Fiber optically coupled laser rangefinder for use in a gimbal systems

• US 9,121,701 B2
• Filed: 08/21/2012
• Issued: 09/01/2015
• Est. Priority Date: 08/23/2011
• Status: Active Grant

• Current Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Shaw, William E., Whaley, Bruce, Hatch, Marcus, Silva, Raymond J., DeFlumere, Michael E.
• Primary Examiner(s): Alsomiri, Isam
• Assistant Examiner(s): Abraham, Samantha K
• Application Number:
  US13/883,183
• Publication Number:
  US 20130222784A1
• Time in Patent Office: 1,106 Days
• Field of Search: 356/4.01, 356/4.07, 356/5.01, 356/5.09, 356/9, 356/625
• US Class Current: 1/1
• CPC Class Codes: G01C 3/02 Details
• CPC Class Codes: G01S 17/08 for measuring distance only indirect measurement G01S17/46; active triangulation systems G01S17/48
• CPC Class Codes: G01S 7/4811 common to transmitter and receiver
• CPC Class Codes: G01S 7/4818 using optical fibres

Abstract

A fiber optically coupled laser rangefinder (LRF) for use in a gimbal system to input/extract a laser beam into/from a camera is disclosed. In one embodiment, the fiber optically coupled LRF includes a gimbal assembly. Further, the gimbal assembly includes a first fiber optic cable for receiving the laser beam from a remote transmitter assembly, a fiber optically coupled laser interface module to receive the laser beam and opposing mirrors to direct the laser beam to a target. In addition, the gimbal assembly includes a second fiber optic cable for transmitting a return laser beam to a remote receiver assembly. The opposing mirrors are further configured to direct the return laser beam from the target to the fiber optically coupled laser interface module. The fiber optically coupled laser interface module is further configured to transmit it to the receiver assembly via the second fiber optic cable.

Claims

1. A fiber optically coupled laser rangefinder (LRF) for use in a gimbal system, comprising:

a gimbal assembly, wherein the gimbal assembly comprises;

a first fiber optic cable for receiving a laser beam from a transmitter assembly remotely located from the gimbal assembly;

a fiber optically coupled laser interface module comprising;

a beam splitter cube configured to receive the laser beam from the first fiber optic cable and linearly polarize the received laser beam;

a quarter wave plate configured to receive the linearly polarized laser beam from the beam splitter cube and to convert the linearly polarized laser beam to a circularly polarized laser beam;

a fold mirror configured to receive the circularly polarized laser beam from the quarter wave plate; and

a dichroic beam splitter configured to receive the circularly polarized laser beam from the fold mirror;

a plurality of opposing mirrors configured to direct the circularly polarized laser beam from the dichroic beam splitter to a target; and

a second fiber optic cable for transmitting a return laser beam to a receiver assembly remotely located from the gimbal assembly, wherein the plurality of opposing mirrors are further configured to direct the return laser beam from the target to the fiber optically coupled laser interface module and wherein the fiber optically coupled laser interface module is further configured to transmit the return laser beam to the remote receiver assembly via the second fiber optic cable, and wherein the quarter wave plate and the beam splitter cube are configured to perform spatial separation of the laser beam and the return laser beam.

2. The fiber optically coupled LRF of claim 1, wherein the dichroic beam splitter is further configured to receive the return laser beam from the plurality of opposing mirrors and direct it to the fold mirror, wherein the fold mirror is further configured to receive the return laser beam from the dichroic beam splitter and direct it to the quarter wave plate, wherein the quarter wave plate is configured to receive the return laser beam from the fold mirror and wherein the beam splitter cube is configured to receive the return laser beam from the quarter wave plate.

3. The fiber optically coupled LRF of claim 2, wherein the fiber optically coupled laser interface module further comprises:

a narrow band pass optical filter configured to receive the return laser beam from the beam splitter cube and transmit the return laser beam to the remote receiver assembly via the second fiber optic cable.

