Masterless Parallel Beidou Common-View Method and System for Wide-Area Time Synchronization

Abstract

The present application provides a masterless parallel Beidou common view method for wide-area time synchronization, including: a Beidou common view server receives first common view data sent by a time reference source with a Beidou common view function and second common view data sent by a time synchronization device; the Beidou common view server calculates the power system time and a first time deviation between the time reference source and the power system time based on the first common view data, and sends the first time deviation to the corresponding time reference source, so that the time reference source adjusts the time information of the time reference source based on the first time deviation; the Beidou common view server matches all visible time reference sources corresponding to the time synchronization device based on the second common view data, calculates the second time deviation between the time synchronization device and all corresponding visible time reference sources, and sends the second time deviation to the corresponding time synchronization device, so that the time synchronization device adjusts the time information of the time synchronization device to synchronize with the power system time based on the second time deviation.

Description

Technical Field

[0001] The present invention relates to the field of time synchronization technology, and in particular to a masterless parallel Beidou common viewing method and system for wide-area time synchronization. Background Art

[0002] Currently, time synchronization devices are installed in every control center, centralized control station, substation, and power plant across the power grid, providing initial regional time synchronization capabilities. These devices primarily utilize satellite timing, a one-way, non-traceable time source. If time deviations occur during conversion, they are undetectable both locally and remotely, and no traceable corrections can be made. Timing applications across the entire power grid only achieve intra-site time synchronization; a wide-area time synchronization network spanning multiple plants and regions has not been established. Timing across the entire power grid operates independently, lacking a unified, traceable reference time source. This makes it impossible to achieve wide-area time synchronization across control centers, substations, and power plants.

[0003] Existing satellite common view methods mostly use a master-slave tree hierarchy to achieve time synchronization. This method has shortcomings: first, in order not to affect the accuracy of the satellite common view method, the master-slave span cannot be greater than 2000km; second, a failure of the common view receiver of the master station will make it impossible for the slave stations to effectively trace and synchronize. Summary of the Invention

[0004] The purpose of this application is to provide a masterless parallel Beidou common view method and system for wide-area time synchronization, which calculates and estimates the time deviation of each time reference source through the common view between each other, establishes the power system time through the time reference source group, calculates the time deviation between each time reference source and the power system time, and adjusts the time of each time reference source in turn, so that the widely distributed time reference sources form a time synchronization timing plane. The more widely distributed time synchronization device can calculate the deviation from the power system time through the common view of Beidou satellites and each common view time reference source and adjust the synchronization, ultimately achieving wide-area time synchronization of the entire power grid.

[0005] In a first aspect, the present application provides a masterless parallel BeiDou common view method for wide-area time synchronization, comprising:

[0006] The Beidou common view server receives first common view data sent by a time reference source having a Beidou common view function and second common view data sent by a time synchronization device;

[0007] The Beidou common view server calculates the power system time and a first time offset between the time reference source and the power system time according to the first common view data, and sends the first time offset to the corresponding time reference source, so that the time reference source adjusts the time information of the time reference source based on the first time offset;

[0008] The Beidou common-view server matches all visible time reference sources corresponding to the time synchronization device based on the second common-view data, calculates a second time deviation between the time synchronization device and all corresponding visible time reference sources, and sends the second time deviation to the corresponding time synchronization device, so that the time synchronization device adjusts the time information of the time synchronization device to synchronize with the power system time based on the second time deviation.

[0009] Preferably, the first common view data includes: a median value of the satellite-to-ground clock difference between the time reference source and the visible satellite within the common view period and a median value of the satellite elevation angle between the time reference source and the visible satellite within the common view period;

[0010] The satellite-to-ground clock difference between the time reference source T and the visible satellite s and the satellite elevation angle of the visible satellite s are The corresponding median values within a common viewing period are calculated by the least squares method. Its calculation expression is as follows:

[0011]

[0012] in, is the satellite-to-ground clock difference and elevation angle at the ith second in the common-view period, and n is the duration of the common-view period.

[0013] Preferably, the BeiDou common view server calculates the time deviation between the time reference source i and the time reference source j with the common view satellite k as a reference according to the first common view data. The expression is as follows:

[0014]

[0015] When the elevation angle of the common view satellite k When the angle is less than the preset angle, the common view satellite k does not participate in the calculation of the time deviation.

