CN-121984631-A - Remote high-precision time service system and method based on time-triggered Ethernet

CN121984631ACN 121984631 ACN121984631 ACN 121984631ACN-121984631-A

Abstract

The invention provides a remote high-precision time service system and a remote high-precision time service method based on a time-triggered Ethernet, which realize absolute time synchronization of one master and multiple slaves in a domain on the basis of compatible time-triggered Ethernet standards, can be used for single time reference of a whole network, can also set a plurality of time synchronization master nodes according to subsystems, each subsystem uses a respective time reference source and a time format, are not interfered with each other, can conveniently realize redundant time synchronization based on priority by only arranging a plurality of time synchronization master nodes using the same time format in the whole network, can set a plurality of time reference redundancy and simultaneously work, and improves the synchronization reliability.

Inventors

LING ZHEN
XU CONG
MENG GONG
WANG YUANJIN
ZHOU HU
HU HAIFENG
ZHENG WEI
ZHONG CHENG
LI WENTING
CHEN PING
YANG JINHE
LU BO

Assignees

北京航天自动控制研究所

Dates

Publication Date: 20260505
Application Date: 20251231

Claims (10)

1. A remote high-precision time service system based on a time triggered ethernet network, the system comprising: The time synchronization master node is provided with an external absolute time input interface, and is connected with GNSS or other time reference sources to acquire accurate UTC or TAI and other time; The time synchronization slave node is 1 or more nodes corresponding to a plurality of receiving times and correcting the self time; A time synchronization master node transmits time information to a plurality of time synchronization slave nodes through multicast information, wherein the slave nodes can be any plurality of nodes; note that the time synchronization master node and the time synchronization slave node are independent of the TTE bus and the synchronization master and synchronization slave settings of the AS6802, and can be selected according to the requirement of system time synchronization; The time triggered Ethernet is used AS a time service time transmission bus, adopts an SAE AS6802 distributed fault-tolerant clock synchronization mechanism, does not need special hard pulse signals, can realize clock synchronization in 100ns of the whole network node, and realizes hybrid communication of three key-level messages of TT frame, RC frame and BE frame from high to low based on the global synchronous clock.
2. The remote high-precision time service system based on the time triggered ethernet as claimed in claim 1, wherein said time synchronization master node is provided with an external absolute time input interface, and is connected to GNSS or other time reference source to obtain accurate UTC or TAI time.
3. The remote high-precision time service system based on the time triggered Ethernet as claimed in claim 2, wherein the time synchronization master node immediately locks the quasi-second time after receiving the externally input time T1, records the cluster period accumulated value CP1, the integrated period accumulated value IP1 and the local transparent clock TC1 corresponding to the TTE global synchronous clock at the moment, and the TTE bus global clock synchronization mechanism can know the deviation of the absolute time and the TTE global synchronous clock, thereby determining the absolute time value corresponding to any global synchronous clock.
4. A remote high-precision time service system based on time triggered Ethernet as recited in claim 3, wherein the master time synchronization node transmits the time information to all slave time synchronization nodes of the selected multicast group by framing absolute time T1, cluster period cumulative number CP1, integration period cumulative number IP1 and node transparent clock cumulative number TC1, or the master time synchronization node calculates the difference between the absolute time and TTE global synchronization clock T1-CP1-IP1-TC1 and transmits the time difference to the slave time synchronization nodes through multicast messages.
5. The remote high-precision time service system based on the time triggered Ethernet as claimed in claim 4, wherein after the time synchronization slave node receives the time message, the cluster period cumulative number CP2, the integrated period cumulative number IP2 and the node transparent clock cumulative number TC2 of the local global synchronous clock are queried, and the absolute time value is recovered according to the received time message and the local global synchronous clock, namely T2=T1+T2+T2+Ip2+Tc2-CP 1-IP1-TC1, the time synchronization slave node corrects the time value of the slave node accordingly, so that the remote high-precision time service between the time master node and the slave node is realized.
6. The remote high-precision time service system based on the time triggered Ethernet as claimed in claim 1, wherein the time synchronization slave node is internally provided with a time timer, and the time correction of the time timer is completed according to the time service time and is based on the local crystal oscillator maintenance time until the next time correction.
7. The remote high-precision time service system based on the time triggered Ethernet as claimed in claim 6 is characterized in that the time synchronization slave node application mode comprises two modes, namely, application software accesses a time timer through a TTE end system read-write interface, a read enable signal is used for triggering and recording the current time, the recorded time is transmitted to the application software through the TTE access interface, a B code or C code output serial port is externally arranged on the time timer, when the whole second time is counted, a second pulse square wave signal is immediately triggered and output, and the current time is output to the serial port from the time timer.
8. A remote high precision time service system based on time triggered ethernet as claimed in any of claims 1-7 wherein the time service precision is better than 800ns.
9. A time service method of a remote high-precision time service system based on a time triggered Ethernet according to any one of claims 1-8 is characterized in that after a time synchronization master node captures a second pulse signal, a global synchronization clock module is triggered immediately to record the current value of a global synchronization clock, the cluster cycle number, the integration cycle number and a transparent clock value of the global synchronization clock at the moment are temporarily stored in a corresponding register, the time synchronization master node waits for a serial port to input UTC/ATI time after receiving the second pulse, the time synchronization master node restarts to enter an initial state and waits for the next second pulse after delaying for a certain time, if a UTC/ATI time code is received before the delay is finished, the time synchronization master node reads the cluster cycle number, the integration cycle number and the transparent clock value recorded by the second pulse trigger, the recorded cluster cycle number, the integration cycle number and the transparent clock value are converted into a timing value t1 = cluster x cluster cycle number + integration x integration cycle + transparent clock value corresponding to TTE clock synchronization start 0 time, the received UTC/ATI time is converted into a time value t2 taking seconds as a unit, the time frame cycle number and the TTC/ATI is set up from the time base of the TTE clock synchronization master node, and the TTC/ATI time can BE transmitted together with the time frame cycle number of a reference frame, and the TTC/ATI time frame can BE selected to complete, and the time frame clock frame cycle number can BE set up from the master node and the time synchronization master node.
10. The method of claim 9, wherein the number of cluster cycles and the number of integrated cycles before the next quasi-second moment are calculated as a synchronization time pre-trigger point after the time synchronization slave node receives the time synchronization frame, the integrated synchronization clock corrected accumulated deviation is calculated for a plurality of times after the synchronization time pre-trigger point is reached, the deviation plus the time difference is loaded into the time comparator, and when the global synchronization clock is equal to the set time value, the quasi-second pulse signal is triggered and output, and then the time code is output at the serial port.

