CN112550380A - Dynamic time synchronization method - Google Patents
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- CN112550380A CN112550380A CN202011376177.3A CN202011376177A CN112550380A CN 112550380 A CN112550380 A CN 112550380A CN 202011376177 A CN202011376177 A CN 202011376177A CN 112550380 A CN112550380 A CN 112550380A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L27/00—Central railway traffic control systems; Trackside control; Communication systems specially adapted therefor
- B61L27/10—Operations, e.g. scheduling or time tables
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B61—RAILWAYS
- B61L—GUIDING RAILWAY TRAFFIC; ENSURING THE SAFETY OF RAILWAY TRAFFIC
- B61L27/00—Central railway traffic control systems; Trackside control; Communication systems specially adapted therefor
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Abstract
The invention relates to a dynamic time synchronization method, which is used for a signal system of an automatic train monitoring system and is used for dynamically adjusting the time of the signal system according to an external clock source and dynamically adjusting the time of each node in the classification of the signal system. Compared with the prior art, the method has the advantages of well protecting the result of time instability caused by time jump type jumping and the like.
Description
Technical Field
The invention relates to a time synchronization method, in particular to a dynamic time synchronization method for an automatic train monitoring system.
Background
In the development process of urban rail transit, strict standards are provided for the train operation process, so that high requirements are provided for time synchronization of a signal system. Under the background, time synchronization between a signal system and an external clock source and between signal system nodes in the rail transit field is mainly based on NTP (network time protocol), and multi-level node synchronization is performed in a layered mode. If a middle node of the multi-level nodes fails, the multi-level nodes cannot continue to perform time synchronization with the upper-level nodes. Through retrieval, for example, chinese patent publication No. CN109367586A discloses a clock synchronization system and method for an urban rail transit signal system, specifically including an external clock source, a communication front-end processor FEP and a signal system, where the signal system includes an application server, a gateway server, an ATS station server, an ATS center workstation, an ATS station workstation, ATC equipment and DCS equipment; the application server acquires a clock source from an external clock source through a communication front-end processor FEP, synchronizes a gateway server, an ATS station server, an ATS center workstation and an ATS station workstation by using the clock source acquired by the FEP, and synchronizes an ATC device and a DCS device by using the clock source acquired by the application server; the interior of the signal system adopts NTP protocol Meinberg tool for synchronization.
Therefore, the synchronization among multiple stages mainly depends on the NTP for synchronization, and the method has the advantage that the client does not jump in time in a large range relative to the server and is fine-tuned progressively. However, this technique has a disadvantage that it takes a long time to correct the situation after a large jump occurs in the server time, and it is difficult for the user to judge the situation.
Disclosure of Invention
The invention aims to provide a dynamic time synchronization method aiming at the high-standard time synchronization requirement of urban rail transit on the synchronization of each node between a signal system and an external time source and between the signal systems and the problem that the synchronization of a multi-level node cannot be switched along with the failure of the node.
The purpose of the invention can be realized by the following technical scheme:
according to one aspect of the invention, a dynamic time synchronization method is provided for a signal system of an automatic train monitoring system, which dynamically adjusts the time of the signal system according to an external clock source and dynamically adjusts the time of each node of the signal system.
As a preferred technical solution, the time for dynamically adjusting the signal system according to the external clock source is divided into two cases:
under the condition that the external clock source and the signal system are interrupted, the first level of the signal system starts the time service of the first level;
and under the condition that the external clock source is communicated with the signal system, the first level of the signal system determines whether to carry out synchronization according to the time difference between the current level of time and the external clock source.
As a preferred technical solution, the dynamic time adjustment for each node of the signal system hierarchy specifically includes:
and for each node of other levels in the signal system, determining whether the node is used as a client and a superior node for time synchronization or is used as the client and a server to start time service after the time synchronization with the superior node is carried out according to the data configuration item.
As a preferred technical scheme, the method comprises the following steps:
the method comprises the following steps: configuring basic parameters of a dynamic time synchronization method;
step two: judging the type of a local signal system and a server corresponding to a superior level according to basic parameters of the dynamic time synchronization method configured in the step one, so as to find a corresponding level;
step three: processing the signal system and the external clock source according to the judgment result of the step two;
step four: and according to the judgment result in the second step, carrying out synchronous processing on each node of other levels in the signal system.
