Electronic wall using high-resolution millimeter-wave radar in conjunction with multiple plane reflectors and retroreflectors

• US 6,950,021 B2
• Filed: 09/23/2003
• Issued: 09/27/2005
• Est. Priority Date: 09/23/2003
• Status: Expired due to Fees

• Current Assignee: Sensor Technologies & Systems, Incorporated (Citizens Financial Group Incorporated)
• Original Assignee: Sensor Technologies & Systems, Incorporated (Citizens Financial Group Incorporated)
• Inventors: Butler, Walker
• Primary Examiner(s): NGUYEN, TAI T
• Application Number:
  US10/668,710
• Publication Number:
  US 20050073411A1
• Time in Patent Office: 735 Days
• Field of Search: 340/545.3, 340/552, 340/564, 340/447, 340/446, 340/556, 342/5, 342/7, 342/28
• US Class Current: 340/545.3
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G08B 13/122 for a perimeter fence features peculiar to electrified fences A01K3/00
• CPC Class Codes: G08B 13/184 using radiation reflectors

Abstract

An apparatus for detection of any intruder passing through an electronic wall is disclosed. The electronic wall is formed by a millimeter-wave radar positioned at one end of the wall and a plurality of combinations of plane reflectors and retroreflectors placed along the floor of the wall as well as on structures at both ends. The wall is formed of a plurality of electromagnetic beams with each beam having two segments, one between the radar antenna and a plane reflector and the second segment between the plane reflector and a retroreflector. A sufficient number of beams inhabit the wall volume to make traversing the wall by an intruder without detection essentially impossible, even though the intruder should attempt such detection avoiding methods as crawling under or jumping over the assumed locations of the beams. The primary means of determining that an intruder is traversing the wall is the detection of one or more electromagnetic beams being partially or completely blocked. A secondary means of detection is the radar reflection from the intruder'"'"'s person that may be used to determine the location of an intruder along the extent of the wall.

Claims

1. An apparatus for detection of any intruder passing through a protected volume, comprising:

a first means for generating and modulating electromagnetic wave energy;

a second means coupled to said first means for radiating said electromagnetic wave energy into said protected volume;

a third means co-located with said second means for collecting a portion of said radiated electromagnetic energy;

a fourth means for reflecting, said fourth means capable of redirecting a portion of said electromagnetic wave energy from said second means toward an associated fifth means for reflecting, said fifth means capable of redirecting said electromagnetic wave energy back along a same line of propagation to said fourth means and thus to said third means, thereby forming an electromagnetic beam comprising radiated and reflected electromagnetic wave energy and having two segments, a first segment between said fourth means and said fifth means, and a second segment between said fourth means and said third means;

a plurality of said fourth means and a plurality of said fifth positioned along a base and ends of said protected volume for forming a plurality of said electromagnetic beams, each said electromagnetic beam comprising said first and second segments with a sum of lengths of said first and second segments being unique;

a structure located at a proximal end of said protected volume and coupled to both said second means and said third means capable of supporting said second means and said third means at a position above said base of said protected volume for providing line-of-sight propagation of said electromagnetic beams between said second means and said third means and each of said plurality of said fourth means;

said structure located at said proximal end of said protected volume also capable of being coupled to and supporting another set of said plurality of said fifth means, thereby providing a terminal end of said plurality of said electromagnetic beams at a plurality of heights above said base of said protected volume at said proximal end;

a structure located at a distal end of said protected volume and coupled to and supporting another set of said plurality of said fourth means at a plurality of heights above said base of said protected volume, thereby providing junctions between said first and second segments of said plurality of said electromagnetic beams at said plurality of heights above said base of said protected volume at said distal end;

a signal processing means coupled to said third means and capable of determining a range to objects irradiated by said radiated electromagnetic wave energy, said signal processing means monitors a presence of said electromagnetic beams associated with each said fourth means and associated said fifth means, and for detecting a physical presence of said intruder within said protected volume, and;

an alarm circuit coupled to said signal processing means for generating an alarm when at least one of said electromagnetic beams is interrupted.