Description

Remote high-precision time service system and method based on time-triggered Ethernet Technical Field The invention belongs to the technical field of time synchronization, and particularly relates to a remote high-precision time service system and method based on a time-triggered Ethernet. Background In the fields of embedded distributed measurement and control systems, industrial automation and the like, all the devices of the system are connected with a network through buses such as Ethernet and the like, and all network nodes generally need to establish a unified time reference to be used as the basis of system cooperative work, real-time data recording analysis and distributed computation. The network node is divided into a master clock and a slave clock in the time synchronization process, wherein the master clock is used for providing absolute time or relative time reference and time is clocked to the slave clock through a bus. The current common time synchronization method comprises bus network synchronization such as NTP, serial port teaching such as IRIG-B code, PPS second pulse + bus synchronization frame and PTP, etc., and the synchronization precision, implementation mode and economy realized by the various methods are different, and the method has various applicable scenes. The method is suitable for a standard Ethernet connected system, does not need special hardware, is complex in software realization, good in economy, and synchronous accuracy only reaches the sub-second level, a serial port time-giving method, such as IRIG-B codes, is simple in technology, good in economy, and has special hardware interface circuit cost, the synchronous accuracy reaches the millisecond level, a PPS second pulse and bus synchronous frame method is adopted, the special interface circuit is adopted for the terminal equipment, a special connecting cable is adopted for the system, the hardware cost is large, the technology is simple, the economy is good, the synchronous accuracy reaches the sub-microsecond level, and the synchronization methods based on 1588V2 such as PTP and the like do not need hardware second pulse synchronous signals, but the bottom layer needs to support 1588V2 chip support, and the technology complexity and the cost are high, and the synchronous accuracy can reach the sub-microsecond level. The Time Triggered Ethernet (TTE) is a high-certainty communication bus based on AS6802 protocol, is a novel bus technology in the field of embedded distributed measurement and control, and is mainly applied to the field of high-end equipment such AS aviation, aerospace and the like. The AS6802 protocol is based on 1588v2 protocol, takes a plurality of selected TTE end nodes AS Synchronization Master (SM) to provide clock sources, generates global synchronization clocks from clock information of a plurality of synchronization masters by using a fault-tolerant clock synchronization algorithm and broadcasts the global synchronization clocks, thereby realizing high-precision relative synchronization of all nodes of the whole network, but not realizing absolute time synchronization of all nodes of the whole network. Patent CN111083776A 'TTE time synchronization method based on 1588 and AS6802 protocol', patent CN118487748A 'time triggered Ethernet clock synchronization method and system based on external clock source', while realizing absolute time synchronization of whole network, PCF synchronization frame format and synchronization mechanism of TTE are changed, which is not compatible with the original standard. Disclosure of Invention The invention aims to solve the problems in the prior art, and comprises 1) adding absolute time, quasi-second pulse receiving, relative clock capturing alignment and framing transmitting functions to a master clock node under the condition of being compatible with the existing AS6802 standard and TTE bus standard, realizing the alignment of absolute time and TTE network global clock, adding absolute time and quasi-second pulse recovering functions to a slave clock node, transmitting the absolute time to the slave clock node through TT frame information by the master clock node, solving the absolute time synchronization problem between the master clock node and the slave clock node, 2) utilizing a TT frame multicasting mechanism to selectively time the absolute time to a plurality of selected equipment nodes, solving the problem that one master clock node synchronizes a plurality of slave clock nodes, and 3) in a complex network system, each subsystem can freely select UTC or ATI or other absolute time with different formats according to requirements for time synchronization, and the time synchronization processes of all subsystems are parallel and independent, have no coupling and mutual influence, and solve the problem that each domain of the complex system adopts different time references or carries out independent formats. The invention provides a high-precision time ser