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

• US 20010035837A1
• Filed: 01/23/2001
• Published: 11/01/2001
• Est. Priority Date: 06/14/1999
• Status: Active Grant

• Current Assignee: Humatics Corporation
• Original Assignee: Time Domain Corporation (Humatics Corporation)
• Inventors: Richards, James L., Fullerton, Larry W.
• Granted Patent: US 6,400,307 B2
• Time in Patent Office: Days
• 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. An intrusion detection system comprising:

a first time modulated ultra wideband (TM-UWB) radar, wherein said first TM-UWB radar is adapted to transmit UWB pulses and receive signal returns, and wherein said UWB pulses have a wavelength corresponding to the center frequency of said UWB pulses;

a second TM-UWB radar, spaced a distance from said first TM-UWB radar, said distance being greater than ¾

of said wavelength, wherein said second TM-UWB radar is adapted to transmit further UWB pulses, and wherein said further UWB pulses have said wavelength; and

a processor in communications with at least said first TM-UWB radar, wherein said processor detects intrusion based on said signal returns.

2. The system of

claim 1

, wherein said first TM-UWB radar receives signal returns that correspond to said UWB pulses transmitted by said first TM-UWB radar, and

wherein said processor detects intrusion based on at least said signal returns that correspond to said UWB pulses transmitted by said first TM-UWB radar.

3. The system of

claim 1

, wherein said first TM-UWB radar receives signal returns that correspond to said further UWB pulses transmitted by said second TM-UWB radar, and

wherein said processor detects intrusion based on at least said signal returns that correspond to said further UWB pulses transmitted by said second TM-UWB radar.

4. The system of

claim 1

, wherein said first TM-UWB radar receives signal returns that correspond to said UWB pulses transmitted by said first TM-UWB radar and signal returns that correspond to said further UWB pulses transmitted by said second TM-UWB radar, and

wherein said processor detects intrusion based on said signal returns that correspond to said UWB pulses transmitted by said first TM-UWB radar and said signal returns that correspond to said further UWB pulses transmitted by said second TM-UWB radar.

5. The system of

claim 1

, wherein said processor detects intrusion by determining whether an alarm condition is met based on said signal returns.

6. The system of

claim 1

, wherein said processor detects intrusion by detecting movement of an object in a given area based on said signal returns.

7. The system of

claim 6

, wherein the object comprises one or more human beings positioned outside of a building and wherein said first and second TM-UWB radars are positioned inside the building.

8. The system of

claim 6

, wherein the given area includes a predetermined boundary, and wherein said processor triggers an alarm when said processor detects penetration of the boundary by the object.

9. The system of

claim 8

, wherein the boundary comprises a first side and a second side, and wherein said processor only triggers the alarm when said processor detects movement toward the first side of the boundary.

10. The system of

claim 8

, wherein the boundary is defined by a location of a window.

11. The system of

claim 6

, wherein the given area comprises a predetermined boundary, and wherein said processor triggers an alarm when said processor detects movement toward, and penetration of, the boundary by the object.

12. The system of

claim 11

, wherein the boundary includes a first side and a second side, and wherein said processor only triggers the alarm when said processor detects movement toward, and penetration of, the first side of the boundary.

13. The system of

claim 11

, wherein the boundary is defined by a location of a window.

14. The system of

claim 11

, wherein the first side of the boundary is outside a building, and wherein the second side of the boundary is inside the building.

15. The system of

claim 1

, wherein said processor generates an image based on said signal returns and detects intrusion based on said image.

16. The system of

claim 15

, wherein said processor generates a reflectogram based on said signal returns and generates said image based on said reflectograms.

17. The system of

claim 1

, wherein said processor generates an image based on said returns signals, subtracts said image from a clutter map to thereby create a differential map, and detects intrusion based on said differential map.

18. The system of

claim 17

, wherein said processor triggers an alarm when it detects intrusion, and wherein said clutter map represents objects that should not cause said processor to trigger the alarm.

19. The system of

claim 17

, wherein said processor updates a track file based on said differential map, tracks movement in a given area based on said track file, and detects intrusion based on the movement.

20. The system of

claim 1

, wherein said first and second TM-UWB radars are positioned along the perimeter of a building.

21. The system of

claim 1

, further comprising:

a first wireless link coupled to said processor; and

a second wireless link coupled to said second TM-UWB radar,

wherein said second wireless link communicates with said first wireless link,

wherein said second TM-UWB radar receives signal returns that correspond to UWB pulses transmitted by said second TM-UWB radar, and

wherein said processor detects intrusion based on said signal returns received by said first and second TM-UWB radars.

