precision time difference estimate based on fitting parameters of the atomic clock's autonomous operation model using historical valid data, thus completing the autonomous correction of the reference clock. Compared to traditional clock synchronization schemes that rely on real-time GNSS measurements, this invention effectively detects GNSS interference and, when GNSS signals are disturbed or distorted, maintains the reference clock's time synchronization accuracy through a historical fitting model without relying on an external timing source. This avoids ePRTC tracking of abnormal timing signals, ensuring stable and accurate clock signal output even under GNSS interference. It effectively solves the problem of GNSS timing being susceptible to electromagnetic interference and attacks leading to clock synchronization failure, improving the reference clock's anti-interference capability and continuous stable operation in complex environments, ensuring the reliability of high-precision time synchronization, and thus maintaining the reliable operation of the communication network time synchronization system. Attached Figure Description

[0015] Figure 1 This is a flowchart of a reference clock calibration method provided in an embodiment of the present invention; Figure 2 This is a flowchart of generating a second detection result provided in an embodiment of the present invention; Figure 3 This is a system schematic diagram of the embodiment of the present invention for improving the anti-interference capability of ePRTC; Figure 4 This is a structural block diagram of a reference clock correction device provided in an embodiment of the present invention; Figure 5 This is a structural block diagram of a reference clock correction device provided in an embodiment of the present invention. Detailed Implementation

[0016] 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, 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 are within the scope of protection of the present invention.

[0017] See Figure 1 , Figure 1 This is a flowchart of a reference clock correction method provided in an embodiment of the present invention, the reference clock correction method including steps S1 to S5.

[0018] S1. Obtain the radio frequency signal output by the GNSS anti-interference antenna.

[0019] For example, the GNSS anti-jamming antenna shares the same frequency as the GNSS receiver of the reference clock. The GNSS receiver refers to a receiving device used to receive satellite navigation signals and demodulate GNSS time signals to provide timing reference for the reference clock; specifically, it can be the GNSS timing receiver in an ePRTC system. The GNSS anti-jamming antenna is a satellite navigation receiving antenna with interference suppression capabilities, capable of suppressing timing-related interference and improving the availability of the timing signal in complex electromagnetic environments. Setting up a GNSS anti-jamming antenna is to suppress and weaken various suppressive interferences that may affect timing at the signal receiving front end, such as continuous wave interference, broadband interference, narrowband interference, and multi-point frequency sweep interference, thereby reducing the impact of timing-related interference on the demodulation of the GNSS receiver's time signal from the source and ensuring that the timing signal can be stably received and used normally in complex electromagnetic environments.

[0020] For example, the radio frequency signal refers to the satellite navigation radio frequency signal received and processed by the GNSS anti-interference antenna, such as including carrier waves, pseudocodes, and navigation message information for timing. The frequency point refers to the operating carrier frequency of the GNSS satellite navigation signal. Setting the GNSS anti-interference antenna and the GNSS receiver with the reference clock to the same frequency point ensures that the radio frequency signal received and processed by the antenna after anti-interference is completely matched with the receiving frequency band of the GNSS receiver. This allows the effective timing signal after the antenna suppresses various types of suppression interference to be normally received and demodulated by the GNSS receiver, avoiding signal attenuation, distortion, or inability to be identified due to frequency mismatch, and ensuring the integrity and reliability of the timing signal from the signal input source.

[0021] S2. Based on the radio frequency signal, determine the first detection result of whether the reference clock has timing interference.

[0022] For example, although the system is equipped with a GNSS anti-jamming antenna capable of suppressing timing interference, in complex electromagnetic environments, interference intensity may still exceed the antenna's suppression capability, interference types may not be completely suppressed, or new types of interference may emerge. This residual interference can still affect the normal output of the GNSS time signal, leading to timing anomalies. Therefore, to accurately identify such interference that still affects timing, an interference detection unit can be installed between the GNSS anti-jamming antenna and the GNSS receiver. This unit can perform signal energy monitoring, spectral characteristic analysis, and time-domain waveform detection on the RF signal output by the GNSS anti-jamming antenna to autonomously determine whether the current signal is affected by interference. For instance, by detecting whether the RF signal power is abnormally increased, whether there are obvious peaks in the spectrum, or whether the time-domain waveform is distorted or truncated, the presence of interference signals can be determined. If interference is detected, the type of interference is further identified, and it is determined whether the interference will prevent the GNSS receiver from outputting a stable and reliable GNSS time signal. If the interference directly affects the time signal output, it is determined to be time-related interference, and a first detection result indicating the presence of time-related interference is generated. If no interference is detected, or the interference does not affect the time signal output, a first detection result indicating the absence of time-related interference is generated.

