A method for refining the time standard of a satellite-ground atomic clock

Abstract

This application discloses a method for refining the time standard of a satellite-ground atomic clock, including the following steps: S1. Receiving satellite signals through each receiver; S2. Each receiver records its own reception time upon receiving the satellite signal and calculates the satellite signal propagation time; S3. Obtaining satellite-based augmented corrections for the satellite signal; S4. Collecting and processing ground-based observation data from each ground reference station; S5. Calculating ground-based corrections based on the ground-based observation data; S6. Fusing the satellite-based and ground-based corrections to obtain a fused correction; S7. Based on the fused correction, correcting the propagation time of the satellite signal received by the receivers of each ground reference station to obtain the distance between the satellite and the receivers of each ground reference station; S8. Using signals from at least four satellites, calculating the clock bias based on the distance and the least squares method; S9. Correcting the receiver clock using the clock bias. This application improves the accuracy and robustness of time correction.

Description

Technical Field

[0001] The present application relates to the technical field of satellite-ground atomic clocks, and in particular, to a method for refining the time standard of a satellite-ground combined atomic clock. Background Art

[0002] Today, as the gross domestic product continues to grow, the supporting role of electricity in social and economic development is becoming increasingly apparent.

[0003] The safe and stable operation of power systems requires time information. In the future, as my country's power grids become interconnected, their dynamic behavior will become increasingly complex and unpredictable compared to independent operation. Therefore, monitoring equipment will be required to periodically monitor and report the status of various parts of the power system to determine whether the power network is operating stably. Currently, power system status monitoring primarily relies on internal remote terminal control systems, data acquisition and monitoring systems, wide-area measurement systems, energy management systems, synchronized phasor measurement units, and other relay protection devices, as well as accident recall and event sequence records.

[0004] Power system status information must be collected in real time, and data collected by different devices must be analyzed on the same timeline. Maintaining the time consistency of internal clocks across monitoring devices in different locations is a prerequisite for accurate status monitoring. Therefore, building a customer-side clock synchronization and trusted traceability network with broad coverage, high accuracy, and strong stability is fundamental to ensuring power system stability.

[0005] Smart electricity meters are now widely deployed. For rate-based metering, the meter's clock is crucial, as it impacts user billing. The stable and reliable operation of electricity meters is crucial to the vital interests of the people and the stability of society. To address the issue of accurate time, timing products such as Beidou and GNSS are being applied across various industries in my country. my country's independently developed Beidou-3 satellite navigation system already provides PNT services globally. As a critical system for ensuring people's livelihoods, the power system is crucial to national and economic security. Using my country's independently controlled satellite navigation system can better ensure safe and reliable system operation.

[0006] Traditional state-domain products derived from real-time GNSS data processing focus on positioning and point-to-point time comparison applications, generally without special processing of the time base. This results in systematic deviations in the clock information obtained from a single station, impacting the timing results of a single GNSS station. While some research has used single-station information externally linked to UTC time to correct the base, the reliability of existing correction methods based on single-station clock information is limited by the quality of the observation data from that single station, resulting in poor robustness. Summary of the Invention

[0007] On the one hand, the present application provides a method for refining the time standard of a joint satellite-ground atomic clock to solve the technical problem that the reliability of the existing single-station clock information correction method is subject to the quality of the single-station observation data and the robustness is poor.

[0008] The technical solutions adopted in this application are as follows:

[0009] A method for refining the time standard of a satellite-ground combined atomic clock comprises the following steps:

[0010] S1. Receive satellite signals through receivers at various ground reference stations;

[0011] S2. The receivers of each ground reference station record their own reception time when receiving satellite signals and calculate the propagation time of the satellite signals;

[0012] S3. Decode the PPP-B2b message for the satellite signal and obtain the satellite-based augmentation correction number;

[0013] S4. Collect and process ground-based observation data from various ground reference stations;

[0014] S5. Based on the processed ground-based observation data, the ground-based corrections of each ground reference station are calculated by network solution method;

[0015] S6. Fusing the satellite-based augmentation correction and the ground-based correction to obtain a fused correction.

