The present invention is directed to an underground as well as above
ground system and method of determining the intrusion into a security
zone. One or more transceivers would transmit a unique electromagnetic
signal which would power a response from one or more RFID transponders.
Each of the transponders would transmit a unique code to the transceiver
indicating that there has been no intrusion in the vicinity of that
transponder. Failure of a transponder to receive a signal produced by a
transponder, would indicate the existence of an intrusion. The
transponders as well as the transceivers can be provided in a PVC pipe
buried in the ground, or provided in or on a structure located on or
above the ground.