| 摘要 |
PROBLEM TO BE SOLVED: To enable a vehicle driver to be notified of road traffic information at appropriate timing by detecting with an atmospheric pressure sensor the situation of a road varying in level in a tunnel, utilizing this information to figure out the position of the vehicle driven, and complementing a position acquired with an acceleration sensor and a gyro sensor with the position so figured out.SOLUTION: A receiving apparatus is provided with an atmospheric pressure sensor that outputs atmospheric pressure data and with data on atmospheric pressure variations relative to the distance in the tunnel stored in a positional data registration memory; when the difference between an atmospheric pressure count measured by the atmospheric pressure sensor when the pertinent vehicle has passed a first position in the tunnel and another atmospheric pressure count measured by the atmospheric pressure sensor when the vehicle has passed a second position deeper into the tunnel than the first position has surpassed the difference between the atmospheric pressure count in the first position and that in the second position provided in the positional data registration memory, the current position of the vehicle figured out by an acceleration sensor is complemented. |
