An airborne multi-source time synchronization method

Abstract

The application discloses an airborne multi-source time synchronization method, which realizes the multi-source time synchronization capability of an airborne platform, improves the reliability of time synchronization, enhances the compatibility and scalability of a time synchronization system architecture, and is realized through the following technical scheme: a typical time synchronization / running time, tracing process and architecture are proposed, and a unified time synchronization / running time, tracing process is formed for the typical time source of the airborne platform. In order to adapt to different time source types, time synchronization is divided into time information synchronization and second pulse synchronization, and after synchronization is completed, a time running unit is entered to perform a period-second operation, and then the operation is sent to a B code coding unit for coding output. In order to improve the flexibility of system design, the time tracing source is divided into automatic tracing and manual tracing, and the automatic tracing process is defaulted to be performed after power-on, the automatic tracing adopts a precision priority strategy, a user can manually select a time source according to requirements, and when a manual tracing instruction is received, a manual tracing mode is entered.

Description

Technical Field

[0001] This invention relates to the field of time synchronization technology, and in particular to an airborne multi-source time synchronization method and system. Background Technology

[0002] High-precision time synchronization is one of the important functions of airborne platforms. Compared with traditional single-platform independent operations, modern advanced combat aircraft increasingly emphasize distributed collaborative operations, data association and fusion of multi-source sensor information, and the aggregation of sensor capabilities between platforms. Airborne time synchronization is the foundation for realizing these capabilities.

[0003] The biggest difference between airborne time synchronization and other time synchronization systems is that airborne time synchronization is a multi-source time synchronization system, with multiple different time sources. Typical time sources include satellite navigation time, data link time, and RTC time. Satellite navigation time is provided by GPS / BeiDou navigation satellites, offering the advantages of all-weather, all-time time synchronization. However, its disadvantage is that navigation satellites are more than 20,000 km above the ground, resulting in a signal strength of less than -130 dBm, making it susceptible to interference. Data link time is obtained through periodic RTT synchronization via the airborne data link. The master and slave data link nodes exchange synchronization information through time slots, calculating and correcting slave node time errors in real time to achieve time synchronization between master and slave data nodes. Data link time offers high accuracy but relies on data link network construction and consumes a certain amount of data link transmission bandwidth. RTC time is provided by a dedicated RTC chip with a built-in battery. Its advantage is power-off timekeeping capability, but its accuracy is relatively poor.

[0004] Regarding airborne time synchronization architecture, domestic and foreign researchers have carried out relevant work in the following aspects: (1) For large-scale airborne time synchronization systems including multiple racks and multiple application interfaces, a multi-level cascaded distribution method is adopted, and time synchronization and unification of the entire aircraft are achieved through time relay. (2) Regarding airborne time synchronization methods and time synchronization architecture, a general time synchronization architecture is proposed, which abstracts the time synchronization architecture into a time link layer, time processing information, and time users. The layers are interconnected through standard interfaces, realizing the generalization and standardization of the time synchronization architecture. (3) Regarding field ground tests, common methods for ground tests and the source of time reference required for the tests are proposed. Summary of the Invention

[0005] To address the aforementioned shortcomings, this invention designs a complete time synchronization / running and time traceability process. Time synchronization is divided into time information synchronization and second pulse synchronization, which can adapt to different time source input types. After synchronization is completed, the system enters the time running unit for periodic second increment, and then sends it to the B-code encoding unit for encoding output. To improve the flexibility of the system design, time traceability is divided into automatic traceability and manual traceability. Automatic traceability is initiated by default upon power-on, employing a precision-priority strategy. Users can manually select the time source according to their needs. Upon receiving a manual traceability command, the system enters manual traceability mode.

[0006] To achieve the above objectives, the present invention employs an airborne multi-source time synchronization method, the method comprising the following steps:

[0007] S1: Time synchronization and timekeeping; wherein: the time synchronization and timekeeping includes: S11: time information synchronization process; S12: second pulse time synchronization process; S13: timekeeping process;

[0008] S2: Time traceability; wherein: the time traceability includes: S21: automatic traceability process; S22: manual traceability process.

