| With the vigorous development of communication systems and the improvement of urban intelligence,daily life has been correspondingly improved in all aspects.Traffic and travel are the things that everyone has to experience and face every day.In order to plan intra-city traffic and ease traffic pressure,more and more cities have begin to build transportation facilities such as metros and light rails.Although these means of transportation have brought great convenience to people’s travel,there are still many hidden dangers.The metro collisions in Hong Kong,Chongqing and other places have aroused heated discussion and concern among the public.Therefore,Metro anti-collision is a new topic that has emerged in recent years.How to safely schedule metro operations in underground areas with weak communication signals and complex environmental conditions to ensure the safety of passengers is a problem worthy studying and discussing.Firstly,in order to prevent metro collision accidents,it is very necessary to measure the dis-tance between the metros traveling on the same track.Secondly,real-time understanding of the metros operation network plays a vital role in preventing metro collision and protect-ing the order of rail transit.Thirdly,by accurately identifying changes in the direction of travel of the metro,it is beneficial to improve the communication efficiency of the metro in the process of ranging and networking.Therefore,the communication technology that can support high-precision ranging and dynamic,real-time networking is the core of this thesis.By consulting a large amount of information,it is known that Ultra-wideband(UWB)tech-nology is an emerging technology with extremely fast response speed,strong adaptability and high ranging accuracy.Many authors have limited their research to the positioning of indoor fixed nodes,and have not risen to the angle of moving node ranging.This thesis will innovatively start from the perspective of metro anti-collision and early warning,and apply UWB technology to urban rail transit networks.Firstly,this thesis uses time of flight(TOF)of signal algorithm to design double-sided two-way ranging(DS-TWR)system based on UWB technology.Secondly,by analyzing the characteristics of metro lines,traffic flow and UWB communication interference in Bei-jing and other places,this thesis designs the multi-node temporary self-assembly network communication protocol and system.Thirdly,this thesis will carry out the design of the anti-collision system hardware system based on STM32F103 processor,power supply,DWM1000 and other modules,and design the software system based on hardware modules,ranging al-gorithms,and network communication protocol.Finally,the prototype of the urban rail transit anti-collision system is designed based on the hardware system and software system.The innovations of this thesis are the distance measurement of the travelling metros,the recognition technology of travelling metro direction changing,and the technology of multi-node temporary self-assembly network.Aiming at the above innovations,this thesis will take the hardware circuit board as the core and take the ranging algorithm and networking protocol as the guide to carry out simulation testing.In general,this thesis will combine the software,hardware design and simulation test results with the actual environment,and develop the practical metro anti-collision prototype from the perspective of application design.Through the research on the key technologies of metro anti-collision system in this thesis,it is hoped that the stable operation of the urban metro network and the safety of passengers can be guaranteed.And it is also hope that this the-sis will make the contribution to the development of the temporary self-assembly network communication protocol. |
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