[0023] S3. Based on the preset high-precision atomic clock output time signal, determine whether there is an abnormality in the GNSS time signal corresponding to the GNSS anti-interference antenna.

[0024] For example, the high-precision atomic clock refers to an atomic clock with high frequency stability, high continuous operation capability, and autonomous timekeeping capability, capable of outputting a stable and reliable time signal for a long period without external time reference, providing a high-precision internal time reference for the ePRTC system. The output time signal of the high-precision atomic clock is generated autonomously by the clock itself, including, for example, a high-precision 1PPS (1 Pulse Per Second) pulse signal and corresponding time information, independent of GNSS satellite time signals, and characterized by continuity, stability, and anti-interference. The GNSS time signal is obtained by receiving and demodulating satellite navigation signals from a GNSS receiver, including, for example, the 1PPS pulse signal output by the GNSS receiver and navigation message time information, used to provide an external time reference for the reference clock. An anomaly in the GNSS time signal refers to situations where the 1PPS signal, time information, or frequency output by the GNSS receiver deviates, jumps, is distorted, or becomes unreliable, including but not limited to deviations between the GNSS 1PPS output and the actual time caused by deception interference, covert interference, signal anomalies, satellite anomalies, etc., thereby affecting the synchronization of the reference clock.

[0025] It should be noted that this invention employs a time output anomaly detection method based on the mean square error of the frequency estimation value of a high-precision atomic clock to determine the second detection result. Relying on the continuity, autonomy, and high frequency stability of the high-precision atomic clock, the difference between the high-precision atomic clock 1PPS output and the GNSS 1PPS output is used as the high-precision atomic clock-GNSS measurement data. Through statistical analysis and evaluation of this measurement data, it is determined whether the GNSS time signal is abnormal. Although step S2 can detect timing interference, it mainly targets suppression interference in the radio frequency domain. It struggles to effectively identify scenarios such as deceptive interference, covert interference, satellite anomalies, and slow signal drift, which do not manifest as obvious radio frequency interference but directly cause GNSS 1PPS time output anomalies. Therefore, step S3 further verifies the output quality of the GNSS time signal in both the time and frequency domains, forming a dual discrimination mechanism with step S2 for interference detection and anomaly detection. This mechanism can identify both radio frequency interference and various non-radio frequency interference-induced GNSS time anomalies, improving the timekeeping reliability and anomaly identification comprehensiveness of the ePRTC system in complex environments.

[0026] Further, see Figure 2 , Figure 2 This is a flowchart of generating a second detection result provided in an embodiment of the present invention, wherein step S3 specifically includes steps S31 to S34.

[0027] S31. Obtain the output time signal of a preset high-precision atomic clock, and measure the time difference sample between the GNSS time signal and the output time signal.

[0028] For example, using a high-precision atomic clock as a reliable time reference, the 1PPS output time signal generated by the clock is acquired, and simultaneously, the GNSS 1PPS time signal, demodulated by a GNSS receiver after receiving satellite signals via an anti-interference antenna, is acquired. The time difference between the high-precision atomic clock 1PPS and the GNSS 1PPS is used as high-precision atomic clock-GNSS measurement data, i.e., a time difference sample, for subsequent frequency fitting and anomaly detection. This time difference sample reflects the phase deviation between the GNSS timing signal and the high-precision atomic clock reference, and is the fundamental data for evaluating the stability of the GNSS time signal.

[0029] S32. Obtain a first time difference sample set measured during a first set time period, and obtain a second time difference sample set measured during a second set time period; wherein, the first set time period is earlier than the second set time period, and is a historical time period without interference or abnormalities.