4. The fiber optically coupled LRF of claim 1, wherein the plurality of opposing mirrors comprise:

a tertiary mirror configured to receive the circularly polarized laser beam from the fiber optically coupled laser interface module;

a secondary mirror configured to receive the circularly polarized laser beam from the tertiary mirror; and

a primary mirror configured to receive the circularly polarized laser beam from the secondary mirror and direct the laser beam to the target.

5. The fiber optically coupled LRF of claim 4, wherein the primary mirror is further configured to receive the return laser beam from the target, wherein the secondary mirror is further configured to receive the return laser beam from the primary mirror, and wherein the tertiary mirror is further configured to receive the return laser beam from the secondary mirror and direct it to the fiber optically coupled laser interface module.

6. The fiber optically coupled LRF of claim 1, wherein the first fiber optic cable is a 11 micrometer (μ

m) fiber optic cable.

7. The fiber optically coupled LRF of claim 1, wherein the second fiber optic cable is a 62 μ

m fiber optic cable.

8. The fiber optically coupled LRF of claim 1, wherein the remote transmitter assembly produces the laser beam and directs the produced laser beam to the fiber optically coupled laser interface module via the first fiber optic cable and wherein the remote receiver assembly receives the return laser beam from the fiber optically coupled laser interface module via the second fiber optic cable and process the return laser beam received from the target.

9. A laser rangefinder (LRF) system, comprising:

a gimbal assembly;

a remote transmitter assembly remotely located from the gimbal assembly; and

a remote receiver assembly remotely located from the gimbal assembly, wherein the gimbal assembly comprises;

a first fiber optic cable for receiving a laser beam from the remote transmitter assembly;

a fiber optically coupled laser interface module comprising;

a beam splitter cube configured to receive the laser beam from the first fiber optic cable and linearly polarize the received laser beam;

a quarter wave plate configured to receive the linearly polarized laser beam from the beam splitter cube and to convert the linearly polarized laser beam to a circularly polarized laser beam;

a fold mirror configured to receive the circularly polarized laser beam from the quart wave plate; and

a dichroic beam splitter configured to receive the circularly polarized laser beam from the fold mirror;

a plurality of opposing mirrors configured to direct the circularly polarized laser beam from the dichroic beam splitter to a target; and

a second fiber optic cable for transmitting a return laser beam to the remote receiver assembly, wherein the plurality of opposing mirrors are further configured to direct the return laser beam from the target to the fiber optically coupled laser interface module and wherein the fiber optically coupled laser interface module is further configured to transmit the return laser beam to the remote receiver assembly via the second fiber optic cable, and wherein the quarter wave plate and the beam splitter cube are configured to perform spatial separation of the laser beam and the return laser beam.

10. The system of claim 9, wherein the dichroic beam splitter is further configured to receive the return laser beam from the plurality of opposing mirrors and direct it to the fold mirror, wherein the fold mirror is further configured to receive the return laser beam from the dichroic beam splitter and direct it to the quarter wave plate, wherein the quarter wave plate is configured to receive the return laser beam from the fold mirror and wherein the beam splitter cube is configured to receive the return laser beam from the quarter wave plate.

11. The system of claim 10, wherein the fiber optically coupled laser interface module further comprises:

a narrow band pass optical filter configured to receive the return laser beam from the beam splitter cube and transmit the return laser beam to the remote receiver assembly via the second fiber optic cable.

12. The system of claim 9, wherein the plurality of opposing mirrors comprise:

a tertiary mirror configured to receive the circularly polarized laser beam from the fiber optically coupled laser interface module;

a secondary mirror configured to receive the circularly polarized laser beam from the tertiary mirror; and

a primary mirror configured to receive the circularly polarized laser beam from the secondary mirror and direct the laser beam to the target.

13. The system of claim 12, wherein the primary mirror is further configured to receive the return laser beam from the target, wherein the secondary mirror is further configured to receive the return laser beam from the primary mirror, and wherein the tertiary mirror is further configured to receive the return laser beam from the secondary mirror and direct it to the fiber optically coupled laser interface module.