| 摘要 |
PURPOSE:To provide a GPS navigation device, by which when a drivers own car is located in a tunnel, the condition is displayed and informed to a driver. CONSTITUTION:In a GPS navigation device adapted to receive a signal from an artificial satellite to measure the current position and display the measured current position together with a map on a screen, a tunnel passing processing means 15 is provided for judging whether the current position is in a tunnel or not when a signal from the artificial satellite is interrupted, and making data processing for highlighting the display of the tunnel on the screen when the car is in the tunnel. When the drivers own car enters the tunnel and a signal from the artificial satellite can not be received, the tunnel on the screen blinks. A driver can image passing through the tunnel so as to prevent the risk of losing sight of driver's own car position. |
