A high-precision clock synchronization method for FC communication network

Abstract

The application relates to the field of clock synchronization technology of communication network terminal equipment, and discloses a high-precision clock synchronization method of FC communication network, wherein after an upper layer application sets a system network time at a clock server, the clock server sends network time information periodically, switches and other network terminals are clock clients, the switch is a clock information transfer device, after receiving the time of the clock server, compensating path delay and residence time, the time is forwarded to other clock clients; after receiving the time forwarded by the switch, the other network terminals as clock clients compensate path delay, so that the network clock synchronization is completed. The application adopts a hardware circuit to send high-precision clock synchronization information, can correct the time information of each clock client according to the switch of the clock client and the residence time on the other clock client, adopts a compensation point-to-point path delay mode to improve the synchronization precision, and can realize several microsecond-level synchronization precision.

Description

Technical Field

[0001] The invention relates to the technical field of clock synchronization of communication network terminal equipment and discloses a high-precision clock synchronization method for an FC communication network. Background Art

[0002] The Fiber Channel (FC) network is the backbone network of the avionics systems of current major fighter jets. It is a communication technology with high real-time performance, high reliability, and high bandwidth. It is used to connect subsystems such as integrated core processors, electronic warfare, display and control systems, communication and navigation, and radar. The clock synchronization of the avionics system is provided through the FC network, thereby completing the processing of key tasks between systems.

[0003] In FC communication network applications, clock synchronization between terminal devices typically uses one terminal on the network as a clock server. The application sets the time on the clock server, encapsulates it into an ELS frame and clock synchronization primitives, and broadcasts it to other terminals. Upon receiving the data, other terminals parse it and obtain the network clock information. The clock synchronization information is sent by the clock server, forwarded by the switch, and finally received and parsed by other clock clients.

[0004] Since mission-critical avionics applications require high time accuracy, existing FC communication networks do not take into account the path delay of terminal devices and the residence time of time information on terminals and switches, making it impossible to achieve high-precision clock synchronization requirements. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-precision clock synchronization method for FC communication networks. The method corrects the time information of each clock client based on its residence time on the switch and other clock clients, and improves the synchronization accuracy by compensating for point-to-point path delay, achieving a synchronization accuracy of several microseconds.

[0006] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0007] A high-precision clock synchronization method for an FC communication network, comprising:

[0008] The upper layer application sets the system network time on the clock server, where the system network time includes year, month, day, hour, minute, second, millisecond, microsecond, and hundred nanosecond. The clock server includes a network terminal device in the FC communication network.

[0009] The clock server sends system network time information to the clock client through the clock sending control circuit; the clock client includes a switch in the FC communication network and other network terminals except the clock server;

[0010] After the switch receives the system network time information sent by the clock server through the clock receiving circuit, it compensates for the path delay and residence time and then forwards it to other clock clients. After receiving the system network time information forwarded by the switch, other network terminals acting as clock clients compensate for the path delay and complete the clock synchronization of the entire network.

[0011] Furthermore, the method for the clock server to send system network time information to the clock client through the clock sending control circuit includes:

[0012] When the clock server receives the system network time sent by the upper layer application, the clock server records the first local RTC value T of the clock server. l0 ;

[0013] The clock server converts the hours, minutes, seconds, milliseconds, microseconds, and nanoseconds of the system network time information into the network system RTC value, and calculates the network system RTC value and the first local RTC value T l0 A first difference Δs between

[0014] The clock server sends the year, month, and day of the system network time information to the switch through ELS frame broadcast. The hours, minutes, seconds, milliseconds, microseconds, and nanoseconds are sent by carrying the clock server system RTC value T s1 The FC clock synchronization primitive is periodically broadcast to the switch; where T s1 = the third local RTC value T sl1 + the first difference Δs, the third local RTC value T sl1 The clock server broadcasts the clock server system RTC value T to the switch s1 The local RTC value of the clock server corresponding to the time.

