Safe Information Supervision System Of Train Movement Based On GPS

Safe information supervision system of train running synthesizes Global Positioning System and Geographic Information System to monitor the safety of trains. It improves the efficiency of railway transportation and is fit for low density railway lines such as Qinghai-Tibet railway.Based on the introduction of the key technologies which are applied to the system, this thesis investigates the design of Geo-database and Map-Matching algorithm and discusses the implementation of the system software. Considering the characteristics of railway field tasks, two display modes, named common digital map and track configuration diagram, are used in the system. The former can look over all trains and geographic information of the segments they runs on. The latter can demonstrate the occupation state of whole station in a style which the railway professionals are familiar with. Geo-database model is designed on the principles of simpleness, practicability and hierarchy. Based on the structure of Geo-database and the assumption that the train always runs on a foreseeable track, the paper designs a dedicated Map-Matching algorithm which is based on railway's one dimension model. The running process of the train is divided into four states: candidate segments are searched and selected based on the topology of tracks; in segments without switch, a point based map matching algorithm is employed; in segments with switch, a curve map matching algorithm is applied. Experimental results indicate that the strategy and algorithm gain not only the ability of real-time matching but also the accuracy of results in simple and complicated situations respectively. In the process of software development, Rational Rose is adopted as the modeling tool. Use case diagram is used in requirement analysis. Sequence diagram and collaboration diagram are used in analysis and design. In this way, complicated functions including map manipulation, track configuration diagram generation, train retracking and real-time monitoring are implemented.The system adopts VC++ and MapX which is a COM map component and its use in Qinghai-Tibet line demonstrates that it fulfills prospective requirements. The software is base on Object Oriented technology, hence, becomes more reusable and more extendable. Finally, several suggestions are put forward.