| 摘要 |
<p>A positioning system composed of a vehicle-mounted device and a portable terminal device. The vehicle-mounted device has vehicle device-side positioning means for obtaining vehicle device-side position measurement data including vehicle device-side position coordinates representing measured position coordinates, and the vehicle-mounted device also has transmission means for transmitting the vehicle device-side position measurement data, obtained by the vehicle device-side positioning means, to the portable terminal device. The portable terminal device has portable device-side positioning means for obtaining portable device-side position measurement data including portable device-side position coordinates representing measured position coordinates, selection means for selecting the vehicle-side positioning means and/or the portable device-side positioning means based on a positioning environment, and vehicle position calculation means for calculating the position of the vehicle based on position coordinates measured by the positioning means selected by the selection means.</p> |
