Scanners

• US 8,674,875 B2
• Filed: 09/07/2007
• Issued: 03/18/2014
• Est. Priority Date: 09/07/2006
• Status: Active Grant

• Current Assignee: BAE Systems Plc, MBDA UK Ltd. (MBDA SAS)
• Original Assignee: MBDA UK Ltd. (MBDA SAS)
• Inventors: Carter, Christopher Ralph, Rowatt, Charles Anthony
• Primary Examiner(s): GREGORY, BERNARR E
• Application Number:
  US12/440,394
• Publication Number:
  US 20100039309A1
• Time in Patent Office: 2,384 Days
• Field of Search: 342/21, 342/22, 342/59, 342/89, 342/90, 342/147, 342/158, 342/175, 342/176, 342/179, 342/195, 342/27, 342/28, 342 52- 55, 342/118, 342127-146, 342/188, 342/196, 342361-366, 342/70
• US Class Current: 342/179
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• 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 13/426 Scanning radar, e.g. 3D radar G01S13/66 takes precedence
• CPC Class Codes: G01S 13/86 Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 7/026 involving the transmission of elliptically or circularly polarised waves
• CPC Class Codes: G07C 9/10 Movable barriers with registering means

Abstract

The invention provides a security scanner that produces a radar profile of a clothed person or another object such as a bag carried by a person at a distance and does not require close proximity of the person or object to the scanner itself. The scanner includes a millimeter wave antenna system optimised for short-range active imaging and arranged to provide rapid high-resolution images of an object or person of interest and processing means for resolving the images so as to detect the presence of predetermined objects. The processing means preferably includes means for comparing contrasts in reflectivity in the scanned images with predetermined expected values from skin and light clothing. The processing means may also include means for detecting predetermined behavioral or physical traits such as the effect on gait on carried weighty objects or stiff structures strapped to the person from the images of a scanned object or person. The scanner may be incorporated within a turnstile access arrangement.

Claims

1. A security scanner, comprising:

a millimeter wave radar arrangement that includes an antenna system for short-range active imaging using a radar waveform having a waveform cycle, wherein the antenna system includes a mirror system for scanning an object or person of interest at one lateral resolution increment per waveform cycle, and generates image signals as a result of the scan; and

processing means for resolving the images generated by the antenna system to detect the presence of predetermined objects.

2. The security scanner according to claim 1, wherein the antenna system utilises circularly polarised radiation.

3. The security scanner according to claim 1, wherein the antenna system comprises a single mono-static antenna element.

4. The security scanner according to claim 1, wherein the antenna system comprises two mono-static antenna elements arranged as a single bi-static antenna.

5. The security scanner according to claim 1, wherein the antenna system comprises at least two mono-static antenna elements arranged as a dual mono-static antenna.

6. The security scanner according claim 1, wherein the antenna system utilises a quasi-optical lens system to collimate the transmitted radar waves and to perform polar analysis of the returned radar waves.

7. The security scanner according to claim 1, wherein the antenna system includes a frequency modulated continuous wave (FMCW) transmitter.

8. The security scanner according to claim 1, wherein the antenna system includes an interrupted frequency modulated (FMICW) transceiver that rejects unwanted signals from objects at a range greater than the object of interest.

9. The security scanner according to claim 7, comprising a low power transmitter.

10. The security scanner according to claim 1, wherein the mirror system includes a plurality of synchronised scanning mirrors arranged to scan in the azimuth plane.

11. The security scanner according to claim 1, wherein the processing means includes means for comparing contrasts in reflectivity in the scanned images with predetermined expected values.

12. The security scanner according to claim 1, wherein the processing means is configured for detecting predetermined behavioural or physical traits from the images of a scanned object or person.

13. The security scanner according to claim 1, wherein the antenna system comprises at least two mono-static antenna elements arranged as a bi-static antenna.

14. A security scanner, comprising:

a millimeter wave radar arrangement that includes an antenna system for short-range active imaging using a radar waveform having a waveform cycle, wherein the antenna system includes a mirror system for scanning an object or person of interest at one lateral resolution increment per waveform cycle, and generates image signals as a result of the scan; and

processing means for resolving the images generated by the antenna system to detect the presence of predetermined objects,

wherein the antenna system includes an interrupted frequency modulated (FMICW) transceiver that rejects unwanted signals from objects at a range greater than the object of interest.