Methods and apparatus for detecting threats in different areas

• US 6,856,272 B2
• Filed: 12/08/2003
• Issued: 02/15/2005
• Est. Priority Date: 08/28/2002
• Status: Active Grant

• Current Assignee: Lester Kosowsky
• Original Assignee: Personnel Protection Technologies, LLC
• Inventors: Kosowsky, Lester, Levitan, Arthur C.
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US10/730,171
• Publication Number:
  US 20040183712A1
• Time in Patent Office: 435 Days
• Field of Search: 342/22, 342/27, 342/52, 342/53, 342/54, 342/55, 342/74, 342/75, 342/81, 342/90, 342/91, 342/92, 342/93, 342/94, 342/95, 342/96, 342/97, 342/114, 342/115, 342/176, 342/179, 342/180, 342/191, 342/192, 342/195, 342/196
• US Class Current: 342/22
• CPC Class Codes: F41H 13/00 Means of attack or defence not otherwise provided for details of radar or sonar systems G01S7/00
• CPC Class Codes: G01S 13/08 Systems for measuring distance only indirect measurement G01S13/46
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
• CPC Class Codes: G01S 13/86 Combinations of radar systems with non-radar systems, e.g. sonar, direction finder
• CPC Class Codes: G01S 13/872 Combinations of primary radar and secondary radar
• CPC Class Codes: G08B 31/00 Predictive alarm systems characterised by extrapolation or other computation using updated historic data

Abstract

Methods and apparatus for early detection and identification of a threat such as individuals carrying hidden explosive materials, land mines on roads, etc. are disclosed. Methods comprise transmitting radar signals in the direction of a potential threat, measuring the energy in reflected signals, dynamically generating a threat threshold value from signals received from multiple areas and comparing the energy in the reflected signals corresponding to different areas to the generated threat threshold value. The threat threshold value may be generated by averaging the weighted reflected energy measured from different areas during a single scan of a region including the different areas. The contribution to the threshold from different areas is weighted in some embodiments as a function of the distance from the transmitter and/or receiver to the particular area. Analysis of areas and treating different areas as segments facilitates accurate analysis and display of threat information.

Claims

1. A method for facilitating detection of a threat, the method comprising:

i) operating a transmitter to transmit signals in the direction of a plurality of cells to pan a scene corresponding to said plurality of cells, at least some cells corresponding to different ranges relative to the transmitter;

ii) operating a detector to detect reflected signals during an analysis period received from said plurality of cells; and

iii) determining a threat reference threshold for the analysis period as a function of the reflected signals detected during the analysis period, said step of determining a threat threshold including;

measuring detected reflected signals corresponding to at least some of said plurality of said cells to generate a measured signal value for each particular one of said at least some cells;

modifying the measured signal values corresponding to some particular ones of said at least some cells by a distance factor corresponding to the distance the particular one of the cells is from the transmitter to generate a modified measured signal value for each of said some particular ones of said cells; and

generating the threat reference threshold as a function of at least some of the modified measured signal values.

2. The method of claim 1, wherein generating the threat reference threshold includes:

averaging the modified measured signal values corresponding to a plurality of cells in which at least one human being is located; and

and establishing said threat reference threshold from the generated average.

3. The method of claim 2, further comprising:

comparing the modified measured signal values of at least some cells to the threat reference threshold; and

signaling a threat when said comparison indicates that the modified measured signal value of one of said at least some cells exceeds said threat reference threshold.

4. The method of claim 3, wherein signaling a threat includes:

displaying an image corresponding to said plurality of cells on a display device; and

locating a visual marker on the portion of the displayed image corresponding to each cell that has a modified measured signal value that exceeds said threat reference threshold.

5. The method of claim 4, wherein said step of displaying an image includes:

operating a processor to generate a perspective view of the plurality of cells, the perspective view including;

preselected shapes used to indicate detected information about different cells; and

cell distance information.