[0009] Optionally, step S11 specifically includes:

[0010] S111: Receives input time; the time information format can be customized according to different user needs.

[0011] S112: Parse to obtain time information;

[0012] S113: Determine the validity of the time information. If the time information is valid, proceed to step S114.

[0013] S114: Determine the continuity of time information. The determination is based on whether the time information is continuous for three seconds. If it is continuous for three seconds, proceed to step S115.

[0014] S115: Synchronize local time using the received time.

[0015] Optionally, step S12 specifically includes:

[0016] S121: Receive the input time and parse it to obtain the second pulse information;

[0017] S122: Calculate the phase difference between the received second pulse information and the local second pulse. The calculation logic is as follows: use the local second pulse as the door opening signal and the received second pulse as the door closing signal. When the received second pulse arrives, output the phase difference value.

[0018] S123: Smooth the phase difference value using a mean-based processing strategy.

[0019] S124: Synchronize the local second pulse using the phase difference smoothing value.

[0020] Optionally, step S13 specifically includes:

[0021] S131: Receive synchronized time information;

[0022] S132: Add 1 second to the received time information;

[0023] S133: Receive synchronized second pulse information;

[0024] S134: Perform +1 second operation on the rising edge of the second pulse;

[0025] S135: Output time information.

[0026] Optionally, step S21 specifically includes:

[0027] S2101: After power-on initialization, determine whether the manual tracing mode is valid. If it is invalid, execute S2102.

[0028] S2102: Set the traceability mode to "automatic traceability mode" and execute S2103;

[0029] S2103: Detect the validity of the time source every 1 second, then execute S2104;

[0030] S2104: Check the validity of the data link time. If it is valid, execute S2105; otherwise, execute S2106.

[0031] S2105: Set the time source to the data link time and execute S2105;

[0032] S2106: Use data link time to encode and output B code, then execute S2113;

[0033] S2107: Determine the validity of the satellite navigation time. If valid, execute S2118; otherwise, execute S2110.

[0034] S2108: Set the time source to satellite time, and execute S2109;

[0035] S2109: Use satellite navigation time to encode B code output, then execute S2113;

[0036] S2110: Determine the validity of the RTC time. If valid, execute S2111; otherwise, execute S2101.

[0037] S2111: Set the time source to RTC time and execute S2112;

[0038] S2112: Use RTC time to encode and output B code, then execute S2113;

[0039] S2113: Determine if a manual tracing instruction has been received. If a manual tracing instruction has been received, proceed with the manual tracing process.

[0040] Optionally, step S22 specifically includes:

[0041] S221: Check if a manual tracing command has been received. If a manual tracing command has been received, execute S222; otherwise, continue to wait.

[0042] S222: Parse the received time source instruction, obtain the sent time source, and execute S223;

[0043] S223: Determine the validity of the received time source. If valid, execute S224; otherwise, execute S228.

[0044] S224: Set the tracing mode to "Manual Tracing" and execute S225;

[0045] S225: Set the time source to receive the time source, and execute S226;

[0046] S226: Use the received time source time to encode B code and output it, then execute S227;

[0047] S227: Check if a manual tracing command has been received. If a manual tracing command has been received, execute S222; otherwise, execute S226.

[0048] S228 reported manual tracing and reporting failed, so S221 was executed.

[0049] To achieve the above objectives, this application also provides an airborne multi-source time synchronization system, the system comprising:

[0050] The time synchronization and timekeeping module is used for time information synchronization process, second pulse time synchronization process, and timekeeping process.

[0051] The time traceability module is used for both automatic and manual traceability processes.

[0052] Compared with the prior art, the beneficial effects of this invention are:

[0053] Based on a general time synchronization architecture, this invention mainly addresses airborne multi-source scenarios. For situations with multiple time sources, it proposes a specific implementation architecture for the time processing center, and performs layered processing of the time synchronization process, thereby achieving an effective unification of time synchronization and timekeeping functions.

[0054] For the time traceability process, this invention proposes a precision priority and judgment strategy, which automatically selects the time source to use based on the precision, while reserving a user selection interface so that users can choose the time source to use according to their needs, thus increasing the flexibility of the system.

