Overview of LIDARLADAR Systems

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Overview of LIDAR/LADAR Systems

• Cindy Scigaj

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Space Based Systems

• Geoscience Laser Altimeter System (ICESat) (Jan
  12, 2003 - Jan 15 earth pointing)
• Mars Orbiter
• LITE aerosol Backscatter Lidar

• Vegetation Canopy Lidar (in stasis)
• SPARCLE EO-2 (Cancelled)
• Mars Polar Lander Lidar (spacecraft lost)
• Calipso (Oct 2004)

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Aircraft based Systemshttp//ltpwww.gsfc.nasa.gov
/eib/

• ER-2 Cloud Lidar System
• Large Aperture Scanning Airborne Lidar (LASAL)
• Laser Vegetation Imaging Sensor (LVIS)
• Scanning Lidar Imager of Canopies by Echo
  Recovery (SLICER)
• Raster Scanning Airborne Lidar (RASCAL)
• Water Vapor Raman Lidar

• Visible and Infrared Lidar (VIRL)
• MACAWS (retired)

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Govt Labs

• NASA JPL Lidar Group
• http//lidar.jpl.nasa.gov/
• NASA GSFC Cloud and Aerosol lidar Group
• http//virl.gsfc.nasa.gov/
• NASA LaRC Lidar Applications Group
• http//asd-www.larc.nasa.gov/lidar/lidar.html
• NOAA ETL Remote Sensing Division
• http//www.etl.noaa.gov/et2/

• Govt Systems
• CALYPSO (Oct 2004)
• Cloud-Aerosol Lidar and Infrared Pathfinder
  Satellite Observations
• http//www-calipso.larc.nasa.gov/calipso.html

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Govt Groups and SystemsNASA -
LRSBhttp//ltpwww.gsfc.nasa.gov/eib/

• NASAs Laser Remote Sensing Branch
• ground-based Scanning Raman Lidar
• Shuttle Laser Altimeter (SLA)
• Mars Orbiter Laser Altimeter (MOLA) for Mars
  Global Surveyor Mission
• Ongoing work
• Geoscience Laser Altimeter System (GLAS) for
  ICESat
• Mercury Laser Altimeter (MLA) for Messenger
  Mission

• Also developing
• Airborne surface imaging lidar
• Airborne Raman Lidar

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Commercial

• ITRES - CASI and LIDAR integration
• http//www.itres.com/docs/casilidar.html

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Lidar Research

• University of Wisconsin Lidar Group
• http//lidar.ssec.wisc.edu/
• Purple Crow Lidar at the University of Western
  Ontario
• http//pcl.physics.uwo.ca/

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Literature

• Global tropospheric wind field
• summary for accurate global tropospheric wind
  data needed for several key unresolved climate
  questions
• Baker et al. Bulletin of the Americal
  Meteorological Society, 1995, Vol 76 pp. 869-888

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Additional Resources

• Bobs Introduction to Lidar - Exploring the
  Atmosphere with Lidars
• http//pcl.physics.uwo.ca/pclhtml/introlidar/intro
  lidarf.html
• www.lidar.com
• Lidar Tutorials
• http//www.ghcc.msfc.nasa.gov/sparcle/sparcle_tuto
  rial.html
• http//aesd.larc.nasa.gov/gl/tutorial/lidar/lidar_
  mn.htm
• NASA Remote Sensing
• http//spacelink.nasa.gov/NASA.Projects/Earth.Scie
  nce/Atmosphere/Remote.Sensing/

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Lidar Specs Out There

• Transmitter
• Wavelength
• Pulse duration
• Pulse repetition rate
• Average power
• Frequency stability
• without I2 - locking
• with I2 - locking

• Receiver
• Telescope
• Type
• Diameter
• Focal length
• Filter bandwidth
• daytime/night time
• FOV
• daytime/night time
• Polarization rejection

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Lidar Specs to look for

• System name
• Detection
• DIAL, topographic, etc
• Laser type
• tunable CO2, OPO, NdYAG
• Wavelength
• Energy
• fpulse
• ?tpulse
• ??
• ?beam

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Things to look for

• Optomechanical design
• optics size, obscurations, etc
• Laser specs
• pulse length, period, power, coherence length,
  polarization)
• Scanning rates
• Altitudes
• Platform stability
• Pointing accuracy
• Noise

• Temporal MTF of range/time gate hardware
• rise times, decay times, etc
• How does range trigger work?

