| 摘要 |
PURPOSE:To always enable accurate detection of the current position, by comparing a moving distance obtained with a Loran C receiver with that obtained with an autonomous navigator to utilize strong points of radio navigation and autonomous navigation methods, eliminating short comings thereof. CONSTITUTION:A microcomputer 2 reads a position data Pc from a Loran C receiver 4. Then, the computer 2 calculates a moving distance from a difference between the present and preceding data Pc. Then, a difference DELTAL is calculated between the moving distance thus obtained and that measured with an autonomous navigator 8. Then, the difference DELTAL is checked whether to be smaller than a specified reference value epsilon or not. When the results of the checking is DELTAL<=epsilon, the data Pc can be determined to be a relatively correct value and hence, the data Pc is provided to the device 8 as initial position data to correct the position. On the other hand, when not DELTAL<=epsilon, the data is supposed to be a false position data due to a reflected radio wave and ignored. Thus, the position data by the device 8 is adopted as present position of an automobile. |
