System and method for standoff detection of human carried explosives

• US 6,967,612 B1
• Filed: 10/22/2004
• Issued: 11/22/2005
• Est. Priority Date: 10/22/2004
• Status: Active Grant

• Current Assignee: Rapiscan Laboratories Incorporated (OSI Systems Incorporated)
• Original Assignee: Science, Engineering and Technology Associates Corporation
• Inventors: Gorman, John D., Douglass, Robert J., Burns, Thomas J. Jr.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US10/970,465
• Time in Patent Office: 396 Days
• Field of Search: 342/22, 342/27, 342/28, 342 52- 59, 342 74-103, 342/175, 342/176, 342179-181, 342188-197, 324/239, 324/647, 340/568.1
• 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 13/34 using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
• CPC Class Codes: G01S 13/66 Radar-tracking systems; Analogous systems
• CPC Class Codes: G01S 13/865 Combination of radar systems with lidar systems
• CPC Class Codes: G01S 13/867 Combination of radar systems with cameras
• CPC Class Codes: G01S 13/887 for detection of concealed objects, e.g. contraband or weapons
• CPC Class Codes: G01S 7/024 using polarisation effects in waveguides H01P1/165; for aerials H01Q, e.g. H01Q15/22, H01Q15/24, H01Q19/195
• CPC Class Codes: G01S 7/412 based on a comparison between measured values and known or stored values
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter
• CPC Class Codes: G01S 7/415 Identification of targets based on measurements of movement associated with the target

Abstract

The system and method for standoff detection of human carried explosives (HCE) is a portable system that automatically detects HCE up to a range of 200 meters and within seconds alerts an operator to HCE threats. The system has radar only, or both radar and video sensors, a multi-sensor processor, an operator console, handheld displays, and a wideband wireless communications link. The processor receives radar and video feeds and automatically tracks and detects all humans in the field of view. Track data continuously cues the narrow beam radar to a subject of interest, the radar repeatedly interrogating cued objects, producing a multi-polarity radar range profile for each interrogation event. Range profiles and associated features are automatically fused over time until sufficient evidence is accrued to support a threat/non-threat declaration hypothesis. Once a determination is made, the system alerts operators through a handheld display and mitigates the threat if desired.

Claims

1. A system for standoff detection of human carried explosives (HCE) within an area under surveillance, comprising:

an active radar system, the radar system having a radar transmitter, a radar receiver, at least one radar antenna, and a field of regard;

a radar tracking control system in physical cooperation with the active radar system, wherein the field of regard of the active radar system is targeted within the area under surveillance, the area of surveillance being greater than the radar field of regard;

a user interface having a video display terminal and a data input means;

a computer in electrical communication with the radar system, the radar tracking control system, and the user interface, the computer having a central processing unit, a memory and computer readable program code stored in the memory, the code including;

radar tracking instruction means for targeting the radar system; and

HCE detection instruction means for detection of human carried explosive devices.

2. The system according to claim 1, wherein the radar tracking control system further includes:

a support structure;

a sensor platform adjustably mounted to the support structure, the radar system mounted to the sensor platform; and

a sensor platform adjusting means for controlling the pan/tilt orientation the sensor platform, the sensor platform adjusting means being in electrical communication with the computer.

3. The system according to claim 2, further comprising an imaging system in electrical communication with the computer, the imaging system having a field of regard spatially and temporally overlapping the radar system field of regard, the imaging system having at least one video output signal electrically connected to the computer.

4. The system according to claim 3, wherein said computer readable program code further comprises means for detecting and tracking a moving human target from the video output signal, the system for standoff detection further comprising means for controlling said imaging system to maintain the track of the moving human target.

5. The system according to claim 3, wherein the imaging system includes:

a wide field of view (WFOV) video camera mounted to the support structure, the WFOV camera having a field of regard encompassing the area of surveillance; and

a variable zoom narrow field of view (NFOV) video camera having a field of regard, the NFOV camera being mounted to the sensor platform, the NFOV camera being boresighted with the radar system, whereby the field of regard of the WFOV camera overlaps the field of regard of the NFOV camera.