[0030] For example, the first set time period can be a historical time period earlier than the current time in the ePRTC system's operation, verified as interference-free and anomaly-free through steps S1 and S2. For instance, it could be the most recent 7 days (denoted as -7.5d to -0.5d) 0.5 days ago. The time difference samples within this time period constitute the first time difference sample set, used to fit a stable and reliable reference frequency. The second set time period can be a 0.5-day period immediately adjacent to the current time (denoted as 0 to -0.5d). The time difference samples within this time period constitute the second time difference sample set, used to fit the current frequency to determine if anomalies exist. Further, by slicing the first set time period into 0.5-day segments, 14 sets of interference-free and anomaly-free time difference subsets can be obtained. Adding one set from the second set time period, a total of 15 time difference sample sets are obtained, denoted as... ,in .

[0031] S33. Based on the first time difference sample set, the reference frequency of the high-precision atomic clock is obtained by fitting, and based on the second time difference sample set, the current frequency of the high-precision atomic clock is obtained by fitting, and the frequency difference between the current frequency and the reference frequency is calculated.

[0032] For example, based on the first time difference sample set, the reference frequency of the high-precision atomic clock is obtained by fitting using the least squares method. This frequency represents the true stable frequency of the atomic clock under ideal, interference-free conditions. Based on the second time difference sample set, the current frequency of the high-precision atomic clock is obtained through fitting. ,correspond In the algorithm The frequency result. Calculate the current frequency. and reference frequency Frequency difference between ,satisfy: The frequency difference This reflects the degree of deviation of the current GNSS time signal from the atomic clock reference frequency.

[0033] S34. Compare the frequency difference with a preset abnormal threshold, and determine a second detection result based on the comparison result to determine whether there is an abnormality in the GNSS time signal.

[0034] For example, the anomaly threshold is obtained based on the root mean square error (RMSE) of the reference frequency. The RMSE calculation process is as follows: based on 14 interference-free and anomaly-free subsets obtained by dividing the first time difference sample set (corresponding to the algorithm in...) ), respectively fitted to obtain 14 sets of frequency values ; at the reference frequency Assuming the true value, the root mean square error (RMS) of these 14 sets of frequency fitting values ​​is calculated. This value represents the inherent fluctuation range of the frequency fitting under interference-free conditions. Three times (for example only; adjustments can be made as needed in practical applications) of the RMS is used as the outlier threshold. ,Right now This threshold conforms to statistical criteria and can effectively distinguish between normal fluctuations and abnormal deviations. The frequency difference obtained in step S33 is then used... With the abnormal threshold If a comparison is made, > If so, the frequency value within the current 0.5-day period is determined to be abnormal, corresponding to an anomaly in the GNSS time signal, and a second detection result indicating the presence of an anomaly is generated; if ≤ If the current frequency value is normal, a second detection result indicating that there is no abnormality is generated.

[0035] It should be noted that the time output anomaly detection method provided by this invention has high sensitivity to GNSS 1PPS anomaly output. Regardless of whether there is interference, as long as an anomaly in the GNSS 1PPS output is detected, an anomaly is marked. The ePRTC system mainly considers the degree of influence of deception interference on the GNSS 1PPS signal. If the deception interference has no effect or a very small effect on the GNSS 1PPS signal output, the purpose of deception will not be achieved. Regardless of whether the type of deception interference is covert, as long as the GNSS 1PPS signal output is abnormal, it can be marked as an anomaly by the above method.

[0036] In this embodiment of the invention, by calculating the frequency difference and comparing it with a preset abnormal threshold, the abnormality of the GNSS time signal can be determined. This can eliminate the influence of interference and abnormal data, establish a stable and reliable frequency reference, avoid misjudgment caused by a single moment or short-term data fluctuation, accurately identify GNSS time signal abnormalities, and improve the stability and anti-interference capability of the reference clock correction.

[0037] S4. When the first detection result indicates the presence of timing interference, or the second detection result indicates an anomaly in the GNSS time signal, the model parameters of the autonomous operation model of the high-precision atomic clock are fitted based on historical valid data to obtain a time difference estimate; wherein, the historical valid data are historical measurement data in which no timing interference was detected and the GNSS time signal did not exhibit any anomalies.