[0015] Furthermore, the method for the switch to receive the system network time information sent by the clock server through the clock receiving circuit includes:

[0016] When the switch receives the time information from the clock server, it records the fourth local RTC value T of the switch at the corresponding time. sw1 , calculate T s1 With the fourth local RTC value T sw1 The second difference Δsw between the switch and the clock server is obtained, and the path delay T between the switch and the clock server is obtained. d1 ;

[0017] The switch broadcasts the year, month, and day to other clock clients, and the hours, minutes, seconds, milliseconds, microseconds, and nanoseconds are calculated based on the second difference Δsw and the path delay T d1 The fifth local RTC value T corresponding to the switch broadcast time sw2 Make corrections to obtain the corrected switch system RTC value T s2Then, the switch system RTC value T is broadcast to other clock clients through the FC clock synchronization primitive. s2 .

[0018] Furthermore, the switch system RTC value T s2 =T sw2 +Δsw+T d1 , Δsw=T s1 -T sw1 .

[0019] Furthermore, after receiving the system network time information forwarded by the switch, other network terminals serving as clock clients compensate for path delays and complete the method of clock synchronization across the entire network, including:

[0020] Other clock clients receive the switch system RTC value T broadcast by the switch s2 Then, calculate the third difference Δc=T s2 -T c1 , where T c1 The RTC value T of the switch system received by the clock client from the switch s2 The sixth local RTC value of the clock client;

[0021] Using the third difference, the path delay T between other clock clients and the switch f2 The second local RTC value T of the current clock client c0 Corrections are made and converted into hours, minutes, seconds, milliseconds, microseconds, and nanoseconds, and then combined with the year, month, and day time to update the time to be synchronized with the system network time.

[0022] Furthermore, using T c ′ 0=T c0 +Δc+T d2 The second local RTC value T of the current clock client c0 Correction is performed and the correction value T is obtained c ′ 0.

[0023] Furthermore, the path delay measurement method includes:

[0024] A switch or other network terminal initiates a path delay request, obtains the local RTC value t1 at the time the request frame is sent, and sends it as the frame payload to the clock server or switch. Path delay measurement requests are initiated from the switch to the clock server and from other network terminals to the switch.

[0025] When the clock server or switch receives a path delay request, it records the local RTC value t2 at the time of receipt;

[0026] When the link is idle, a path delay response frame is sent, and t1, t2, and the local RTC value t3 of the response frame are used as the frame payload and returned to the switch or other corresponding network terminal;

[0027] When the switch or other network terminal receives the path delay response frame, the local RTC value t4 at the receiving time is obtained;

[0028] according to Calculate the path delay T di , where i = 1 or 2. When i = 1, it represents the path delay between the switch and the clock server. When i = 2, it represents the path delay between other network terminals and the switch.

[0029] Compared with the existing technology, the present invention has the following advantages: the present invention uses hardware circuits to send high-precision clock synchronization information, can correct the time information of each clock client according to the residence time on the clock client's switch and other clock clients, and improve the synchronization accuracy by compensating for point-to-point path delay, and can achieve synchronization accuracy of several microseconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a flow chart of the high-precision clock synchronization method for an FC communication network in Example 1 or 2. DETAILED DESCRIPTION

[0031] The present invention will be described in further detail below with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0032] Example 1

[0033] See also Figure 1 , a high-precision clock synchronization method for an FC communication network, comprising:

[0034] The upper layer application sets the system network time on the clock server, where the system network time includes year, month, day, hour, minute, second, millisecond, microsecond, and hundred nanosecond. The clock server includes a network terminal device in the FC communication network.

[0035] The clock server sends system network time information to the clock client through the clock sending control circuit; the clock client includes a switch in the FC communication network and other network terminals except the clock server;

[0036] After the switch receives the system network time information sent by the clock server through the clock receiving circuit, it compensates for the path delay and residence time and then forwards it to other clock clients. After receiving the system network time information forwarded by the switch, other network terminals acting as clock clients compensate for the path delay and complete the clock synchronization of the entire network.

