| 摘要 |
A transmitting unit has a transmitter for transmitting signals of coded information about a position close to the unit in a space substantially unreachable by a satellite-based navigating system so as to provide a receiver arranged on a moving object present in said space with this position information for determining the position of the object. The transmitter is adapted to normally be in an inactive non-transmitting state, and the unit further comprises means adapted to detect movement of an object within a space and activate the transmitter to transmit signals only when movement of an object in the space is detected.
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