[0038] For example, when the first detection result indicates the presence of timing interference, or the second detection result indicates an anomaly in the GNSS time signal, it means that the GNSS timing signal is unreliable or has failed, and cannot continue to provide accurate timing reference for the reference clock. It is necessary to switch to the autonomous timekeeping mode based on a high-precision atomic clock. The historical valid data refers to historical measurement data that has been verified in steps S1-S2 as having no timing interference and has been marked as anomaly-free in step S3. Selecting this type of data as historical valid data ensures that the data used for model fitting comes from ideal scenarios where GNSS timing is normal and there is no interference or deception. This ensures that the inherent frequency and phase characteristics of the high-precision atomic clock are accurately reflected, avoiding abnormal data contaminating model parameters and ensuring the reliability and stability of the autonomously operating model. For example, all historical measurement data within 7.5 days of the ePRTC system's operation that meets the conditions of no interference and no anomalies can be selected, or the measurement data without interference and no anomalies from the most recent 7 days can be selected to balance data volume and timeliness. The high-precision atomic clock autonomous operation model refers to a mathematical model that, when GNSS timing fails, autonomously calculates the time difference between the high-precision atomic clock and the GNSS receiver based solely on the inherent characteristics of the high-precision atomic clock.

[0039] Further, in step S4, the step of fitting the model parameters of the autonomous operation model of the high-precision atomic clock based on historical valid data to obtain the time difference estimate includes: fitting the historical valid data using the least squares method to obtain the model parameters of the autonomous operation model of the high-precision atomic clock; wherein, the model parameters include a reference frequency and an initial phase; and calculating the time difference estimate between the high-precision atomic clock and the GNSS receiver based on the reference frequency and the initial phase using the autonomous operation model.

[0040] For example, the autonomous running model satisfies: (1); in, This is the time difference measurement between the 1PPS signal of the high-precision atomic clock and the 1PPS signal of the GNSS receiver. The current moment; This is the reference time, i.e., the starting time of the historical valid data; The reference frequency (full reference frequency) of the high-precision atomic clock is compared with the reference frequency obtained in step S3 based on interference-free and anomaly-free data fitting. The physical meanings are consistent; both are the true values ​​of the stable frequency of a high-precision atomic clock under ideal conditions. The fitting results of step S3 can be directly reused or refitted based on longer historical valid data. The initial phase refers to the reference time. The initial phase offset between the high-precision atomic clock and the GNSS receiver; This represents random error, specifically measurement noise and model residuals.

[0041] For example, the model parameters include a reference frequency. and initial phase All parameters were obtained by fitting historical valid data using the least squares method. To improve computational efficiency, the recursive least squares method was preferred for fitting, enabling efficient updating and iteration of model parameters. It should be noted that... It is a measured value, the reference frequency. and initial phase The parameter fitting process based on the least squares method can be referred to the existing technology, and will not be described in detail here.

[0042] For example, based on the fitted model parameters, the estimated time difference between the high-precision atomic clock and the GNSS receiver is calculated by autonomously running the model; that is, the model output after ignoring random error terms. (2); in, This is the estimated time difference value, which is used to replace the real-time measured time difference data when GNSS timing fails, providing a reliable input for subsequent reference clock correction.

[0043] In this embodiment of the invention, by utilizing historical data free from interference and anomalies, the phase and frequency variation patterns of a high-precision atomic clock can be accurately established, avoiding interference from abnormal data on model parameters and ensuring the stability and reliability of model parameters. At the same time, the least squares method has high fitting accuracy and high computational efficiency, and can quickly obtain a stable and reliable reference frequency and initial phase. This enables the autonomous operating model to accurately calculate the time difference estimate when the GNSS signal is interfered with or abnormal, providing a stable and reliable correction basis for the reference clock. This effectively solves the problem that traditional solutions cannot continuously and accurately achieve clock correction when GNSS timing fails, and improves the continuous working capability and correction accuracy of the reference clock in complex electromagnetic environments.

[0044] S5. Perform clock correction on the reference clock based on the time difference estimate.

[0045] For example, to meet the full calibration requirements of the ePRTC system, the time difference estimate can be used as a basis. The total float correction is calculated using the following formula: (3); in, This is the time difference measurement between the ePRTC local clock 1PPS signal and the high-precision atomic clock 1PPS signal.

