To provide a technique which enables a mobile terminal device to secure the precision of its own position and realizes power saving and reduction of communication expenses.
The mobile terminal device is moved to acquire its own position information by communication with a base station until arriving at a preset prescribed position before a main transmission position. When arriving at the prescribed position, the mobile terminal device switches to operation for acquiring its own position information by reception of GPS position information from operation for acquiring position information by communication with the base station. When arriving at the mail transmission position, the mobile phone terminal automatically transmits a preserved mail to a destination address.
Kyosuke Tanaka
Takashi Sasaki