[0016] Preferably, when there are N time reference sources i and j, s The average time deviation between the time reference source i and the time reference source j is The calculation expression is as follows:

[0017]

[0018] in, For sequence The maximum and minimum values in ;

[0019] Calculate the time deviation sequence of each time reference source that can be seen by both Its expression is as follows:

[0020]

[0021] where \(i,j = 1,2,\cdots,N\) u , \(i\lt j\), is the number of time reference sources;

[0022] Estimate the time deviation estimate value that satisfies the time deviation correlation topology matrix \(G\) between time reference sources by using the least squares method Its expression is as follows:

[0023]

[0024] where \(i,j = 1,2,\cdots,N\) u , \(i\lt j\), \(N\) u is the number of time reference sources;

[0025] Obtain the time \(T\) of the time reference source at the location of the Beidou common view server u1 , and calculate the time \(T\) of the time reference source with Beidou common view function Ti , and its calculation expression is as follows:

[0026]

[0027] Calculate the calculated value \(T\) of the power system time through weighted average pc , and its expression is as follows:

[0028]

[0029] where \(a\) i is the weight of the time reference source \(i\) participating in the calculation of the power system time;

[0030] Obtain the power system time \(T\) through Kalman filtering p The calculation expression is as follows:

[0031] \(T\) <00000l0>=T p-1 +K p (T pc -T p-1 )

[0032] where \(K\) p is the filtering coefficient of the Kalman filtering.

[0033] Preferably, calculate the first time deviation \(\Delta T\) between the time reference source and the power system time Ti , and its expression is as follows:

[0034] \(\Delta T\) Ti =T Ti-T p

[0035] Where i = 1, 2, ..., N u , N u is the number of time reference sources.

[0036] Preferably, the second common view data includes: the median value of the satellite-to-ground clock difference within the common view period and the median value of the satellite elevation angle within the common view period; the satellite-to-ground clock difference between the time synchronization device u and the visible satellite s and the satellite elevation angle of the visible satellite s are respectively The corresponding median values within a common viewing period are calculated by the least squares method. Its calculation expression is as follows:

[0037]

[0038] in, are the satellite-to-ground clock difference and satellite elevation angle at the ith second in the common-view period, and n is the duration of the common-view period.

[0039] Preferably, the BeiDou common view server calculates the time deviation between the time synchronization device u and the time reference source j with the common view satellite k as a reference based on the second common view data. Its expression is as follows:

[0040]

[0041] When the satellite elevation angle of the common view satellite k When the angle is less than the preset angle, the common view satellite k does not participate in the calculation of the time deviation.

[0042] Preferably, when there are N time synchronization devices u and time reference source j, s The average time deviation between the time synchronization device u and the time reference source j is The calculation expression is as follows:

[0043]

[0044] in, Sequence The maximum and minimum values in ;

[0045] When there is a deviation ΔT between the time synchronization device and the time reference source calculated by weighted average u , its calculation expression is as follows:

[0046]

[0047] Among them, b jis the weight of the time deviation of the time synchronization device, N c is the number of commonly visible time reference sources.

[0048] Preferably, the weight b of the time deviation of the time synchronization device is j It is determined based on relevant information of the time reference source; the relevant information includes the accuracy of the time reference source, the stability of the time reference source, the distance between the time reference source and the time synchronization device, and the number of satellites in common view between the time reference source and the time synchronization device.

[0049] In a second aspect, the present application also provides a wide-area time-synchronized masterless parallel BeiDou common-view system, comprising:

[0050] Time reference sources with Beidou common view capability deployed in various regulatory agencies;

[0051] A time synchronization device that uses BeiDou satellites to share common sight with some or all of the time reference sources;

[0052] A BeiDou common view server connected to the time reference source and the time synchronization device for network communication, receiving the first common view data sent by the time reference source and the second common view data sent by the time synchronization device;

[0053] The Beidou common view server is used to calculate and generate the power system time and a first time offset between the time reference source and the power system time according to the first common view data, and send the first time offset to the time reference source to adjust the time information of the time reference source;

[0054] The Beidou common view server is used to calculate a second time offset between the time synchronization device and the time reference source according to the second common view data, and send the second time offset to the time synchronization device to adjust the time information of the time synchronization device.

[0055] Preferably, the time reference source consists of a Beidou common view receiver and an atomic frequency standard source; the atomic frequency standard source is a cesium atomic frequency standard source or a hydrogen atomic frequency standard source; the Beidou common view receiver is provided with a network communication interface for communicating with the Beidou common view server respectively.

