Cellular radar

• US 6,690,318 B1
• Filed: 12/27/2002
• Issued: 02/10/2004
• Est. Priority Date: 12/27/2002
• Status: Expired due to Fees

• Current Assignee: General Atomics, Inc.
• Original Assignee: General Atomics, Inc.
• Inventors: Tsunoda, Stanley I.
• Primary Examiner(s): Tarcza, Thomas H.
• Assistant Examiner(s): ALSOMIRI, ISAM A
• Application Number:
  US10/330,656
• Time in Patent Office: 410 Days
• Field of Search: 342/59, 342/74, 342/126, 342/148, 342/158, 342/160, 342/450, 340/3.1, 340/541, 340/552, 340/825
• US Class Current: 342/59
• CPC Class Codes: G01S 13/5242 with means for platform motion or scan motion compensation, e.g. airborne MTI
• CPC Class Codes: G01S 13/726 Multiple target tracking
• 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 13/9029 specially adapted for moving target detection within a single SAR image or within multiple SAR images taken at the same time
• CPC Class Codes: G01S 2013/466 by Trilateration, i.e. two antennas or two sensors determine separately the distance to a target, whereby with the knowledge of the baseline length, i.e. the distance between the antennas or sensors, the position data of the target is determined
• CPC Class Codes: G01S 7/003 Transmission of data between radar, sonar or lidar systems and remote stations

Abstract

A cellular radar system is disclosed for detecting and tracking objects in a surveillance area that is divided into cells. Each cell is scanned by at least two radars to produce two (or more) respective datastreams for the cell. Orbiting unmanned air vehicles can be used as radar platforms. The resulting datastreams for each cell are then multilaterated by a processor to produce a multilaterated datastream for each cell. The multilaterated datastreams for all cells are then combined by the processor and the resulting data used to detect or track one or more objects in the surveillance area. The fused multilaterated datastreams allow objects to be tracked as they move from cell to cell.

Claims

1. A method for detecting an object in a surveillance area, said method comprising the steps of:

partitioning the surveillance area into a plurality of cells;

radar scanning each said cell with at least two radars to produce at least two respective radar datastreams for each cell;

multilaterating said radar datastreams for each said cell to produce a multilaterated datastream for each said cell;

combining said multilaterated datastreams; and

using said combined multilaterated datastreams to detect an object in the surveillance area.

2. A method as recited in claim 1 wherein each said cell is hexagonally shaped.

3. A method as recited in claim 2 wherein said radar scanning step comprises the step of simultaneously orbiting about the center of each hexagonally shaped cell with a radar equipped unmanned air vehicle, with each said radar equipped unmanned air vehicle scanning two adjacent hexagonally shaped cells.

4. A method as recited in claim 1 wherein said step of radar scanning each cell with at least two radars is accomplished with at least two radar-equipped unmanned air vehicles.

5. A method as recited in claim 1 wherein said radar scanning step is accomplished using radar in ground moving target indication (GMTI) mode.

6. A method as recited in claim 5 further comprising the step of radar scanning the surveillance area with a radar in synthetic aperture radar (SAR) mode to create a stationary image for the surveillance area and the step of using said stationary image with said multilaterated datastreams to detect an object in the surveillance area.

7. A method as recited in claim 1 further comprising the step of radar scanning in at least one said cell using radar in high-range resolution (HRR) mode.

8. A system for detecting an object in a surveillance area made up of a plurality of cells, said system comprising:

a plurality of radars, each radar for scanning at least one cell and creating a datastream for each cell scanned;

a plurality of radar positioning means, each said radar positioning means for maintaining a said radar at positions to allow at least two cells to each be scanned by at least two said radars to produce at least two respective datastreams for each cell;

means for multilaterating datastreams to produce a multilaterated datastream for each cell; and

means for displaying said multilaterated datastreams to provide an indication of the object in the surveillance area.

9. A system as recited in claim 8 wherein at least one said radar positioning means comprises an unmanned air vehicle (UAV).

10. A system as recited in claim 8 wherein each said radar is configurable into a ground moving target indication (GMTI) mode and a high-range resolution mode (HRR).

11. A system as recited in claim 8 wherein said means for multilaterating datastreams comprises a computer processor.

12. A system as recited in claim 8 wherein said means for multilaterating datastreams comprises a computer processor located at a base site and wherein said system further comprises a plurality of high speed links for communication between said plurality of radars and said base station.

13. A system as recited in claim 8 wherein at least one said radar is configurable into a synthetic aperture radar (SAR) mode.

14. A method for detecting an object in a surveillance area, said method comprising the steps of:

dividing the surveillance area into a plurality of cells;

providing a plurality of radar equipped air vehicles;

radar scanning each cell with at least two radar equipped air vehicles to produce at least two respective radar datastreams for each cell; and

using said radar datastreams for each cell to provide an indication of the object in the surveillance area.

15. A method as recited in claim 14 wherein each said cell is hexagonally shaped.

16. A method as recited in claim 15 wherein said radar scanning step comprises the step of simultaneously orbiting about the center of each hexagonally shaped cell with a said radar equipped air vehicle, with each said radar equipped air vehicle scanning two adjacent hexagonally shaped cells.

17. A method as recited in claim 14 wherein at least one said radar equipped air vehicle is unmanned.

18. A method as recited in claim 14 wherein said radar equipped air vehicles are unmanned.

19. A method as recited in claim 14 wherein said radar scanning step is accomplished using radar in ground moving target indication (GMTI) mode.

20. A method as recited in claim 19 further comprising the step of radar scanning the surveillance area with a radar in synthetic aperture radar (SAR) mode to create a stationary image for the surveillance area and the step of using said stationary image with said multilaterated datastreams to detect an object in the surveillance area.