CN-122001512-A - LKJ clock synchronization method and system based on multisource reliability arbitration

CN122001512ACN 122001512 ACN122001512 ACN 122001512ACN-122001512-A

Abstract

The invention discloses an LKJ clock synchronization method and system based on multisource reliability arbitration, wherein the method comprises the steps of S1) constructing a multisource time information acquisition and transmission system, S2) carrying out multidimensional trust evaluation on a clock source, S3) carrying out timing urgency calculation and trigger judgment, S4) carrying out self-adaptive timing strategy arbitration, S5) carrying out timing execution and state closed loop updating, and adopting a vehicle-ground cooperative framework, wherein the system comprises a vehicle-mounted timing subsystem, a vehicle-ground cooperative communication subsystem and a ground decision support subsystem, thereby improving LKJ timing robustness and success rate and enhancing the intelligentization and self-adaptation capability of LKJ timing.

Inventors

HU DONGLIANG
WANG JIANGYING
LIU ZHANG
WEI BAOSHENG
YANG QINGXIANG
ZHAO JUNFENG
YAN XIN
LIU GUANGPENG
WANG JINGXIN

Assignees

河南思维自动化设备股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260313

Claims (10)

1. The LKJ clock synchronization method based on multi-source reliability arbitration is characterized by comprising the following steps, S1, constructing a multisource time information acquisition and transmission system, acquiring various time reference source information, train running state and communication link quality information in real time, and forming a basic time data pool; S2) carrying out multi-dimensional trust evaluation on the clock source, constructing a multi-dimensional trust evaluation model, and calculating a trust score C i (t) of each available time source i based on the multi-dimensional trust evaluation model; Determining comprehensive optimal time T opt (T) based on the trust score C i (T), calculating real-time deviation delta T (T) of LKJ local clock time T lkj (T) and T opt (T) and change rate d (delta T)/dt thereof, further calculating time urgency U (T), comparing U (T) with a dynamic trigger threshold T dyn adaptively adjusted according to the current running state of a train, and judging that time correction requirements exist when U (T) is greater than T dyn , namely entering a strategy arbitration flow; S4, performing self-adaptive timing strategy arbitration, wherein the optimal timing strategy is arbitrated and selected from a preset strategy library according to the trust distribution of the current available time source, the running state of the train and the safety constraint condition; s5), timing execution and state closed loop updating are carried out.
2. The LKJ clock synchronization method based on multi-source reliability arbitration of claim 1, wherein in step S1), the time reference source information at least comprises satellite original time service information provided by a vehicle-mounted Beidou receiving module, server local calendar clock information acquired from a ground server by a vehicle-to-ground wireless communication network, time information of a ground standard network time source server and ground atomic clock time information.
3. The LKJ clock synchronization method based on multi-source reliability arbitration of claim 1 wherein in step S2), the multi-dimensional reliability assessment model integrates at least four dimensional itemization indexes of availability assessment A i (t), short-term stability assessment S i (t), consistency assessment H i (t) and historical health assessment H i hist (t); the calculation formula of the trust score C i (t) is as follows: C i (t)=w a ⋅ A i (t)+ w s ⋅S i (t)+ w c ⋅H i (t)+ w h ⋅ H i hist (t);C i (t)∈[0,1]; Wherein w a ,w s ,w c ,w h is a preset weight coefficient, and satisfies w a + w s + w c + w h =1; The usability assessment A i (t) is used for judging whether the time source meets the basic access and use conditions; The short-term stability evaluation S i (T) is used for measuring the output fluctuation condition of a time source in a recent time window T s , and the time window T s is 1 hour by calculating the Allen variance (ALLAN VARIANCE) or standard deviation of a time sequence in the time window T s and normalizing the Allen variance or standard deviation to a [0,1] interval, wherein the smaller the jitter is, the higher the value of S i (T) is; the consistency assessment H i (t) is used for assessing consistency between the time source and other high-trust reference sources; Setting the medium confidence threshold value as theta mid , wherein all available reference sources are A j (t) =1, J is taken as the reference source, and then all available reference sources with the confidence level higher than the medium confidence threshold value theta mid are taken as J, wherein J meets the conditions that A j (t) =1 and C j (t)＞θ mid Calculating an absolute value d of the time deviation between the time source i and the reference source J, and taking a minimum value d min of the absolute value of the time deviation; Calculating a consistency score H i (t)=exp(-α⋅d min by an exponential decay function, wherein alpha is a sensitivity coefficient; The historical health assessment H i hist (t) is based on the historical performance of the time source i over a long period of at least 30 days, and a long-term health baseline score is calculated by recording the historical confidence average, the number of large hops and the number of arbitrated exclusions by other sources.
4. The LKJ clock synchronization method based on multi-source reliability arbitration of claim 1, wherein in the step S3), the calculation formula of the timing urgency U (T) is U (T) = |DeltaT (T) |+β|d (DeltaT)/dt|, wherein β is a rate of change weight coefficient for amplifying the risk of rapid increase of deviation; The self-adaptive adjustment method of the dynamic trigger threshold T dyn comprises the following steps: when the train is in an in-garage parking maintenance state, dynamically triggering a threshold value T dyn = +/-1 second; When the train runs at a high speed in the positive line interval, the dynamic trigger threshold T dyn is = ±10 seconds, and the judgment is carried out together with the safety condition of parking or in a degradation mode.
