Multifunction Aircraft Lidar

• US 20110043785A1
• Filed: 08/18/2009
• Published: 02/24/2011
• Est. Priority Date: 08/18/2009
• Status: Active Grant

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Larsen, Ty Aaby, Paranto, Joseph Nolan, Cates, Michael C.
• Granted Patent: US 8,508,721 B2
• Time in Patent Office: Days
• US Class Current: 356/28
• CPC Class Codes: G01P 3/366 by using diffraction of light for measuring speed of fluids G01P5/26
• CPC Class Codes: G01P 5/26 by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave
• CPC Class Codes: G01S 17/18 wherein range gates are used
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 17/95 for meteorological use
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A multifunction light detection and ranging (LIDAR) system for aircraft or other applications may use autodyne techniques. An autodyne system can use a single laser source and a single detector. The autodyne technique can mix two signal beams to produce a “beat note” at the frequency difference between the beams. Autodyne detection can leverage photon counting to support significantly reduced system complexity. Reduced complexity may provide solutions with significantly reduced power consumption, lighter weight, smaller volume, and lower cost. The multifunction LIDAR system can detect and identify regions of weather hazards such as lightning storms, aircraft wake vortex, clear air turbulence, and wind shear. The multifunction LIDAR system may also be configured to measure aircraft air and ground speed in multiple dimensions as well as aircraft altitude.

Claims

1. A method for operating a multifunction LIDAR, the method comprising:

generating an electromagnetic source beam;

splitting the electromagnetic source beam to provide a first measuring beam and a second measuring beam;

directing the first measuring beam and the second measuring beam onto areas of a subject medium;

collecting a first return beam from the first measuring beam reflected off of the subject medium;

collecting a second return beam from the second measuring beam reflected off of the subject medium;

combining the first return beam and the second return beam to generate an autodyne signal; and

determining characteristics of the subject medium from the autodyne signal.

2. The method of claim 1, further comprising performing range gating on the autodyne signal.

3. The method of claim 1, wherein determining characteristics comprises processing the autodyne signal to identify a velocity associated with the subject medium from a peak frequency of the autodyne signal.

4. The method of claim 1, further comprising determining an intensity of the autodyne signal.

5. The method of claim 1, wherein determining characteristics comprises determining an air speed associated with an aircraft.

6. The method of claim 1, wherein determining characteristics comprises determining a ground speed associated with an aircraft.

7. The method of claim 1, wherein determining characteristics comprises identifying weather phenomena.

8. The method of claim 1, wherein generating an electromagnetic source beam comprises pulsing a laser.

9. The method of claim 1, wherein the subject medium comprises regions of atmosphere.

10. The method of claim 1, wherein the subject medium comprises regions of ground.

11. A computer-readable storage medium having computer-executable instructions stored thereon which, when executed by a computer system, cause the computer system to:

receive, from a LIDAR system, an autodyne signal associated with a subject medium;

identify a peak frequency of the autodyne signal; and

determine a velocity associated with the subject medium from the peak frequency.

12. The computer-readable storage medium of claim 11, wherein the computer system is further caused to identify atmospheric phenomena based on the velocity associated with the subject medium.

13. The computer-readable storage medium of claim 11, wherein the computer system is further caused to determine an airspeed associated with an aircraft from the velocity associated with the subject medium.

14. The computer-readable storage medium of claim 11, wherein the computer system is further caused to determine a groundspeed associated with an aircraft from the velocity associated with the subject medium.

15. The computer-readable storage medium of claim 11, wherein the computer system is further caused to perform range timing while receiving the autodyne signal.

16. The computer-readable storage medium of claim 15, wherein the range timing is used to determine an altitude associated with an aircraft.

17. A multifunction LIDAR system comprising:

a transmitter configured to generate an optical beam;

an optical splitter configured to generate two measuring beams from the optical beam;

a detector configured to receive an autodyne beam, wherein the autodyne beam combines two return beams generated by reflecting the two measuring beams off of a subject medium; and

a signal processor in electrical communication with the detector and configured to determine characteristics of the subject medium based upon the autodyne beam.

18. The multifunction LIDAR system of claim 17, wherein the characteristics comprises an air vortex or turbulence.

19. The multifunction LIDAR system of claim 17, wherein the characteristics comprises air or ground speed associated with an aircraft.

20. The multifunction LIDAR system of claim 17, wherein the characteristics comprises weather phenomena.