As a preferred technical solution, the basic parameters in the first step include the interval of periodic checking time service, the allowable range of time error θ, the IP address of the external clock source, the upper and lower level relationship of time synchronization, and the parameters of the command and the command execution result related to the required execution time synchronization
As a preferred technical solution, the processing of the signal system and the external clock source in step three specifically includes:
a first level: starting a time server under the condition that the connection between the time server and an external clock source is interrupted;
and a second level: and when the local clock is connected with the external clock source and the time difference between the local time and the reply time of the external clock source is within theta, the local clock is forced to carry out time synchronization with the external clock source, and if the time difference exceeds theta, an alarm is output.
As a preferred technical solution, the step four includes specifically performing synchronization processing on each node of other levels in the signal system:
and determining whether to be used as the time synchronization of the client and the superior node only or to be used as the time synchronization of the client and the superior node and then start time service according to the data configuration item.
As a preferred technical solution, the basic parameters of the first step further include:
the first level and the external clock source force the time synchronization time range, the first level continuously requests the external clock source for 3 times of time interval and automatically starts time service after the first level and the superior clock source are disconnected for many times.
As a preferred technical scheme, the method is based on the subsystem communication relation among automatic train monitoring systems, and the type of each subsystem and the corresponding superior node are predefined according to the characteristics of information interaction.
As a preferred technical solution, the method directly takes the corresponding host time as the local time for the standby machine, and even if the standby machine is hot, the time synchronization of the next stage is not affected.
Compared with the prior art, the invention has the following advantages:
1. and each level dynamically acquires the IP of the superior host according to the hot standby condition of the superior node, and the time for reaching the goal dynamically follows the superior node.
2. And carrying out time synchronization on a host which serves as a client and a server (C/S) within a time difference allowable range, and generating an alarm outside the time difference allowable range to prevent the result of time instability caused by jump-type jump among time.
3. At present, the dynamic time synchronization method based on the automatic train monitoring system is successfully applied to urban rail transit operations such as Chengdu, Hohaote, Shenzhen and the like, and faults caused by time asynchronism do not occur.
Drawings
FIG. 1 is a schematic diagram of a multi-level time synchronization network according to the present invention;
FIG. 2 is a flow chart of the present invention for implementing time synchronization.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, shall fall within the scope of protection of the present invention.
The invention provides a dynamic time synchronization method for an automatic train monitoring system (ATS) of urban rail transit, which is beneficial to maintaining the time consistency among subsystems in the ATS system and effectively assisting the function of the ATS system. The method is based on the subsystem communication relation among ATS systems, and the type of each subsystem and the corresponding superior node are predefined according to the characteristics of information interaction. For different configuration types, the NTP information interaction with the upper host node is determined as the client only, and forced synchronization with the upper host is carried out regardless of time errors. Or as both a client and a server, dynamically acquiring the IP address of the superior host or the superior master control, calculating the difference between the acquired time of the superior host or the master control and the local time for the host, performing time forced synchronization within a time error range, starting a time server, and outputting an alarm prompt outside the time error range; and for the standby machine, the corresponding host time is directly acquired as the local time, and the next-stage time synchronization is not influenced even if each node is in hot standby. Compared with the prior art, the method has the advantages that each level of time dynamically follows the superior node, and the result of unstable time caused by time jump type jumping is well protected.
The invention is divided into the time service of the first level of the signal system starting itself under the condition of the external clock source and the signal system interruption for the signal system and the external clock source processing mode; under the condition that the external clock source is communicated with the signal system, the first level of the signal system determines whether to carry out synchronization or not according to the time difference between the current level of time and the external clock source. And for each node of other levels in the signal system, determining whether the node is used as a client (C) and an upper node for time synchronization or is used as a client and a server (C/S) and is started for time service after the time synchronization with the upper node according to the data configuration item.
The invention is further illustrated below, the method of the invention comprising the steps of:
s1: configuring basic parameters of a dynamic time synchronization method;
s2: according to the basic parameters of the dynamic time synchronization in the step S1, including the interval of the periodic check time service and the time error allowable range θ, each node type of the signal system, and the upper level service node and the upper level node type are determined.
S3: according to step S2, for the C/S master at the first level of the signaling system, periodically sending standard NTP time synchronization information to the external clock NTP server, and the external clock system returning the current time t1The first-level host of the signal system acquires the local time t2The first level host of the signal system receives the time and satisfies | t1-t2|<And theta, adjusting the local time and starting the local NTP time service, otherwise, outputting an alarm. If the response of the external clock NTP server is not received, the response is not received for 3 times continuously, the first-level host of the signal system and the external clock source NTP server are considered to have communication faults, an alarm is output, and the first-level host of the signal system makes the first-level host of the signal system perform self-operationTime is synchronized for a level of NTP servers.