[0016] S7. Based on the fused corrections, the propagation time of the satellite signal received by the receiver of each ground reference station is corrected to obtain the distance between the satellite and the receiver of each ground reference station;

[0017] S8. Receive signals from at least four satellites via receivers at each ground reference station, and calculate a receiver clock bias of each ground reference station based on the distance and a least squares method.

[0018] S9. Using the calculated receiver clock bias, correct the receiver clocks of the ground reference stations.

[0019] Furthermore, in step S6, when fusing the satellite-based augmentation correction number and the ground-based correction number, weighted averaging and Kalman filtering are used to perform the fusion to obtain a fused correction number.

[0020] Furthermore, the step S9 specifically includes the steps of:

[0021] S91, the receiver will use the clock x corrected based on the receiver clock deviation k (i) sent to the data center;

[0022] S92. The data center receives the most recently corrected clock x of each receiver. k (i) and update the variance of each receiver. The formula for updating the variance is:

[0023]

[0024] S93. The data center updates the weight of each receiver according to the updated variance:

[0025]

[0026] S94. The data center calculates the optimal estimated time of this correction time point based on the weight of each receiver. The calculation formula is:

[0027]

[0028] S95. Calculate the clock difference between the data center and each receiver using the following method:

[0029] D k (i)=2*[T k -x k (i)];

[0030] S96. Correct the data center clock to:

[0031]

[0032] S97. Correct each receiver clock to:

[0033] x k (i) = X k +D k (i)

[0034] Among them, F k (i) represents the tolerance of the i-th receiver at the k-th correction, E k-1 (i) represents the average value of the i-th receiver at the k-1th correction, γ k (i) represents the weight of the i-th receiver at the k-th correction, D k (i) represents the clock difference between the data center and each receiver calculated at the kth correction of the i-th receiver, T k represents the data center clock at the kth revision, x k (i) represents the kth corrected clock of the i-th receiver, and N represents the total number of receivers connected to the data center.

[0035] Furthermore, the step S1 further includes the steps of:

[0036] S11. performing Fourier transform on the satellite signals collected by the receivers of each ground reference station;

[0037] S12. Compare the spectrum characteristics in the current environment with the spectrum characteristics in the daily environment to find the frequency component A that does not exist in the daily environment;

[0038] S13. Design a corresponding filter according to the frequency component A to filter the frequency component A.

[0039] Furthermore, the step S12 specifically includes the following steps:

[0040] S121, setting a threshold θ;

[0041] S122. For each frequency f, calculate the spectrum difference ΔS(f)=S current (f)-S daily (f), where S daily (f) represents the signal spectrum in daily environment, S daily (f) represents the current signal spectrum;

[0042] S123. Identify the frequency of significant differences and determine whether |ΔS(f)| is greater than θ. If it is greater than θ, it indicates that the frequency f is a frequency component A that does not exist in daily environments.

[0043] Furthermore, in step S121, the threshold θ is calculated by the following method:

[0044] θ=μ+k·σ

[0045] Where μ is S daily (f) is the average value, σ is S daily (f) is the mean standard deviation of the two products, k is a constant.

[0046] Furthermore, the step S13 specifically includes the following steps:

[0047] S131. Filter the frequency component A through the transfer function H(z):

[0048]

[0049] Among them, f A represents the frequency of the frequency component A that you want to eliminate, T represents the sampling interval, r represents the notch parameter, the closer r is to 1, the narrower and deeper the notch is, and the closer r is to 0, the wider and shallower the notch is, and z represents a complex variable.

[0050] Furthermore, the step S8 specifically includes the steps of:

[0051] S81. Receive signals from at least four satellites at each ground reference station to obtain observation data, and calculate the rough clock bias and station center coordinates of each ground reference station based on the observation data and the least squares method.

