CN104468072B - A kind of IMA platform clocks synchronous method - Google Patents
A kind of IMA platform clocks synchronous method Download PDFInfo
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- CN104468072B CN104468072B CN201410735935.4A CN201410735935A CN104468072B CN 104468072 B CN104468072 B CN 104468072B CN 201410735935 A CN201410735935 A CN 201410735935A CN 104468072 B CN104468072 B CN 104468072B
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Abstract
The present invention proposes a kind of IMA platform clocks synchronous method, includes the following steps：1) detection and receiving time synchronization message when detecting the time synchronization message of mistake, report timing error, and abandon the message；2) when master clock node receives the absolute length of a game of system, which is converted into 64 time datas, and calibrate or update the RTCs values of master clock accordingly；It is dispatched simultaneously according to system communication, each fixed time period is by system reference time " broadcast " to being attached thereto local clock (switching node)；A kind of stratification distributed clock relative synchronization technology of the present invention and method, (containing the network switch), other avionics function device/subsystems so that each function module of IMA systems, relative system fiducial time be maintained in certain error allowable range it is harmonious, synchronize orderly work；The passage of each nodal clock at any time brings time deviation, each node to need the time calibration of periodic receipt system to system in order to prevent simultaneously.
Description
Technical field
The invention belongs to airborne embedded computer system technologies, realize a kind of comprehensively modularized avionics system
(IMA) clock synchronizing method of core processing platform is mainly used between each node of IMA systems (equipment or module) of new generation
Time synchronization.
Background technology
Synthesization, networking technology introduce so that traditional aviation electronics function device or subsystem " concentration " are current
One function module of integrated treatment platform, and interconnected by a kind of switching network, it is asynchronous to constitute a complicated distribution
Real time processing system.The execution of system task is shared out the work and helped one another dependent on each node (at such as calculating of function treatment, data, figure
Reason etc.), real-time Communication for Power can efficiently accomplish.How to ensure the time synchronization between each asynchronous working node in system, and prevents
Since time drift brings work chaotic or mistake to system, it has also become a key technology of system design, core is to be
Clock of uniting synchronizes.
Traditional shared-bus avionics system, due to its centralized control, unified reference clock and low time resolution
Rate cannot be satisfied the time synchronization requirement of the airborne distributed real time processing system of networking of modern complexity；In addition airborne number
It is a kind of switch type asynchronous communication networks according to network, time synchronization of the agreement between system node is not required, and IMA systems
System application needs its function module, equipment/subsystem harmonious orderly under unified reference time benchmark to work, common to complete system
System real-time task, such as temporal correlation record, data validity judge, the confirming proper of timing results.Therefore for reality
The time synchronization of existing IMA platforms or even entire avionics system, there is an urgent need to develop a kind of new stratification clock relative synchronization sides
Method is realized with adapting to modern IMA System Developments needs between system reference time, local reference time and node time
It is effectively synchronous, it is ensured that system coordination orderly works.
Invention content
In order to solve the technical problem in the presence of background technology, the present invention proposes that a kind of stratification distributed clock is opposite
Simultaneous techniques and method so that each function module of IMA systems (containing the network switch), other avionics function device/subsystems, phase
To system reference time be maintained in certain error allowable range it is harmonious, synchronize orderly work；It is each in order to prevent simultaneously to save
The passage of Dot Clock at any time brings time deviation, each node to need the time calibration of periodic receipt system to system.
Technical solution of the invention：A kind of IMA platform clocks synchronous method, it is characterised in that：The method includes
Following steps：
1) detection and receiving time synchronization message when detecting the time synchronization message of mistake, report timing error, and abandon
The message；
2) when master clock node receives the absolute length of a game of system, which is converted into 64 time numbers
According to, and the RTCs values of master clock are calibrated or updated accordingly；It is dispatched simultaneously according to system communication, each fixed time period is by system
Fiducial time " broadcast " is to being attached thereto local clock (switching node)；
3) it when IMA platform local clock nodes receive the fiducial time of master clock node, calculates local clock and is
Difference (the △ RTC of system fiducial timei=RTCi- RTCs), its local clock (RTC is updated or calibrated accordinglyi=RTCs+ △
RTCi)；It is dispatched simultaneously according to system communication, reads local RTCiTime value, and it is forwarded to the all-network node being attached thereto
(switching node containing cascade, local node)；
4) when IMA platform nodes receive the fiducial time of local clock node, local clock and partial reference are calculated
Difference (the △ RTC of timej=RTCj-RTCl), and this nodal clock (RTC is updated accordinglyj=RTCl+△RTCj)；If this section
Point is cascade switching node, then is dispatched according to system communication, reads local reference time RTCj, and is forwarded to and is attached thereto
Each node of this LAN (switching node containing cascade)；
5) step 1) -- step 4) is repeated, until system is closed.
