Design And Implement Of Train Approaching Alarm System Based On LoRa

In railway safety protection,accidents such as casualties,equipment damage,and withdrawal of train often occur,because construction workers do not receive the train approaching information in time and cannot evacuate quickly.Adopting a stable and reliable train approaching alarm system to ensure personnel safety and traffic safety is one of the urgent needs of railway departments.In view of the above problems and extensive research on railway safety protection,this thesis designs a train approaching alarm system based on LoRa.The system mainly plays a supporting role in railway safety protection operations.When the train reaches the protection range covered by the system,the system broadcasts the train location information.After receiving the alarm information of the train,the alarm terminal will remind all persons optionally by voice,vibration,light,etc.,so that the guards can know the location of nearby trains in time and get off the road in time.The system has the characteristics of high stability,low power consumption,strong scalability,and convenient construction.The thesis completes the system architecture design,and divides the system into four layers of perception layer,network layer,field application layer and background application layer.The first three layers mainly work along the railway,and the background application layer is fixedly arranged in the work area or workshop of permanent way.The thesis completes the design of the system working method,divides the system working method into two states,hibernation state and working state,and introduces the system working method and the transition relationship between the two states in detail.The thesis takes the test location of Jigongshan Tunnel in Luohe District,Xinyang City as an example,and gives the layout and installation methods of the network layer nodes.Based on the introduction of system architecture design and system working methods,this thesis focuses on the hardware scheme design,protocol process design,and anti-interference design in the electrified railway environment.The section of hardware scheme design describes the systematic design of the hardware circuit of the network layer and the field application layer in detail.Based on that the hardware circuit block diagram is given,the circuit schematic design of each functional module and the PCB design of each circuit system are given.The section of protocol process design describes in detail the protocol processes contained in the network layer and the field application layer,including the ad hoc network protocol used in the networklayer,the field data upload protocol,by which the network layer upload data to the background application layer,the alarm distance control protocol,by which the alarm terminal control the distance from the alarm start point to the constructors,and the alarm terminal data upload protocol,by which the alarm terminal upload the alarm terminal data to the background application layer.The section of anti-interference design in the electrified railway environment analyzes the electromagnetic interference,electric field interference and environmental interference along the railway in detail,and designs external interface module circuits and software mechanisms with anti-interference ability.At the end of the thesis,the system test and analysis of test data are completed.The test content mainly includes hardware test,power consumption test and field test.Through multiple test content and analysis of test data,it is verified that the system can provide a high-reliability function,and the expected results are obtained.