6. The system according to claim 5, wherein the code further comprises threat motion detection instruction means for determining the threat potential of a target based upon the motion of the target.

7. The system according to claim 5, wherein the code further comprises sequential hypothesis testing instruction means for fusing radar measurements over multiple observations of the target.

8. The system according to claim 1, further comprising an imaging system producing an output signal connected to said computer, the imaging system being selected from the group consisting of Ladar, Lidar, infrared, multispectral, hyperspectral, imaging radar, and visible light range video.

9. The system according to claim 8, wherein said computer readable program code further comprises means for detecting and tracking a moving human target from the output signal of said imaging system, the system for standoff detection further comprising means for controlling said imaging system to maintain the track of the moving human target.

10. The system according to claim 1, wherein the radar system has at least one transmit polarization and at least one receive polarization.

11. The system according to claim 10, wherein the radar system has an orthogonal pair of transmit polarizations.

12. The system according to claim 10, wherein the radar system has an orthogonal pair of receive polarizations.

13. The system according to claim 1, wherein the field of regard has a range between about fifteen meters and two hundred meters.

14. The system according to claim 1, further comprising a portable wireless handheld console in electrical communication with the computer.

15. The system according to claim 1, wherein the code further comprises:

classifying instruction means for classifying the composition of the human carried explosive; and

filtering instruction means for rejecting false alarm events.

16. The system for standoff detection of human carried explosives according to claim 1, further comprising a threat-mitigating device in communication with the computer.

17. The system for standoff detection of human carried explosives according to claim 1, further comprising a threat interdiction system in communication with said computer.

18. The system for standoff detection of human carried explosives according to claim 17, wherein the threat interdiction system includes a water cannon controlled by said computer.

19. The system for standoff detection of human carried explosives according to claim 18, wherein said threat interdiction system includes an active denial radar system controlled by said computer.

20. The system according to claim 1, wherein the computer is communicatively linked to a computer network.

21. The system according to claim 1, wherein the radar system operates with a center frequency between about 10 GHz and 110 GHz.

22. A method for the standoff detection of human carried explosives (HCE) within an area of observation, comprising the steps of:

cueing at least one radar system at a field of regard containing at least one human target;

collecting RF signature data for the at least one human target;

measuring radar signature changes associated with the interaction between radar signatures of the at least one human target and an explosive device carried by the at least one human target;

statistically combining radar signatures over multiple observations of the at least one target;

determining the threat status of the target; and

providing the data to a user interface.

23. The method according to claim 22, further comprising the step of manually targeting the human target with a narrow field of view (NFOV) video camera boresighted to the radar field of regard.

24. A method for the standoff detection of human carried explosives (HCE) within an area of observation using a plurality of HCE detection systems, each HCE system having a radar system, a radar field of regard, an imaging system, and a computer, the method comprising the steps of:

communicatively linking together the plurality of HCE detection systems;

overlapping the radar field of regard of the plurality of HCE detection systems;

creating a plurality of simultaneous radar signatures of the radar field of regard from different look angles;

determining the threat potential of a target based upon the combined data of the plurality of radar signatures.

25. A method for detecting explosive devices, the method comprising the steps of:

illuminating a candidate threat with polarized radiation;

collecting a first reflected radiation from the candidate threat, the first reflected radiation having a polarization identical to that of the illuminating radiation;

collecting a second reflected radiation from the candidate threat, the second reflected radiation having a polarization orthogonal to that of the illuminating radiation; and

detecting the change in polarization state induced by the candidate threat.

26. The method for detecting explosive devices according to claim 25, further comprising the step of processing multiple measurements, of reflected radiation taken over a predetermined period of time.

27. The method for detecting explosive devices according to claim 25, wherein the step of detecting the change in polarization state further includes the step of measuring and calculating a ratio between the received co-polarized return energy divided by cross-polarized return energy accumulated over the predetermined period of time.