[0055] This invention refines the time synchronization / running and time tracing processes at the time processing layer, which can be implemented using separate resources without affecting the airborne link, application terminal, and airborne time synchronization architecture. This improves the efficiency of airborne integrated systems and the application capability of the architecture on different platforms and airborne architectures. Attached Figure Description

[0056] Figure 1 This is an architecture diagram for multi-source time synchronization and traceability;

[0057] Figure 2 This is a flowchart of time synchronization and timing.

[0058] Figure 3 This is a flowchart of automatic tracing in time-based tracing;

[0059] Figure 4 This is a flowchart of manual tracing in time tracing.

[0060] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0061] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0062] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0063] This invention relates to airborne time synchronization systems, such as... Figure 1 As shown, a standardized design architecture is adopted, and a complete time synchronization / running and time traceability process is designed. Time synchronization is divided into time information synchronization and second pulse synchronization, which can adapt to different time source input types. After synchronization is completed, the time running unit performs periodic second addition, and then sends it to the B code encoding unit for encoding output. To improve the flexibility of the system design, time traceability is divided into automatic traceability and manual traceability. Automatic traceability is initiated by default upon power-on, and the automatic traceability adopts a precision-first strategy. Users can manually select the time source according to their needs. When a manual traceability command is received, the system enters manual traceability mode.

[0064] The time synchronization process performs validity checks and three-second continuous checks on the time source, increasing the robustness of time synchronization. Second pulse synchronization employs a method of calculating the phase difference to synchronize the local second pulse, effectively ensuring the airborne time synchronization function maintains its timekeeping capability even when the external time source is invalid. Through smoothing the phase difference, the problem of external second pulse jitter caused by noise or external interference can be effectively resolved. Regarding the time tracing strategy, a precision-priority automatic tracing strategy is used by default. However, considering the flexibility of the system design and user needs, a manual tracing interface is added, which can receive manual tracing commands from the system and select the appropriate time source based on these commands.

[0065] In this embodiment, the airborne multi-source time synchronization method specifically includes the following steps:

[0066] 1. Time synchronization and timing process:

[0067] For time synchronization and timing procedures, see Figure 2 The time synchronization process includes time information synchronization and second pulse synchronization. The former is used to synchronize year, month, day, hour, minute, and second information, while the latter is used to synchronize information below the second. After synchronization is complete, the synchronized second pulse is used for timekeeping.

[0068] 1.1 Time Information Synchronization Process:

[0069] a) Receive the input time. The time information format can be customized according to different user needs. Proceed to step b).

[0070] b) Parse the obtained time information and proceed to step c);

[0071] c) Check the validity of the time information. If the time information is valid, proceed to step d). The logic for this check is as follows:

[0072] 1) Check if the month information value is between 1 and 12. If it is between 1 and 12, it is valid; otherwise, it is invalid.

[0073] 2) Check if the date information value is between 1 and 31. If it is between 1 and 31, it is valid; otherwise, it is invalid.

[0074] 3) Check if the hourly information value is between 0 and 23. If it is between 0 and 23, it is valid; otherwise, it is invalid.

[0075] 4) Check if the minute information value is between 0 and 59. If it is between 0 and 59, it is valid; otherwise, it is invalid.

[0076] 5) Check if the value of the second information is between 0 and 59. If it is between 0 and 59, it is valid; otherwise, it is invalid.

[0077] d) Determine the continuity of time information. The criterion is whether the time information is continuous for three seconds. If it is continuous for three seconds, proceed to step e). The logic for determining the continuity of three seconds is as follows:

[0078] 1) Receive the current time information and save its year, month, day, hour, minute, and second information to the first frame of time data;

[0079] 2) Receive the current time information and determine whether the year, month, day, hour, and minute information are the same as the first frame of time data, and whether the second information is equal to the second information of the first frame of time data + 1. If yes, save the current received time to the second frame of time data and jump to step 3). If no, save the current received time information to the first frame of time data and jump to step 1).

[0080] 3) Receive the current time information and determine whether the year, month, day, hour, and minute information are the same as the second frame time data, and whether the second information is equal to the second frame time data seconds information + 1. If yes, proceed to step 4); if no, save the currently received time information to the first frame time data and simultaneously proceed to step 1).

