| Urban transport system is a dynamic and complex system. In the construction process, timely and effective traffic information services are needed to improve the quality of traffic management and control, which plays an important role in improving utilization of the urban road network, alleviating urban road congestion and enhancing the city's comprehensive strength. A good traffic information service needs to use efficient traffic information collection method and provide effective traffic information to user timely. So accurate vehicle positioning, correct map matching,effective traffic information parameter estimation and timely dissemination of information are essential.With the vigorous development of Chinese self-developed Beidou Navigation System, Beidou technology will be widely used in the field of intelligent transportation, so information service technology based on Beidou Navigation System has a significant application. At present, the Beidou Navigation System for traffic information services technology is still relatively scarce. There is a huge development space. Because the satellite navigation system has a certain degree of inherent defects,so how precisely obtain vehicle position data and map-matching data should be studied intensively. Therefore, from the view of improving the quality of information service and aiming at the deficiency of existing research, combination vehicle positioning technology, map matching technology, travel time estimation techniques and information dissemination technology are researched based on Beidou Satellite Navigation System. Research achievements made in the paper includes the following four aspects.1?For vehicle positioning technology, the information fusion algorithm of the BD/INS Integration based on the improved federated Kalman filter is proposed.According to the different working conditions of the system, the algorithm adopts to different information distribution principle. It can effectively reduce the error or failure affects during operation of the Beidou system and the INS system. It improves the positioning accuracy, and ensures the stability and reliability of the positioning results. Finally the accuracy of the algorithm was verified through the actual carexperiment.2?For map matching technology, a map matching algorithm based on improved fuzzy logic and information feedback is proposed for the Beidou data with a large number of low frequency in the center. The algorithm includes single match and delay matching. It effectively solves the problem that the central end of Beidou floating car data quantity is big and the problem of long interval sampling. The algorithm not only ensures the center map matching real-time requirements but also improves the matching accuracy and effectively reduce the error matching phenomenon. Finally,the effectiveness of the proposed algorithm is verified by the actual data of the Beidou system floating car.3?For travel time estimation techniques, the Beidou floating car data are analyzed firstly. Then the error reasons about the existing algorithms of travel time estimation are pointed out. In order to reduce the impact of these errors, five correction methods of travel time estimation error correction are constructed. Finally,the real road section is selected to verify, and the method is compared with the license plate recognition method. The effectiveness of the method is verified.4?For information dissemination technology, based on the research of the two-way communication technology of the Beidou short message, the demand of the emergency traffic information is analyzed, and the solution of the key technology in the process of information release is put forward. The Beidou short message for traffic incident under the city traffic information is applied. Based on the traffic incident, the spatial and temporal cooperative distribution strategy of the Beidou traffic information is proposed. Finally the rationality and validity of this method.are verified through the field verification. |
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