[0056] By adopting the technical solution of the present application, the time deviations of each time reference source can be calculated and estimated through the common visibility between each other, and the power system time is established through the time reference source group, and the time deviations between each time reference source and the power system time are calculated. The time of each time reference source is adjusted in turn, so that the widely distributed time reference sources form a time synchronization timing plane. The more widely distributed time synchronization device can calculate the deviation from the power system time through the common visibility of the Beidou satellite and each common visibility time reference source and adjust the synchronization, and finally realize the wide-area time synchronization of the entire power grid. The effective effect is that the establishment of a unified power system time for the entire power grid does not depend on the operating status of individual time reference sources, and the time synchronization of the time synchronization device does not depend on the operating status of individual time reference sources, which improves the robustness and timing accuracy of wide-area time synchronization and realizes true wide-area time synchronization for the entire network. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0058] Figure 1 A flowchart of a masterless parallel BeiDou common view method for wide-area time synchronization provided in an embodiment of the present application;

[0059] Figure 2 A schematic diagram of a flow chart for calculating the power system time and the time deviation from the time reference source provided in an embodiment of the present application;

[0060] Figure 3 A schematic diagram of the process of synchronizing the time synchronization device and the power system provided in an embodiment of the present application;

[0061] Figure 4 A schematic diagram of a process for monitoring time deviation and frequency deviation provided in an embodiment of the present application;

[0062] Figure 5 A schematic diagram of the structure of a masterless parallel BeiDou common view system with wide-area time synchronization provided in an embodiment of the present application. DETAILED DESCRIPTION

[0063] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0064] The purpose of this application is to provide a wide-area time-synchronized masterless parallel Beidou common viewing method and system, in order to make the above-mentioned purposes, features and advantages of this application more obvious and easy to understand. The application will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0065] Example 1

[0066] like Figure 1 As shown, the masterless parallel BeiDou common view method for wide-area time synchronization in the embodiment of the present application includes:

[0067] S01: A Beidou common view server receives first common view data sent by a time reference source with a Beidou common view function and second common view data sent by a time synchronization device;

[0068] In an embodiment of the present application, in order to solve the implementation path from regional synchronization of the power system to wide-area synchronization, a time reference source with a Beidou common view function is deployed in regulatory agencies at the provincial level and above. The time reference source obtains the first common view data of the Beidou satellite visible to it and sends it to the Beidou common view server; at the same time, a time synchronization device is deployed in the power system area, and the time synchronization device obtains the second common view data of the Beidou satellite visible to it and sends it to the Beidou common view server.

[0069] In this embodiment, the first common view data includes the median value of the satellite-to-ground clock difference between the time reference source and the visible satellites during the common view period, and the median value of the satellite elevation angle between the time reference source and the visible satellites during the common view period. When obtaining the median value of the satellite-to-ground clock difference, the time reference source first obtains the satellite-to-ground clock difference between the time reference source and the visible satellites, which is expressed as follows:

[0070]

[0071] in, is the satellite-to-earth clock difference between the time reference source T and the visible satellite s, is the pseudorange between the time reference source T and the visible satellite s, is the true distance between the time reference source T and the visible satellite s, is the ionospheric delay between the time reference source T and the visible satellite s, is the tropospheric delay between the time reference source T and the visible satellite s, Δt T is the antenna and processing conversion delay of the time reference source T, and c is the speed of light.

[0072] After obtaining the satellite-to-earth clock difference between the time reference source T and the visible satellite s Then, the median value of the satellite-earth clock error within the corresponding common view period is calculated by the least squares method. Its calculation expression is as follows:

[0073]

[0074] in, is the satellite-to-ground clock difference in the ith second during the common viewing period, and n is the duration of the common viewing period.

[0075] In this embodiment, when the time reference source obtains the median value of the satellite elevation angle, it first obtains the satellite elevation angle between the time reference source and the visible satellite, which is expressed as follows:

[0076]

[0077] in, is the satellite elevation angle between the time reference source T and the visible satellite s, is the observation vector between the time reference source T and the visible satellite s in the east, north and sky directions.

[0078] After obtaining the satellite elevation angle between the time reference source T and the visible satellite s Then, the median value of the satellite elevation angle within the corresponding common view period is further calculated by the least squares method. Its calculation expression is as follows:

[0079]

[0080] in, is the satellite elevation angle at the ith second in the common viewing period, and n is the duration of the common viewing period.

[0081] In this embodiment, the second common view data includes the median value of the satellite-to-earth clock difference between the time synchronization device and the visible satellites within the common view period and the median value of the satellite elevation angle between the time synchronization device and the visible satellites within the common view period.

