Car Navigation Systems And Their Common Technology Platform

With the development of the technology of microelectronics, computer, space and mapping, VLS (Vehicle Location System) make a rapid progress. Today, by combining GPS with other technology (for example a real-time map-matching algorithm) VLS can get an exact position when the car runs along the street. Requirement of much Vehicle Location System is same .So it's essential to build a universal platform. The building of an universal platform is one of nine key technological problem in ITS (Intelligent Transportation System).The paper is based on the eGps Vehicle Location System and the CCsuMap component that I developed as a main developer.VLS is a kind of ITS. It also is an integrated system that combines effectively GPS, GIS and Computer together.The paper systemically states the technology of position and the theory of GIS that are used in VLS. According to the practical problem, absolute position is adopted as the primary technology of position in the CCsuMap component .At the same time, compared with the raster data model, the data of map is organized by vector data model.In fact, the success of the VLS depends on the precision of position. In VLS, the data are composed of static data (electronic map) and dynamic data (position data). The paper gives some methods to better the precision of the VLS by analyzing how to get the data. At last, the paper gives a real-time map-matching algorithm to improve the precision of the system.The paper introduces the theory that is used to build a universal platform for VLS. The CCsuMap can be partitioned into three modules that are data organizing module of electronic map, communication module and algorithm module. The data-organizing module is the primary module. The map in the CCsuMap is designed by OO (Object Oriented) method that is an effective method .At the same time, the CCsuMap has a GPSCom communication control to solve the communication problem between the GPS device and the computer.Label is an important part of the electronic map .How to annotate the label directly decides the quality of the electronic map. The paper discusses the policies of annotating label. Getting the shortest way between the two positions is an important function in VLS. The paper betters the Classic Dijkstra algorithm according to the actual need in VLS. At last, the CCsuMap adopt STL (Standard Template Library) asits primary library that improve the robustness and reliability of system.