Research And Implementation On The Data Safety Of ATS System

As a subsystem of CBTC (Communications-Based Train Control), ATS (Automatic Train Supervision) system is responsible for the command and supervision of train operation, and it is essential to ensure the improvement of the train operation efficiency. Database is an important component of ATS system, which plays a key role in the safe operation of ATS. In order to provide various subsystems real-time effective, safe and reliable information, how to ensure the data safety is crucial.At present, in the theory research of rail transit system mostly research is in a sporadic state, which can not meet the requirements of the development of rail transportation. It is a trend to make full use of existing science and technology, especially database technology to build urban rail data safety system. Combining the characteristics of ATS systems, the paper carrier out all-round research of the data safety at all stages of the system data, including the design of data structure, the source, the use and the maintenance of the data.First of all, the paper introduces the situation and function of database in ATS system and analysis safety requirements of the ATS system, such as data consistency. Then the paper analyses the data types and functions of ATS system, including linefield data, timetable data, device data and so on.Secondly, the paper brings forward the module of data management in the ATS system and introduces the design of data management module and its components and structure. Then the paper studies the safety policy of data management module, including the ATS system data access control, data download strategy and audit strategy, data availability design and man-machine interface design. Based on the research, the paper does the modeling for data management module using Colored Petri Net (CPN) and modeling tool CPN Tools and validates the properties of data management module. The module meets the demands and requirements of real-time and correctness, which proves that the model meets the demand of data safety in the system.Finally, the paper implements the system according to safety policy of data management module in the ATS system, in which the system allocates each system user the appropriate role so that the user could only operate limited system data. And it effectively prevents users from the misoperation of the database data. Audit mechanisms play a major user of the system, which provides a monitoring to ensure the data safety of the system from another view. The introduction of transaction mechanisms and comparison of the data version resolve the problem of data inconsistencies which are caused by the data redundancy and concurrency control.The data management module that is implemented based on the research of the paper has been successfully applied in ATS system of Dalian 3rd Line, and it solves thesafety problems effectively in the project.