[0037] In this embodiment, after the upper-layer application sets the system network time on the clock server, the clock server periodically transmits network time information. Switches and other network terminals act as clock clients. The switches, acting as clock information relays, receive the time from the clock server, compensate for path delay and residence time, and then forward it to other clock clients. Other network terminals, acting as clock clients, compensate for path delay after receiving the time forwarded by the switch, thereby achieving network-wide clock synchronization. This invention utilizes hardware circuitry to transmit high-precision clock synchronization information. This allows for correction of each clock client's time information based on its residence time on the switch and other clock clients. It also improves synchronization accuracy by compensating for point-to-point path delays, achieving synchronization accuracy of several microseconds. This ensures time consistency across devices and systems and the accuracy of critical data processing.

[0038] Example 2

[0039] See also Figure 1 , a high-precision clock synchronization method for an FC communication network, comprising:

[0040] Step 1: The upper layer application sets the system network time on the clock server, where the system network time includes year, month, day, hour, minute, second, millisecond, microsecond, and nanosecond. When the clock server receives the system network time sent by the upper layer application, the clock server includes a network terminal device in the FC communication network.

[0041] In this embodiment, the clock synchronization period of all terminal devices is set to 50ms, the point-to-point path delay measurement period is 100ms, and the clock synchronization function is enabled;

[0042] The upper layer application sets the time of the clock server, for example, 08:00:1 second:50 milliseconds:20 microseconds:300 nanoseconds on August 8, 2024. The current local RTC time of the clock server is 00:20:1 second:20 milliseconds:30 microseconds:900 nanoseconds after power-on, which is the first local RTC value T of the clock server. l0 It is 12010200309 hundred nanoseconds.

[0043] Step 2: The clock server sends the system network time information to the clock client through the clock transmission control circuit. The clock client includes the switch in the FC communication network and other network terminals except the clock server. The specific transmission process is as follows:

[0044] 2.1 The clock server converts the hours, minutes, seconds, milliseconds, microseconds, and nanoseconds of the system network time information into the system network RTC value, and calculates the first difference Δs between the system network RTC value and the local RTC value of the clock server;

[0045] In this embodiment, August 8, 2024 is written into the year, month, and day register of the clock server, and the system network RTC value T is calculated for the hour, minute, second, millisecond, microsecond, and nanosecond. s0 , get T s0 =288010500203 hundred nanoseconds; calculate the first difference Δs=T s0 -T sl0 , that is, Δs = 276000299894 hundred nanoseconds.

[0046] 2.2 The clock server broadcasts the year, month, and day of the system network time information to the switch via ELS frames;

[0047] 2.3 Hours, minutes, seconds, milliseconds, microseconds, and nanoseconds are transmitted by carrying the RTC value T of the clock server system s1 The FC clock synchronization primitive is periodically broadcast to the switch;

[0048] In this embodiment, the current third local RTC time is 00:20: 1 second: 20 milliseconds: 35 microseconds: 200 nanoseconds, T sl1 =12010200352 hundred nanoseconds, then T s1 =Δs+T sl1 = 288010500246 hundred nanoseconds. The clock server broadcasts the FC clock synchronization primitive. The period is the clock synchronization period. The hours, minutes, seconds, milliseconds, microseconds, and hundred nanoseconds are transmitted by carrying the RTC value T of the clock server system. s1 The broadcast is sent to the switch.

