Design And Key Technologies Of Bus Rapid Transit System Based On RFID

With the development of urbanization in China,more and more people enter urban life,which puts forware higher requirements for urban public traffic optimization.Bus Rapid Transit(BRT)is a new type of public transportation.It combines the advantages of low cost and flexible construction of common bus system,and the advantages of fast speed,safe and comfortable and high punctuality of rail transit.BRT’s high efficient is mainly reflected in priority of BRT bus.On the one hand,the BRT buses have their own special public transport routes;On the other hand,the BRT buses have priority to pass at the intersection.When the bus reaches intersection,by extending the green light time or shorten the red light time,we can shorten the waiting time of the bus.This priority is the key technology of BRT system.To achieve this priority,it is necessary to check the status of bus at the intersection.This paper proposed a BRT intersection detection scheme base on Radio Frequency Identification(RFID).This scheme installs tags in front of BRT bus,and installs readers above the traffic lights.Tags and readers communicates via 2.4GHz radio channel.By analyzing the Received Signal Strength Indicator(RSSI)and the Time of Flight(TOF)of the tag data received by the reader,the position information of the bus is calculated and the information of the bus is deduced based on the position information.After analyzed,if the bus needs priority,the reader sends the control information to the traffic light control system.This paper realizes the bus location scheme based on RSSI and TOF.RSSI utilizes the spatial fading characteristics of signals to perform distance mapping.However,because RSSI is very volatile in real environment,this paper proposes a non-decreasing filtering method to reduce the fluctuation of RSSI.The TOF utilizes the signal transmission time and signal speed for distance mapping.This paper realizes the distance measurement method based on round trip time to eliminate the influence of time synchronization.Based on the actual data characteristics,this paper proposes three data analysis methods based on linear fitting,Kalman filter and wareform matching.Among them,the wareform matching method is based on round-trip time data distribution characteristics.By extracting parameters of the wareform to map the distance,this method gets the best measurement error.The system runs well in actual test.It is a practical solution.