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Research paper : Integrated development of automotive navigation and route guidance system (H. Ito )−165−Synthesiology - English edition Vol.4 No.3 (2012) 2.3.2 Turning point of map database: Use of drive controlThis is the application of map data to driving. Of the roadmap data, the road information such as incline and curves are used to automatically conduct shift up/down of automatic transmission, speed control, and suspension tuning, and these are expected to be useful for safe driving. Although some cars already possess the shift-down function of automatic transmission before a curve, such application may determine the information to be included in the next-generation map information, and therefore, may be a major issue in the future. 2.3.3 Creation of new servicesTelematicsNote 12) is becoming widespread. This is a service provided by the car manufacturer to its customer to aid driving by exchanging information such as traffic jams through dialog on the telephone or interactive communication. The emergency communication service that provides rescue response in case of accidents and breakdowns is currently in operation.3 Changes in the technology3.1 Navigation technology: Position identification technology as a core technologyAs mentioned in subchapter 2.1, car navigation started with the application of electronics to the compass. Since electronic data for bearings were necessary for dead reckoning, the geomagnetic sensor was employed. Although geomagnetism was a small value around 3×104 nT, its disadvantages were increased errors due to the magnetization of the vehicle body, power lines, railroads, and mountains. One of the causes of the body magnetization was the electric current in the overhead wires while driving through a railway crossing, in addition to the partial magnetization that occurred when the iron material is pressed in the pressing process during automobile production. Also, one of the characteristics of geomagnetism is that the magnetic pole and the true poles of the earth do not match, and it is usable only with limited precision in countries with small land area like Japan and where the declination fits within approximately 5 to 9 degrees west. In countries like the United States, the distance between the east and west coasts is so large that the declination is too large to be usable. Therefore, when introducing the electronic compass, its use was limited for use in Japan. The demagnetization device for the whole automobile was created as a measure against magnetization during production, and the completed products were demagnetized. To continuously check the magnetization accumulated by driving, the car was rotated 360 degrees and the geomagnetic sensor output was electronically corrected.By estimating the current position (dead reckoning) by calculating the travel distance and speed (from vehicle speed sensor for speedometer; later from wheel rotation sensors) and bearing data (electronic compass), and by calculating and displaying the distance and bearing to the destination, the NAVICOM and then the early navigation[3] were realized. On the other hand, the Electro Gyrocator obtained the changes in azimuth using the gas rate gyroscope, but later this was downsized and the product evolved by using on-board optical fiber gyroscope and vibratory gyroscope[2].The situation improved when it became possible to continuously receive the current position by using the GPS of the American military satellites. The early GPS for nonmilitary use had poor accuracy of about 100 m, and reception was cut off in some places such as the shadows of buildings, underground, and tunnels. The current position was estimated using the GPS data and map matching. However, there were road structures that caused errors such as the overlapping layer of regular roads and highways. Therefore, the navigation was usually corrected by the speed and distance signals built into the automobiles, the detection of rotational difference of the left and right wheels, and the acceleration sensors and gyroscope built in the device. The differential GPS system that corrected the GPS data using fixed (broadcasting) stations with known positions was introduced, but this was terminated as the GPS increased in accuracy. In the future, the position precision is expected to improve through the GPS data supplementation by the quasi-zenith satellite Michibiki that is being developed in Japan. 3.2 Roadmap database: Core technology 2 – placing the car position onto the mapThe second technological development was the development of the roadmap database. The database is the data for drawing the map that serves as the interface for the user, and for defining the road network. The network is expressed by the link (the road) and the node (intersection), and is used for route finding, required time calculation, traffic jam information processing, and others. There are various levels of roads from community roads to highways, and different people are often in charge of management, and considerable cost is required for the database creation as well as its update and correction. Therefore, while the databases were started by individual manufacturers, the Naviken (currently, the Navigation System Researchers’ Association) and the Japan Digital Road Map Association were established to standardize the format, data, and registration method. Later, the Japanese car manufacturers, navigation manufacturers, and map companies created the map data for navigation known as the KIWI format. This was standardized as JIS D 0810, and later as ISO/TSNote 13) 20452 at the ISO/TC204/WGNote 14)3 (see subchapter 4.1 for ISO/TC204). From the beginning, there were arguments that it was unnecessary to include the map data for remote areas where no one would go, and the mechanism for providing the necessary map data by telecommunication, for example iFormat, was introduced. The GISNote 15) is being researched mainly by the Geographical Survey Institute of Japan, Ministry of Land,

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