| 摘要 |
PURPOSE:To urge the calibration of position data by alarming the generation of an error, by judging and displaying the generation of the error of estimated position data on the basis of the continuous distance of the non-coincidence of an estimated position with the present position on a road. CONSTITUTION:The present point is inputted by an operating part 2 to be set initially and a vehicle is allowed to run while a distance signal and an azimuth signal are inputted at every predetermined time from a running distance detection part and a running direction detecting part 4 in the first estimated position calculation part 6 to calculate an estimated position on the basis of dead reckoning. On the basis of the difference between this data and the road data stored in a road map memory 5, a road position is detected by the second estimated position calculating part 6'. It is judged whether this difference is within a predetermined threshold value and the data of the memory 5 or the data of the estimated position is displayed on a display 1 as the present position. When said difference is the threshold value or more, the running distance in a free mode state is measured by a free mode measuring part 7 and, when said distance reaches a predetermined distance, the generation of an error is judged by an error generation discriminating part 8 and the display signal of a running locus is formed by the display signal forming part 9 and displayed on the display to be confirmed by a driver. |
