| 摘要 |
PURPOSE:To accurately detect the running direction of a vehicle by correcting outputted data of geomagnetic sensor after the vehicle passes through a railroad crossing or when the present location of the vehicle is uncertain (inaccurate). CONSTITUTION:The changing rate of angular data from an angular speed sensor 2 of a road section of the present location derived from road data of a data group of a map of an area of a specified range including the present location of the vehicle and outputted data of the geomagnetic sensor 1 are both monitored, and temporary correction value is sought based on the angular data and the outputted data when the changing rate of each is detected to be smaller than the specified values. Then while correcting the change in this temporary correction value, a standard deviation of a multiple number of temporary correction value is sought, when this standard deviation becomes smaller than the specified value, an average value of the multiple number of the temporary correction values is sought, and this is taken as the correction value utilized for correcting the outputted data of the geomagnetic sensor. Thus, when the vehicle body is magnetized by being passed through a railroad crossing or when the present value of the vehicle is uncertain due to error in angle, detection of the running direction of the vehicle can be accurately carried out without carrying out correction of one revolution again. |
