| 摘要 |
PURPOSE:To enable the position of an automobile to be displayed by one line segment or a triangular area by displaying the line segment or a triangle or error having one or three selected source stations as origins when radio wave is received from two or less or three or more source stations, respectively. CONSTITUTION:A navigation system 1 is composed of a direction, intensity and station detector 2, a map memory 3, an operating switch 4, a controller 5 and a CRT display unit 6. Receiving radio wave, the detector 2 outputs the identification code of a source station and the arriving direction and radio field intensity of the radio wave to a controller 5. When the radio wave is received from three or more source stations, the controller 5 selects three source stations D1-D3 and forms an area U based on a triangle of error having the source stations D1-D3 as origins by line segments l1-l3 extending in the reverse directions to the arriving directions of the radio waves. When the radio wave is received from one or two stations, one line segment l' is obtained for one source station with the most strong radio field intensity. The obtained area U or line segment l' is superposed on a stored (3) road map and displayed on the display unit 6 whereby the position of an automobile is read. |
