Concealed object detection

• US 6,831,590 B1
• Filed: 09/12/2002
• Issued: 12/14/2004
• Est. Priority Date: 09/12/2001
• Status: Expired due to Term

• Current Assignee: L3harris Fuzing and Ordnance Systems Incorporated
• Original Assignee: CyTerra Corp. (L3Harris Technologies, Inc.)
• Inventors: Duvoisin, Herbert III, Steinway, William, Stilwell, Gregory, Fine, David H.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): Alsomiri, Isam
• Application Number:
  US10/241,835
• Time in Patent Office: 824 Days
• Field of Search: 342/22, 342/27, 342/42, 342/43, 342/51, 342/90, 342/192, 342/197, 342/173, 342/176
• US Class Current: 342/22
• 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: G01S 13/886 for alarm systems alarms with electrical actuation G08B13/22
• CPC Class Codes: G01S 7/411 Identification of targets based on measurements of radar reflectivity G01S7/415 takes precedence
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 9/27 Spiral antennas

Abstract

A concealed object detection system for detecting objects concealed on a person includes radar transponders that are each configured and positioned to direct a radar signal at a person and to detect a portion of the radar signal reflected by the person. A processor connected to the radar transponders processes the portions of the radar signals detected by the radar transponders to determine whether the person is carrying a concealed object. The system may produce a real-time alert, such as an audible alert, when a concealed object is detected.

Claims

1. A concealed object detection system for detecting objects concealed on a person, the system comprising:

radar transceivers that are each configured and positioned to direct a radar signal at a person and to detect a portion of the radar signal reflected by the person; and

a processor connected to the radar transceivers and operable to process the portions of the radar signals detected by the radar transceivers to conduct a test to determine whether the person is carrying a concealed object, in which a first characteristic of a first dielectric constant associated with the person is determined from the portions of the radar signals detected by the radar transceivers and a second characteristic of a second dielectric constant associated with the concealed object is determined from the portions of the radar signals detected by the radar transceivers.

2. The system of claim 1 wherein the the first characteristic of the first dielectric constant includes a value of the first dielectric constant.

3. The system of claim 1 wherein the first dielectric constant is associated with skin of the person.

4. The system of claim 1 wherein the processor is further operable to conduct the test using a frequency-stepped scheme in which the radar signal comprises frequencies at defined intervals throughout a defined frequency range.

5. The system of claim 4 wherein the defined frequency range is approximately 1.5 to 10 GHz.

6. The system of claim 1 wherein the processor is further operable to conduct the test based on a difference between the first characteristic of the first dielectric constant and the second characteristic of the second dielectric constant.

7. The system of claim 1 wherein the radar transceivers are implemented within a portable scanner.

8. The system of claim 1 wherein the radar transceivers are vertically stacked within a plurality of posts, and further wherein the plurality of posts are arranged around a central point.

9. The system of claim 8 wherein the radar transceivers include a vertical beam array and a horizontal beam array for scanning the radar signal in vertical and horizontal directions about the central point.

10. The system of claim 1 wherein the processor is further operable to determine a location of the concealed object relative to the person.

11. The system of claim 1 wherein the radar transceiver includes a spiral antenna.

12. A method comprising:

outputting transmitted radar signals in a direction of a person;

receiving reflected radar signals that are reflected from the person and from a concealed object carried by the person;

determining from the reflected radar signals a first characteristic of a first dielectric constant associated with the person;

determining from the reflected radar signals a second characteristic of a second dielectric constant associated with the concealed object, and

detecting the concealed object using the reflected radar signal and based on the first characteristic of the first dielectric constant associated with the person and the second characteristic of the second dielectric constant associated with the concealed object.

13. The method of claim 12 wherein determining the first characteristic of the first dielectric constant comprises determining a value of the first dielectric constant.

14. The method of claim 12 wherein detecting the concealed object comprises determining a dielectric constant of skin of the person.

15. The method of claim 12 wherein detecting the concealed object comprises comparing the first dielectric constant and the second dielectric constant.

16. The method of claim 12 wherein detecting the concealed object comprises

determining the first dielectric constant, based on the reflected radar signals;

determining the second dielectric constant, based on the reflected radar signals; and

determining that a defined discrepancy exists between the first and second dielectric constants.

17. The method of claim 12 wherein determining the first characteristic of the first dielectric constant comprises determining a value of the first dielectric constant by individually analyzing the person.