[0046] For example, the clock unit uses total time difference correction. As input, the frequency and phase of the local clock are adjusted and locked in real time through an internal phase-locked loop (PLL), based on the total time difference correction. The clock unit compensates for the phase and frequency deviations between the local clock and the high-precision time reference, synchronizing the 1PPS signal output by the local clock with the 1 clock signal to the high-precision time reference. This achieves high-precision and high-stability clock signal output. In addition, the clock unit can also output other types or formats of clock signals according to actual application requirements. Thus, even in scenarios where GNSS timing signals are disturbed or abnormal, the reference clock can still continuously, stably, and reliably output high-precision clock signals, completing the autonomous correction and anti-interference timekeeping of the reference clock.

[0047] It should be noted that in step S4, if the first detection result indicates the absence of timing interference and the second detection result indicates the absence of anomalies in the GNSS time signal, the GNSS timing signal is in a reliable and stable normal operating state and can continue to provide accurate timing reference for the reference clock without triggering the time difference estimation process based on the high-precision atomic clock autonomous operation model. In this scenario, the system maintains the normal timing operation mode. At this time, in step S5, the time difference between the real-time measured high-precision atomic clock 1PPS and the GNSS receiver 1PPS can be directly calculated. Combining the real-time measured time difference between the local clock and the atomic clock The total time difference correction amount is calculated. The clock unit is input and performs clock correction based on real-time GNSS timing data to ensure high-precision synchronization between the reference clock output and the GNSS time base. At the same time, it continuously collects interference-free and anomaly-free time difference measurement data, updates and expands the historical valid data set, and reserves high-quality training data for the subsequent autonomous operation model fitting, further improving the parameter reliability and time difference estimation accuracy of the model under abnormal scenarios.

[0048] Further, see Figure 3 , Figure 3 This is a system schematic diagram for improving the anti-interference capability of ePRTC according to an embodiment of the present invention. The system includes a GNSS anti-interference antenna, a GNSS receiver, a high-precision atomic clock, an interference detection unit, a time interval measurement unit 1, a time interval measurement unit 2, an information processing unit, and a clock unit. The functions of each module are as follows: 1) A GNSS anti-jamming antenna, with the same frequency as the GNSS receiver used in ePRTC, is used to receive satellite navigation radio frequency signals and suppress suppression-type timing interference such as continuous wave interference, broadband interference, narrowband interference, and multi-point frequency sweep interference at the front end, and outputs the processed radio frequency signal; the radio frequency signal output by the antenna is divided into two paths, one of which is sent to the GNSS receiver to demodulate the timing information and 1PPS signal; the other path is sent to the interference detection unit to identify timing-type interference; 2) GNSS receiver, which receives radio frequency signals after anti-interference processing, completes satellite signal acquisition, tracking and demodulation, and outputs receiver time stamp information and 1PPS time signal to provide external time reference for the system; 3) High-precision atomic clocks provide an autonomous and highly stable internal time reference for the ePRTC system. Typically, a cesium clock outputs a 1PPS pulse signal and a 10MHz frequency reference signal, enabling continuous and stable operation without relying on GNSS time synchronization. 4) Time interval measurement unit 1 receives data from a high-precision atomic clock (1PPS) and a GNSS receiver (1PPS), measures the time difference between the two, and outputs the result. (High-precision atomic clock - GNSS time difference measurement value), used for frequency fitting and anomaly detection; 5) Time interval measurement unit 2 receives 1PPS from the ePRTC local clock and 1PPS from the high-precision atomic clock, measures the time difference between the two, and outputs... (Local clock-atomic clock time difference measurement), used for the final total time difference correction calculation; 6) Interference detection unit: Based on the radio frequency signal output by the GNSS anti-interference antenna, it detects the presence of timing interference by analyzing signal energy, spectrum characteristics, and time-domain waveform, and outputs interference type information. 7) Information processing unit, receiving time stamp information from GNSS receiver, interference type information from interference detection unit, and time interval measurement unit 1. , Time interval measurement unit 2 Based on a high-precision atomic clock frequency lag estimation algorithm, for Frequency fitting and anomaly labeling are performed to identify GNSS time signal anomalies. When timing interference or GNSS time signal anomalies are detected, the parameters of a high-precision atomic clock autonomous operation model are fitted based on historical valid data without interference or anomalies to calculate the estimated time difference. , combined Calculate the total time difference correction. It outputs to the clock unit; at the same time, it outputs time stamp signals (such as standard synchronization signals for high-precision time information) and completes system communication interaction (such as bidirectional data transmission and command interaction between the information processing unit and various modules inside the system and external devices). 8) Clock unit, receiving the total time difference correction output from the information processing unit. The system uses an internal phase-locked loop to train the local clock in frequency and phase, locking it to a high-precision atomic clock reference. Finally, it outputs a 1PPS pulse signal, a 10MHz frequency signal, and other clock signals to achieve continuous high-precision time synchronization for the ePRTC system in GNSS interference or abnormal scenarios. In addition, the 10MHz signal output by the high-precision atomic clock also serves as the frequency reference for the clock unit, further ensuring the frequency stability of the clock output.