[0081] 4) Output a success flag for three consecutive seconds;

[0082] e) Synchronize local time using the received time;

[0083] 1.2 Second Pulse Time Synchronization Process:

[0084] a) Receive the input time and parse it to obtain the second pulse information;

[0085] b) Calculate the phase difference between the received second pulse information and the local second pulse. The calculation logic is as follows: use the local second pulse as the door opening signal and the received second pulse as the door closing signal. When the received second pulse arrives, output the phase difference value.

[0086] c) Smooth the phase difference values ​​using a mean-based approach. Each phase difference value has the same weight, and the smoothing data length is 10. Before smoothing, outlier removal is required. The specific steps are as follows:

[0087] 1) Allocate a data buffer of length 10 for smoothing operations, and initialize the data length N to 0;

[0088] 2) Receive a new phase difference value, determine whether the phase difference value is greater than 1s. If it is greater than 1s, it will be identified as an outlier and treated as invalid data. If it is not greater than 1s, store the latest received smoothed data into the data buffer area, and determine whether the data length is greater than 10. If it is not greater, increment the data length by 1.

[0089] 3) Perform a smoothing operation on the data. The smoothing process adopts the mean processing strategy. The phase difference values ​​are weighted equally in each step. If the data length is less than 10, the average is performed according to the actual data length. If the data length is greater than or equal to 10, the average is performed according to the data length of 10, and the phase smoothing value is output.

[0090] 3) Synchronize the local second pulse using the phase difference smoothing value. The specific processing logic is as follows:

[0091] 1) Local second pulse rising edge detection: When the local second pulse rising edge is detected, time counting is performed using the local clock. Counting time = current count value * counting precision. Counting precision = 1 / local clock frequency. Assuming the clock frequency is 100MHz and the current count value is 90, then the counting precision is 10ns and the counting time is 900ns. Proceed to step 2).

[0092] 2) Determine if the counting time is greater than the phase difference smoothing value. If the counting clock is less than the phase difference smoothing value, return to step 1) to continue counting. If the counting clock is greater than or equal to the phase difference smoothing value, output the synchronized second pulse.

[0093] 1.3 Timekeeping Process:

[0094] a) Receive the synchronized time information and proceed to step b);

[0095] b) Increment the received time information by 1 second, then proceed to step c);

[0096] c) Receive the synchronized second pulse information and proceed to step d);

[0097] d) Perform a +1 second operation on the rising edge of the second pulse, then jump to step e);

[0098] e) Output running time information.

[0099] 2. Time traceability process, see Figure 3 and Figure 4 :

[0100] 2.1 Automated traceability process:

[0101] a) After power-on initialization, check if the manual tracing mode is valid. If invalid, proceed to b).

[0102] b) Set the traceability mode to "Automatic Traceability Mode" and proceed to step c);

[0103] c) Detect the validity of the time source every 1 second, then proceed to step d);

[0104] d) Determine the validity of the data link time. If valid, proceed to step e); otherwise, proceed to step g.

[0105] e) Set the time source to the data link time and proceed to step f);

[0106] f) Use the data link time to encode and output the B code (period 1s), then jump to step m);

[0107] g) Determine the validity of the satellite navigation time. If valid, proceed to step h); otherwise, proceed to step j.

[0108] h) Set the time source to satellite time and proceed to step i);

[0109] i) Use satellite navigation time to encode and output B code (period 1s), then jump to step m);

[0110] j) Determine the validity of the RTC time. If valid, proceed to step k); otherwise, proceed to step a).

[0111] k) Set the time source to RTC time and jump to step l);

[0112] l) Use the RTC time to encode and output the B code (period 1s), then jump to step m);

[0113] m) Determine if a manual tracing instruction has been received. If a manual tracing instruction has been received, proceed to the manual tracing process; otherwise, proceed to step c).

[0114] 2.2 Manual traceability process:

[0115] a) Check if a manual tracing instruction has been received. If a manual tracing instruction has been received, proceed to step b); otherwise, continue waiting.

