Optical autocovariance lidar

• US 8,077,294 B1
• Filed: 01/21/2009
• Issued: 12/13/2011
• Est. Priority Date: 01/17/2008
• Status: Active Grant

• Current Assignee: Ball Aerospace & Technologies Corporation (Ball Corporation)
• Original Assignee: Ball Aerospace & Technologies Corporation (Ball Corporation)
• Inventors: Grund, Christian J., Pierce, Robert M.
• Primary Examiner(s): Tarcza, Thomas
• Assistant Examiner(s): Ratcliffe, Luke
• Application Number:
  US12/357,251
• Time in Patent Office: 1,056 Days
• Field of Search: 356 301- 285
• US Class Current: 356/4.01
• CPC Class Codes: G01N 21/65 Raman scattering
• 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: G01S 7/4802 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/499 using polarisation effects
• 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

Lidar systems and methods are provided. The lidar system includes an optical autocovariance receiver and one or more chemical composition sensors or processors, in addition to a Doppler signal processor for obtaining relative wind speed information. The additional processors may include a high spectral resolution lidar signal processor and/or a differential absorption lidar processor that receive input signals from the optical autocovariance receiver. Receivers that may be incorporated into the lidar system, in addition to the optical autocovariance receiver, include a depolarization receiver, a Raman receiver, and/or an Etalon receiver.

Claims

1. A lidar system, comprising:

a telescope;

an optical autocovariance receiver, wherein the optical autocovariance receiver is provided with an input signal by the telescope;

a Doppler signal processor, wherein an output from sensors included in the optical autocovariance receiver is provided to the Doppler signal processor; and

a physical property sensor, wherein the physical property sensor is provided with an input signal by the telescope.

2. The system of claim 1, wherein the physical property sensor comprises at least one of a differential absorption lidar and signal processor and a high spectral resolution lidar and processor determining aerosol optical properties, and wherein the output from sensors included in the optical autocovariance receiver is provided to the at least one of a differential absorption lidar signal processor and a high spectral resolution lidar processor.

3. The system of claim 1, wherein the physical property sensor comprises a differential absorption lidar signal processor determining chemical composition and a high spectral resolution lidar processor determining aerosol optical properties, and wherein the output from sensors included in the optical autocovariance receiver is provided to the differential absorption lidar signal processor and the high spectral resolution lidar processor.

4. The system of claim 1, further comprising:

a Raman receiver, wherein the Raman receiver is provided with an input signal by the telescope.

5. The system of claim 4, further comprising:

a dichroic mirror, wherein a first portion of an input signal from the telescope is passed by the dichroic mirror for provision to the optical autocovariance receiver, and wherein a second portion of an input signal from the telescope is directed by the dichroic mirror to the Raman receiver.

6. The system of claim 1, further comprising:

a depolarization receiver, wherein the depolarization receiver is provided with an input signal by the telescope.

7. The system of claim 6, further comprising:

a polarizing beam splitter, wherein a first portion of an input signal from the telescope is passed by the polarizing beam splitter for provision to the optical autocovariance receiver, and wherein a second portion of an input signal from the telescope is directed by the polarizing beam splitter to the depolarization receiver.

8. The system of claim 1, further comprising:

an Etalon receiver, wherein the Etalon receiver is provided with an input signal by the telescope.

9. The system of claim 1, further comprising:

a laser, wherein a sample of an output from the laser is provided to the optical autocovariance receiver.

24. The system of claim 1, wherein the optical autocovariance receiver includes:

a beam splitter, wherein the beam splitter is operable to split light received as an input to the autocovariance receiver into first and second beam paths;

a first arm, wherein the first arm has a first nominal path length, and wherein the first beam path includes the first arm;

a second arm, wherein the second arm has a second nominal path length, wherein the second arm is sub-divided into at least first, second and third areas, and wherein the second beam path includes the second arm;

at least first, second and third detectors, wherein the first detector is located to receive light from the first area and the first arm, wherein the second detector is located to receive light from the second area and the first arm, and wherein the third detector is located to receive light from the third area and the first arm.

