Study On Occupancy Inspection Subsystem Of Modern Tram

To travel with a fast and convenient way is one of the important symbols of modern society.In recent years, subway, light rail, bus rapid transit(BRT) and other modern public transport modes have been widely put into use in domestic cities to meet the needs of people's travel demands. Besides, modern tram is re-entered into the modern urban public transport system because of its energy conservation and environment protection, convenient, safe, efficient and other advantages, and usher in the development boom. However, because of the complexity and particularity of urban road, the technology of occupancy inspection and positioning used in railway and metro system can't be directly applied to the modern tram system, so it has become a difficult and a key problem in the modern tram signal control system. Therefore, it is significant to develop a set of intelligent and suitable signal control system for modern tram,which has independent property rights, economic, environmental protection and high efficiency. According to the characteristics of modern tram, we make corresponding improvements on occupancy inspection technology and vehicle positioning technology that have already existing. We use vehicle detector and satellite positioning system to achieve the accurate occupancy inspection and the position, provide reliable guarantee to safe and efficient operation of the tram.Firstly, on the study of occupancy inspection, we use loop vehicle detector on the entrance to achieve reliable occupancy inspection when the tram drives to the rail switch. We designed the hardware circuit and the software code, used dual channel detection technology in the design of hardware, optimized frequency acquisition and filtering function in the design of software. With these efforts, we improve the sensitivity, accuracy and stability of the detector. The processed occupancy information transferred to the control system through the CAN communication circuit, so that the function of occupancy inspection subsystem is achieved. Secondly, on the study of continuous positioning, we use GPS to position the tram when it drives on the track. The vehicle terminal collects and transfers the information to the server through GPRS wireless communication technology in real time, so the tram can make communication with monitoring system. We designed software of the monitoring system and the communication service, used GIS technology to make the position and trail of the tram can be displayed on the digital map. By these methods, we can get real time occupancy information of related roads. Finally, in order to improve the matching accuracy of the tram's trail and the actual road, we used map matching algorithm in the design of GIS monitoring system. With the combination of geometric matching algorithm and pattern recognition algorithm, we proposed a comprehensive map matching algorithm. By using this algorithm,the position of the tram can be displayed more accurately on digital map and the matching tothe road can be more accurate. In addition, on the rail switch we use vehicle detector to achieve reliable occupancy inspection, on the one hand, the switch control system can get accurate occupancy information, on the other hand, it can be regard as an additional position mode when the system can't get the position information because of the poor GPS signal.