Train Auxiliary Anti-collision Early-warning System Based On UWB Ranging And Positioning

Generally,ATP(Automatic Train Protection)ensures the safe operation of the train,which is the subsystem of ATC(automatic train control),and also the key equipment to ensure the safe operation of the train and realize the overspeed protection.However,in recent years,due to the failure of ATP system,many rear end collision accidents have occurred on urban rail trains running in China,resulting in casualties and economic losses.Based on the above considerations,this paper studies a train auxiliary anticollision early warning system,which is suitable for urban rail transit operation conditions and independent of ATP system,as the backup of ATP anti-collision function,to ensure the safe operation of metro trains.The main work of this paper is as follows:(1)This paper studies and designs a train aided anti-collision early warning system based on UWB(ultra wide band)wireless ranging and positioning,analyzes and summarizes the advantages and disadvantages of several wireless ranging and positioning technologies for urban rail transit operation lines,and presents a UWB Wireless ranging and positioning method suitable for urban rail transit operation conditions.In the actual operation of urban rail trains,in order to ensure the safety of train operation,it is necessary to establish communication with adjacent trains and accurately measure the interval distance.Then the influence of external power amplifier,antenna gain and signal frequency on distance is analyzed theoretically.This paper analyzes the ranging principle of unilateral two-way ranging and bilateral two-way ranging,and compares the ranging accuracy.(2)In order to realize the ranging function of the system,the hardware and software of the ranging terminal are designed.The hardware design includes power supply unit,communication unit and main control unit.The software design includes the sending and receiving of data frame,the working principle of base station mode and label mode.(3)By comparing the common toa(time of arrival)and TDOA(time difference of arrival)positioning algorithms in the field of wireless positioning,the Chan algorithm in TDOA positioning is selected to simulate and analyze the actual running track of the train.In order to obtain the track position of the train in operation,a train track determination system composed of UWB positioning base station,positioning server,transfer server,background management terminal and time synchronizer is presented.In order to realize the early warning function of the system for the adjacent trains on the same line,the working principle of the system control module is analyzed,and the early warning display terminal is designed to provide necessary information and alarm prompt to the train driver.(4)The function test of Train Auxiliary anti-collision early warning system is designed.Function test includes static test and dynamic test.The static test tests the farthest communication distance and ranging accuracy of the ranging terminal,and the safety warning function and communication stability of the dynamic test and test system.The experimental results show that the system meets the main functional requirements,and provides the direction and ideas for the future development of the train auxiliary anti-collision early warning system.