2. An apparatus for detection of intruder passing through a protected volume, comprising:

a transmitter for generating and modulating electromagnetic energy;

an antenna coupled to said transmitter for radiating said electromagnetic wave energy into said protected volume;

a receiver coupled to said antenna for receiving a portion of said radiated electromagnetic energy;

a plane reflector capable of redirecting a portion of said radiated electromagnetic wave energy from said antenna toward an associated retroreflector, said retroreflector capable of redirecting said electromagnetic wave energy back along a same line of propagation to said plane reflector and thus to said antenna, thereby forming an electromagnetic beam comprising radiated and reflected electromagnetic wave energy and having two segments, a first segment between said plane reflector and said retroreflector, and a second segment between said plane reflector and said antenna;

a plurality of said plane reflectors and said associated retroreflectors positioned at a plurality of locations along a base and ends of said protected volume capable of forming a plurality of said electromagnetic beams each having said first and second segments, a sum of said first and second segments for each said electromagnetic beam having a unique value;

a sensor structure located at a proximal end of said protected volume and coupled to said antenna for supporting said antenna at a position above said base of said protected volume for providing line-of-sight propagation of said plurality of said electromagnetic beams between said antenna and each of said plane reflectors, said sensor structure also coupled to and supporting another set of said plurality of said retroreflectors, thereby providing a terminal end of said plurality of said electromagnetic beams at a plurality of heights above said base of said protected volume at said proximal end, junctions between said first and second segments of said electromagnetic beams being provided by said plurality of said plane reflectors positioned at said plurality of locations along said base of said protected volume;

a reflector structure located at a distal end of said protected volume and coupled to another set of said plurality of said plane reflectors for supporting said plane reflectors at a plurality of heights above said base of said protected volume, thereby providing said junctions between said segments of said plurality of said electromagnetic beams at said plurality of heights above said base of said protected volume at said distal end, said terminal end of said electromagnetic beams being provided by said plurality of said retroreflectors positioned at said plurality of locations along said base of said protected volume;

a signal processing circuit coupled to said receiver and capable of determining a range to objects irradiated by said radiated electromagnetic wave energy, said signal processing circuit monitors a presence of said plurality of said electromagnetic beams formed by each said plane reflector and said associated retroreflector for detecting a physical presence of said intruder within said protected volume, and;

an alarm circuit coupled to said signal processing circuit for generation of an alarm when at least one of said electromagnetic beams is partially or completely interrupted.

3. An apparatus as claimed in claim 2, wherein said transmitter generates said electromagnetic wave energy in a millimeter-wave region of an electromagnetic spectrum;

and said receiver receives energy in said millimeter-wave region of said electromagnetic spectrum.

4. An apparatus as claimed in claim 2, wherein said antenna comprises means for radiating said electromagnetic wave energy into said protected volume and minimizing radiation outside said protected volume.

5. An apparatus as claimed in claim 2, wherein said plurality of said plane reflectors positioned at said plurality of locations along said base of said protected volume and coupled to said reflector structure at said plurality of heights above said base of said protected volume comprise reflectors capable of redirecting substantially all incident electromagnetic wave energy from said antenna toward locations of said associated retroreflectors.

6. An apparatus as claimed in claim 2, wherein said plurality of said retroreflectors positioned at said plurality of locations along said base of said protected volume and coupled to said sensor structure at said plurality of heights above said base of said protected volume comprise retroreflectors capable of returning substantially all incident electromagnetic wave energy along a path opposite in direction but parallel to a path of said incident electromagnetic wave energy.

7. An apparatus as claimed in claim 2, wherein each said electromagnetic beam comprises a substantial portion of said electromagnetic wave energy incident upon said plane reflector and returned by said retroreflector, and said signal processing circuit and said alarm circuit responsive to high signal-to-noise ratio energy in said electromagnetic beams to provide high probability of detection of said intruder while providing low probability of false alarm.

8. An apparatus as claimed in claim 2, wherein said antenna is located at a position sufficiently high above said base of said protected volume, and wherein said plurality of said plane reflectors are located at positions along said base of said protected volume and a portion of said plurality of said plane reflectors are positioned in a vertical arrangement on said reflector structure, and wherein said plurality of said retroreflectors are located at positions along said base of said protected volume and a portion of said plurality of said retroreflectors are positioned in a vertical arrangement on said sensor structure to generate a sufficient number of said electromagnetic beams with beam-to-beam spacing sufficiently small and upper beam height sufficiently high to preclude said intruder passing through said volume without detection.

9. A method of detecting an unauthorized intrusion, comprising:

generating and modulating electromagnetic wave energy;

radiating said electromagnetic wave energy into a plurality of sections along a protected region;

redirecting a portion of said radiated electromagnetic wave energy from at least one of said sections to another section of said protected region;

reflecting said redirected electromagnetic wave energy from said another section back along a same line of propagation to said at least one of said sections from which said electromagnetic wave energy was redirected,

collecting said reflected electromagnetic wave energy from said at least one of said sections, thereby providing a terminal end for said portion of said electromagnetic wave energy; and

indicating an occurrence of an unauthorized intrusion upon interruption of said electromagnetic wave energy along any line of propagation.