5. The LKJ clock synchronization method based on multi-source reliability arbitration of claim 1, wherein in step S4), the preset policy library at least comprises: When a single time source i exists, the trust degree C i (t) of the single time source i is higher than a preset high threshold value theta high , namely C i (t)＞θ high , and the train state meets the preset safe timing condition, the single high-reliability source is adopted for automatic timing; When a plurality of time sources with the trust degree between a medium threshold value theta mid and a high threshold value theta high , namely theta mid ＜C i (t)＜θ high and good consistency with each other exist, adopting the weighted fusion results of the sources to correct time; When the integral credibility of the available time source is lower than a medium threshold value theta mid , namely C i (t)＜θ mid , or the deviation value between the optimal source and the suboptimal source exceeds a preset deviation, pushing multi-source time information, credibility score and conflict point analysis to a ground operation and maintenance terminal to request manual confirmation and decision, and after the comprehensive judgment of ground personnel, selectively executing timing or neglecting; And (3) delaying early warning, and delaying timing and sending early warning information when the timing urgency U (T) exceeds the dynamic trigger threshold T dyn but the current train running state does not meet the safety condition of any timing strategy.
6. The LKJ clock synchronization method based on multi-source reliability arbitration according to claim 1, wherein in step S5), the timing operation is performed according to the arbitration result, if the timing is automatically or manually confirmed, a timing instruction is issued to the LKJ host, the clock calibration is completed by adopting a designated time source, after the timing is completed, the related information of the timing event is recorded, the related information comprises the adopted time source, the timing amount, the deviation before and after the timing and the triggering strategy, and meanwhile, the historical health record H i hist (t) of each related time source is updated by utilizing the data observed in the timing process and the follow-up short time.
7. An LKJ clock synchronization system based on multi-source reliability arbitration, which comprises the LKJ clock synchronization method based on multi-source reliability arbitration as set forth in any one of claims 1 to 6, and is characterized in that the system adopts a vehicle-ground cooperative architecture, and comprises a vehicle-mounted timing subsystem, a vehicle-ground cooperative communication subsystem and a ground decision support subsystem, wherein the vehicle-mounted timing subsystem is in communication connection with the vehicle-ground cooperative communication subsystem, the vehicle-ground cooperative communication subsystem is in communication connection with the ground decision support subsystem, The vehicle-mounted subsystem is used for collecting multi-source time information and train running states, and carrying out local trust evaluation, timing urgency calculation and strategy arbitration execution; the vehicle-ground cooperative communication subsystem is used for realizing the transmission of time data, state information and control instructions between the vehicle-mounted subsystem and the ground decision support subsystem; The ground decision support subsystem is used for converging and managing multi-source time data, running a strategy arbitration algorithm to generate timing decisions, and providing man-machine interaction and historical data analysis functions.
8. The LKJ clock synchronization system based on multi-source reliability arbitration of claim 7 wherein the on-board timing subsystem comprises a multi-source time acquisition module, a local agent and preprocessing module and an on-board arbitration and policy enforcement module; The multi-source time acquisition module is used for receiving and processing satellite time service information sent by the Beidou receiving module, acquiring ground NTP time and ground server time through the wireless communication reloading device and reading an LKJ local clock; The local agent and preprocessing module is used for carrying out preliminary verification, filtering and time stamping on the collected time data and packaging train running state information, wherein the train running state information comprises speed, running mode and position; The vehicle-mounted arbitration and strategy execution module integrates time source trust level rapid evaluation, time correction urgency calculation, historical health evaluation and strategy arbitration logic, completes dynamic trust level evaluation of available time sources, calculates time correction urgency, and operates a strategy arbitration algorithm according to an evaluation result, a train real-time state and preset safety rules.
9. The LKJ clock synchronization system based on multi-source reliability arbitration of claim 7, wherein the vehicle-ground cooperative communication subsystem is used for transmitting time data, state information and control instructions among vehicles, uploading time source original information, time source informativeness information, timing execution strategy information, timing urgency and historical health information after vehicle-mounted local processing to a ground system through a vehicle-ground wireless network, and forwarding the time source information and timing instruction information sent by the ground to LKJ equipment.
10. The LKJ clock synchronization system based on multi-source reliability arbitration of claim 7 wherein the ground decision support subsystem comprises a multi-source time pool management module, a timing arbitration and decision module, a human-machine interaction and operation terminal, and a history database and diagnosis module, wherein, The multi-source time pool management module is used for converging original time data and ground time reference data uploaded by a plurality of locomotives, and performing alignment and storage on the trust degree, the timing urgency degree and the historical health degree of each time source calculated by the vehicle; the timing arbitration and decision module is used for running a strategy arbitration algorithm and generating timing decisions; the man-machine interaction and operation and maintenance terminal is used for visually displaying clock states, time source trust cloud charts, timing alarms, strategy suggestions and manual confirmation interfaces of each locomotive to operation and maintenance personnel; The historical database and diagnosis module stores clock deviation, trust and timing event data with long period and is used for trend analysis, performance evaluation and fault root auxiliary diagnosis.

