Research On Core Technologies Of Mobile Navigation System

With the development of GPS technology and the popularity of embedded devices, mobile navigation systems are used more and more frequently. The mobile navigation system development is related to GIS, GPS, embedded system, mobile communication technologies, etc. In this paper, we designed the structure of a navigation system and did research on several core technologies, including the structure and management of geography data, route planning algorithm and the design of a mobile navigation server.In this paper, we divided our system into eight main modules and analyzed each of them in order to implement all system functions. We did research on the multilevel structure and management of geography data and discuss the strategies which affect system efficiency the most, including data indexing and data compression. We did research on Dijkstra algorithm and A* algorithm. Based on hierarchical route planning algorithm, we proposed an improved algorithm which is suitable for embedded system. By importing functional road class information into every road hierarchy and dynamically switching road hierarchy, this algorithm decreases the computing time of hierarchical route planning algorithm. The number of road hierarchy can be reduced, so the amount of data can be compressed accordingly. We introduce some concepts into the algorithm such as "road class upgrading distance" and "road class lagging function", and discuss them afterward. Experiment result shows that the proposed algorithm can satisfy the need of efficient route planning in embedded system. In order to contain more data and to gain more computing power, we designed a remote server, distributed its modules into several levels and designed an efficient strategy for map data buffering.On the basis of summing up, we discussed the potential improvements on mobile navigation system at the end of this paper.