[0116] b) Parse the received time source instruction to obtain the sent time source, and jump to step c);

[0117] c) Determine the validity of the received time source. If valid, proceed to step d); otherwise, proceed to step h.

[0118] d) Set the traceability mode to "Manual Traceability" and proceed to step e);

[0119] e) Set the time source to receive the time source, then jump to f);

[0120] f) Encode and output B code using the received time source time (period 1s), then jump to step g);

[0121] g) Check if a manual tracing instruction has been received. If a manual tracing instruction has been received, proceed to step b); otherwise, proceed to step f.

[0122] h) If manual tracing report fails, proceed to step a).

[0123] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0124] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0125] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0126] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. An airborne multi-source time synchronization method, characterized in that, The method includes the following steps: S1: Time synchronization and timekeeping; wherein: the time synchronization and timekeeping includes: S11: time information synchronization process; S12: second pulse time synchronization process; S13: timekeeping process; S2: Time traceability; wherein: the time traceability includes: S21: automatic traceability process; S22: manual traceability process; Step S12 specifically includes: S121: Receive the input time and parse it to obtain the second pulse information; S122: Calculate the phase difference between the received second pulse information and the local second pulse. The calculation logic is as follows: use the local second pulse as the door opening signal and the received second pulse as the door closing signal. When the received second pulse arrives, output the phase difference value. S123: Smooth the phase difference value using a mean-based processing strategy. S124: Synchronize the local second pulse using the phase difference smoothing value; Step S13 specifically includes: S131: Receive synchronized time information; S132: Add 1 second to the received time information; S133: Receive synchronized second pulse information; S134: Perform +1 second operation on the rising edge of the second pulse; S135: Output timekeeping information; Step S21 specifically includes: S2101: After power-on initialization, determine whether the manual tracing mode is valid. If it is invalid, execute S2102. S2102: Set the traceability mode to "automatic traceability mode" and execute S2103; S2103: Detect the validity of the time source every 1 second, then execute S2104; S2104: Check the validity of the data link time. If valid, proceed to S2105; otherwise, proceed to S2106. S2105: Set the time source to the data link time and execute S2105; S2106: Use data link time to encode and output B code, then execute S2113; S2107: Determine the validity of the satellite navigation time. If valid, execute S2118; otherwise, execute S2110. S2108: Set the time source to satellite time, then execute S2109; S2109: Use satellite navigation time to encode B code output, then execute S2113; S2110: Determine the validity of the RTC time. If valid, execute S2111; otherwise, execute S2101. S2111: Set the time source to RTC time, then execute S2112; S2112: Use RTC time to encode and output B code, then execute S2113; S2113: Determine if a manual tracing instruction has been received. If a manual tracing instruction has been received, proceed with the manual tracing process.

2. The airborne multi-source time synchronization method as described in claim 1, characterized in that, Step S11 specifically includes: S111: Receives input time; the time information format can be customized according to different user needs. S112: Parse to obtain time information; S113: Determine the validity of the time information. If the time information is valid, proceed to step S114. S114: Determine the continuity of time information. The determination is based on whether the time information is continuous for three seconds. If it is continuous for three seconds, proceed to step S115. S115: Synchronize local time using the received time.

3. The airborne multi-source time synchronization method as described in claim 1, characterized in that, Step S22 specifically includes: S221: Check if a manual tracing command has been received. If a manual tracing command has been received, execute S222; otherwise, continue to wait. S222: Parse the received time source instruction, obtain the sent time source, and execute S223; S223: Determine the validity of the received time source. If valid, execute S224; otherwise, execute S228. S224: Set the tracing mode to "Manual Tracing" and execute S225; S225: Set the time source to receive the time source, and execute S226; S226: Encode and output B-code using the received time source time, then execute S227; S227: Check if a manual tracing command has been received. If a manual tracing command has been received, execute S222; otherwise, execute S226. S228 reported manual tracing and reporting failed, so S221 was executed.

4. An airborne multi-source time synchronization system, employing the airborne multi-source time synchronization method as described in claim 1, characterized in that, The system includes: The time synchronization and timekeeping module is used for time information synchronization process, second pulse time synchronization process, and timekeeping process. The time traceability module is used for both automatic and manual traceability processes.

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