[0082] When the time synchronization device obtains the median value of the satellite-to-ground clock difference, it first obtains the satellite-to-ground clock difference between the time synchronization device and the visible satellite. The expression is as follows:

[0083]

[0084] in, is the satellite-to-earth clock difference between the time synchronization device u and the visible satellite s, is the pseudorange between the time synchronization device u and the visible satellite s, is the true distance between the time synchronization device u and the visible satellite s, is the ionospheric delay between the time synchronization device u and the visible satellite s, is the tropospheric delay between the time synchronization device u and the visible satellite s, Δt u is the antenna and processing conversion delay of the time synchronization device u, and c is the speed of light.

[0085] After obtaining the satellite-to-earth clock difference between the time synchronization device u and the visible satellite s Then, the median value of the satellite-earth clock error within the corresponding common view period is calculated by the least squares method. Its calculation expression is as follows:

[0086]

[0087] in, is the satellite-to-ground clock difference in the ith second during the common viewing period, and n is the duration of the common viewing period.

[0088] When the time synchronization device obtains the median value of the satellite elevation angle, it first obtains the satellite elevation angle between the time synchronization device and the visible satellite. The expression is as follows:

[0089]

[0090] in, is the satellite elevation angle between the time synchronization device u and the visible satellite s, is the observation vector between the time synchronization device u and the visible satellite s in the east, north and sky directions.

[0091] After obtaining the satellite elevation angle of the time synchronization device u and the visible satellite s Then, the median value of the satellite elevation angle within the corresponding common view period is calculated by the least squares method. Its calculation expression is as follows:

[0092]

[0093] in, is the satellite elevation angle at the ith second in the common viewing period, and n is the duration of the common viewing period.

[0094] After obtaining the corresponding first common-view data and second common-view data in the above manner, the time reference source and the time synchronization device transmit them to the Beidou common-view server for processing.

[0095] S02. The Beidou common view server calculates the power system time and a first time offset between the time reference source and the power system time according to the first common view data, and sends the first time offset to the corresponding time reference source, so that the time reference source adjusts the time information of the time reference source based on the first time offset;

[0096] refer to Figure 2 As shown, in an embodiment of the present application, after receiving the first common view data, the Beidou common view server processes the first common view data sent by all time reference sources to obtain the power system time, which is the unified time of the power system.

[0097] Among them, when the Beidou common-view server calculates the power system time based on the first common-view data, first, the Beidou common-view server calculates the time deviation between time reference sources with the same common-view satellite as the reference according to the first common-view data. The calculation formula is as follows:

[0098]

[0099] Among them, is the time deviation between time reference source i and time reference source j with the common-view satellite k as the reference; and when the satellite elevation angle of the common-view satellite k is less than the preset angle, for example, when this common-view satellite k does not participate in the calculation of this time deviation

[0100] When there are N s common-view satellites between time reference source i and time reference source j, further calculate the average time deviation between time reference source i and time reference source j. The calculation formula is as follows:

[0101]

[0102] Among them, is the maximum and minimum values in the sequence ;

[0103] Furthermore, based on the average time deviation between each time reference source, calculate the time deviation sequence that can be commonly viewed pairwise for each time reference source. The expression is as follows:

[0104]

[0105] Among them, i, j = 1, 2,..., N u , i < j, is the number of time reference sources;

[0106] Furthermore, estimate the time deviation estimation value that satisfies the time deviation correlation topology matrix G between time reference sources by the least squares method. The expression is as follows:

[0107]

[0108] Among them, i, j = 1, 2,..., N u , i < j, N u is the number of time reference sources; between the topology matrix G and the time deviation estimation value , satisfy:

[0109] Furthermore, the BeiDou common view server uses the time reference source T at its location. u1 Estimated time deviation Calculate the time T of other time reference sources with Beidou common view function Ti , its calculation expression is as follows:

[0110]

[0111] Furthermore, the calculated value T of the power system time is calculated by weighted average pc , its calculation expression is as follows:

[0112]

[0113] Among them, a i is the weight of time reference source i participating in the power system time calculation;

[0114] Furthermore, the calculated value T of the power system time is calculated by the Kalman filter algorithm. pc Processing is performed to obtain the power system time T p , the calculation expression is as follows:

[0115] T p =T p-1 +K p (T pc -T p-1 )

[0116] Among them, K p is the filter coefficient of the Kalman filter.