[0049] Step 3: After receiving the system network time information sent by the clock server through the clock receiving circuit, the switch compensates for the path delay and residence time before forwarding it to other clock clients. After receiving the system network time information forwarded by the switch, other network terminals acting as clock clients compensate for the path delay and complete the clock synchronization of the entire network. The specific receiving and supplementing process is as follows:

[0050] 3.1 After receiving the time information from the clock server, the switch broadcasts the year, month, and day to other clock clients;

[0051] 3.2 The switch receives the RTC value T from the clock server system s1 Then calculate T s1 and the switch's local RTC value T sw1A second difference Δsw between

[0052] In this embodiment, the current switch local RTC time is 00:20:1 second:20 milliseconds:36 microseconds:100 nanoseconds, so the fourth local RTC value T sw1 =12010200361 hundred nanoseconds, then Δsw=276000299885 hundred nanoseconds;

[0053] 3.3 Obtain the path delay T between the switch and the clock server d1 and the switch local time T sw2 , using the second difference Δsw and the path delay T d1 The fifth local RTC value T corresponding to the switch broadcast time sw2 Make corrections to obtain the corrected switch system RTC value T s2 ; The switch broadcasts the switch system RTC value T to other clock clients through the FC clock synchronization primitive s2 ;

[0054] In this embodiment, T d1 is 100 nanoseconds, the current fifth local RTC value T sw2 If it is 00:20:1 second:20 milliseconds:45 microseconds:300 nanoseconds, then T s2 =T sw2 +Δsw+T d1 = 288010500339 nanoseconds, T s2 Broadcasted through the FC clock synchronization primitive.

[0055] 3.4 Other clock clients receive the switch system RTC value T broadcast by the switch s2 Then, calculate the third difference Δc=T s2 -T c1 , where T c1 The RTC value T of the switch system received by the clock client from the switch s2 The sixth local RTC value of the clock client;

[0056] In this embodiment, the clock client receives T s2 The local RTC time corresponding to the moment is 00:20:1 second:20 milliseconds:46 microseconds:200 nanoseconds, T c1 =12010200462 hundred nanoseconds, then Δc = 276000299877 hundred nanoseconds, write Δc into the RTC difference register of the clock client;

[0057] 3.5 Using the third difference, the path delay T between other clock clients and switches d2(This embodiment takes 100 nanoseconds) for the second local RTC value T of the clock client. c0 Correction is performed to obtain the correction value T c ′ 0=T c0 +Δc+T d2 In this embodiment, the local RTC time of a clock client is 00:30:10 seconds:20 milliseconds:40 microseconds:300 nanoseconds, then the second local RTC value T of the current clock client is c0 =18100200403 hundred nanoseconds, the corrected T c ′ 0=294100500281;

[0058] 3.6 Correction value T c ′ 0 is converted to hours, minutes, seconds, milliseconds, microseconds, and nanoseconds, and then combined with the year, month, and day time, it is updated to the time synchronized with the system network time of August 8, 2024 08:10:10 seconds: 50 milliseconds: 28 microseconds and 100 nanoseconds.

[0059] Ideally, without considering crystal oscillator clock drift, the actual network system time should be 08:10:10 seconds:50 milliseconds:29 microseconds 700 nanoseconds. Therefore, the FC communication network high-precision clock synchronization method of this embodiment can obtain synchronization time with an accuracy of several microseconds.

[0060] It should be noted that the path delay measurement method in this embodiment includes:

[0061] A switch or other network terminal initiates a path delay request, obtains the local RTC value t1 at the time the request frame is sent, and sends it as the frame payload to the clock server or switch. Path delay measurement requests are initiated from the switch to the clock server and from other network terminals to the switch.

[0062] When the clock server or switch receives a path delay request, it records the local RTC value t2 at the time of receipt;

[0063] When the link is idle, a path delay response frame is sent, and t1, t2, and the local RTC value t3 of the response frame are used as the frame payload and returned to the switch or other corresponding network terminal;

[0064] When the switch or other network terminal receives the path delay response frame, the local RTC value t4 at the receiving time is obtained;

[0065] according to Calculate the path delay T di, where i = 1 or 2. When i = 1, it represents the path delay between the switch and the clock server. When i = 2, it represents the path delay between other network terminals and the switch.

