Lidar Research Progress * †

Space Dynamics Laboratory

Utah State University 

presented for the

Wind Lidar Working Group

Frisco, CO

June 29 – 30, 2004

 

 * S. Cornelsen, J. Cutts, C. Earl, D. Huish, T. Wilkerson

 † supported by IPO(NPOESS), NASA-Goddard and SDL

Tom.Wilkerson@sdl.usu.edu

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Outline

• Campaign history• Multiple cloud layers• Comparison of HOE lidar wind results with other

methods• Sonde wind variability (space/time averaging)• HARLIE analysis using Hough transform• Development of airborne lidar

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Joint Lidar Measurement Campaigns

• March 1999 Logan, UT HOLO-1

• June 1999 Manchester, NH HOLO-2

• Sept./Oct. 2000 DoE ARM/SGP Site, OK WVIOP

• November 2001 Wallops Island, VA HARGLO-2

• April 2002 Ft. Bliss, TX (with D.R.I.) SERDP

• May/June 2002 DoE ARM/Homestead, OK IHOP-2002

Instruments:

HARLIE holographic scan lidar & SkyCam for cloud video imagery,

AROL-2 profiler for HOLO-1, and GLOW Doppler lidar for HARGLO-2 & IHOP

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Multi-Cloud Comparison

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Harlie vs. Sonde

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0

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50

60

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0.020.100.180.260.340.420.500.580.660.740.820.900.981.061.141.221.301.381.461.541.621.701.781.861.942.022.102.182.262.342.422.502.582.662.742.822.902.983.06Standard Deviation of Velocity [m/s]

Number of Occurrences

Sonde Wind Precision (IHOP 2002)

Conclusion: Sondes provide a reasonable standard for wind measurement.

Mean: 0.549 m/s

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Automatic HARLIE Analysis usingthe Hough Transform

R = A sin ( + B) + Cwind speed ~ 1/Adirection - Brotation offset - C

•The wave image is displayed with rotations as a function of scan angle, R( )

•The equation for the matched sine curve is as follows:

•The Hough Transform generates a surface C (A ,B) = R - A sin ( + B) for each (R, ) pixel. Intensity of C depends on pixel brightness

•The surfaces intersect one another to form bright spots in the “accumulation matrix” in the (A ,B ,C) space. These spots identify the dominant wind speed and direction in the wave image.

Scan Angle

Ro

tatio

ns

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Current Work on theHough Transform

• Improving the existing noise removal techniques and image pre-processing for better curve matches

• Increasing program functionality and versatility with added features

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UVC-12 HOE Transceiver

• Hologram 12", 45• Weight 107 lbs.• Length, diam. 24"• 3-Rod truss• Convex secondary• External PMTs• Net optical eff. 5%• Timing belt drive

• Finite Element Analysis

Displacement Stress

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Outcomes

• Excellent teamwork with USU science/engineering students and our NASA-Goddard colleagues

• Continuing critical comparisons of HOE lidar wind results with other methods

• HOE lidar and cloud tracking suitable for 24/7 operations• HOE lidar supports calibration and validation for wind

sensors• Collaborative development of new instruments for lidar

winds• Design rugged UVC lidars for airborne Cal/Val –

Proteus, ER-2

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Way Forward for SDL in the IPO/NPOESS Framework

• Continue detailed analysis of HOE lidar campaign data

– Compare with GLOW & other instruments (IHOP, etc.)

– Eliminate occasional artifacts - e.g., in Hough transform

• Optimize UVC lidar designs and measurement scenarios for possible use in regional/global Cal/Val

– Tradeoffs in specifications and performance

– Composite material designs - SDL program

– Convertible UVC Cassegrain design

• Continue dialogue and collaboration with IPO & NASA