Concealed object detection

• US 7,064,701 B2
• Filed: 12/13/2004
• Issued: 06/20/2006
• Est. Priority Date: 09/12/2001
• Status: Expired due to Fees

• Current Assignee: L3 Fuzing & Ordnance Systems, Inc. (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications CyTerra Corporation (L3Harris Technologies, Inc.)
• Inventors: Duvoisin, Herbert III, Fine, David H., Steinway, William, Stilwell, Gregory
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): ALSOMIRI, ISAM A
• Application Number:
  US11/009,135
• Publication Number:
  US 20050099331A1
• Time in Patent Office: 554 Days
• Field of Search: 342/22, 342/27, 342/42
• 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. An object detection system for detecting objects carried by 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 an object to be detected, 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 object to be detected is determined from the portions of the radar signals detected by the radar transceivers, and

analyze the portions of the radar signals in comparison with pre-determined types of items, and, based on the comparison, to output an indication of a detected object.

2. The system of claim 1 wherein a radar transceiver is operable to output the transmitted radar frequency signal throughout a frequency range of approximately 1.5 to 10 GHz.

3. The system of claim 1 wherein a dielectric constant of the detected object is less than 5.

4. The system of claim 1 wherein the detected object comprises a plastic or paper material.

5. The system of claim 1 wherein the detected object comprises a metallic object.

6. The system of claim 1 wherein the processor is operable to implement a frequency-stepped radar transmission scheme.

7. The system of claim 1 wherein:

the radar transceivers are vertically stacked within each of a plurality of posts, and

the plurality of posts are arranged around a central point.

8. The system of claim 7 wherein the radar transceivers include a vertical beam array and a horizontal beam array for scanning the transmitted radar frequency signal in vertical and horizontal directions about the central point.

9. The system of claim 8 wherein the processor is operable to make a determination that the detected object is in the vicinity of the central point.

10. The system of claim 9 wherein a height of the posts and scanning angles of the detectors selected to provide a whole-body scan of the person located in the vicinity of the central point.

11. The system of claim 10 wherein the processor is operable to determine a location of the detected object relative to the person.

12. The system of claim 11 wherein the processor is operable to determine reflectivity measurements associated with a surface reflectivity of the person and clothing of the person.

13. The system of claim 12 wherein a two-dimensional display is created based on the reflectivity measurements.

14. The system of claim 1 wherein the processor is operable to determine whether the object to be detected is being concealed by the person.

15. The system of claim 1 wherein the processor is operable to determine whether the object to be detected is in contact with the person.