Free space optical communication

• US 7,885,548 B1
• Filed: 01/24/2007
• Issued: 02/08/2011
• Est. Priority Date: 01/24/2007
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Nelson, Ryan L., Uhlhorn, Brian L.
• Primary Examiner(s): Tran; Dzung D
• Application Number:
  US11/657,240
• Time in Patent Office: 1,476 Days
• Field of Search: 398/129, 398/130, 398/131, 398/123, 398/18, 359/334, 375/356
• US Class Current: 398/131
• CPC Class Codes: H04B 10/1127 using two distinct parallel optical paths

Abstract

Free space optical communication systems, methods, and apparatuses are provided. A free space optical communication system embodiment includes a light source for emitting a light beam toward a receiver, where the light beam includes a signal to be transmitted, an output lens through which the light beam is directed toward the receiver, and an actuator coupled to the light source for moving the light source to adjust the diameter of the light beam.

Claims

1. A free space optical communication system, comprising:

a light source for emitting a light beam toward a receiver, where the light beam includes a signal to be transmitted;

an output lens through which the light beam is directed toward the receiver; and

an actuator coupled to the light source and configured to adjust a distance between the light source and the output lens in order to adjust the diameter of the light beam in response to relative position changes between the receiver and the light source while the light source and receiver are moving relative to each other.

2. The system of claim 1, where the actuator is a worm gear.

3. The system of claim 1, where the light source is an optical fiber.

4. The system of claim 1, where the actuator is a piezo-electric actuator.

5. The system of claim 1, where the system includes a data rate adjustor for adjusting the data rate based upon the position of the light source.

6. The system of claim 5, where the data rate adjustor is an application specific integrated circuit.

7. The system of claim 1, where the system includes an actuator coupled to the output lens for moving the lens to adjust the diameter of the light beam.

8. The system of claim 1, where the system includes a radio frequency communication link as a redundant communication link.

9. A free space optical communication apparatus, comprising:

a light source for emitting a light beam toward a receiver, where the light beam includes a signal to be transmitted;

an output lens through which the light beam is directed toward the receiver; and

an actuator coupled to the output lens and configured to adjust a distance between the lens and the light source in order to adjust the diameter of the light beam in response to relative position changes between the receiver and the light source while the light source and receiver are moving relative to each other.

10. The apparatus of claim 9, where the apparatus includes a control apparatus for driving the actuator based on information about a position of the receiver to adjust the diameter of the light beam.

11. The apparatus of claim 9, where the free space optical communication apparatus is mounted to an unmanned aerial vehicle (UAV).

12. The apparatus of claim 9, where the free space optical communication apparatus is included with a gimbal tracking actuator for movement of the apparatus based upon information about a position of the receiver.

13. The apparatus of claim 12, where the apparatus includes instructions executable on a processor and stored in memory to track the position of multiple receivers and calculate the adjustment of the output lens and the gimbal tracking actuator to direct the light beam from a first receiver to a second receiver of the multiple receivers.

14. A free space optical communication apparatus, comprising:

a light source for emitting a light beam toward a receiver, where the light beam includes a signal to be transmitted;

an output lens through which the light beam is directed toward the receiver;

an actuator coupled to the output lens and configured to adjust a distance between the lens and the light source in order to adjust the diameter of the light beam in response to relative position changes between the receiver and the light source while the light source and receiver are moving relative to each other; and

where the lens is formed from a material having lens focal modifying characteristics.

15. The apparatus of claim 14, where the lens is formed from a material selected from a group of materials, including:

liquid crystal;

polymer; and

water.

16. A method of providing free space optical communication, comprising:

receiving an incoming beacon signal from a communication apparatus;

adjusting a distance between a lens and a light source in an unmanned aerial vehicle based on a position of the incoming beacon signal received in order to alter a light beam diameter in response to relative position changes between a source of the incoming beacon signal and the light source while the light source and the source of the incoming beacon signal are moving relative to each other; and

transmitting the light beam through the lens to direct the beam toward the source of the incoming beacon signal, where the light beam includes a signal to be transmitted.

17. The method of claim 16, where the method includes adjusting the intensity of the light beam based upon the position of the light source.

18. The method of claim 17, where the method includes adjusting the intensity of the light beam based upon position information provided by the beacon signal.

19. The method of claim 18, where the method includes moving the beam in six degrees of freedom to adjust the diameter of the beam and the direction of the beam.

20. The method of claim 19, where the first diameter is larger than the second diameter.

21. The method of claim 20, where the first diameter is sized to provide a broad diameter, low rate signal transmission beam for aiding in locating the unmanned aerial vehicle with the communication apparatus.

22. The method of claim 18, where adjusting the distance between a lens and the light source includes moving the light source to a first position that provides a first beam diameter and moving the light source to a second position that provides a second beam diameter.

23. The method of claim 18, where the method includes evaluating a number of environmental conditions and positioning the light source based upon at least one of the number of environmental conditions.

24. The method of claim 18, where the method includes receiving a beacon signal from a beacon source proximate to the light beam receiver.

25. The method of claim 24, where adjusting the distance between a lens and the light source includes moving the light source based upon positioning information received in the beacon signal.