On The Positioning Technology For Vehicle Navigation System

Intelligent Vehicle Positioning and Navigation System is a typical representation of new type electronic productions on vehicle. Its application greatly alleviated the trouble of city transportation system and improved the efficiency of road. In the near 21st century, intelligent and information technology inevitably has applied to transportation system and tools. Faced to this development, Intelligent Vehicle Positioning and Navigation System will undoubtedly provide with a fine future applications.The vehicle navigation system can mainly be classified into two kinds, one is independent navigation system and the other is centre-decided navigation system. In independent navigation system, the functions of position and path-planning are all realized in the vehicle terminal, and in central-decided navigation system, some functions (such as path-planning and navigation map) must be realized through the communication network. Compared to independent navigation system, in central- decided navigation system, the vehicle terminal requires low hardware and its cost is low. Central-decided navigation system also has some other advantages, it is easy to provide added service, and the path-planning is easy to add dynamic traffic information. Due to these advantages, central-decided navigation system has broad application prospects in the popularization course of the vehicle navigation system. Moreover, the central-decided navigation system is suitable for transportation trade, as it is very apt to realize fleet management.This paper researches the positioning technology of the vehicle navigation system. There are four parts. The position data processing of the vehicle terminal; the design of quick road choice method in map matching; the map matching algorithm and implement; the position algorithm of the vehicle terminal in the central-decided navigation system. The main research contentsare as follows:1.The position data processing of the vehicle terminal is studied in this paper. This paper studies the GPS positioning modes in the vehicle navigation system, and analyzes the main errors that Influence the positioning accuracy. Then this paper introduces the basic principle of Dead Reckoning system and analyzes the errors of a few adoptable DR sensors. At the same time, an Integrated Kalman Filter mechanism to realize the optimal synthesis of GPS/DR integrated navigation system is designed. And its algorithm is presented. The test results show that the positioning accuracy of the GPS/DR integrated navigation system can be greatly improved by using the adaptive Integrated Kalman Filter.2.The design of quick road choice method in map matching is studied in this paper. According to the traditional plane grid partition structure of the map matching algorithm for vehicle positioning system, a novel quick choice method for roads to be matched was presented based on the network structure partition of a two-level overlapping road. The principle of the algorithm was analyzed in detail. The technology of road information picking and storing relevant to the algorithm was investigated. Experimental results show that the data of spatial data index table are reduced effectively and the search efficiency is guaranteed in map matching process by this algorithm. The conflict occurred due to grid size among data quantity in index table, search time-consuming and data validity was solved. As a result, the simple, convenient and clear road choice process is better than traditional method in map matching calculation.3.The map matching algorithm and implement is studied in this paper. A dynamic map-matching method for adaptability is presented by analyzing the change in requirement of map-matching performance in the process of vehicular navigation. The method is provided with the capability of identifying three different states (selecting a road initially, selecting a follow-up road and positioning in the known road) and determining corresponding algorithms of map-matching dynamically. In order to satisfy the needs of map-matching in different states, some algorithms are developed respectively. Simulated experiments show that the method implements more timely map-matching successfully.4.The position algorithm of the vehicle terminal in the central-decided navigation system is researched in this paper. According to the characteristic ofthe central-decided navigation system, the position algorithm is researched. The position algorithm of the vehicle terminal is partitioned two sections, initialization position and process position. This paper introduces initial road network and its building method, data structure. Simulated experiments show that the method implement.Although this paper has studied on some problems and some key technologies in the positioning technology of vehicle navigation system, it's far from enough and there are still many problems which are requested deeply research and solution. And some algorithms need to be made perfect. However, due to the widespread application prospect of the central-decided vehicle navigation system, the theory and the practice research in this paper will be contributed to the future work.