[0117] The BeiDou common view server calculates the power system time T based on the first common view data. p Afterwards, further, through the first time deviation ΔT between each time reference source and the power system time Ti , its calculation expression is as follows:

[0118] ΔT Ti =T Ti -T p

[0119] Where i = 1, 2, ..., N u , N u is the number of time reference sources, the BeiDou common view server calculates the first time deviation ΔT between the time reference source and the power system time Ti Sent to the corresponding time reference source, each time reference source passes the corresponding time deviation ΔT Ti Adjust its own time information so that the time information of each time reference source is consistent with the power system time.

[0120] S03. The Beidou common-view server matches all visible time reference sources corresponding to the time synchronization device based on the second common-view data, calculates a second time deviation between the time synchronization device and all corresponding visible time reference sources, and sends the second time deviation to the corresponding time synchronization device, so that the time synchronization device adjusts the time information of the time synchronization device to synchronize with the power system time based on the second time deviation.

[0121] refer to Figure 3 As shown, in an embodiment of the present application, after adjusting the time information of each time reference source to be consistent with the power system time, the time deviation between each time synchronization device and the time reference source is further calculated based on the second common view data sent by the time synchronization device. Specifically, after receiving the second common view data, the Beidou common view server matches each time synchronization device with all corresponding common viewable time reference sources based on the second common view data, further calculates the time deviation between the time synchronization device and each time reference source, calculates the weighted average of these time deviations, and then sends the weighted average time deviation to the time synchronization device, adjusting the time information of the time synchronization device to be consistent with the power system time.

[0122] After receiving the second common view data, the Beidou common view server further combines the time information of the corresponding visible time reference source matched with the time synchronization device to calculate the time deviation between the time synchronization device and the corresponding common view time reference source. The calculation expression is as follows:

[0123]

[0124] in, is the time deviation between the time synchronization device u and the time reference source j with the common view satellite k as the reference, and when the satellite elevation angle of the reference common view satellite k is When the angle is smaller than the preset angle, e.g. Then the common view satellite k does not participate in the calculation of time deviation

[0125] Furthermore, when there are N s When there are 1 satellite in common view, calculate the average time deviation between the time synchronization device u and the time reference source j Its calculation expression is as follows:

[0126]

[0127] in, Sequence The maximum and minimum values in ;

[0128] When the time synchronization device exists N c When there are a common viewable time reference source, the weight of the time deviation between the time synchronization device and each time reference source is further determined. Specifically, the weight of the time deviation is determined according to the relevant information of the time reference source, for example, the weight of the time deviation is determined by the accuracy of the time reference source, the weight of the time deviation is determined by the stability of the time reference source, the weight of the time deviation is determined by the distance between the time reference source and the time synchronization device, and the weight of the time deviation is determined by the number of common view satellites between the time reference source and the time synchronization device. In this embodiment, when determining the weight of the time deviation, it is also possible to combine multiple of the above-mentioned relevant information, for example, the weight of the time deviation is determined based on the accuracy and stability of the time reference source, and the weight of the time deviation is also determined based on the accuracy, stability and number of common view satellites of the time reference source, etc. The above is only an exemplary explanation. Specifically, when determining the weight of the time deviation, it can also be determined in combination with one or more of the other relevant information, which will not be repeated here.

[0129] Furthermore, the deviation ΔT between the time synchronization device and the time reference source is calculated by weighted average u , its calculation expression is as follows:

[0130]

[0131] Among them, b j is the weight of the time deviation of the time synchronization device, N c is the number of commonly visible time reference sources.

[0132] refer to Figure 4 As shown, in an embodiment of the present application, the Beidou common view server also monitors the time deviation and frequency deviation of each time reference source, monitors the time deviation and frequency deviation of each time synchronization device, and compares the time deviation and frequency deviation of each time reference source with the time deviation and frequency deviation of each time synchronization device to form a change curve of the time deviation and frequency deviation, and determines the time accuracy and frequency accuracy of each time reference source and each time synchronization device through the change curve.

[0133] In the embodiment of the present application, during the common viewing period T w The time accuracy of the internal time reference source and time synchronization device is ΔT T and ΔT u , the corresponding frequency standard source accuracy is

[0134] Example 2

[0135] like Figure 5As shown, the wide-area time synchronized masterless parallel Beidou common view system in this embodiment includes: a time reference source and a time synchronization device, wherein the time reference source and the time synchronization device respectively establish communication connections with the Beidou common view server through the power dispatching communication network.