[0049] In this embodiment of the invention, a dual judgment mechanism of radio frequency interference detection and atomic clock reference anomaly verification accurately identifies timing interference or GNSS time signal anomalies. Upon anomaly triggering, the system fits the parameters of the atomic clock's autonomous operation model based on historical valid data, thereby calculating a high-precision time difference estimate and completing the autonomous correction of the reference clock. Compared to traditional clock synchronization schemes that rely on real-time GNSS measurements, this invention effectively detects GNSS interference and, when GNSS signals are disturbed or distorted, maintains the reference clock's time synchronization accuracy through a historical fitting model without relying on an external timing source. This avoids the ePRTC tracking abnormal timing signals, ensuring stable and accurate clock signal output even under GNSS interference. It effectively solves the problem of GNSS timing being susceptible to electromagnetic interference and attacks leading to clock synchronization failures, improving the reference clock's anti-interference capability and continuous stable operation in complex environments, ensuring the reliability of high-precision time synchronization, and thus maintaining the reliable operation of the communication network time synchronization system.

[0050] See Figure 4 , Figure 4 This is a structural block diagram of a reference clock correction device 100 provided in an embodiment of the present invention. The reference clock correction device 100 includes: The radio frequency signal acquisition module 11 is used to acquire the radio frequency signal output by the GNSS anti-interference antenna; The first detection module 12 is used to determine, based on the radio frequency signal, a first detection result indicating whether the reference clock is subject to timing interference. The second detection module 13 is used to determine whether there is an abnormal second detection result in the GNSS time signal corresponding to the GNSS anti-interference antenna, based on the preset output time signal of the high-precision atomic clock. The time difference estimation module 14 is used to obtain a time difference estimate by fitting the model parameters of the autonomous operation model of the high-precision atomic clock based on historical valid data when the first detection result indicates the presence of timing interference or the second detection result indicates an anomaly in the GNSS time signal. The correction module 15 is used to perform clock correction on the reference clock based on the time difference estimate.

[0051] It is worth noting that the working process of each module in the reference clock correction device 100 described in the embodiments of the present invention can refer to the working process of the reference clock correction method described in the above embodiments.

[0052] See Figure 5 , Figure 5 This is a structural block diagram of a reference clock correction device 200 provided in an embodiment of the present invention. The reference clock correction device 200 includes a processor 21, a memory 22, and a computer program stored in the memory 22 and executable on the processor 21. When the processor 21 executes the computer program, it implements the steps in the various reference clock correction method embodiments described above.

[0053] For example, the computer program may be divided into one or more modules / units, which are stored in the memory 22 and executed by the processor 21 to complete the present invention. The one or more modules / units may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program in the reference clock correction device 200.

[0054] The reference clock correction device 200 may include, but is not limited to, a processor 21 and a memory 22. Those skilled in the art will understand that the schematic diagram is merely an example of the reference clock correction device 200 and does not constitute a limitation on the reference clock correction device 200. It may include more or fewer components than illustrated, or combine certain components, or different components. For example, the reference clock correction device 200 may also include input / output devices, network access devices, buses, etc.

[0055] The processor 21 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor. The processor 21 is the control center of the reference clock correction device 200, connecting all parts of the reference clock correction device 200 via various interfaces and lines.

[0056] The memory 22 can be used to store the computer programs and / or modules. The processor 21 implements various functions of the reference clock correction device 200 by running or executing the computer programs and / or modules stored in the memory 22 and calling the data stored in the memory 22. The memory 22 may mainly include a program storage area and a data storage area. The program storage area may store the operating system, at least one application program required for a function (such as sound playback function, image playback function, etc.), etc.; the data storage area may store data created according to the use of the mobile phone (such as audio data, phonebook, etc.). In addition, the memory 22 may include high-speed random access memory, and may also include non-volatile memory, such as hard disk, memory, plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0057] If the integrated module / unit of the reference clock correction device 200 is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the methods of the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by the processor 21, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying the computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc.