[0052] S82. Establishing an error model, wherein the error model includes an ionosphere error model and a troposphere error model;

[0053] S83. For each ground reference station, use the error model, the fused correction number and the rough clock bias to calculate the precise clock bias, and iterate repeatedly until the precise clock bias is stable within the set range to obtain the clock bias of each receiver.

[0054] On the other hand, the present application also provides an electronic 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, the steps of the method for refining the time standard of the satellite-ground joint atomic clock are implemented.

[0055] On the other hand, the present application also provides a storage medium, which includes a stored program, and when the program is run, controls the device where the storage medium is located to execute the steps of the time standard refinement method of the satellite-ground joint atomic clock.

[0056] This application has the following beneficial effects:

[0057] 1) This application obtains and calculates satellite-based augmentation corrections and ground-based corrections for satellite-based and ground-based data respectively, and then fuses the satellite-based augmentation corrections and the ground-based corrections to ensure that information obtained from two different data sources is considered and utilized, avoiding one-sided consideration and utilization of a single data source, thereby improving the accuracy of time correction.

[0058] 2) This application uses both satellite-based data and ground-based data. This multi-data source approach can back up each other. When one data source has a problem, the other data source is still available, thereby ensuring the continuity and stability of time synchronization and higher robustness.

[0059] 3) This application collects and processes the observation data of each ground reference station and calculates the ground correction number of each ground reference station through a network solution method. This method abandons the excessive reliance on the data of a single ground reference station and instead considers the data of multiple ground reference stations, thereby reducing the impact of single data quality problems on time synchronization, avoiding reliability being restricted by the quality of single-station observation data, and further improving the robustness and reliability of time synchronization.

[0060] In addition to the above-described purposes, features and advantages, the present application also has other purposes, features and advantages. The present application will be further described in detail below with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of this application. The exemplary embodiments and descriptions of this application are intended to explain this application and do not constitute an improper limitation on this application. In the accompanying drawings:

[0062] Figure 1 It is a flow chart of the time standard refinement method of the satellite-ground combined atomic clock according to the preferred embodiment of the present application.

[0063] Figure 2 It is a schematic flow chart of the sub-steps of step S1 of the preferred embodiment of the present application.

[0064] Figure 3 It is a schematic flow chart of the sub-steps of step S8 of the preferred embodiment of the present application.

[0065] Figure 4 This is a schematic block diagram of an electronic device entity according to a preferred embodiment of the present application.

[0066] Figure 5 It is a diagram of the internal structure of a computer device according to a preferred embodiment of the present application. DETAILED DESCRIPTION

[0067] The embodiments of the present application are described in detail below with reference to the accompanying drawings, but the present application can be implemented in a variety of different ways defined and covered below.

[0068] like Figure 1 As shown, the preferred embodiment of the present application provides a method for refining the time standard of a satellite-ground combined atomic clock, comprising the steps of:

[0069] S1. Receive satellite signals through receivers at various ground reference stations;

[0070] S2. The receivers of each ground reference station record their own reception time when receiving satellite signals and calculate the propagation time of the satellite signals;

[0071] S3. Decode the PPP-B2b message for the satellite signal and obtain the satellite-based augmentation correction number;

[0072] S4. Collect and process ground-based observation data from various ground reference stations;

[0073] S5. Based on the processed ground-based observation data, the ground-based corrections of each ground reference station are calculated by network solution method;

[0074] S6. Fusing the satellite-based augmentation correction and the ground-based correction to obtain a fused correction.

[0075] S7. Based on the fused corrections, the propagation time of the satellite signal received by the receiver of each ground reference station is corrected to obtain the distance between the satellite and the receiver of each ground reference station;

[0076] S8. Receive signals from at least four satellites via receivers at each ground reference station, and calculate a receiver clock bias of each ground reference station based on the distance and a least squares method.

