| 摘要 |
<p>A heading of a vehicle is detected by correcting an output of a gyro (1) with an offset value stored in an offset memory (11). A location detecting unit (3) estimates a current location of the vehicle by dead reckoning. When the vehicle continues to travel over a predetermined period of time, the headings of links before and after the current location of the vehicle are read out of a road map memory (5), and a difference between the two link headings is detected as a first heading change amount. The location detecting unit (3) accumulates outputs of the gyro (1) obtained during a period corresponding to the first heading change amount after the offset correction, and this accumulated value is detected as a second heading change amount. Based on the first and second heading change amounts, a new offset value is calculated. This new offset value is stored in the offset memory (11). <IMAGE></p> |