10. A lidar system, comprising:

a laser;

an optical autocovariance receiver;

a first optical element operable to provide a sample of a signal generated by the laser to the optical autocovariance receiver;

a telescope, wherein the telescope is operable to provide collected photons to the optical autocovariance receiver;

a Doppler signal processor operable to calculate a relative wind speed from information provided by the optical autocovariance receiver;

at least one of;

a high spectral resolution lidar signal processor operable to determine characteristic of a target volume from information provided by the optical autocovariance receiver;

a differential absorption lidar signal processor operable to determine a characteristic of a target volume from information provided by the optical autocovariance receiver;

an etalon receiver operable to determine a characteristic of a target volume, wherein the telescope is operable to provide collected photons to the etalon receiver;

a Raman receiver operable to determine a characteristic of a target volume, wherein the telescope is operable to provide collected photons to the Raman receiver;

a depolarization receiver operable to determine a characteristic of a target volume, wherein the telescope is operable to provide collected photons to the depolarization receiver.

11. The system of claim 10, wherein the lidar system includes a high spectral resolution lidar signal processor operable to determine a characteristic of a target volume from information provided by the optical autocovariance receiver.

12. The system of claim 10, wherein the lidar system includes a differential absorption lidar signal processor operable to determine a characteristic of a target volume from information provided by the optical autocovariance receiver.

13. The system of claim 12, wherein the differential absorption lidar signal processor is in communication with a laser control, wherein the laser includes one or more lasers, and wherein the laser control causes signals of different wavelengths to be transmitted from the one or more lasers.

14. The system of claim 10, wherein the lidar system includes an etalon receiver operable to determine a characteristic of a target volume, wherein the telescope is operable to provide collected photons to the etalon receiver.

15. The system of claim 14, wherein photons collected by the telescope pass to the etalon receiver before at least some of those photons are provided to the optical autocovariance receiver.

16. The system of claim 10, wherein the lidar system includes a Raman receiver operable to determine a characteristic of a target volume, wherein the telescope is operable to provide collected photons to the Raman receiver.

17. The system of claim 10, wherein the lidar system includes a depolarization receiver operable to determine a characteristic of a target volume, wherein the telescope is operable to provide collected photons to the depolarization receiver via a polarizing beam splitter.

18. The system of claim 10, wherein the optical autocovariance receiver includes at least two photon-counting detectors.

19. The system of claim 10, wherein the optical autocovariance receiver includes at least three multiple pixel detector arrays.

25. The system of claim 10, wherein the sample of a signal generated by the laser and provided to the optical autocovariance receiver includes a spectral calibration signal.

20. A method for obtaining information about a target volume, comprising:

transmitting light to a target volume;

collecting photons reflected from the target volume using a telescope, wherein the collected photons include photons transmitted to the target volume;

providing at least some of the photons reflected from the target volume and collected by the telescope to a first receiver, wherein the first receiver is an optical autocovariance receiver;

determining a first characteristic of the target volume, wherein the first characteristic includes an optical frequency of the photons reflected from the target volume and collected by the telescope using information provided by the optical autocovariance receiver, and wherein the optical frequency of the photons reflected from the target volume and collected by the telescope is used to determine a relative wind speed within the target volume;

determining a second characteristic of the target volume, wherein the second characteristic is different than the first characteristic.

21. The method of claim 20, wherein the second characteristic is calculated from information provided by the optical autocovariance receiver.

22. The method of claim 20, further comprising:

providing at least some of the photons reflected from the target volume and collected by the telescope to a second receiver, wherein the second characteristic is calculated from information provided by the second receiver.

23. The method of claim 20, further comprising:

providing a sample of light transmitted by the laser to the target volume of the optical autocovariance receiver;

taking a reference autocovariance function phase measurement from the sample, wherein the autocovariance function is shifted by a fixed amount to obtain the reference autocovariance function.