| 摘要 |
A wireless communication device communicates Radio Frequency (RF) signals with a wireless communication network, and receives navigation signals from a constellation of satellites orbiting the Earth. When the device travels to an area where the RF signals from the network are weak or non-existent, the device automatically activates its Global Positioning Satellite (GPS) receiver, and periodically saves its location to memory. If a user of the device becomes lost, the device can use the saved locations to generate directions to return the user to, or near, the network coverage area.
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