[0066] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-precision clock synchronization method for an FC communication network, characterized in that: include: The upper layer application sets the system network time on the clock server, where the system network time includes year, month, day, hour, minute, second, millisecond, microsecond, and hundred nanosecond. The clock server includes a network terminal device in the FC communication network. The clock server sends the system network time information to the clock client through the clock sending control circuit, including: when the clock server receives the system network time sent by the upper layer application, the clock server records the first local RTC value of the clock server The clock server converts the hours, minutes, seconds, milliseconds, microseconds, and nanoseconds of the system network time information into the network system RTC value, and calculates the network system RTC value and the first local RTC value The first difference between The clock server sends the year, month, and day of the system network time information to the switch through ELS frame broadcast, and the hours, minutes, seconds, milliseconds, microseconds, and nanoseconds are sent by carrying the RTC value of the clock server system. The FC clock synchronization primitive is periodically broadcast to the switch; = Third local RTC value +First Difference , the third local RTC value Broadcasts the clock server system RTC value to the switch for the clock server The clock client includes a switch in the FC communication network and other network terminals except the clock server; After the switch receives the system network time information sent by the clock server through the clock receiving circuit, it compensates for the path delay and residence time and then forwards it to other clock clients. After receiving the system network time information forwarded by the switch, other network terminals acting as clock clients compensate for the path delay and complete the clock synchronization of the entire network.

2. The high-precision clock synchronization method for FC communication network according to claim 1, characterized in that: The method for a switch to receive system network time information sent by a clock server through a clock receiving circuit includes: When the switch receives the time information from the clock server, it records the fourth local RTC value of the switch at the corresponding time. ,calculate with the fourth local RTC value The second difference between , and obtain the path delay between the switch and the clock server ; The switch broadcasts the year, month, and day to other clock clients, and the hours, minutes, seconds, milliseconds, microseconds, and nanoseconds are calculated by the second difference. and path delay The fifth local RTC value corresponding to the switch broadcast time Make corrections to obtain the corrected switch system RTC value Then, the switch system RTC value is broadcast to other clock clients through the FC clock synchronization primitive. .

3. The high-precision clock synchronization method for FC communication network according to claim 2, characterized in that: Switch system RTC value , .

4. The high-precision clock synchronization method for FC communication network according to claim 2, characterized in that: After receiving the system network time information forwarded by the switch, other network terminals acting as clock clients compensate for path delays and complete network-wide clock synchronization. The following methods are used: Other clock clients receive the switch system RTC value broadcast by the switch Then, calculate the third difference ,in The switch system RTC value broadcast by the switch received by the clock client The sixth local RTC value of the clock client; Using the third difference, the path delay between other clock clients and the switch Second local RTC value for the current clock client Corrections are made and converted into hours, minutes, seconds, milliseconds, microseconds, and nanoseconds, and then combined with the year, month, and day time to update the time to be synchronized with the system network time.

5. The high-precision clock synchronization method for FC communication network according to claim 4, characterized in that: use Second local RTC value for the current clock client Correction is performed and the correction value is obtained .

6. The high-precision clock synchronization method for FC communication network according to claim 4, characterized in that: Path delay measurement methods include: The switch or other network terminal initiates a path delay request and obtains the local RTC value at the time the request frame is sent. , sent as a frame payload to the clock server or switch; the path delay measurement request direction is: the switch initiates it to the clock server, and other network terminals initiate it to the switch; When the clock server or switch receives a path delay request, it records the local RTC value at the time of receipt. ; When the link is idle, a path delay response frame is sent and 、 And the local RTC value of the response frame As the frame payload, it is returned to the switch or other corresponding network terminals; When a switch or other network terminal receives a path delay response frame, it obtains the local RTC value at the time of reception. ; according to Calculating path delay ,in =1 or 2, =1 indicates the path delay between the switch and the clock server. =2 indicates the path delay between other network terminals and the switch.

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