System and method for intrusion detection using a time domain radar array

• US 6,400,307 B2
• Filed: 01/23/2001
• Issued: 06/04/2002
• Est. Priority Date: 06/14/1999
• Status: Expired due to Term

• Current Assignee: Humatics Corporation
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Richards, James L., Fullerton, Larry W.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US09/767,131
• Publication Number:
  US 20010035837A1
• Time in Patent Office: 497 Days
• Field of Search: 342/21, 342/22, 342/28, 342/27, 342/58, 342/59, 342/60, 342/179, 342/194, 342/195
• US Class Current: 342/28
• 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 13/56 for presence detection presence detection using near field arrangements G01V3/00, e.g. G01V3/08, G01V3/12; burglar, theft or intruder alarms with electrical actuation G08B13/22 - G08B13/26
• CPC Class Codes: G01S 13/87 Combinations of radar systems, e.g. primary radar and secondary radar
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• 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 13/888 through wall detection
• CPC Class Codes: G01S 13/89 for mapping or imaging
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations
• CPC Class Codes: G01S 7/4004 of parts of a radar system
• CPC Class Codes: G08B 13/1636 using pulse-type detection circuits

Abstract

A system and method for highly selective intrusion detection using a sparse array of time modulated ultra wideband (TM-UWB) radars. Two or more TM-UWB radars are arranged in a sparse array around the perimeter of a building. Each TM-UWB radar transmits ultra wideband pulses that illuminate the building and the surrounding area. Signal return data is processed to determine, among other things, whether an alarm condition has been triggered. High resolution radar images are formed that give an accurate picture of the inside of the building and the surrounding area. This image is used to detect motion in a highly selective manner and to track moving objects within the building and the surrounding area. Motion can be distinguished based on criteria appropriate to the environment in which the intrusion detection system operates.

Claims

1. A method for detecting motion of an object using at least first and second ultra wide band (UWB) radars that are separated from one another, comprising the steps of:

(a) receiving first time modulated UWB (TM-UWB) pulses at the first and second UWB radars, the first TM-UWB pulses generated by an UWB transmitter moving along a calibration path, the calibration path defining an area to be monitored;

(b) determining positions of the first and second UWB radars in relation to each other and the calibration path based on the first TM-UWB pulses received at the first and second UWB radars;

(c) transmitting second TM-UWB pulses from the first UWB radar;

(d) transmitting third TM-UWB pulses from the second UWB radar;

(e) receiving signal returns at at least one of the first and second TM-UWB radars; and

(f) detecting motion within the area to be monitored based on the received signal returns.

2. The method of claim 1, wherein said step (b) comprises:

(b.1) generating calibration data based on the first TM-UWB pulses- and

(b.2) determining the positions of the first and second UWB radars in relation to each other and the calibration path on the calibration data.

3. The method of claim 1, further comprising g a step of generating an image based on the signal returns.

4. The method of claim 1, wherein said step (f) comprises the steps of:

(f.1) generating reflectogram data based on the signal returns;

(f.2) generating an image based on the reflectogram data; and

(f.3) detecting motion based on the image.

5. The method of claim 1, wherein said step (f) comprises:

(f.1) generating an image based on the signal returns;

(f.2) subtracting the image from a clutter map to thereby create a differential map; and

(f.3) detecting motion based on the differential map.

6. The method of claim 5, further comprising a step of triggering an alarm when motion is detected, and wherein the clutter map represents objects that should not cause the triggering of the alarm.

7. The method of claim 1, wherein said step (a) further comprises moving the UWB transmitter along the calibration path.

8. The method of claim 1, wherein said step (e) comprises receiving signal returns at both the first and second UWB radars.

9. A system for detecting motion of an object, comprising:

a first ultra wide band (UWB) radar adapted to receive first time modulated UWB (TM-UWB) pulses from an UWB transmitter moving along a calibration path defining a region to be monitored, said first UWB radar also adapted to transmit second TM-UWB pulses;

a second UWB radar separated from said first UWB radar, said second UWB radar adapted to receive said first TM-UWB pulses from the UWB transmitter moving along the calibration path, said first UWB radar also adapted to transmit third TM-UWB pulses; and

a processor in communications with said first and second UWB radars;

wherein said first and second UWB radars are also adapted to determine calibration data from the first TM-UWB pulses, to receive signal returns, and to forward the calibration data and signal return data to said processor,

wherein said processor is adapted to determine positions of said first and second UWB radars in relation to each other and the calibration path based on the calibration data, and to detect motion within the region to be monitored based on the signal return data.

10. The system of claim 9, wherein the region includes a boundary having a first side and a second side, and wherein said processor triggers an alarm when it detects motion toward the first side of the boundary.

11. The system of claim 10, wherein the boundary is defined by a location of a window.

12. The system of claim 10, wherein the region includes a predetermined boundary, and wherein said processor triggers an alarm when said processor detects motion toward, and penetration of, the boundary by an object.

13. The system of claim 10, wherein the boundary includes a first side and a second side, and wherein said processor only triggers the alarm when said processor detects motion toward, and penetration of, the first side of the boundary.

14. The system of claim 13, wherein the boundary is defined by a location of a window.

15. The system of claim 14, wherein the first side of the boundary is outside a building, and wherein the second side of the boundary is inside the building.

16. The system of claim 9, wherein the processor generates an image based on the signal returns and detects motion based on the image.

17. The system of claim 9, wherein said processor generates one or more reflectograms based on the signal returns and generates the image based on the one or more reflectograms.

18. The system of claim 9, wherein said processor generates an image based on the returns signals, subtracts the image from a clutter map to thereby create a differential map, and detects motion based on the differential map.

19. The system of claim 18, wherein said processor triggers an alarm when it detects motion, and wherein the clutter map represents objects that should not cause the processor to trigger the alarm.