System time synchronization is synchronized and 2 self-contained process progress of system time synchronization using master clock.
System time synchronization synchronous, two level local clock and nodal clock, three-level nodal clock using level-one local clock
What three levels carried out.
System time synchronization uses RTC clock relative synchronization mode.
IMA platform clock synchronization systems, it is characterised in that：The system comprises the distributed real-time clocks (RTC) of layering
Synchronization architecture, RTC synchronous circuits, wherein RTC synchronous circuits are distributed in each network equipment of system, with its present position according to
Master clock, local clock and the nodal clock of secondary composition system, and master clock node calibrate successively with synchronize be attached thereto
The time value of local clock and nodal clock, and then reach the relative synchronization of the time of whole system.
Distributed real-time clock (RTC) synchronization architecture of layering includes master clock and backup master clock, local benchmark
Clock, nodal clock, wherein master clock and the absolute length of a game that the input of backup master clock is system, output are local clock
Fiducial time；The input of local clock is main clock reference time, and output is nodal clock fiducial time；Nodal clock inputs
For local clock reference time, the node benchmark reference time value after being calibrated for time error is exported.
RTC circuit includes the real-time clock for the incremental count that a length is 64, resolution ratio is 1us, RTC control electricity
Road, master clock and backup master clock, local reference clock, nodal clock, wherein RTC are distributed in each network terminal of system,
Input connection RTC control circuits write logic, the reading logic of output connection RTC control circuits.
It is an advantage of the invention that：
1) the more Domain Synchronous structures of hierarchy type, each switching node respectively form a relatively independent LAN of system
Time domain so that system synchronization control is simple, and is easily achieved.
2) precision synchronization time is high, when using high-resolution real-time clock, clock relative synchronization mechanism and hierarchy type multistage
Between synchronization process structure, eliminate switching network transmitting and scheduling delay, improve system synchronization time precision.
3) there is good versatility and fault-tolerant ability, can be applied to switching network processing system and highly reliable airborne point
Cloth real time processing system.
Description of the drawings
Fig. 1 is IMA platform stratification clock system structures.
Fig. 2 is IMA platform clock synchronization process flow charts.
Specific implementation mode：
The present invention is a kind of IMA platform clocks synchronous method, and implementation principle is：System is arranged in each node of system first
One 1us resolution ratio, 64 bit lengths real-time clock (RTC) realizes that node local zone time keeps, counts, and receives system
Synchronous and time calibration；Master clock source of the node as system is assigned, system time service (such as GPS) and synchronous, generation are received
System reference time (RTCS), and dispatched periodical delivery system fiducial time in system communication, synchronous IMA systems are each
LAN fiducial time (contains network switching node)；Pass through the time calibration of each LAN switching node and synchronous forwarding clothes again
Business synchronizes the synchronization between all processing nodes inside each LAN, and then realizes the time synchronization of IMA plateform systems；It relies on
System communication configures, master clock node broadcasting system fiducial time over data networks, to calibrate the clock value of each node
(RTCi), i.e., 1. calculate error (the △ RTC of local clock and system reference timei=RTCi-RTCS), it 2. updates and calibrates this
Ground clock RTCi(RTCs=RTCi+△RTCi)；To ensure as time goes by, there is big drift or deviation in each nodal clock,
And then chaotic or mistake, system is brought to use periodically (such as 50ms) Time Synchronization Mechanism, use simultaneously to system work
Dual redundant master clock design of node, to eliminate the Single Point of Faliure of system, it is ensured that system synchronization reliability.
