| 摘要 |
A communication system for tracking an asset globally accesses multiple communication networks and switches among them, choosing the most economic, available communication mode without need for a constant power supply. An integrated motion sensor uses a combination of GPS updating and dynamic movement calculation to obtain the most reliable position estimation. Current location is identified within a small radius at all times. While taking advantage of the GPS system to obtain accurate location information, direct exposure to GPS satellites is not required at all times. The system obtains position information from GPS satellites whenever valid GPS signals are available, and provides its own location tracking capability when GPS signals are not accessible. The position accuracy of the device is preferably within a 20-meter radius from the exact location.
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