[0136] In an embodiment of the present application, a time reference source is provided in a regulatory agency to provide time information for the regulatory agency, and the time reference source is composed of an atomic frequency standard source and a Beidou common-view receiver, wherein the atomic frequency standard source can be a cesium atomic frequency standard source or a hydrogen atomic frequency standard source, for providing time information; wherein the Beidou common-view receiver is used to obtain the first common-view data of the Beidou satellite visible to it, for example, the median value of the satellite-to-ground clock difference between the time reference source and the visible Beidou satellite within the common-view period and the median value of the satellite elevation angle; the Beidou common-view server obtains the power system time and the first time deviation between each time reference source and the power system time by calculation based on the received first common-view data, and sends the first time deviation to each time reference source, and adjusts the time of each time reference source to make it consistent with the power system time.

[0137] A time synchronization device is set up in each power system area to provide time information for each power system area. The time synchronization device can have a common view with some or all of the Beidou satellites. The second common view data of the Beidou satellites that are visible to it is sent to the Beidou common view server. The Beidou common view server matches the time synchronization device with all the corresponding common view time reference sources based on the received second common view data, calculates the second time deviation between the time synchronization device and its corresponding common view time reference source, and sends the second time deviation to the time synchronization device to adjust the time of each time synchronization device to make it consistent with the power system time.

[0138] In an embodiment of the present application, when obtaining the median value of the satellite-to-ground clock difference and the median value of the satellite elevation angle between the time reference source and the visible Beidou satellite within a common view period (e.g., 1 minute to 10 minutes), the time reference source is obtained as follows:

[0139] The satellite-to-ground clock difference and satellite elevation angle of the time reference source T and the visible Beidou satellite s are The median value of the satellite-earth clock error within the corresponding common view period is calculated by the least squares method. and the median value of the satellite elevation angle Its calculation expression is as follows:

[0140]

[0141] in, are the satellite-to-ground clock difference and satellite elevation angle at the ith second in the common-view period, and n is the duration of the common-view period.

[0142] The BeiDou common view server calculates the time deviation between time reference source i and time reference source j with BeiDou satellite k as the common view reference Among them, when the satellite elevation angle of Beidou satellite k When the angle is smaller than the preset angle (for example: ), then the BeiDou satellite k does not participate in the calculation of the time deviation Its calculation expression is as follows:

[0143]

[0144] When there are N time reference sources i and j s When there are co-viewing satellites, the average time deviation between time reference source i and time reference source j is:

[0145]

[0146] in, For sequence The maximum and minimum values in ;

[0147] Furthermore, the BeiDou common view server calculates the time deviation sequence of each time reference source that can be viewed together. Where i, j = 1, 2, ..., N u ,i <j,N u is the number of time reference sources.

[0148] Furthermore, the BeiDou common view server uses the least squares method to estimate the time deviation estimated value that satisfies the time deviation correlation topology matrix G between the time reference sources. Where i, j = 1, 2, ..., N u ,i <j,N u is the number of time reference sources. Among them, the topology matrix G and the time deviation estimate satisfy:

[0149] The time T when the BeiDou common view server obtains the time reference source of the BeiDou common view server's location u1 , then the time of other time reference sources

[0150] The BeiDou common view server further uses weighted average to calculate the calculated value of the power system time T pc , its calculation expression is as follows:

[0151]

[0152] Among them, a i is the weight of time reference source i participating in the power system time calculation;

[0153] The BeiDou common view server further uses Kalman filtering to calculate the power system time T p , its calculation expression is as follows:

[0154] T p =T p-1 +K p (T pc -T p-1 )

[0155] Among them, K p is the filter coefficient of the Kalman filter.

[0156] The BeiDou common view server calculates the power system time T based on the first common view data. p Afterwards, further, through the first time deviation ΔT between each time reference source and the power system time Ti , its calculation expression is as follows:

[0157] ΔT Ti =T Ti -T p

[0158] Where i = 1, 2, ..., N u , N u is the number of time reference sources, the BeiDou common view server calculates the first time deviation ΔT between the time reference source and the power system time Ti Sent to the corresponding time reference source, each time reference source passes the corresponding time deviation ΔT Ti Adjust its own time information so that the time information of each time reference source is consistent with the power system time.

[0159] In an embodiment of the present application, when the time synchronization device obtains the median value of the satellite-to-ground clock difference and the median value of the satellite elevation angle between the time synchronization device and the visible Beidou satellite within a common viewing period (for example, 1 minute to 10 minutes), the time synchronization device obtains the median value of the satellite-to-ground clock difference and the median value of the satellite elevation angle in the following manner:

[0160] The satellite-to-ground clock difference and satellite elevation angle between the time synchronization device u and the visible Beidou satellite s are The median value of the satellite-earth clock error within the corresponding common view period is calculated by the least squares method. and the median value of the satellite elevation angle Its calculation expression is as follows:

[0161]

[0162] in, are the satellite-to-ground clock difference and satellite elevation angle at the ith second in the common view period, respectively, and n is the duration of the common view period (for example, if the common view period is 1 minute, n is 60).

