| 摘要 |
PURPOSE:To accurately detect the running direction of a vehicle by correcting outputted data of a geomagnetic sensor after passing through a railroad crossing. CONSTITUTION:The efficiency of outputted data of the geomagnetic sensor 1 is monitored, when the changing rate exceeds a set value, outputted data at the time when changing rate of the outputted data is decreased is taken as corrected data, and compensating the outputted data of the geomagnetic sensor 1 is carried out based on this corrected data. Thus even when a vehicle body is magnetized when it is passed through, the running direction of the vehicle can be accurately detected without carrying out correction of one revolution again. |