22. The system of

claim 1

, wherein said first TM-UWB radar receives signal returns that correspond to UWB pulses transmitted by said second TM-UWB radar, and wherein said first and second TM-UWB radars are synchronized.

23. The system of

claim 1

, wherein said second TM-UWB radar receives signal returns that correspond to UWB pulses transmitted by said second TM-UWB radar, wherein said first TM-UWB radar receives signal returns that correspond to UWB pulses transmitted by said second TM-UWB radar, wherein said first and second TM-UWB radars are synchronized, and wherein said processor detects intrusion based on said signal returns received by said first and second TM-UWB radars.

24. An intrusion detection system comprising:

a first time modulated ultra wideband (TM-UWB) radar, wherein said first TM-UWB radar is adapted to transmit UWB pulses in a given area and to receive signal returns, wherein said UWB pulses have a wavelength corresponding to the center frequency of said UWB pulses;

a second TM-UWB radar, spaced a distance from said first TM-UWB radar, said distance being greater than ¼

of said wavelength, wherein said second TM-UWB radar is adapted to transmit further UWB pulses in said given area, wherein said further UWB pulses have said wavelength; and

a processor in communications with at least said first TM-UWB radar, wherein said processor detects motion within said given area based on said signal returns.

25. The system of

claim 24

, wherein said first TM-UWB radar receives signal returns that correspond to said UWB pulses transmitted by said first TM-UWB radar, and

wherein said processor detects intrusion based on at least said signal returns that correspond to said UWB pulses transmitted by said first TM-UWB radar.

26. The system of

claim 24

, wherein said first TM-UWB radar receives signal returns that correspond to said further UWB pulses transmitted by said second TM-UWB radar, and

wherein said processor detects intrusion based on at least said signal returns that correspond to said further UWB pulses transmitted by said second TM-UWB radar.

27. The system of

claim 24

, wherein said first TM-UWB radar receives signal returns that correspond to said UWB pulses transmitted by said first TM-UWB radar and signal returns that correspond to said further UWB pulses transmitted by said second TM-UWB radar, and

wherein said processor detects intrusion based on said signal returns that correspond to said UWB pulses transmitted by said first TM-UWB radar and said signal returns that correspond to said further UWB pulses transmitted by said second TM-UWB radar.

28. A method for detecting intrusion, comprising the steps of:

a. transmitting ultra wideband (UWB) pulses from a first location, wherein said UWB pulses have a wavelength corresponding to the center frequency of said UWB pulses;

b. transmitting further UWB pulses having said wavelength from a second location, wherein said second location is spaced a distance from said first location, said distance being greater than ¼

of said wavelength;

c. receiving signal returns at at least said first location; and

d. detecting intrusion based on said signal returns.

29. The method of

claim 28

, wherein said step d. comprises the steps of:

i. generating an image based on said signal returns; and

ii. detecting intrusion based on said image.

30. The method of

claim 28

, wherein said step d. comprises the steps of:

i. generating reflectogram data based on said signal returns;

ii. generating an image based on said reflectogram data; and

iii. detecting intrusion based on said image.

31. The method of

claim 30

, wherein said step d.iii. comprises the steps of:

(1) subtracting said image from a clutter map to thereby create a differential map; and

(2) detecting intrusion based on said differential map.

32. The method of

claim 31

, wherein said step d.iii.(2) comprises the steps of:

(a) updating a track file based on said differential map;

(b) tracking movement of an object based on said track file; and

(c) triggering an alarm based on said movement.

33. The method of

claim 28

, further comprising the step of determining relative positions of said first location and said second location with respect to one another prior to said step d..

34. The method of

claim 33

, wherein said step of determining relative positions comprises the steps of:

i. receiving additional UWB pulses, at said first and second locations;

ii. generating calibration data based on said additional UWB pulses; and

iii. determining said relative positions based on said calibration data.

35. The method of

claim 34

, wherein said additional UWB pulses are generated by a transmitter moving along a calibration path.

36. The method of

claim 28

, wherein said step d. comprises the step of:

i. determining whether an alarm condition has been met based on said signal returns.

37. The method of

claim 28

, wherein step c. comprises the step of receiving signal returns at said first location and said second location, and wherein step d. comprises the step of detecting intrusion based on said signal returns received at said first location and said second location.