摘要 |
A system and method are provided for automatically detecting intrusion in an off-limits zone. The system includes a transmitter transmitting a signal along a path likely to encounter an intruder to the off-limits zone and a modulating reflector for receiving the transmitted signal. The modulating reflector includes a modulator receiving the received signal and generating a modulated signal having a characteristic. The modulating reflector transmits the modulated signal to be received by a receiver located to receive the modulated signal. The system further includes a processor coupled to the transmitter and to the receiver, the processor being configured to process the received modulated signal and to initiate an action as a function of the characteristic in the received modulated signal.
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