[0077] S9. Using the calculated receiver clock bias, correct the receiver clocks of the ground reference stations.

[0078] Compared with the prior art, this embodiment has the following beneficial effects:

[0079] 1) This embodiment obtains and calculates satellite-based augmentation corrections and ground-based corrections for satellite-based and ground-based data, respectively, and then fuses the satellite-based augmentation corrections and the ground-based corrections. This ensures that information obtained from two different data sources is considered and utilized, avoiding the one-sided consideration and utilization of a single data source, thereby improving the accuracy of time correction.

[0080] 2) This embodiment uses both satellite-based data and ground-based data. This multi-data source approach can back up each other. When one data source encounters a problem, the other data source is still available, thereby ensuring the continuity and stability of time synchronization and achieving higher robustness.

[0081] 3) This embodiment collects and processes observation data from various ground reference stations and calculates the ground corrections for each ground reference station through a network solution method. This method abandons excessive reliance on data from a single ground reference station and instead considers data from multiple ground reference stations, thereby reducing the impact of single data quality issues on time synchronization, avoiding reliability being constrained by the quality of single-station observation data, and further improving the robustness and reliability of time synchronization.

[0082] In a preferred embodiment of the present application, in step S6, when fusing the satellite-based augmentation correction number and the ground-based correction number, weighted averaging and Kalman filtering are used to perform the fusion to obtain the fused correction number.

[0083] Fusion of ground-based and satellite-based corrections typically employs mathematical methods such as weighted averaging and Kalman filtering to optimally combine data from different sources. For example, a common approach uses Kalman filtering to combine the high-precision corrections from ground-based stations with the global coverage capabilities of satellites, dynamically adjusting the weights to achieve optimal time synchronization and position accuracy.

[0084] In a preferred embodiment of the present application, step S9 specifically includes the following steps:

[0085] S91, the receiver will use the clock x corrected based on the receiver clock deviation k (i) sent to the data center;

[0086] S92. The data center receives the most recently corrected clock x of each receiver. k (i) and update the variance of each receiver. The formula for updating the variance is:

[0087]

[0088] S93. The data center updates the weight of each receiver according to the updated variance:

[0089]

[0090] S94. The data center calculates the optimal estimated time of this correction time point based on the weight of each receiver. The calculation formula is:

[0091]

[0092] S95. Calculate the clock difference between the data center and each receiver using the following method:

[0093] D k (i)=2*[T k -x k (i)];

[0094] S96. Correct the data center clock to:

[0095]

[0096] S97. Correct each receiver clock to:

[0097] x k (i) = X k +D k (i)

[0098] Among them, F k (i) represents the tolerance of the i-th receiver at the k-th correction, E k-1 (i) represents the average value of the i-th receiver at the k-1th correction, γ k (i) represents the weight of the i-th receiver at the k-th correction, D k (i) represents the clock difference between the data center and each receiver calculated at the kth correction of the i-th receiver, T k represents the data center clock at the kth revision, x k (i) represents the kth corrected clock of the i-th receiver, and N represents the total number of receivers connected to the data center.

[0099] This embodiment ensures the accuracy of overall clock synchronization by considering the clock data of all receivers and assigning weights to them. By calculating the variance of each receiver and assigning weights to them, it is ensured that even if there are problems or large deviations in the clock data of some receivers, it will not have a significant impact on the overall clock synchronization. By centrally managing the clock data of each receiver in the data center, clock synchronization can be easily monitored and managed to ensure the stable operation of the system. By continuously collecting and correcting the clock data of each receiver, it is ensured that the system can adapt to various changes and achieve dynamic clock synchronization. Through two-way clock synchronization between the data center and the receiver, even if there is a problem with the clock of the data center, it can be corrected through the clock data of the receiver, ensuring the reliability of the system.