28. A system for standoff detection of human carried explosives (HCE) within an area of surveillance, comprising:

(a) detecting means for repetitively scanning the area of surveillance and for detecting and tracking a human target within the area of surveillance;

(b) a radar transmitter for transmitting a narrow beam of polarized electromagnetic radiation;

(c) focusing means for automatically focusing and triggering the beam of polarized radiation emitted by the transmitter onto at least a portion of the human target detected by the detecting means;

(d) a radar receiver for receiving a portion of the beam transmitted by the radar transmitter reflected from the human target and polarized orthogonal to the transmitted beam;

(e) a data storage device having target reference data stored thereon, including radar signatures corresponding to humans with and without explosives carried on their person;

(f) computing means for continuously comparing a reflected beam received by the radar receiver to the reference data to determine when the human target is carrying explosives and for continuously assessing the target detection and tracking data to determine a threat level; and

(g) alarm means for alerting an operator of the system when the threat level determined by the computing means exceeds a threshold.

29. The system for standoff detection according to claim 28, wherein said detecting means comprises a scanning radar.

30. The system for standoff detection according to claim 28, wherein said detecting means comprises at least one visible light range video camera.

31. The system for standoff detection according to claim 30, wherein said at least one camera comprises a wide field of view camera and a narrow field of view camera.

32. The system for standoff detection according to claim 28, wherein said detecting means comprises an imaging system selected from the group consisting of Ladar, Lidar, infrared, multispectral, hyperspectral, imaging radar, and visible light range video.

33. The system for standoff detection according to claim 28, wherein said focusing means comprises a two-axis pan and tilt gimbal and a platform mounted on the gimbal, said detecting means comprising an imaging sensor mounted on the platform, said radar transmitter and said radar receiver including an antenna system mounted on said platform and co-boresighted with said imaging sensor.

34. The system for standoff detection according to claim 28, wherein said detecting means comprises at least one camera, said focusing means comprising:

a two-axis pan and tilt gimbal;

a platform mounted on the gimbal, said radar transmitter and said radar receiver including an antenna system mounted on said platform; and

a controller connected to the gimbal and to the detecting means, the controller being programmed to pan and tilt the gimbal according to a time, frame, and location determined by said detecting means.

35. The system for standoff detection according to claim 28, wherein said radar transmitter transmits a beam of radiation having a millimeter wavelength.

36. The system for standoff human detection according to claim 28, wherein said radar transmitter and said radar receiver comprise separate modules.

37. The system for standoff detection according to claim 28, wherein said radar transmitter and said radar receiver are combined to form a transceiver.

38. The system for standoff detection according to claim 28, wherein said radar transmitter and said radar receiver comprise a cross-polarized system having vertical polarization in transmit and horizontal polarization in receive.

39. The system for standoff detection according to claim 28, wherein said radar transmitter and said radar receiver comprise a cross-polarized system having horizontal polarization in transmit and vertical polarization in receive.

40. The system for standoff detection according to claim 28, wherein said radar transmitter and said radar receiver comprise a fully polarized system.

41. The system for standoff detection according to claim 28, further comprising means for interdicting the human target when the threat potential exceeds the threshold.

42. A method for the standoff detection of human carried explosives (HCE) within an area of observation using a plurality of HCE detection systems, each HCE system having a radar system, a radar field of regard, an imaging system, and a computer, the method comprising the steps of:

communicatively linking together the plurality of HCE detection systems;

coordinating the radar field of regard of the plurality of HCE detection systems to encompass a range of interest;

creating a plurality of simultaneous radar signatures of the radar field of regard from different look angles;

determining the threat potential of a target based upon the combined data of the plurality of radar signatures.

43. The method for the standoff detection of human carried explosives (HCE) according to claim 42, wherein said coordinating step further comprises overlapping at least two of the HCE detection system radar fields of regard, said determining step further comprising collating and contrasting views of the same radar field of regard taken from different look angles.

44. The method for the standoff detection of human carried explosives (HCE) according to claim 42, wherein said coordinating step further comprises spacing at least two of the HCE detection system radar fields of regard apart sequentially, said determining step further comprising collating and contrasting views of the radar field of regard taken from sequential fields in order to evaluate the threat potential.

45. The method for the standoff detection of human carried explosives (HCE) according to claim 44, wherein said sequential fields are abutting.

46. The method for the standoff detection of human carried explosives (HCE) according to claim 44, wherein said sequential fields are spaced apart from each other by an interval.