System and method for automatically acquiring a target with a narrow field-of-view gimbaled imaging sensor

• US 7,636,452 B2
• Filed: 03/23/2005
• Issued: 12/22/2009
• Est. Priority Date: 03/25/2004
• Status: Active Grant

• Current Assignee: Rafael - Armament Development Authority Ltd.
• Original Assignee: Rafael Advanced Defense Systems Limited (Government of Israel)
• Inventors: Kamon, Ishay
• Primary Examiner(s): Werner; Brian P
• Assistant Examiner(s): MACKOWEY, ANTHONY M
• Application Number:
  US11/086,466
• Publication Number:
  US 20050218259A1
• Time in Patent Office: 1,735 Days
• Field of Search: 382/103, 382/106, 382/294, 382/295, 348/153, 348/208.14, 348/208.15, 348/152, 348/159, 89/410.5, 89/361.1, 235/405, 235/409, 235/410, 235/411
• US Class Current: 382/103
• CPC Class Codes: F41G 3/326 for checking the angle between the axis of the gun sighting device and an auxiliary measuring device F41G3/323 takes precedence
• CPC Class Codes: F41G 5/08 Ground-based tracking-systems for aerial targets

Abstract

A system for automatically acquiring a target with a narrow field-of-view gimbaled imaging sensor. The system includes a target-detection subsystem including one or more target-detection imaging sensor with a first field-of-view, a target-tracking subsystem and a processing system in communication with the target-detection subsystem and the target-tracking imaging subsystem. The target-tracking subsystem includes a target-tracking imaging sensor with a second field-of-view smaller than the first field-of-view, and a gimbal mechanism for controlling a viewing direction of the target-tracking imaging sensor. The processing system includes a target transfer module responsive to detection of a target by the target-detection subsystem to process data from the target-detection subsystem to determine a target direction vector, operate the gimbal mechanism so as to align the viewing direction of the target-tracking imaging sensor with the target direction vector, derive an image from the target-tracking imaging sensor, correlate the image with one or more part of an image from the target-detection subsystem to derive a misalignment error, and supply the misalignment error to the target-tracking subsystem for use in acquisition of the target.

Claims

1. A system for automatically acquiring a target with a narrow field-of-view gimbaled imaging sensor, the system comprising:

(a) a target-detection subsystem including at least one target-detection imaging sensor having a first field-of-view;

(b) a target-tracking subsystem including;

(i) a target-tracking imaging sensor having a second field-of-view significantly smaller than said first field-of-view, and

(ii) a gimbal mechanism for controlling a viewing direction of said target-tracking imaging sensor; and

(c) a processing system in communication with said target-detection subsystem and said target-tracking imaging subsystem, said processing system including a target transfer module responsive to detection of a target by said target-detection subsystem to;

(i) process data from said target-detection subsystem to determine a target direction vector,

(ii) operate said gimbal mechanism so as to align the viewing direction of said target-tracking imaging sensor with said target direction vector,

(iii) derive an image from said target-tracking imaging sensor,

(iv) correlate said image with at least part of an image from said target-detection subsystem by correlating features of said images to achieve image registration, thereby deriving a misalignment error, said correlating being based at least in part on background features not corresponding to the target, and

(v) supply said misalignment error to said target-tracking subsystem for use in acquisition of the target.

2. The system of claim 1, further comprising at least one missile countermeasure subsystem associated with said target-tracking subsystem.

3. The system of claim 1, wherein said target-detection subsystem includes a plurality of said target-detection imaging sensors deployed in fixed relation to provide an effective field-of-view significantly greater than said first field of view.

4. The system of claim 1, wherein corresponding regions of said images from said target-tracking imaging sensor and from said target-detection imaging sensor have angular pixel resolutions differing by a factor of at least 2:

1.

5. The system of claim 1, wherein said target transfer module is configured to correlate said image from said target-tracking imaging sensor with an image sampled from said target-detection imaging sensor at a time substantially contemporaneous with sampling of said image from said target-tracking imaging sensor.

6. The system of claim 1, wherein said target-tracking subsystem is configured to be responsive to said misalignment error to operate said gimbal mechanism so as to correct alignment of the viewing direction of said target-tracking imaging sensor with the target.

7. A method for automatically acquiring a target by using a system with a target-detection subsystem including at least one target-detection imaging sensor having a first field-of-view and a target-tracking subsystem including an imaging sensor having a second field-of-view significantly smaller than said first field-of-view, the method comprising:

(a) employing the target-detection subsystem to detect a target;

(b) determining from said target-detection subsystem a target direction vector;

(c) operating a gimbal mechanism of the target-tracking subsystem so as to align a viewing direction of the target-tracking imaging sensor with the target direction vector;

(d) deriving an image from said target-tracking imaging sensor;

(e) correlating said image with at least part of an image from said target-detection subsystem by correlating features of said images to achieve image registration, thereby deriving a misalignment error, said correlating being based at least in part on background features not corresponding to the target; and

(f) supplying said misalignment error to the target-tracking subsystem for use in acquisition of the target.

8. The method of claim 7, further comprising operating a missile countermeasure subsystem associated with the target-tracking subsystem.

9. The method of claim 7, wherein the target-detection subsystem includes a plurality of said target-detection imaging sensors deployed in fixed relation to provide an effective field-of-view significantly greater than said first field of view.

10. The method of claim 7, wherein corresponding regions of said images from said target-tracking imaging sensor and from said target-detection imaging sensor have angular pixel resolutions differing by a factor of at least 2:

1.

11. The method of claim 7, wherein said correlating is performed using an image sampled from the target-detection imaging sensor at a time substantially contemporaneous with sampling of said image from the target-tracking imaging sensor.

12. The method of claim 7, further comprising correcting alignment of the viewing direction of said target-tracking imaging sensor as a function of said misalignment error.