It is by the setting one in each node of system (interchanger, function module, the network equipment) that IMA platform clocks, which synchronize,
Real-time clock specifies a node as system master clock source, and passes through network configuration periodicity delivery system fiducial time, school
Each nodal clock of Barebone makes each node of system keep relative time clock deviation, harmonious orderly work with respect to master clock node.The party
Method specific implementation mode is described as follows：
1, IMA platforms distributed clock synchronous system architecture and circuit explanation
1) stratification distributed clock synchronous system architecture explanation：This method uses 3 layers of distributed frame, as shown in Figure 1,
Wherein the 1st layer is system master clock source and backup master clock source (RTCs), acceptable system time service and time synchronization, real-time time
The publication of conversion, master clock update or time calibration and system reference time to each interchanger；2nd layer be system area benchmark when
Clock (RTCl), it resides in each network switching node of IMA platforms (including remaining interchanger), receives the base from system master clock
Between punctual, the fiducial time of calibration and each LAN of more new system, while it is each that system reference time after calibration is transmitted to local
Node (function module, external node) in cascade network interchanger, this domain, realizes the time synchronization in this LAN；3rd
Layer is nodal clock, resides at each function module of IMA platforms, in external node, when receiving the partial reference from this LAN
Between it is synchronous, calculate the difference of local clock and partial reference time, and update and calibration node local clock (RTC accordinglyj)。
2) clock synchronization circuit explanation：The RTC synchronous circuits of a standard, length are designed in each network node of IMA platforms
Degree is 64, resolution ratio 1us, incrementally counts, can be operated by end system controller " read/write "；Clock synchronization circuit
There is provided RTC Framing Error Detections, frame length detection, remaining processing and read/write operation function, it is ensured that RTC integralities and correctness.
2, clock synchronizes process description：
1) detection and reception of time synchronization message：If message detection inerrancy is transferred to step 2), otherwise the time is same
Step failure, abandons the time message.
2) the absolutely judgement and processing of length of a game：The time service of realization system or system reference time synchronize, when node s is received
The time arrived is global absolute time (including date, Hour Minute Second information), and the time is converted to 64 times first
Data as the system reference time, and update or calibrate the RTC of master clock accordinglysValue；Match simultaneously according to grid
It sets, system reference time " broadcast " to the switching node being attached thereto, is otherwise transferred to by each fixed time period (such as 50ms)
Step 3)；
3) judgement and processing of system reference time：Realize that the time synchronization of each node of IMA platforms, fiducial time come from
The master clock node of system calculates its clock and system reference time if the time that node i receives is system reference time
Difference (△ RTCi=RTCi-RTCs), and its local clock (RTC is updated or calibrated accordinglyi=RTCs+△RTCi)；It such as wants defeated
When going out time synchronization frame (level-one switching node), then local RTC is readiTime value, and it is forwarded to the all-network being attached thereto
Node (switching node containing cascade, local node), is otherwise transferred to step 4)；
4) judgement and processing of partial reference time：Realize the time synchronization between each node, benchmark inside LAN
Switching node of the time from this LAN, i.e., if when the time that node j is received is the partial reference from higher level's LAN
Between, then calculate difference (the △ RTC of local clock and partial reference timej=RTCj-RTCl), and this nodal clock is updated accordingly
(RTCj=RTCl+△RTCj)；If this node is cascade switching node, when time synchronization frame exports, local part is read
Fiducial time RTCjTime value, and it is forwarded to each node of this LAN (switching node containing cascade, local node), otherwise it is transferred to step
It is rapid 5)；
If 5) system is closed, out of service, it is otherwise transferred to step 1), repeats the operation of next round time synchronization.
Claims (6)
1. a kind of IMA platform clocks synchronous method, it is characterised in that：It the described method comprises the following steps：
1) detection and receiving time synchronization message when detecting the time synchronization message of mistake, report timing error, and abandon this and disappear
Breath；
2) when master clock node receives the absolute length of a game of system, which is converted into 64 time datas, and
The RTCs values of master clock are calibrated or updated accordingly, wherein RTCs is denoted as the time value of the master clock RTC of system reference time,
RTC full name in English is Real-Time Clock, and Chinese name is known as real-time clock；It is dispatched simultaneously according to system communication, Mei Gegu
Fix time the period by system reference time " broadcast " to being attached thereto local clock；
3) when IMA platform local clock nodes receive the fiducial time of master clock node, local clock and system base are calculated
Difference △ RTC between punctuali, wherein △ RTCi=RTCi- RTCs updates or calibrates its local clock RTCi, wherein RTC accordinglyi
=RTCs+ △ RTCi；It is dispatched simultaneously according to system communication, reads local RTCiTime value, and it is forwarded to all nets being attached thereto
Network node, wherein RTCiIndicate the time value of local clock i；
4) when IMA platform nodes receive the fiducial time of local clock node, local clock and partial reference time are calculated
Difference △ RTCj, wherein △ RTCj=RTCj-RTCl, and this nodal clock RTC is updated accordinglyj, RTCj=RTCl+△RTCj；Such as
This node of fruit is cascade switching node, then is dispatched according to system communication, reads local reference time RTCj, and be forwarded to therewith
Each node of this connected LAN, wherein RTCjIndicate the time value of nodal clock j, RTClIt is denoted as local fiducial time
The time value of local clock RTC；
5) step 1) -- step 4) is repeated, until system is closed.
