Research On Redundancy-based Integrated Train Positioning Method

The train operation control system supervises,controls and adjusts the running speed and braking mode of the train according to the objective conditions and actual conditions of the train running on the line,which ensures the safe and fast running of the train.Automatic train positioning technology is essential for train control system to achieve train interval control and speed control.The existing CTCS-3 train control system is based on the wheel speed sensors and transponders toward the direction of autonomous train positioning.The next generation train control system for the positioning of the train positioning puts forward requests of autonomous vehicles,high positioning reliability,high availability.The combined positioning method based on multi-sensor fusion makes the high-reliable on-board train positioning possible.The sensors play their respective advantages in a variety of complex scenarios,and can improve the positioning accuracy,continuous and reliable train positioning function.In order to further meet the requirements of high reliability and high availability in train operation,the positioning unit design based on redundant voting structure needs to be considered.The thesis studies the structure of train positioning unit based on redundancy technology,analyzes and verifies the reliability and availability of the redundant positioning structure.The main work of the thesis is as follows:the structural design and optimization of the train redundant positioning unit,the reliability and usability analysis of the redundant positioning unit and usability verification based on measured data.(1)The thesis classifies the failure types of the positioning sensors based on the reliability theory researching on the failure characteristics of GNSS sensors and ODO sensors.Then,the self-checking method of positioning sensor on soft fault and the voting detection method on hard fault to improve the reliability of train combination positioning is designed.(2)The thesis designs the structure of train positioning units based on redundancy technology,combined with diagnosis and voting methods of the hard fault and soft fault in GNSS and ODO sensors,and then compares the reliability of different redundant positioning structures by Reliability Block Diagram.In order to solve the redundancy design problems with optimized reliability under the restricted constraints,the thesis designs improving 2ooN redundancy structure and find the optimal solution of the redundant allocation model.(3)The thesis estimates the soft failure rate of GNSS and ODO units based the collected data of on-board positioning unit on Qinghai-Tibet line,and estimates the availability performance of designed redundant positioning unit based on Markov Chain.The results show that 2oo3 positioning unit has better availability than 2oo2 positioning unit considering the soft fault.The experimental results show that the designed 2oo3 redundant system has higher reliability,availability and positioning accuracy based on actual measured data.