Travel-time Collection Technology Research For Sections Of City Road Network Based On Individual 3GS Probe Vehicle

Travel-time of sections, as one of the most important traffic parameter data, has been highly valued by traffic management and control departments. So, how to dynamic, cheapness and efficient get the travel-time of every section using GPS/GIS/GPRS(3GS for short) integrated probe vehicle becomes a very important concern in modern urban city of traffic crowed management.In order to get travel-time using concept, first, we need clearly know the exactly borderline positions of section which would be reserarched, after that, could collect travel-time parameter data bases vehicle's in-time from the entrance and out-time after the exit. In area of urban city, it is a complex work to fix on borderline positions for sections of all kinds of roads. So, founding an abstractive sections-of model is the foundation and gurantee in Large-scale travel-time collection. Further, it also need use the longitiude, latitude coordinates and UTC information which got by the GPS receiver and combining 3GS probe vehicle's system functions, and development effective travel-time collection methodology, to make sure travel-time collection's success in large area urban road network.This paper describes a new and systemic method for sections travel-time collection by using 3GS probe vehicle. It solves sections-of for urban road network using virtual-node and real-node firstly, including related data organizing rules in GIS vector map which making sure the frame could be operated easily. With the demand of travel-time collection, also including GPS data quality and GIS map characters, this paper researches and improves map matching algorithm to improve GPS data accuracy. Based on the virtual-nodes and real-nodes, and improved GPS data(MMGPS), according to the concept of travel-time which defined by Traffic Engineering, the author devises time calculating method in real-nodes for GPS points, further more, also devises direction distinguishing method and real-node selecting method, to make sure travel-time dynamic and continous collection by 3GS probe vehicle in urban road networks. Sample periods of GPS, transmit periods of GPRS, and analysis periods for travel-time composes the last research concerns of this paper.By using real GPS data and GIS vector map, verifying the technology based on 3GS probe vehicle for sections travel-time collection is right. Because the 3GS probe vehicle could work individually, if one vehicle could make true travel-time collection, it also make all of them do as itself.