Optical payload with integrated laser rangefinder and target designator

• US 8,139,205 B2
• Filed: 05/11/2009
• Issued: 03/20/2012
• Est. Priority Date: 05/12/2008
• Status: Expired due to Fees

• Current Assignee: Teledyne FLIR LLC (Teledyne Technologies Incorporated)
• Original Assignee: FLIR Systems, Inc. (Teledyne Technologies Incorporated)
• Inventors: McKaughan, Stephen V., Rombult, Philip A., Campbell, Robert J. Jr.
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): RATCLIFFE, LUKE D
• Application Number:
  US12/463,882
• Publication Number:
  US 20120038901A1
• Time in Patent Office: 1,044 Days
• Field of Search: 356 301- 285
• US Class Current: 356/5.01
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors
• CPC Class Codes: H04N 23/50 Constructional details
• CPC Class Codes: H04N 23/661 Transmitting camera control signals through networks, e.g. control via the Internet
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 23/90 Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A compact optical payload for an unmanned aircraft includes two infrared cameras for wide and narrow field viewing, a daylight color camera, a laser pointer and a laser range finder.

Claims

1. An optical payload, comprising:

a laser rangefinder transmitter module comprising a rangefinder laser configured to emit a pulsed laser rangefinder beam and a small aperture telescopic lens system configured to substantially collimate and point the laser rangefinder beam at a target area;

a laser target designator module comprising a designator laser configured to emit a pulsed laser target designator beam, a large aperture telescopic lens system configured to substantially collimate and point the designator beam at the target area, a laser rangefinder receiver module, first optical elements disposed along a first optical path between the large aperture telescopic lens system and the designator laser configured to direct the pulsed laser target designator beam from the designator laser to the large aperture telescopic lens system; and

,

second optical elements disposed along a second optical path between the large aperture telescopic lens system and the laser rangefinder receiver module configured to direct energy of the pulsed laser rangefinder beam that is reflected by the target area and collected by the large aperture telescopic lens system onto the laser rangefinder receiver module;

wherein both the first optical elements and the second optical elements include a beam splitter, wherein the beam splitter and the first and second optical elements are configured to direct the laser target designator beam from the laser target designator module to the large aperture telescopic lens system and to direct the energy of the pulsed laser rangefinder beam that is reflected by the target area and collected by the large aperture telescopic lens system to the laser rangefinder receiver module, and wherein the beam splitter comprises a dichroic filter configured with a maximum spectral transmission substantially matched with a spectral emission of the designator laser and further configured with a maximum spectral reflectance substantially matched with the spectral emission of the rangefinder laser.

2. The optical payload of claim 1 wherein the rangefinder laser has a spectral output in the range of 1500 to 1800 nanometers.

3. The optical payload of claim 2 wherein the rangefinder laser has a spectral output substantially centered at 1535 nanometers.

4. The optical payload of claim 3 wherein the rangefinder laser comprises an Erbium glass rod pumped by one or more pumping sources.

5. The optical payload of claim 4 wherein the rangefinder laser is configured to generate laser pulses having pulse durations ranging from 5 to 25 nanoseconds with pulse energies ranging from 2 to 8 mJ.

6. The optical payload of claim 1 wherein the designator laser has a spectral output substantially centered at 1064 nanometers.

7. The optical payload of claim 6 wherein the designator laser comprises a neodymium-doped yttrium aluminum garnet laser crystal pumped by one or more pumping sources.

8. The optical payload of claim 7 wherein the designator laser is configured to generate laser pulses having a minimum pulse duration of 10 nanoseconds and a minimum pulse energy of 30 mJ.

9. The optical payload of claim 8 wherein the designator laser is modulated to emit laser pulses at a frequency ranging from 8 to 20 pulses per second.

10. The optical payload of claim 1 wherein the laser rangefinder transmitter module and the laser target designator module are mechanically independent modules.

11. The optical payload of claim 1 wherein the beam splitter is configured to transmit the laser target designator beam and to reflect the energy of the pulsed laser rangefinder beam that is reflected by the target area.

12. The optical payload of claim 11 wherein the first optical elements further comprise two mirrors disposed between the beam splitter and the large aperture telescopic lens system.

13. The optical payload of claim 11 wherein the second optical elements further comprise a mirror and a focusing lens set for focusing the energy of the pulsed laser rangefinder beam that is reflected by the target area onto an active area of the laser rangefinder receiver module.

14. The optical payload of claim 1 further comprising a fiber optic element extending between the laser rangefinder transmitter module and the laser designator module for directing at least a portion of the energy of each pulse of the laser rangefinder beam onto an active area of the laser rangefinder receiver module.

