| 摘要 |
PURPOSE:To detect the error of an azimuth sensor and to enhance reliability, by calculating the movement of the sun and that of the moon from present position data and present time data and displaying the apparent directions of both of the sun and the moon with respect to the advance direction of a vehicle. CONSTITUTION:A CPU 3 obtains detection data from both of an advance azimuth sensor 1 and a moving distance detection sensor 2 to calculate the present place and supplies a display signal, wherein the present place data is arranged on the map data obtained from a memory means 4, to a display apparatus 6 through a display control apparatus 5. Further, the CPU 3 receives not only data of a month, a day and a time from a clock 7 by the operation of an operation input means 9 but also the data relating to the movement of the sun and that of the moon from a movement data recording means 8 and displays the apparent positions of both of the sun and the moon at that time of the apparatus 6 in such a state that the advance direction of a vehicle is turned upwardly. A driver compares said display positions with the actual positions of the sun and the moon and detects the error of the azimuth sensor 1 and confirms that usual display coincides with the actual positions to make it possible to enhance the reliability of the whole of the apparatus. |
