| 摘要 |
PURPOSE: To display the present position of a vehicle accurately by correcting the calculated position of the vehicle, even though the width of the road, and the circular arc locus length at a turning might be different, by providing various means including a running distance detection on means, a bearing detection means, a position calculation means, and a position correction means. CONSTITUTION: The present position of a vehicle after left turn or right turn is corrected to the position adding a correction amount to the running distance of the vehicle after the vehicle passes the middle point of a circular arc form bending locus. This correction amount is found by subtracting the circular arc length of the bending locus from the middle point of the circular arc bending locus, to the terminal of the bending locus, from the distance between a check point (provided at the intersection of the center line of the road prior to the left turn or the right turn, and the center line of the road after the left turn or the right turn), and the crossing point of a perpendicular hung from the terminal of the circular arc bending locus to the center line after the left turn or the right turn, and the center line of the road after the left turn or the right turn. Consequently, regardless of the length of the width of the road before and after the left turn or the right turn, and regardless of the condition of varying the circular arc length of the bending locus by the bending angle, they are absorbed, and an accurate present position can be found. |
