| 摘要 |
PURPOSE:To make it possible to prevent correction errors due to change in lanes and passing and effects due to the disturbance in geomagnetism by specify ing the most frequency bearing at a specified distance as the bearing of a sensor at this time point when the reference bearing of a bearing sensor is corrected. CONSTITUTION:A beacon receiver 22, a geomagnetism sensor 24 as a sensor, a gyroscope 25 and a vehicle speed sensor 26 are connected to a controller 28 to which a storage device 27 is connected. When a vehicle runs at, e.g. a high speed of 60km/H or more (or low-speed running less than 60km/H) for specified distance set in response to the vehicle speed, the bearing is detected with a bearing sensor for a section of about 60m (or 30m) with a beacon receiving point as the center in the controller 28. The most frequently stored bearing in the advancing direction of a vehicle 20 is made to be the sensor bearing at this time. The difference between this bearing and the bearing based on beacon data is corrected. The reference bearing of the bearing sensor is corrected based on the difference. Therefore, the correction errors when the temporally change in lanes and passing of the vehicle occur at the beacon data receiving point can be eliminated. |
