Optically multiplexed dual line of sight flir system

• US 5,418,364 A
• Filed: 04/28/1993
• Issued: 05/23/1995
• Est. Priority Date: 09/04/1991
• Status: Expired due to Fees

• Current Assignee: Northrop Grumman Corporation
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Norris, Victor J. Jr., Clarke, William F., Hurt, Fred S., Hale, Robert A.
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/054,109
• Time in Patent Office: 755 Days
• Field of Search: 250/334, 250/348, 250/347, 244/3.16
• US Class Current: 250/334
• CPC Class Codes: F41G 3/24 Bombsights

Abstract

A dual line of sight forward looking infrared (FLIR) navigation and targeting system including two separate infrared turrets housing respective optical gimbal assemblies which simultaneously provide two independently controlled lines of sight, one of which has wide field(s) of view for implementing a pilotage function and the other has narrow magnified field(s) of view for implementing a targeting function. Both lines of sight are merged following individual temperature compensating image gain and level adjusting operations in an optical multiplexer assembly, the output of which is coupled to a single IR detector in the form of a focal plane array having time delay integration. Two separate FLIR video image signals are generated in a single common processor, one for pilotage and one for targeting which can be viewed simultaneously and independently. The processor is also utilized and integrated with a radar system.

Claims

1. An independent dual line of sight forward looking infrared navigation and target acquisition and tracking system mounted on an aircraft for providing separate pilotage and targeting functions, comprising:

a first and a second line of sight optical gimbal assembly, independently controllable by an operator located in said aircraft, for receiving respective infrared images in first and second fields of view directed along separate first and second lines of sight, said first field of view comprising a relatively wide pilotage field of view and said second field of view comprising a relatively narrow targeting field of view;

first and second turret means located on a fuselage portion of said aircraft for respectively housing said first and second gimbal assembly;

first and second image deroll means located in respective optical paths of said first and second lines of sight for correcting any roll disorientation of the respective images introduced by said gimbal assemblies so that said images remain oriented with the line of vision of said operator;

first and second thermal reference means respectively located in said optical paths for continually inserting separate reference temperatures into a video data stream outputted from infrared detector means responsive to the respective images in said first and second field of view so that the dynamic response of both said images is independently adjusted and maintained in accordance with the level of respective scene information observed by said gimbal assemblies;

an optical multiplexer assembly including image scanner means located adjacent said first and second thermal reference means for receiving roll corrected infrared images from said gimbal assemblies and generating a single multiplexed output of two consecutive infrared images, one of said first field of view and one of said second field of view,

said optical multiplexer assembly additionally including autofocus means in each of said optical paths for maintaining focus of said images for temperature changes encountered by said aircraft during aircraft operations;

infrared detector means responsive to said single multiplexed output of two consecutive infrared images and generating said video data stream; and

signal processor means coupled to said infrared detector means and being responsive to said video data stream outputted from said infrared detector means for generating first and second video image signals, respectively, of said pilotage field of view and said targeting field of view for selective viewing by said operator.

2. The system as defined by claim 1 wherein said relatively narrow targeting field of view comprises a magnified field of view.

3. The system as defined by claim 1 wherein said first and second image deroll means each includes a deroll prism.

4. The system as defined by claim 3 wherein said first and second thermal reference means are located between the respective deroll prisms of said first and second image deroll means and said image scanner means.

5. The system as defined by claim 1 wherein said signal processor means includes signal conditioner means responsive to said first and second thermal reference means for generating control signals coupled to said infrared detector means for controlling the signal gain of said video data stream.

6. The system as defined by claim 5 wherein said infrared detector means includes a plurality of detector channels and wherein said control signals from said signal conditioner means equalizes the respective gains of said plurality of detector channels.

7. The system as defined by claim 1 wherein said signal processor means is also responsive to radar signals for generating radar video signals for viewing by said operator.

8. The system as defined by claim 6 wherein said signal processor means comprises a multi-sensor processor having respective digital signal and data processors for both infrared signals and radar signals and including a common memory coupled to all said processors.

9. The system as defined by claim 1 wherein said first and second turret means are located on a front fuselage portion of said aircraft.

10. The system as defined by claim 9 wherein said operator comprises a pilot of said aircraft.

11. The system as defined by claim 10 wherein signal processor means comprises a multisensor signal processor for controlling said gimbal assemblies and generating pilotage and targeting video signals for selective viewing by a pilot of said aircraft.

12. The system as defined by claim 1 wherein said optical multiplexer assembly includes input means directed toward said infrared energy in said first and second fields of view, mechanical scanner means located adjacent said input means and having first and second reflective image surfaces of the respective infrared energy in said first and second fields of view, an optical multiplexer located between said scanner means and said detector means, and being operable to alternate the blocking and passing of infrared energy directed thereto from said first and second reflective image surfaces of said scanner means.

13. The system as defined by claim 1 wherein said first and second thermal reference means each comprise hot and cold thermal reference means respectively located in said first and second fields of view and defining the outer edges of the energy applied to said first and second reflective image surfaces.

14. The system as defined by claim 13 wherein said scanner means comprises a pivotally oscillated scanner member including opposite flat first and second reflective image surfaces.

15. The system as defined by claim 14 wherein said thermal reference means and said reflective image surfaces are mutually offset with respect to one another and additionally including first and second stationary mirror means respectively located therebetween.

16. The system as defined by claim 14 wherein said optical multiplexer assembly further includes a rotating disk having an open portion for passing infrared image signals and a blocking portion for interrupting infrared image signals.

17. The system as defined by claim 16 wherein the pivotally oscillated scanner member and the rotating multiplexer disk are operated in synchronism.

18. The system as defined by claim 16 and additionally including first and second stationary mirror means respectively located between said first and second reflective image surface of said planar scanner member and said open and blocking portions of said rotating multiplexer disk.