S4: according to step S2, for the C/S master at the second level of the signaling system, periodically and dynamically sending standard NTP time synchronization information to the first-level NTP time server, which returns the current time t3And the local node acquires the local time t4Local node receives time and satisfies | t3-t4|<And theta, adjusting the local time and starting the local NTP time service, otherwise, outputting an alarm. And if the response of the upper-level node is not received, outputting an alarm.
S5: according to step S2, the C/S master and the slave at the third level of the signaling system periodically and dynamically send the standard NTP time synchronization information to the second-level master NTP server, which returns the current time t5And the local node acquires the local time t6Local node receives time and satisfies | t5-t6|<And theta, adjusting the local time and starting the local NTP time service, otherwise, outputting an alarm. And if the response of the master control NTP time server is not received, outputting an alarm. Optionally, periodically sending standard NTP time synchronization information to a main control NTP time server for a host C and a standby machine at the third level of the signal system, and adjusting local time after receiving a response; if no answer is received, the local time is taken as the standard.
S6: according to the steps S2, S3 and S4, the standard NTP time synchronization information is periodically sent to the corresponding host for the C/S standby machines at the first level and the second level of the signal system, and the local time is adjusted after the response is received; if no answer is received, the local time is taken as the standard.
S7: optionally, in the step S3, no matter how much the time difference between the first level of the signal system and the time server of the external clock source is, after the operation is performed, the local time is forcibly adjusted to be the same as the time of the external clock source, and the local time server is started.
S8: optionally, in the step S3, the step S2 is configured with a forced synchronization time t, and in a time difference t range between the first level of the signal system and the time server of the external clock source, the local time is forced to be adjusted to be the same as the time of the external clock source, and the local time server is started.
The detailed description is given with reference to the accompanying drawings
As shown in fig. 1, in the overall multi-level time synchronization network method provided in the embodiment of the present invention, a next level sends standard NTP time synchronization information to an upper level, requests time information, and the upper level replies current time information. Each level has a master-slave that does not affect the next level in the event of a failure of a master at one level.
The following describes the implementation principle of the dynamic time synchronization method in the embodiment of the present invention with reference to fig. 2, including the following steps:
s1: basic parameters of the method for configuring dynamic time synchronization include the interval of periodic check time service, the allowed range of time error, the IP address of an external clock source, the time error of the first-level forced synchronization with the external clock source, the upper-level and lower-level relation of time synchronization (including a local node, a local NTP service type, a higher-level service node and a corresponding hot standby node), a command related to required execution time synchronization and a result returned after the command is executed.
S2: the type of the signal system is determined according to the basic parameters of the dynamic time synchronization method in step S1, and different operations are performed according to the specific type.
And for the C type IP address of the time service end, performing forced time synchronization with the time service end in any time difference range.
And for the IP address of the C/S type acquisition time service end, judging whether the local signal system is a host, and dynamically modifying the IP address of the requested superior time service end under the condition of the host. The same operation as the C type is performed in the standby state.
S3: according to the signal system type judged in the step S2, periodically checking the local time service starting state for the C/S type, sending standard NTP time synchronization information to the corresponding host in the local non-starting time service state, outputting an alarm if no response is received, otherwise judging the time difference between the reply time and the local time after receiving the response, performing forced time synchronization within the range less than the set time difference, and starting the local time server; and if the time difference is larger than the set value, outputting an alarm. Under the state of local started time service, periodically sending standard NTP time synchronization information to a corresponding host, outputting an alarm if a response is not received, judging the difference between the time replied and the local time if the response is received, and using a current time server to perform time synchronization within the range of less than the set time difference; and if the time difference is larger than the set value, outputting an alarm.
While the invention has been described with reference to specific embodiments, the invention is not limited thereto, and various equivalent modifications and substitutions can be easily made by those skilled in the art within the technical scope of the invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A dynamic time synchronization method is used for a signal system of an automatic train monitoring system and is characterized in that the method dynamically adjusts the time of the signal system according to an external clock source and dynamically adjusts the time of each node of the signal system in a grading way.