[0163] The BeiDou common view server calculates the time deviation between the time synchronization device u and the time reference source j with BeiDou satellite k as the common view reference Among them, when the satellite elevation angle of Beidou satellite k When the angle is smaller than the preset angle (for example ), then the BeiDou satellite k does not participate in the calculation of the time deviation Its calculation expression is as follows:

[0164]

[0165] When there are N s When there are co-viewing satellites, the average time deviation between the time synchronization device u and the time reference source j is:

[0166]

[0167] in, Sequence The maximum and minimum values in ;

[0168] When the time synchronization device exists N c When a BeiDou common view server uses multiple time reference sources that can be viewed together, the BeiDou common view server further determines the weight of the time deviation between the time synchronization device and each time reference source. Specifically, the weight of the time deviation is determined based on relevant information about the time reference source, where the relevant information includes the accuracy of the time reference source, the distance of the time reference source, the number of satellites in common view between the time reference source and the time synchronization device, etc. For example, the weight of the time deviation can be determined based on the accuracy of the time reference source, the stability of the time reference source, the distance between the time reference source and the time synchronization device, or the number of satellites in common view between the time reference source and the time synchronization device. In this embodiment, when determining the weight of the time deviation, multiple pieces of the above relevant information can be combined, for example, the weight of the time deviation can be determined based on the accuracy and stability of the time reference source, or the accuracy, stability, and number of satellites in common view between the time reference source and the time synchronization device. The above is merely an example.

[0169] Based on the above-mentioned scheme of the present application, the time deviations of each time reference source can be calculated and estimated by co-visibility between each other, the power system time is established through the time reference source group, the time deviations between each time reference source and the power system time are calculated, and the time of each time reference source is adjusted in turn, so that the widely distributed time reference sources form a time synchronization timing plane. The more widely distributed time synchronization device can calculate the deviation from the power system time through co-visibility with the Beidou satellite and each co-visible time reference source and adjust the synchronization, and finally realize the wide-area time synchronization of the entire power grid. Its advantages are: the establishment of a unified power system time for the entire power grid does not depend on the operating status of individual time reference sources, and the time synchronization of the time synchronization device does not depend on the operating status of individual time reference sources, which improves the robustness and timing accuracy of wide-area time synchronization and realizes true wide-area time synchronization for the entire network.

[0170] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0171] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.

Claims

1. A masterless parallel BeiDou common view method for wide-area time synchronization, characterized in that: The masterless parallel Beidou common viewing method for wide-area time synchronization includes: The Beidou common view server receives first common view data sent by a time reference source having a Beidou common view function and second common view data sent by a time synchronization device; The Beidou common view server calculates the power system time and a first time offset between the time reference source and the power system time according to the first common view data, and sends the first time offset to the corresponding time reference source, so that the time reference source adjusts the time information of the time reference source based on the first time offset; The Beidou common-view server matches all visible time reference sources corresponding to the time synchronization device based on the second common-view data, calculates a second time offset between the time synchronization device and all corresponding visible time reference sources, and sends the second time offset to the corresponding time synchronization device, so that the time synchronization device adjusts the time information of the time synchronization device to synchronize with the power system time based on the second time offset; The first common view data includes: the median value of the satellite-to-ground clock difference between the time reference source and the visible satellite within the common view period and the median value of the satellite elevation angle between the time reference source and the visible satellite within the common view period; the satellite-to-ground clock difference between the time reference source T and the visible satellite s and the satellite elevation angle of the visible satellite s are respectively and The corresponding median values within a common viewing period are calculated by the least squares method. and Its calculation expression is as follows: in, is the satellite-to-ground clock difference and satellite elevation angle at the ith second in the common-view period, and n is the duration of the common-view period.

2. The masterless parallel BeiDou common view method for wide-area time synchronization according to claim 1, characterized in that: The Beidou common view server calculates the time deviation between the time reference source i and the time reference source j based on the first common view data with the common view satellite k as a reference. The expression is as follows: When the median value of the satellite-to-ground clock error within the common viewing period of the common viewing satellite k is When the angle is less than the preset angle, the common view satellite k does not participate in the calculation of the time deviation.