[0100] like Figure 2 As shown, in a preferred embodiment of the present application, step S1 further includes the following steps:

[0101] S11. performing Fourier transform on the satellite signals collected by the receivers of each ground reference station;

[0102] S12. Compare the spectrum characteristics in the current environment with the spectrum characteristics in the daily environment to find the frequency component A that does not exist in the daily environment;

[0103] S13. Design a corresponding filter according to the frequency component A to filter the frequency component A.

[0104] To address the issue of strong electromagnetic energy in the base station environment, which significantly interferes with GNSS signals, this embodiment performs a Fourier transform on the satellite signals collected by the receiver. The spectral characteristics of the current environment are compared with those of everyday environments to identify frequency component A, which does not exist in daily life. A filter is then designed based on frequency component A to filter out frequency component A. This method removes electromagnetic wave spectrum that does not exist in everyday environments, thereby reducing interference from electromagnetic waves in the environment on the measurement signal.

[0105] In a preferred embodiment of the present application, step S12 specifically includes the following steps:

[0106] S121, setting a threshold θ;

[0107] S122. For each frequency f, calculate the spectrum difference ΔS(f)=S current (f)-S deily (f), where S daily (f) represents the signal spectrum in daily environment, S current (f) represents the current signal spectrum;

[0108] S123. Identify the frequency of significant differences and determine whether |ΔS(f)| is greater than θ. If it is greater than θ, it indicates that the frequency f is a frequency component A that does not exist in daily environments.

[0109] This embodiment compares the threshold with the spectrum difference and determines that the frequency with a spectrum difference greater than the threshold is electromagnetic energy that has a greater interference with the base station signal. This is based on the principle that most electromagnetic interference is random and sporadic, so this method can accurately determine electromagnetic interference.

[0110] In a preferred embodiment of the present application, in step S121, the threshold θ is calculated by the following method:

[0111] θ=μ+k·σ

[0112] Where μ is S daily (f) is the average value, σ is S dauly (f) is the mean standard deviation of the two products, k is a constant.

[0113] In this embodiment, different thresholds are set for different daily environments. If the environment has a high average value and a high standard deviation, the threshold is also high, and vice versa. This can avoid the reduction of the recognition sensitivity of the interference electromagnetic waves due to the threshold being too high, and can also avoid the false alarm caused by the recognition sensitivity of the interference electromagnetic waves being too high due to the threshold being too low. All of this is adaptive according to the environmental conditions.

[0114] In a preferred embodiment of the present application, step S13 specifically includes the following steps:

[0115] S131. Filter the frequency component A through the transfer function H(z):

[0116]

[0117] Among them, f A represents the frequency of the frequency component A to be eliminated, T represents the sampling interval, r represents the notch parameter. The closer r is to 1, the narrower and deeper the notch is, while the closer r is to 0, the wider and shallower the notch is. z represents a complex variable. By using the above method, the frequency component A can be filtered out to prevent electromagnetic interference from the signal.

[0118] like Figure 3 As shown, in a preferred embodiment of the present application, step S8 specifically includes the following steps:

[0119] S81. Receive signals from at least four satellites at each ground reference station to obtain observation data, and calculate the rough clock bias and station center coordinates of each ground reference station based on the observation data and the least squares method.

[0120] S82. Establishing an error model, wherein the error model includes an ionosphere error model and a troposphere error model;

[0121] S83. For each ground reference station, use the error model, the fused correction number and the rough clock bias to calculate the precise clock bias, and iterate repeatedly until the precise clock bias is stable within the set range to obtain the clock bias of each receiver.

