Method and apparatus for detecting a moving object through a barrier

• US 6,466,155 B2
• Filed: 03/30/2001
• Issued: 10/15/2002
• Est. Priority Date: 03/30/2001
• Status: Expired due to Term

• Current Assignee: ENSCO, Incorporated (Teris LLC)
• Original Assignee: ENSCO, Incorporated (Teris LLC)
• Inventors: Taylor, David W. A., Faulkner, William Todd
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): ANDREA, BRIAN K
• Application Number:
  US09/821,092
• Publication Number:
  US 20020140597A1
• Time in Patent Office: 564 Days
• Field of Search: 342/22, 342/28, 342/159, 342/162
• US Class Current: 342/22
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/04 Systems determining presence of a target based on relative movement of target G01S13/56
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/50 Systems of measurement based on relative movement of target
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/888 through wall detection
• CPC Class Codes: G01S 2013/0263 Passive array antenna
• CPC Class Codes: G01S 7/14 Sector, off-centre, or expanded angle display
• CPC Class Codes: G01S 7/292 Extracting wanted echo-signals

Abstract

The method and apparatus for detecting a moving object through a barrier uses radar imaging and a multiplicity of spatially separated antennas to acquire full-waveform radar data that accurately represents the measurement of the propagating wavefield. The data is enhanced by subtracting an estimate of previously recorded background data, and beamforming of the enhanced data is performed to compute an image from the data provided on multiple channels.

Claims

1. A method for detecting a moving object through a barrier with a radar system which includes:

transmitting and/or receiving radar signals through said barrier using a multiple radar antenna array to form a plurality of separate channels;

acquiring full waveform radar data signals through said barrier on each said channel, each of the acquired full waveform radar data signals providing a representation of a measured wave field; and

beamforming the full waveform radar data signals to combine the radar data signals from said plurality of channels to provide one or more detected images.

2. The method of claim 1 which includes using a multiple antenna array formed by a plurality of spaced, co-located transmitting and receiving radar antenna pairs.

3. The method of claim 1 which includes sequentially switching between said plurality of separate channels to sequentially acquire full waveform radar data signals from each channel.

4. The method of claim 1 which includes acquiring prior to acquiring said full waveform data signals background data signals indicative of background conditions which will have a negative influence on full waveform data signals to be acquired on each such channel and

enhancing said acquired full waveform data signals from each channel by removing therefrom previously acquired background data signals.

5. The method of claim 4 which includes displaying one or more of the images provided by beamforming.

6. The method of claim 4 which includes acquiring said background data signals by transmitting and/or receiving radar .signals through said barrier using the multiple antenna array with no moving object present.

7. The method of claim 6 which includes sequentially switching between said plurality of separate channels to acquire said background data signals and subsequently sequentially switching between said plurality of separate channels to acquire full waveform radar data signals from each channel.

13. The method of claim 5 which includes deleting redundant detected images resulting from beamforming when multiple detected images occur.

14. The method of claim 13 which includes computing the power level of the radar data signals forming each detected image and deleting images from the display having a power level below a threshold value.

8. A method for detecting a moving object through a barrier with a radar system which includes:

transmitting and/or receiving radar signals through said barrier using a multiple radar antenna array to form a plurality of separate channels;

acquiring full waveform radar data signals through said barrier on each said channel;

beamforming the full waveform radar data signals to combine the radar data signals from said plurality of channels to provide one or more detected images; and

deconvolving the full waveform radar data signals prior to beamforming by developing prior to acquiring said full waveform radar data signals an estimate of the impulse response in the time domain for the radar system and using such estimate of the impulse response to correct said full waveform radar data signals.

9. The method of claim 8 which includes displaying one or more of the images provided by beamforming.

10. The method of claim 8 which includes acquiring prior to acquiring said full waveform data signals background data signals indicative of background conditions which will have a negative influence on full waveform data signals to be acquired on each such channel and

enhancing said acquired full waveform data signals from each channel by removing therefrom previously acquired background data signals.

11. The method of claim 10 which includes acquiring said background data signals by transmitting and/or receiving radar signals through said barrier using the multiple antenna array with no moving object present.

12. The method of claim 11 which includes sequentially switching between said plurality of separate channels to acquire said background data signals and subsequently sequentially switching between said plurality of separate channels to acquire full waveform radar data signals from each channel.

15. A method for detecting a moving object through a barrier with a radar system which includes:

transmitting and/or receiving radar signals through said barrier using a multiple radar antenna array to form a plurality of separate channels;

acquiring full waveform radar data signals through said barrier on each said channel, each of the acquired full waveform radar data signals providing a representation of a measured wave field;

beamforming the full waveform radar data signals to combine the radar data signals from said plurality of channels to provide one or more detected images;

acquiring prior to acquiring said full waveform data signals background data signals indicative of background conditions which will have a negative influence on full waveform data signals to be acquired on each such channel;

enhancing said acquired full waveform data signals from each channel by removing therefrom previously acquired background data signals;

displaying one or more of the images provided by beamforming;

deleting redundant detected images resulting from beamforming when multiple detected images occur;

computing the power level of the radar data signals forming each detected image and deleting images from the display having a power level below a threshold value; and

deconvolving the full waveform radar data signals prior to beamforming by developing prior to acquiring said full waveform radar data signals an estimate of the impulse response in the time domain for the radar system and using such estimate of the impulse response to correct said full waveform radar data signals.

16. The method of claim 15 which includes developing said background data signals by transmitting and/or receiving radar signals through said barrier using the multiple antenna array with no moving object present.

17. The method of claim 16 which includes sequentially switching between said plurality of separate channels to sequentially acquire full waveform radar data signals from each channel.

18. The method of claim 17 which includes sequentially switching between said plurality of separate channels to acquire said background data signals and subsequently sequentially switching between said plurality of separate channels to acquire full waveform radar data signals from each channel.

19. The method of claim 18 which includes using a multiple antenna array formed by a plurality of spaced, co-located transmitting and receiving radar antenna pairs.