Research And Realization Of Automobile Navigation Engine Technology

Automobile navigation engine, should realize the functions such as map display, route plan, voice guidance and retrievals of points of interest and so on, the quality of navigation engine directly determines the whole performance of navigation products. The development of domestic automobile navigation system is mostly based on the second platform, only those interfaces or functions belong to the second platform can be used, this has played a great role on the autonomy of the development and improvement of engine functions. In response to this limitation, this paper suggested realize the core functions of engine through independent development mode. The structure and functions designed by this way tend to be more reasonable and perfect.Considering the complexities of road conditions and traffic rules, this paper used cross road model to describe the actual crossing intersections, established the road network data model according to node-link relation based on multilayer grid index. The format of map files designed on the basis of new engine framework mentioned above, has greatly improved the speed of map data reading.The speed of map display influences the user experience directly, in view of problems, like limited resources of embedded devices and slow speed of map display, this paper suggested divide the whole map data into background data, road data and data of points of interest, and construct indexes according to its hierarchical block, so maps of different scales match along with different map data files, by this we can quickly locate the data needed. At the same time, divided the geographical elements into different levels, only displayed the corresponding class elements in light of the current scale, this reduced data redundancy, speeded up the speed of the map display, enhanced user experience.Route plan is the core issue of antomobile navigation. In actual navigation, traffic restrictions of turns and the delays at the intersections will make the result of route plan inaccurate or even wrong. This paper expressed the traffic redirection restrictions by establishing the table of redirection restrictions with the dual-graph, could match the actual route plan better. In view of the slow speed of navigation instruments, adopted bi-directional heuristic search algorithm with the combination of layered strategy, search from the start and the end at the same time respectively, and improved the structure of A algorithm and the method to expand node. The results of actual runs showed that using this algorithm, could greatly reduce the number of sections involved in the path calculation, save storage space and raise the efficiency of route plan.Finally, this paper used certain part of Wuhan urban road network data as the study object and maked empirical research and testing for major work. Theoretical analysis and the actual operating results showed that the major work this paper had done overcomed the insufficiency during current development process of navigation engine, thus greatly enhanced the speed of map display, and provided effective route plan under the circumstances of traffic redirection restrictions.