[0058] Furthermore, the present invention also provides a computer program product, including a computer program / instructions that, when executed by a processor, implement the reference clock correction method as described in any of the above embodiments.

[0059] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A reference clock calibration method, characterized in that, include: Acquire the radio frequency signal output by the GNSS anti-jamming antenna; Based on the radio frequency signal, a first detection result is determined to determine whether the reference clock is subject to timing interference. Based on the output time signal of a preset high-precision atomic clock, a second detection result is used to determine whether there is an anomaly in the GNSS time signal corresponding to the GNSS anti-interference antenna. When the first detection result indicates the presence of timing interference, or the second detection result indicates an anomaly in the GNSS time signal, the model parameters of the autonomous operation model of the high-precision atomic clock are fitted based on historical valid data to obtain the time difference estimate. The reference clock is calibrated based on the estimated time difference.

2. The reference clock calibration method as described in claim 1, characterized in that, The GNSS anti-jamming antenna has the same frequency as the GNSS receiver of the reference clock.

3. The reference clock calibration method as described in claim 1, characterized in that, The second detection result, which determines whether there is an anomaly in the GNSS time signal corresponding to the GNSS anti-jamming antenna based on the output time signal of a preset high-precision atomic clock, includes: Acquire the output time signal of a preset high-precision atomic clock, and measure the time difference sample between the GNSS time signal and the output time signal; A first time difference sample set measured during a first set time period is obtained, and a second time difference sample set measured during a second set time period is obtained; wherein, the first set time period is earlier than the second set time period, and is a historical time period without interference or anomalies; The reference frequency of the high-precision atomic clock is obtained by fitting the first time difference sample set, and the current frequency of the high-precision atomic clock is obtained by fitting the second time difference sample set. The frequency difference between the current frequency and the reference frequency is calculated. The frequency difference is compared with a preset anomaly threshold, and a second detection result is determined based on the comparison result to determine whether there is an anomaly in the GNSS time signal.

4. The reference clock calibration method as described in claim 3, characterized in that, The anomaly threshold is obtained based on the root mean square error of the reference frequency.

5. The reference clock calibration method as described in claim 1, characterized in that, The historical valid data refers to historical measurement data in which no timing interference was detected and the GNSS time signal showed no abnormalities.

6. The reference clock calibration method as described in claim 1 or 5, characterized in that, The process of fitting model parameters of the autonomous operation model of the high-precision atomic clock based on historical valid data to obtain time difference estimates includes: The historical valid data are fitted using the least squares method to obtain the model parameters of the autonomous operation model of the high-precision atomic clock; wherein, the model parameters include the reference frequency and the initial phase; Based on the reference frequency and the initial phase, the estimated time difference between the high-precision atomic clock and the GNSS receiver is calculated using the autonomous operation model.

7. A reference clock correction device, characterized in that, include: The radio frequency signal acquisition module is used to acquire the radio frequency signal output by the GNSS anti-interference antenna; The first detection module is used to determine, based on the radio frequency signal, a first detection result indicating whether the reference clock is subject to timing interference. The second detection module is used to determine whether there is an abnormal second detection result in the GNSS time signal corresponding to the GNSS anti-interference antenna, based on the output time signal of a preset high-precision atomic clock. The time difference estimation module is used to obtain a time difference estimate by fitting the model parameters of the autonomous operation model of the high-precision atomic clock based on historical valid data when the first detection result indicates the presence of timing interference or the second detection result indicates an anomaly in the GNSS time signal. The correction module is used to perform clock correction on the reference clock based on the time difference estimate.

8. A reference clock calibration device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor, wherein the processor, when executing the computer program, implements the reference clock correction method as described in any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored computer program, wherein, when the computer program is executed, it controls the device on which the computer-readable storage medium is located to perform the reference clock correction method as described in any one of claims 1 to 6.

10. A computer program product, characterized in that, It includes computer instructions that, when executed by a processor, implement the reference clock correction method as described in any one of claims 1 to 6.

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