| 摘要 |
PURPOSE:To ensure the arrival to the destination, by drawing and displaying the shortest distance to the destinating from the present position, based on a plurality of intersections and the route between the intersections, which are obtained by map data. CONSTITUTION:A speed sensor 10 detects the running speed of a vehicle and generates a series of speed pulses having a frequency that is proportional to the running speed. An azimuth sensor 20 detects the advancing azimuth of the vehicle with the true north as a reference in relation to the horizontal component direction of geomagnetism, and generates an azimuth signal. Road map data corresponding to a plurality of road maps are stored in cassette tape in advance. An external input device 30 searches and reads the road map data corresponding to the desired road map from the cassette tape under the control of a microcomputer 50 and generates a map data signal. |