[0122] This embodiment first receives signals from four or more satellites and uses the least squares method to solve for the receiver clock bias, which requires the use of the distance between the satellite and the receiver of each ground reference station calculated in step S7. In the Global Navigation Satellite System (GNSS), the positioning process of the receiver is based on measuring and calculating the signal propagation time from the satellite to the receiver, thereby deriving the distance. These distance measurements, combined with the known satellite positions, allow the receiver to calculate its own three-dimensional position (longitude, latitude, altitude) and the bias of the receiver clock. Next, this embodiment achieves accurate correction of the clock bias of each ground reference station by combining rough clock bias, correction number and error model. By repeatedly iteratively correcting the clock bias, it ensures that the final clock bias is stable within an acceptable range, thereby enhancing the stability of synchronization. By establishing an error model (including an ionospheric error model and a tropospheric error model), this embodiment can consider and correct errors from various sources to obtain corrections. The corrections here include the fused tropospheric error, ionospheric error, satellite orbit error, and clock bias. These fused errors are incorporated into the observation equation, and then the least squares method is used to iteratively calculate a more accurate clock bias, thereby ensuring the system's robustness to errors. By repeatedly iteratively correcting the clock bias, the system can dynamically adjust the clock bias based on actual conditions, ensuring real-time synchronization.

[0123] like Figure 4 As shown, another preferred embodiment of the present application further provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the steps of the time standard refinement method of the satellite-ground joint atomic clock in the above-mentioned embodiment are implemented.

[0124] like Figure 5 As shown, another preferred embodiment of the present application further provides a computer device, which can be a terminal or a liveness detection server, and its internal structure diagram can be as shown in FIG. Figure 5As shown. The computer device includes a processor, memory, and a network interface connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The network interface of the computer device is used to communicate with other external computer devices via a network connection. When executed by the processor, the computer program implements the steps of the above-mentioned method for refining the time standard of the satellite-ground combined atomic clock.

[0125] Those skilled in the art will understand that Figure 5 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0126] A preferred embodiment of the present application further provides a storage medium, which includes a stored program. When the program is executed, the device where the storage medium is located is controlled to execute the steps of the time standard refinement method of the satellite-ground joint atomic clock in the above embodiment.

[0127] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0128] If the functions described in the method of this embodiment are implemented in the form of a software functional unit and sold or used as an independent product, they can be stored in a storage medium readable by one or more computing devices. Based on this understanding, the part of the embodiment of the present application that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for enabling a computing device (which can be a personal computer, server, mobile computing device or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program code.

[0129] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code. The scheme in the embodiment of the present application can be implemented in various computer languages, for example, object-oriented programming language Java and literal translation scripting language JavaScript, etc.

[0130] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0131] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0132] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 The steps for the function specified in one or more boxes.

[0133] Anything not described in detail in this application is a well-known technology to those skilled in the art. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, and all of these should be included in the scope of the claims of the present invention.

Claims

1. A method for refining the time standard of a satellite-ground combined atomic clock, characterized in that: Including steps: S1. Receive satellite signals through receivers at various ground reference stations; S2. The receivers of each ground reference station record their own reception time when receiving satellite signals and calculate the propagation time of the satellite signals; S3. Decode the PPP-B2b message for the satellite signal and obtain the satellite-based augmentation correction number; S4. Collect and process ground-based observation data from various ground reference stations; S5. Based on the processed ground-based observation data, the ground-based corrections of each ground reference station are calculated by network solution method; S6. Fusing the satellite-based augmentation correction and the ground-based correction to obtain a fused correction. S7. Based on the fused corrections, the propagation time of the satellite signal received by the receiver of each ground reference station is corrected to obtain the distance between the satellite and the receiver of each ground reference station; S8. Receive signals from at least four satellites via receivers at each ground reference station, and calculate a receiver clock bias of each ground reference station based on the distance and a least squares method. S9. Using the calculated receiver clock bias, correct the receiver clocks of the ground reference stations.

2. The time standard refinement method of the satellite-ground combined atomic clock according to claim 1 is characterized in that: In step S6, when the satellite-based augmentation correction number and the ground-based correction number are fused, weighted averaging and Kalman filtering are used to perform the fusion to obtain a fused correction number.

