Analysis On Key Techniques In Traffic Information Collecting And Application Based On Probe Vehicle

Most of Chinese major cities have plunged into a situation of "providing ineffective transport supply for disordered transport demand," which leads to urban traffic problems, such as traffic congestion, traffic accidents and so on. Research on probe vehicle technology is being a significant field of intelligent transportation system (ITS) and is applied in the solutions of urban traffic problems in many metropolises.Firstly, this paper focuses on the current situation of probe vehicle information system and traffic state detection. Then the basic concepts and mechanism related to probe vehicle technology, and types divided by vehicle types and collecting equipments' mechanisms are presented. And its status in the area of information collection and applications are reasoned in terms of technical features, advantages and disadvantages.Secondly, based on the meaning of probe vehicle information system, the paper determines its main functions by analyzing users and their various needs of probe vehicle information systems and figures system's logical framework, data flow diagram, as well as the physical framework out from the view of system logic functions and data exchange.Thirdly, this thesis considers the principals and collecting errors of GPS receivers collecting probe vehicle data, defines the form of probe vehicle data, analyzes technical parameters of collecting equipments, chooses an optimized information encoded algorithm, builds transmission medium, format, and probe vehicle data transmission protocol (PVDTP) to ensure data security, and studies different information-sharing mechanisms of hierarchical sharing and homoclass sharing.Finally, a model and algorithm of traffic state detection with rough set theory is established, which chooses average speed, maximum speed and minimum speed as condition attributes, and traffic state as decision attribute. A case study is carried out to gain detection rules of traffic state based on the probe vehicle data, achieve road segment traffic state identification and provide certain theoretical reference.