15. The optical payload of claim 14 further comprising a signal processor in communication with the laser rangefinder receiver module for processing photo current signals generated thereby.

16. A method for operating an optical payload, the method comprising:

emitting a pulsed laser rangefinder beam from a laser rangefinder transmitter module;

collimating the pulsed laser rangefinder beam and directing the collimated pulsed laser rangefinder beam onto a target area using a small aperture telescopic lens system attached to the laser rangefinder transmitter module;

collecting energy of the collimated pulsed laser rangefinder beam that is reflected by the target area using a large aperture telescopic lens system and directing energy collected thereby onto a laser rangefinder receiver module;

emitting a pulsed laser target designator beam from a designator laser housed within a laser target designator module;

collimating the laser target designator beam and directing the collimated laser target designator beam onto the target area using the large aperture telescopic lens system;

coupling energy from the laser rangefinder beam into a first end of a fiber optic element and directing a second end of the fiber optic element onto an active area of the laser rangefinder receiver module to generate a first photocurrent in response to laser rangefinder beam pulses;

generating a second photocurrent response to the laser rangefinder beam energy that is reflected by the target area and collected by the large aperture telescopic optical system;

communicating each of the first and second photocurrent responses to a signal processor;

calculating a range from the payload to the target area according to a temporal separation between the first and second photocurrent responses;

wherein the large aperture telescopic lens system and laser rangefinder receiver module are housed in the laser target designator module; and

,

wherein the laser rangefinder transmitter module and the laser target designator module are mechanically independent modules.

17. The method of claim 16, further comprising:

capturing first images, with a narrow field of view, at a first infrared wavelength range of the target area;

capturing second images, with a wide field of view, at a second infrared wavelength range of the target area, wherein the first and second infrared wavelength ranges are substantially different, and wherein the narrow field of view and the wide field of view may be independently pointed to the target area; and

capturing third images at a visible wavelength range of the target area.

18. The method of claim 16, wherein the directing the energy onto the laser rangefinder receiver module and the directing the collimated laser target designator beam comprises using a dichroic filter configured with a maximum spectral transmission substantially matched with a spectral emission of the designator laser and further configured with a maximum spectral reflectance substantially matched with the spectral emission of the pulsed laser rangefinder beam.

19. An optical payload, comprising:

a laser rangefinder transmitter module comprising a rangefinder laser configured to emit a pulsed laser rangefinder beam and a small aperture telescopic lens system configured to substantially collimate and point the laser rangefinder beam at a target area;

a laser target designator module comprising a designator laser configured to emit a pulsed laser target designator beam, a large aperture telescopic lens system configured to substantially collimate and point the designator beam at the target area, a laser rangefinder receiver module, first optical elements disposed along a first optical path between the large aperture telescopic lens system and the designator laser configured to direct the pulsed laser target designator beam from the designator laser to the large aperture telescopic lens system;

second optical elements disposed along a second optical path between the large aperture telescopic lens system and the laser rangefinder receiver module configured to direct energy of the pulsed laser rangefinder beam that is reflected by the target area and collected by the large aperture telescopic lens system onto the laser rangefinder receiver module; and

a fiber optic element extending between the laser rangefinder transmitter module and the laser designator module configured to direct at least a portion of the energy of each pulse of the laser rangefinder beam onto an active area of the laser rangefinder receiver module.

20. The optical payload of claim 19, further comprising:

a signal processor in communication with the laser rangefinder receiver module and configured to determine a range from the optical payload to the target area based on the energy directed by the fiber optic element to the laser rangefinder receiver module; and

a beam splitter, wherein the beam splitter and the first and second optical elements are configured to direct the laser target designator beam from the laser target designator module to the large aperture telescopic lens system and to direct the energy of the pulsed laser rangefinder beam that is reflected by the target area and collected by the large aperture telescopic lens system to the laser rangefinder receiver module, and wherein the beam splitter comprises a dichroic filter configured with a maximum spectral transmission substantially matched with a spectral emission of the designator laser and further configured with a maximum spectral reflectance substantially matched with the spectral emission of the rangefinder laser.

21. The optical payload of claim 20, wherein the rangefinder laser comprises an Erbium glass rod having a spectral output in the range of 1500 to 1800 nanometers, wherein the designator laser comprises a neodymium-doped yttrium aluminum garnet laser crystal having a spectral output substantially centered at 1064 nanometers, and wherein the laser rangefinder transmitter module and the laser target designator module are mechanically independent modules.