3. The masterless parallel BeiDou common view method for wide-area time synchronization according to claim 2, characterized in that: When the time reference source i and the time reference source j are N s The average time deviation between the time reference source i and the time reference source j is The calculation expression is as follows: in, and For sequence The maximum and minimum values in ; Calculate the time deviation sequence of each time reference source that can be seen by both Its expression is as follows: Where i, j = 1, 2, ..., N u ,i <j,N u is the number of time reference sources; The time deviation estimated value that satisfies the time deviation correlation topology matrix G between time reference sources is estimated using the least squares method. Its expression is as follows: Where i, j = 1, 2, ..., N u ,i <j,N u is the number of time reference sources; Get the time T of the time reference source at the Beidou common view server location T1 , and calculate the time T of the time reference source with Beidou common view function Ti , its calculation expression is as follows: The calculated value T of the power system time is calculated by weighted average pc , which is expressed as follows: Among them, a i is the weight of time reference source i participating in the power system time calculation; The power system time T is obtained by Kalman filtering p The calculation expression is as follows: T p =T p-1 +K p (T pc -T p-1 ) Among them, K p is the filter coefficient of the Kalman filter.

4. The masterless parallel BeiDou common view method for wide-area time synchronization according to claim 3, characterized in that: Calculate the first time deviation ΔT between the time reference source and the power system time Ti , which is expressed as follows: ΔT Ti =T Ti -T p Where i = 1, 2, ..., N u , N u is the number of time reference sources.

5. The masterless parallel BeiDou common view method for wide-area time synchronization according to claim 1, characterized in that: The second common view data includes: a median value of the satellite-to-ground clock difference within the common view period and a median value of the satellite elevation angle within the common view period; The satellite-to-ground clock difference between the time synchronization device u and the visible satellite s and the satellite elevation angle of the visible satellite s are and The corresponding median values within a common viewing period are calculated by the least squares method. and Its calculation expression is as follows: in, are the satellite-to-ground clock difference and satellite elevation angle at the ith second in the common-view period, and n is the duration of the common-view period.

6. The masterless parallel BeiDou common view method for wide-area time synchronization according to claim 5, characterized in that: The Beidou common view server calculates the time deviation between the time synchronization device u and the time reference source j based on the second common view data with the common view satellite k as a reference Its expression is as follows: When the median value of the common view satellite k When the angle is less than the preset angle, the common view satellite k does not participate in the calculation of the time deviation. When the time synchronization device u is N away from the time reference source j s The average time deviation between the time synchronization device u and the time reference source j is The calculation expression is as follows: in, and Sequence The maximum and minimum values in ; When there is N s When there are two time reference sources that can be viewed together, the deviation ΔT between the time synchronization device and the time reference source is calculated by weighted average. u , its calculation expression is as follows: Among them, b j is the weight of the time deviation of the time synchronization device, N c is the number of commonly visible time reference sources.

7. The masterless parallel BeiDou common view method for wide-area time synchronization according to claim 6, characterized in that: The weight b of the time deviation of the time synchronization device j is determined based on the relevant information of the time reference source; The relevant information includes the accuracy of the time reference source, the stability of the time reference source, the distance between the time reference source and the time synchronization device, and the number of satellites in common view between the time reference source and the time synchronization device.

8. A wide-area time-synchronized masterless parallel BeiDou common-view system, characterized in that: The wide-area time-synchronized, masterless, parallel BeiDou common-view system adopts the wide-area time-synchronized, masterless, parallel BeiDou common-view method according to any one of claims 1 to 7 for satellite common-view, and the wide-area time-synchronized, masterless, parallel BeiDou common-view system includes: Time reference sources with Beidou common view capability deployed in various regulatory agencies; A time synchronization device that uses BeiDou satellites to share common sight with some or all of the time reference sources; A BeiDou common view server connected to the time reference source and the time synchronization device for network communication, receiving the first common view data sent by the time reference source and the second common view data sent by the time synchronization device; The Beidou common view server is used to calculate and generate the power system time and a first time offset between the time reference source and the power system time according to the first common view data, and send the first time offset to the time reference source to adjust the time information of the time reference source; The Beidou common view server is used to calculate a second time offset between the time synchronization device and the time reference source according to the second common view data, and send the second time offset to the time synchronization device to adjust the time information of the time synchronization device.

9. The wide-area time synchronized masterless parallel BeiDou common view system according to claim 8, characterized in that: The time reference source is composed of a Beidou common view receiver and an atomic frequency standard source; The atomic frequency standard source is a cesium atomic frequency standard source or a hydrogen atomic frequency standard source; The Beidou common view receiver is provided with a network communication interface for communicating with the Beidou common view server respectively.

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