2. A dynamic time synchronization method as claimed in claim 1, wherein the time for dynamically adjusting the signal system according to the external clock source is divided into two cases:
under the condition that the external clock source and the signal system are interrupted, the first level of the signal system starts the time service of the first level;
and under the condition that the external clock source is communicated with the signal system, the first level of the signal system determines whether to carry out synchronization according to the time difference between the current level of time and the external clock source.
3. The dynamic time synchronization method according to claim 1, wherein the dynamic time adjustment for each node in the signal system hierarchy specifically comprises:
and for each node of other levels in the signal system, determining whether the node is used as a client and a superior node for time synchronization or is used as the client and a server to start time service after the time synchronization with the superior node is carried out according to the data configuration item.
4. A dynamic time synchronization method as claimed in claim 1, characterized in that said method comprises the steps of:
the method comprises the following steps: configuring basic parameters of a dynamic time synchronization method;
step two: judging the type of a local signal system and a server corresponding to a superior level according to basic parameters of the dynamic time synchronization method configured in the step one, so as to find a corresponding level;
step three: processing the signal system and the external clock source according to the judgment result of the step two;
step four: and according to the judgment result in the second step, carrying out synchronous processing on each node of other levels in the signal system.
5. A dynamic time synchronization method as claimed in claim 4, wherein the basic parameters in the first step include the interval of periodical checking time service, the allowable range of time error θ, the IP address of the external clock source, the upper and lower level relationship of time synchronization, and the parameters of the command and the command execution result related to the required execution time synchronization.
6. A dynamic time synchronization method according to claim 4, wherein the processing of the signal system and the external clock source in the third step is specifically:
a first level: starting a time server under the condition that the connection between the time server and an external clock source is interrupted;
and a second level: and when the local clock is connected with the external clock source and the time difference between the local time and the reply time of the external clock source is within theta, the local clock is forced to carry out time synchronization with the external clock source, and if the time difference exceeds theta, an alarm is output.
7. A dynamic time synchronization method as claimed in claim 4, wherein the step four of performing synchronization processing on each node of other levels in the signal system specifically comprises:
and determining whether to be used as the time synchronization of the client and the superior node only or to be used as the time synchronization of the client and the superior node and then start time service according to the data configuration item.
8. The dynamic time synchronization method according to claim 6, wherein the basic parameters of the first step further comprise:
the first level and the external clock source force the time synchronization time range, the first level continuously requests the external clock source for 3 times of time interval and automatically starts time service after the first level and the superior clock source are disconnected for many times.
9. The dynamic time synchronization method according to claim 1, wherein the method is based on a subsystem communication relationship between automatic train monitoring systems, and the type of each subsystem and the corresponding superior node are predefined according to the characteristics of information interaction.
10. A dynamic time synchronization method as claimed in claim 1, wherein the method directly takes the corresponding host time as the local time for the standby machine, and the next stage of time synchronization is not affected even if each node is hot standby.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102684808A (en) * | 2012-06-06 | 2012-09-19 | 哈尔滨工业大学 | Self-adaptive clock synchronous system |
| CN104821870A (en) * | 2015-02-13 | 2015-08-05 | 北京科东电力控制系统有限责任公司 | Master station smart power grid scheduling technology support system-based clock synchronization method |
| EP2923913A1 (en) * | 2014-03-25 | 2015-09-30 | Hitachi, Ltd. | Automatic train operation system |
| CN107070579A (en) * | 2017-05-16 | 2017-08-18 | 中国船舶重工集团公司第七0九研究所 | Three-level time server is controlled and fault-tolerance approach |
| CN109367586A (en) * | 2018-10-19 | 2019-02-22 | 卡斯柯信号有限公司 | A kind of city rail traffic signal system clock system and method |
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2020
- 2020-11-30 CN CN202011376177.3A patent/CN112550380A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102684808A (en) * | 2012-06-06 | 2012-09-19 | 哈尔滨工业大学 | Self-adaptive clock synchronous system |
| EP2923913A1 (en) * | 2014-03-25 | 2015-09-30 | Hitachi, Ltd. | Automatic train operation system |
| CN104821870A (en) * | 2015-02-13 | 2015-08-05 | 北京科东电力控制系统有限责任公司 | Master station smart power grid scheduling technology support system-based clock synchronization method |
| CN107070579A (en) * | 2017-05-16 | 2017-08-18 | 中国船舶重工集团公司第七0九研究所 | Three-level time server is controlled and fault-tolerance approach |
| CN109367586A (en) * | 2018-10-19 | 2019-02-22 | 卡斯柯信号有限公司 | A kind of city rail traffic signal system clock system and method |
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