MICROWAVE INTRUSION DETECTING SYSTEM AND APPARATUS

• US 3,733,602 A
• Filed: 05/20/1971
• Issued: 05/15/1973
• Est. Priority Date: 05/20/1971
• Status: Expired due to Term

• Current Assignee: Laverne A. Wente, Virgil A. Cuckler
• Original Assignee: Laverne A. Wente, Virgil A. Cuckler
• Inventors: Cuckler, Virgil A., Wente, Laverne A.
• Primary Examiner(s): Borchelt, Benjamin A.
• Assistant Examiner(s): Montone, G. E.
• Application Number:
  US05/145,169
• Time in Patent Office: 726 Days
• Field of Search: 343/5PD,6.5R 340/258R,258B
• US Class Current: 342/27
• CPC Class Codes: G01S 13/76 wherein pulse-type signals are transmitted
• CPC Class Codes: G08B 13/2491 Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field

Abstract

A digital microwave intrusion detecting system and apparatus is disclosed wherein a plurality of repeater/transponders with receiving and transmitting antennas define a perimeter and in response to each interrogation pulse sent down the perimeter reply pulses are received back at the monitoring location corresponding in number to the last transponder to send a reply. The location of the perimeter violation is defined by the last transponder to reply to an interrogation pulse. If a certain number of replies, for example one, are not received back from all transponders in response to an interrogation pulse a warning signal is given and if a different number of replies are not received back, as for example, two in succession, an alarm signal is given that the perimeter has been violated.

Claims

1. A microwave system for detecting the passing of an object through a perimeter and identifying the location of such passing through comprising:

a pulse transmitter at one location for generating a series of RF pulses at a definite pulse repetition rate, at least one transponder at a second location spaced from said transmitter and defining a perimeter therewith, said transponder being adapted to receive said RF pulses from said transmitter and to generate and transmit RF pulses corresponding thereto, a receiver at said one location adapted to receive said RF pulses from said transponder, the pulse repetition time of said transmitter being greater than the range time of the transmitted RF pulse to said transponder and return to the receiver, and an indicating system at said receiver for giving one form of signal when one number of RF pulses is not received in response to a specified number of transmitted RF pulses and for giving a second form of signal when a second number of RF pulses is not received in response to the same specified number of transmitted RF pulses.

2. The system according to claim 1 wherein said one number of RF pulses is one and said second number of RF pulses is two successive pulses.

3. A microwave system for detecting the passing of an object through a perimeter and identifying the location of such passing through comprising:

a pulse transmitter at one location for generating a series of RF pulses at a definite pulse repetition rate, a series of RF pulse receiving and transmitting members at successively spaced locations from said transmitter, each of said RF pulse receiving and transmitting members being adapted to receive the RF pulses from the preceding transmitting member and to transmit an RF pulse corresponding to each received RF pulse to the succeeding receiving and transmitting member, certain of said RF pulse receiving and transmitting members being transponders and being adapted to transmit an RF pulse corresponding to each received RF pulse back to the preceding RF pulse receiving and transmitting member, a terminal transponder at a location spaced from the last one of said RF pulse receiving and transmitting members and defining a perimeter therewith and said transmitter, said terminal transponder being adapted to receive said RF pulses from the last of said RF pulse receiving and transmitting members and to generate an RF pulse corresponding to each received RF pulse and to transmit same back through said perimeter of said series of pulse receiving and transmitting members, a receiver at said one location adapted to receive the pulses coming back through said perimeter, the pulse repetition time of said transmitter being greater than the range time of a transmitted pulse through said pulse receiving and transmitting members and said transponder and return through the same pathway to said receiver, and a register at said receiver for indicating in response to each RF pulse transmitted from said one location, the number of returned RF pulses corresponding to the number of transponders transmitting an RF pulse.

4. The system according to claim 3 wherein the number of RF pulses received by the receiver at said one location corresponds to the location of the last transponder to transmit an RF pulse back through the perimeter.

5. The system according to claim 4 including an indicating system at said one location for giving a signal when a specified number of RF pulses from the transponder beyond the last transponder to respond in response to the same number of RF pulses transmitted from said one location fail to return through the perimeter to said one location.

6. The system according to claim 5 wherein said signal comprises one form of signal upon failure of one number of pulses to return and a second form of signal upon failure of a second number of pulses to return.

7. The system according to claim 6 wherein said one form of signal occurs upon failure of one pulse to return from a particular location and said second form of signal occurs upon failure of two successive pulses to return from said particular location.

8. A microwave system for detecting the passing of an object through a perimeter and identifying the location of such passing through comprising:

a pulse transmitter at one location for generating a series of RF pulses at a definite pulse repetition rate, a series of transponders at successively spaced locations from said transmitter, each of said transponders being adapted to receive the RF pulses from the preceding transponder and to transmit an RF pulse corresponding to each received RF pulse to the succeeding transponder and back through the preceding transponder, a terminal transponder at a location spaced from the last one of said transponders and defining a perimeter therewith and said transmitter, said terminal transponder being adapted to receive said RF pulses from the last of said transponders and to generate an RF pulse corresponding to each RF pulse received from the last of said transponders and to transmit same back through said perimeter of said series of transponders, receiver at said one location adapted to receive the pulses coming back through said perimeter, the pulse repetition time of said transmitter being greater than the range time of a transmitted pulse through said transponders and said terminal transponder and return through the same pathway to said receiver, each of said transponders being adapted to fail to transmit a signal when none is received thereby, and a register at said receiver for indicating the number of returned pulses corresponding to the number of transponders transmitting an RF pulse in response to each RF pulse transmitted from said one location.

9. The system according to claim 8 including indicating means at said one location for giving one form of signal when a specified number of RF pulses from the transponder beyond the last transponder to respond, in response to the same number of RF pulses transmitted from said one location, fail to return through the perimeter to said one location, and a second form of signal when a specified number of successive RF pulses from the transponder beyond the last transponder to respond, in response to the same number of RF pulses transmitted from said one location, fail to return through the perimeter to said one location.

10. The system according to claim 8 wherein the register provides a single digital signal whose position corresponds to the number of returned pulses.

11. The system according to claim 10 including data indicating means at said one location for giving one form of signal when a specified number of RF pulses from the transponder beyond the last transponder to respond, in response to the same number of RF pulses transmitted from said one location fail to return through the perimeter to said one location and a second form of signal when a specified number of successive RF pulses from the transponder beyond the last transponder to respond, in response to the same number of RF pulses transmitted from said one location, fail to return through the perimeter to said one location.

12. The system according to claim 8 wherein the transmitter includes a circulator for directing transmitted RF pulses only to a transponder and directing received RF pulses only to a receiver.

13. The system according to claim 3 wherein each one of said series of pulse receiving and transmitting members includes a delay means to prevent initiation of transmission of a pulse until after all of a received pulse has been received.

14. The system according to claim 11 wherein the indicating means includes counter means for adding the number of successive pulses failing to return through the perimeter, a warning signal operative in response to said counter means when a specified number of pulses fail to return and an alarm signal operative in response to said counter and gate means responsive to said counter when a specified number of successive pulses fail to return through the perimeter.

15. The system according to claim 2 wherein each one of said series of pulse receiving and transmitting members includes means having two positions, one for effecting only relaying on of an RF received pulse to a succeeding one of said pulse receiving and transmitting members and a second for effecting relaying on of an RF received pulse to a succeeding one of said pulse receiving and transmitting members and substantially simultaneous therewith relaying back of said received pulse to a preceding one of said pulse receiving and transmitting members.