2. IMA platform clocks synchronous method according to claim 1, it is characterised in that：When system time synchronization uses main
Clock synchronizes and 2 self-contained process progress of system time synchronization.
3. IMA platform clocks synchronous method according to claim 1, it is characterised in that：System time synchronization uses level-one
Local clock is synchronous, two level local clock is synchronous with nodal clock, three-level nodal clock synchronizes what three levels carried out.
4. IMA platform clocks synchronous method according to claim 1, it is characterised in that：System time synchronization is using real-time
Clock RTC relative synchronization modes.
5.IMA platform clock synchronization systems, it is characterised in that：The system comprises the distributed real-time clock RTC of layering synchronizations
Architecture, RTC synchronous circuits, wherein RTC synchronous circuits are distributed in each network equipment of system, with its present position successively structure
At the master clock of system, local clock and nodal clock, and master clock node calibrate successively with synchronize the local that is attached thereto
The time value of clock and nodal clock, and then reach the relative synchronization of the time of whole system；
When the distributed real-time clock RTC synchronization architectures of layering include master clock and backup master clock, local clock, node
Clock, wherein master clock and the absolute length of a game that the input of backup master clock is system, output are local clock reference time；Office
The input of domain clock is main clock reference time, and output is nodal clock fiducial time；Nodal clock input is local clock
Fiducial time exports the node benchmark reference time after being calibrated for time error.
6. IMA platform clocks synchronization system according to claim 5, it is characterised in that：Real-time clock RTC circuit includes one
Real-time clock, RTC control circuits, master clock and the backup master clock of the incremental count that a length is 64, resolution ratio is 1us,
Local reference clock, nodal clock, wherein RTC are distributed in each network terminal of system, and input connection RTC control circuits are write
Logic, the reading logic of output connection RTC control circuits.
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| CN105553592B (en) * | 2015-12-10 | 2018-04-17 | 中国航空工业集团公司西安航空计算技术研究所 | A kind of IMA processor systems clock synchronizing method |
| CN106650128B (en) * | 2016-12-28 | 2019-11-19 | 北京华大九天软件有限公司 | A kind of method of graphic software platform timing topology and timing dependence |
| CN107026703B (en) * | 2017-05-19 | 2019-01-11 | 北京航天自动控制研究所 | A kind of tandem type method for synchronizing time in hybrid network |
| CN107517435B (en) * | 2017-08-15 | 2020-06-23 | 杭州电子科技大学信息工程学院 | Sound wave synchronous acquisition system and method based on wireless sensor network |
| CN110932811B (en) * | 2019-11-01 | 2021-05-25 | 华迪计算机集团有限公司 | Network clock system of electronic government internal network |
| CN111107623A (en) * | 2019-12-10 | 2020-05-05 | 陕西凌云电器集团有限公司 | System clock synchronization method |
| EP3902166B1 (en) * | 2020-04-21 | 2022-03-23 | TTTech Computertechnik Aktiengesellschaft | Fault tolerant time server for a real-time computer system |
| CN113497663A (en) * | 2021-05-28 | 2021-10-12 | 中国航空工业集团公司沈阳飞机设计研究所 | Distributed network architecture and time synchronization method thereof |
| CN117155503B (en) * | 2023-08-29 | 2024-04-19 | 中国科学院国家授时中心 | Extensible cascading quantum time synchronization system |
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| CN1232585A (en) * | 1996-09-30 | 1999-10-20 | 诺基亚电信公司 | Hierarchical synchronization system |
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