The Reserch Of The Map Database Hierarchical Indexing Mechanism Based On Navigation Path Optimization

As the application of embedded navigation system becomes increasingly widespread, people are using the embedded navigation systems are also increasingly strong demand for the product, its market is expanding. Along with China's own satellite navigation system developed by compass has entered a new stage of development and construction, the Chinese autonomous navigation system is also more mature, and therefore the value of the embedded navigation system is also expanding.Path planning is an important part of the embedded navigation system, its road network data and navigation path searching algorithm is the selection efficiency and optimality of the two characteristics. As the complexity of the current road network continues to expand and the emergence of three-dimensional electronic map, directly led to qualitative change in the amount of data path planning,and because of qualitative change in the amount of data,the data are difficult to be read from external memory into memory with all the data for path planning service, this will also lead to the search path data retrieval algorithms in external memory media sites (such as SD card).The past data retrieval is generally assumed to be planned in memory is considered as a whole, which gives the traditional planning algorithms and the data retrieval algorithms to bring the problems of unsuitable and low efficiency. Therefore,under the requirements of new path data index storage,this paper stand the point of the path of data storage and search premises, the hierarchical index of the research is to quickly retrieve the data path of data storage as the focus of this article.Based on the above issues, this research for the external memory and navigation path optimization based on the hierarchical map database indexing mechanism, focusing on the following aspects:(1) First,massive digital map road network data by organized in the SD card,and the new efficient HRN(Hierarchical road network)model is researched for the fast retrieval of data path planning,and optimize the hierarchical topology further.(2) Based on the HRN model,research the new effective organization for the lowest layers of mapping data with other entities to achieve the effective organization of data storage in the SD card and easy path of tightening the purpose of data retrieval.(3) To limit the external memory amount of data in the SD card loaded is the prerequisite for the efficiency of path planning search algorithm,this paper study the hierarchical index of data path planning based on the G-SDBCScan (Geospatial Database Convergence Scan) to meet their data storage and search site changes.(4) The application of the embedded databse in a hierarchical storage design and data retrieval to validate the adaptive of hierarchical indexing mechanismAt last,this paper take an embedded Linux operating system and QT / Embeded as research and experiment platform, through the use of navigation optimization algorithm is a static path planning massive data and verify the external memory path data for the hierarchical mass index of the effectiveness of the mechanism.