MAP DISTRIBUTION SYSTEM USING SCRIPT DIFFERENCE DATA

When the world's first commercial GPS (Global Positioning System) car navigation system was put on the market in 1990, the system only had functions for vehicle location detection and map display. Today, 10 years after the first system, the basic functions have come to include route guidance by intersection turn maps with voice guidance and traveler information using the VICS (Vehicle Information and Communication System) service. In recent years, wireless data communications has become popular due to the wide use of cellular phones, and car navigation systems able to use wireless data communication functions have been developed. With these car navigation systems, users can obtain available up-to-date data, generally POI (Point Of Interests) data, by wireless communications. As car navigation systems continue to become more advanced, users will come to want up-to-date map data more and more to use their car navigation systems at full value. This problem can be solved by the wireless distribution of up-to-date map data. Due to the poor state of the present wireless communications band, however, map data of a huge data size cannot be distributed. To address this problem, the authors consider distributing the differences - between the disc data stored in the vehicle and the up-to-date map data managed at a distribution center - to the in-vehicle navigation system. They further consider using script data to enable the navigation system to restructure the up-to-date map data. They developed a map distribution prototype system following the above considerations, and confirmed the effectiveness of the map distribution system in providing up-to-date map data in a vehicle navigation system.