6. The method of claim 3, further comprising:

marking displayed cells having modified measured signal values exceeding said threshold in a distinctive manner on said display to distinguish them from displayed cells which do not have modified measured signal values exceeding said threat reference level.

7. The method of claim 6, wherein marking displayed cells in a distinctive manner includes using a first display color for cells having modified a measured signal value exceeding said threat reference level and a second color for cells which do not have a modified measured signal value exceeding said threat reference level, said first color being different from said second color.

8. The system of claim 7, further comprising:

receiving a friend indicator signal from a cell with a modified measured signal value exceeding said threat reference level; and

distinctively marking the cell corresponding to the received friend indicator signal to indicate the presence of a friend in the corresponding cell.

9. The method of claim 8, further comprising:

leaving cells which do not have a human presence blank in said displayed image.

10. The method of claim 1,

wherein said transmitted signals are radar signals,

wherein each cell corresponds to a different transmitter azimuth and range;

and

wherein the method further comprises;

periodically repeating steps i, ii, and iii.

11. The method of claim 1, wherein said measured signal values are energy values.

12. A system for detecting a threat located in one of a plurality of areas corresponding to different locations, the system comprising:

a transmitter that transmits radar signals in the direction of said plurality of areas;

a detector which detects a reflected portion of the signals, the detector measuring the energy in the detected reflected portion of the signals corresponding to each area, to generate a detected energy measurement for each particular one of said areas;

means for modifying the detected energy measurements corresponding to some areas by a distance factor corresponding to the distance the area is from the transmitter to generate a modified measured detected energy value for each of said some areas;

means for generating a threat reference threshold as a function of at least some of the modified measured detected energy values; and

a comparator for comparing at least some of the modified detected energy measurements to said threat reference threshold to identify areas of possible threats indicated by the modified detected energy measurement of an area exceeding said threat reference threshold.

13. The system of claim 12, further comprising:

a display processor; and

a display, said display processor generating a visual representation on said display of at least some of said plurality of areas and indicating on said visual representation areas having modified detected energy values which exceed said threat reference threshold.

14. The system of claim 13, wherein said visual representation includes distance information.

15. The system of claim 14, wherein a first display color is used to mark areas of the visual representation corresponding to areas having modified detected energy values which exceed said threat reference threshold and a second display color is used to mark areas having modified detected energy values which are below said threat reference threshold, said first and second colors being different.

16. The system of claim 15, further comprising:

a receiver for receiving friend indicator signals from said areas, said visual representation including a friend indicator marker on display areas corresponding to an area from which a friend indicator signal was received.

17. The system of claim 16, wherein said visual representation includes a visual image of the physical areas to which each visual representation image area corresponds.

18. The system of claim 12, wherein said means for generating the threat reference threshold includes:

means for averaging the modified detected energy values corresponding to a plurality of cells.

23. The method of claim 18, wherein said scene is an indoor scene.

19. A method for facilitating detection of a threat, the method comprising:

i) operating a transmitter to transmit signals in the direction of a plurality of cells to pan a scene corresponding to said plurality of cells;

ii) operating a receiver to detect reflected signals during an analysis period received from said plurality of cells, at least some of said cells being at different distances from the receiver; and

iii) determining a threat reference threshold for the analysis period as a function of the reflected signals detected during the analysis period, said step of determining a threat threshold including;

measuring detected reflected signals corresponding to at least some of said plurality of said cells to generate a measured signal value for each particular one of said at least some cells;

modifying the measured signal values corresponding to some particular ones of said at least some cells by a distance factor corresponding to the distance the particular one of the cells is from the receiver to generate a modified measured signal value for each of said some particular ones of said cells; and

generating the threat reference threshold as a function of at least some of the modified measured signal values.

20. The method of claim 19, wherein generating the threat reference threshold includes:

averaging the modified measured signal values corresponding to a plurality of cells in which at least one human being is located; and

and establishing said threat reference threshold from the generated average.

21. The method of claim 20, wherein the measured signal values are energy values.

22. The method of claim 19, wherein said scene is an outdoor scene.