| 摘要 |
PROBLEM TO BE SOLVED: To provide a navigation system which enables a plurality of users to share information about their respective positions and messages, reduces a processing load on a navigation device, and also enables friends to exchange messages in real time.SOLUTION: A navigation system comprises: portable terminal devices A, B and C; a navigation device which is loaded on a vehicle boarded by a user of the portable terminal device C; and an information server 30 which communicates with the portable terminal devices A, B and C. The system collectively transmits pieces of user position information received from the respective portable terminal devices A, B and C to the navigation device 10 at predetermined time intervals. Also, the system transmits a user message received from each of the portable terminal devices A, B and C to the navigation device 10 at each reception. |
