| 摘要 |
<p>The present invention relates to a system for tracking an object. The object to be tracked is provided with an identification device having a transmitter with a remote-activation capability and being suited for emitting electromagnetic energy with an individually identifiable signal in the radio-frequency spectrum when activated. Two different interrogation signals are transmitted in the system to which signals the identification devices respond. The wide-coverage signal activates the tracking signal of the identification device and the narrow-range signal activates the identification device to send its identification code signal.</p> |