Description

LKJ clock synchronization method and system based on multisource reliability arbitration Technical Field The invention belongs to the technical field of train operation monitoring, and particularly relates to an LKJ clock synchronization method and system based on multisource reliability arbitration. Background The train operation monitoring and recording device (LKJ) is one of the core guarantee equipment for the railway driving safety of China, and the core functions of the device comprise train overspeed protection, driver driving assistance, operation state recording, cooperative control with an ATP system and the like. The accuracy of the calendar clock in the device directly determines the speed-distance calculation accuracy, the validity of temporary speed limit control, the time sequence authenticity of event records and the cooperative consistency of the time logic of train control systems such as ATP and the like. The accuracy of the time information directly relates to the time sequence accuracy of the driving control logic, the authenticity of the running record and the objectivity of accident tracing and responsibility definition. The existing LKJ system mainly adopts three technical schemes of BDS satellite timing, wireless reloading device timing and ground manual confirmation timing, wherein the three technical schemes are mutually split. BDS satellite timing is to calibrate LKJ host clock by using timing signals provided by Beidou satellite navigation system in China. The method has the advantages of authoritative time source, higher precision, independent controllability and no dependence on a ground communication network. However, the defect is also obvious that in the areas where satellite signals are blocked or interfered, such as tunnels, mountain areas, dense building groups and the like, time service signals are easy to lose or unstable, so that the time service function is intermittently disabled. The time correction of the wireless reloading device is based on an LKJ wireless reloading system, and the ground server corrects the vehicle-mounted LKJ clock through a Network Time Protocol (NTP) or directly downloading server time through a vehicle-ground wireless communication link. The scheme is convenient for centralized operation and maintenance management, but highly depends on the continuity and quality of the wireless communication link of the vehicle-ground, and in areas with network interruption, delay jitter or poor signals, the timing function cannot be normally executed. And (3) the ground manual confirmation timing step, namely introducing a ground manual confirmation link on the basis of BDS timing and wireless replacement timing, and determining whether to execute timing by an operation and maintenance personnel after comprehensively comparing multiple paths of time sources by a ground server. The scheme has higher safety, but has slow response speed, frequent manual intervention and is still limited by the quality of a communication link. These schemes have certain limitations in terms of reliability, precision, intelligence and adaptivity of timing functions, and are specifically expressed as follows: 1) Scheme mutual fracture lacks cooperative linkage mechanism At present, each timing scheme operates with independent logic, and a unified cooperative strategy and priority switching rule are not formed. Taking a typical scenario as an example, when a vehicle-mounted BDS signal is blocked and invalid and a vehicle-ground network is still available, BDS satellite timing cannot function, and meanwhile, if a wireless reloading device timing cannot be triggered due to operation condition limitation (such as unstable communication link signal), a system can not complete effective calibration within a timing window, so that timing opportunity is missed. 2) Timing criteria are fixed, and threshold setting lacks adaptivity The key timing threshold in the existing scheme is set based on experience or engineering default values, and the whole scheme has the characteristics of 'fixed threshold + static condition'. The setting is difficult to dynamically adjust aiming at different locomotive equipment states (such as crystal oscillator aging rate difference), running environments (such as unstable satellite signals caused by building or geographical environments) and communication quality changes (time delay, packet loss and link fluctuation), so that the application range and robustness of a timing strategy are limited. 3) Lack of characterization of time source quality and long-term health The current validity judgment of the time source mainly stays on the shallow conditions of available/unavailable, such as indexes of satellite quantity, connection state and the like. For the health states with more engineering significance such as long-term stability, abrupt jump, slow precision drift and the like of a time source, the lack of a continuous monitoring and quantitative evaluation