3. The time standard refinement method of the satellite-ground combined atomic clock according to claim 1, characterized in that: The step S9 specifically includes the following steps: S91, the receiver will use the clock x corrected based on the receiver clock deviation k (i) sent to the data center; S92. The data center receives the most recently corrected clock x of each receiver. k (i) and update the variance of each receiver. The formula for updating the variance is: S93. The data center updates the weight of each receiver according to the updated variance: S94. The data center calculates the optimal estimated time of this correction time point based on the weight of each receiver. The calculation formula is: S95. Calculate the clock difference between the data center and each receiver using the following method: D k (i)=2*[T k -x k (i)]; S96. Correct the data center clock to: S97. Correct each receiver clock to: x k (i)=X k +D k (i) Among them, F k (i) represents the tolerance of the i-th receiver at the k-th correction, E k-1 (i) represents the average value of the i-th receiver at the k-1th correction, γ k (i) represents the weight of the i-th receiver at the k-th correction, D k (i) represents the clock difference between the data center and each receiver calculated at the kth correction of the i-th receiver, T k represents the data center clock at the kth revision, x k (i) represents the kth corrected clock of the i-th receiver, and N represents the total number of receivers connected to the data center.

4. The time standard refinement method of the satellite-ground combined atomic clock according to claim 1, characterized in that: The step S1 further comprises the steps of: S11. performing Fourier transform on the satellite signals collected by the receivers of each ground reference station; S12. Compare the spectrum characteristics in the current environment with the spectrum characteristics in the daily environment to find the frequency component A that does not exist in the daily environment; S13. Design a corresponding filter according to the frequency component A to filter the frequency component A.

5. The time standard refinement method of the satellite-ground combined atomic clock according to claim 4 is characterized in that: The step S12 specifically includes the following steps: S121, setting a threshold θ; S122. For each frequency f, calculate the spectrum difference ΔS(f)=S current (f)-S daily (f), where S daily (f) represents the signal spectrum in daily environment, S curreut (f) represents the current signal spectrum; S123. Identify the frequencies of significant differences and determine whether |ΔS(f)| is greater than θ. If it is greater than θ, it indicates that the frequency f is a frequency component A that does not exist in daily environments.

6. The time standard refinement method of the satellite-ground combined atomic clock according to claim 5, characterized in that: In step S121, the threshold θ is calculated by the following method: θ=μ+k·σ Where μ is S daily (f) is the average value, σ is S daily (f) is the mean standard deviation of the two products, k is a constant.

7. The time standard refinement method of the satellite-ground combined atomic clock according to claim 4 is characterized in that: The step S13 specifically includes the following steps: S131. Filter the frequency component A through the transfer function H(z): Among them, f A represents the frequency of the frequency component A that you want to eliminate, T represents the sampling interval, r represents the notch parameter, the closer r is to 1, the narrower and deeper the notch is, and the closer r is to 0, the wider and shallower the notch is, and z represents a complex variable.

8. The time standard refinement method of the satellite-ground combined atomic clock according to claim 1, characterized in that: The step S8 specifically includes the following steps: S81. Receive signals from at least four satellites at each ground reference station to obtain observation data, and calculate the rough clock bias and station center coordinates of each ground reference station based on the observation data and the least squares method. S82. Establishing an error model, wherein the error model includes an ionosphere error model and a troposphere error model; S83. For each ground reference station, use the error model, the fused correction number and the rough clock bias to calculate the precise clock bias, and iterate repeatedly until the precise clock bias is stable within the set range to obtain the clock bias of each receiver.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the time standard refinement method of the satellite-ground combined atomic clock are implemented as claimed in any one of claims 1 to 8.

10. A storage medium comprising a stored program, which controls a device where the storage medium is located to execute the steps of the time standard refinement method of a satellite-ground combined atomic clock according to any one of claims 1 to 8 when the program is executed.

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