1 / 27

December 8-9, 2009 Seattle, WA

LATMIX Planning Meeting LIDAR for LATMIX. December 8-9, 2009 Seattle, WA. Brian M. Concannon Jennifer E. Prentice NAVAIR brian.concannon@navy.mil jenifer.prentice@navy.mi (301) 342-2034 (301) 342-2025 Jim Ledwell Gene Terray WHOI jledwell@whoi.edu eterray@whoi.edu

rwinstead
Download Presentation

December 8-9, 2009 Seattle, WA

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LATMIX Planning Meeting LIDAR for LATMIX December 8-9, 2009 Seattle, WA Brian M. Concannon Jennifer E. Prentice NAVAIR brian.concannon@navy.mil jenifer.prentice@navy.mi (301) 342-2034 (301) 342-2025 Jim Ledwell Gene Terray WHOI jledwell@whoi.edu eterray@whoi.edu (508) 289-3305 (508)289-2438 Miles Sundermeyer UMASS, Dartmouth msundermeyer@umassd.edu (508) 999-8892

  2. Lidar 101 Laser Receiver Amplitude (dB) Backscatter Less Turbid Time (depth) The slope of the lidar waveform is dependent on the inherent optical properties and is different for different water types. Bottom return

  3. Time or Distance Ksys (m-1) Amplitude (dB) Depth (m) Depth (m) Depth (m) Waveform Slope vs. Depth Color Coded Slope vs. Depth A=e-2KsysD Lidar Data Acquisition & Processing

  4. Lidar System Flown 2008 and 2009

  5. Telescope Modifications for LATMIX Dye Return Dichroic Beam Splitter Lidar Return Simultaneous collection of Blue backscatter and Green dye fluorescence

  6. Lidar Volume Mapping Approaches

  7. T0 Altitude LATMIX Lidar Vertical Resolution f (laser pulse width, system bandwidth, dig sample rate) Laser pulse width = 10 ns -> 1.1 meter depth in water System Bandwidth = 100 MHz (log amp, PMT) = 10 ns Digitizer Sample Rate = 400 MSPS = 2.5 ns per sample Bottom Line: Depth Resolution ~ 1meter with 4X oversample Note: relative depth accuracy ~10 centimeters

  8. LATMIX Lidar Horizontal Resolution f(scan pattern, pulse rate, platform speed, platform altitude) Scan Pattern = circular cone Full Angle = 39 deg Scan Rate up o 15 Hz Pulse Rate – up to 1700 Hz Platform Speed = 100 m/s (1 km/10 sec) Conservative Example: 100 m/s along track 305 m alt 1000 Hz PRF 11.5 Hz scan rate Swath Width = 216 m Min Horizontal = 8 m Min Along Track = 8 m Notes - back scan fill - Peak perf ~ 6 m Across Track Res is f (scan speed, PRF) A/C track Swath Width is f (scan angle, Alt) Along Track Res is f (scan speed, A/C speed)

  9. Flight Patterns vs. Time Evolution Racetrack 9 km/ (100 m/s) = 90 sec = 1.5 min 5.5 km 30 sec leader (3 km) 0.100 m/s x T sec = N km For T =45 sec: Whole Pattern = 7 minute Across track map speed = 1.5 km/hr (20% overlap) 30 sec leader (3 km)

  10. Flight Patterns vs. Time Evolution Dog Bone 5.5 km 30 sec leader (3 km) 100 m/s x T sec = N km T = 45 sec Whole Pattern = 9 min Revisit mid-point every 5 min Across track map speed = 1.9 km/h (33% overlap, ) 30 sec leader (3 km) 17.5 km/ (100 m/s) = 175 sec = 3.25 min

  11. Performance and Flight Limitations Lidar Fog, Low Clouds, Rain Must Monitor Op Area • Aircraft/Crew • Predicted or Actual • Lightning • Strong Turbulence • 12 – 14 hour duty day

  12. Dye mapping OpportunitySept 12, 2008 • 024315-024335 UTC • Equivalent to 024301-024319 GPS Time Intensity vs. Position Dye Returns Depth vs. Position Dye Returns

  13. Environmental Transect June 24, 2009 N. Sargasso Sea Hatteras Data Start and End Latitude (deg)

  14. 01:24:18 (UTC) End of Transect SE

  15. 01:30:35 UTC Southbound Pass

  16. 01:38:30 UTC Northbound Pass

  17. Lidar Data Analysis Goals The measured backscatter (480 nm) and fluorescence (~520 nm) intensities will be used to • Map the 3D dye concentration with 5-10 m horizontal and ~1 m vertical resolutions • Study the temporal evolution of the dye patch • Estimate the along- and cross-isopycnal diffusivities • Track the floats and AUV

  18. Questions?

  19. BACKUP

  20. Mapping Floaters and AUV’s Blue Return ~ E x Area x R( bb) ~ E x 20 m2 x 0.0005 ~ E x 0.01 AUV Return ~ E x Area x R( bb) ~ E x ? m2 x ? ~ E x 0.25 x 0.2 ~ E x 0.05 Automating sorting through the data to find 1 shot requites the AUV/floater return look VERY different

  21. Mapping Floaters and AUV’s Lidar will only detect light within it’s scanning, instantaneous FOV 45º LED upward looking cone of light LED - LIDAR can detect 10-6 W easily - Ratio of LIDAR Aperture to LED Spot at 325m separation = 10-5 - attenuation in water ~ e-1.5 = 0.22 - LED Power > 0.2 W (515 to 525 nm) Retro-Reflective Surface - 0.1 m2 Retro tape on ground required ND 3 in Rx for 5 m spot at 305 m - attenuation in water ~ e-3 = 0.05 - 0.01 m retro-tape = easy detection LED retro

  22. 01:43:45 UTC Eastbound Pass

  23. 01:51:53 UTC Westbound Pass

  24. Intensity vs. Position Dye Returns Sept. 12, 2008 Forward Scan Aft Scan

  25. Depth vs. Position Dye Returns Sept. 12, 2008 • Depth calculated at 50% rise of max peak • Surface onset calculated at 50% rise of surface flash

  26. Light in the Ocean http://oceanexplorer.noaa.gov/explorations/04deepscope/background/deeplight/deeplight.html Basic illustration of the depth at which different colors of light penetrate ocean waters. Longer wavelength light (reds and oranges) is absorbed more quickly than shorter wavelength light (greens and blues).

  27. HITS 4.1 All Tanker Types + Merchants TW

More Related