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Sort outTypes of LIDAR vs applications

• DIAL
• Elastic scattering
• Rayleigh scattering
• Fluorescence
• Raman
• Broadband lidar
• Doppler lidar
• Random Code Modulation

• http//www.etl.noaa.gov/et2/lidar
• Clouds, Aerosols, and Climate
• Water Vapor
• Marine Ecology
• Air Quality
• Mesoscale and Boundary Layer Processes
• Topographic
• Bathymetry
• Imaging Laser Altimetry
• http//www.geolas.com/Pages/laser.html

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Techniques of Laser Enviromental Sensingtaken
from Laser Remote Sensing Fundamentals and
Applications by Raymond M. Measures pgs (206-207)

• Rayleigh Scattering
• Mie Scattering
• Raman Scattering
• Resonance Scattering
• Fluorescence
• Absorption
• Differential absorption and scattering (DAS)

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Techniques of Laser Enviromental Sensingtaken
from Laser Remote Sensing Fundamentals and
Applications by Raymond M. Measures (pgs 206-207)

• Rayleigh Scattering
• Laser radiation elastically scattered from atoms
  or molecules is observed with no change of
  frequency

• Mie Scattering
• Laser radiation elastically scattered from small
  particulates or aerosols (of size comparable to
  wavelength of radiation) is observed with no
  change in frequency

h?
h?
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Techniques of Laser Enviromental Sensingtaken
from Laser Remote Sensing Fundamentals and
Applications by Raymond M. Measures (pgs 206-207)

• Raman Scattering
• Laser radiation inelastically scattered from
  molecules is observed with a frequency shift
  characteristic of the molecule (h? - h? E)

• Resonance Scattering
• Laser radiation matched in frequency to that of
  a specific atomic transition is scattered by a
  large cross section and observed with no change
  in frequency

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Techniques of Laser Enviromental Sensingtaken
from Laser Remote Sensing Fundamentals and
Applications by Raymond M. Measures (pgs 206-207)

• Fluorescence
• Laser radiation matched to a specific electronic
  transition of atom or molecule suffers absorption
  and subsequent emission at lower frequency
  collision quenching can reduce effective cross
  section of this process broadband emission is
  observed with molecules

• Absorption
• Observe attenuation of laser beam when frequency
  matched to the absorption band of given molecule

Excited level
Electronically excited vibrational levels
h?
Ground level
h?
h?
Ground level
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Techniques of Laser Enviromental Sensingtaken
from Laser Remote Sensing Fundamentals and
Applications by Raymond M. Measures (pg 207)

• Differential absorption and scattering (DAS)
• The differential attenuation of two laser beams
  is evaluated from their backscattered signals
  when the frequency of one beam is closely matched
  to a given molecular transition while the others
  frequency is somewhat detuned from the transition

Excited level
h?2
h?1
h?2
Ground level
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LITELidar In-space Technology Experiment Science
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ICESat(aka Laser Altimetry Mision)The Ice,
Cloud, and Elevation Satellite

• Launched Jan 12, 2003
• Jan 15, 2003 Earth pointing
• Measures
• ice sheet elevations
• changes in elevation through time
• height profiles of clouds and aerosols
• land elevations
• vegetation cover
• approximate sea thickness.

• Geoscience Laser Altimeter System (GLAS) - sole
  instrument
• Combinination surface lidar with dual wavelength
  cloud and aerosol lidar

Images and info from http//icesat.gsfc.nasa.gov/
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ICESat(aka Laser Altimetry Mision)The Ice,
Cloud, and Elevation Satellite

• First laser-ranging instrument for continuous
  global observations of Earth
• Mission data will be distributed and archived by
  the National Snow and Ice Data Center

• More detailed info
• ICESat FACT SHEET (.pdf)
• ICESat BROCHURE (.pdf)
• ICESat LITHO (.pdf)
• Environmental Assessment for ICESat (.pdf)
• National Environmental Policy Act (.pdf)

Images and info from http//icesat.gsfc.nasa.gov/
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ICESat(aka Laser Altimetry Mision)The Ice,
Cloud, and Elevation Satellite

• http//glas-scfweb.gsfc.nasa.gov/

• More detailed info
• ICESat FACT SHEET (.pdf)
• ICESat BROCHURE (.pdf)
• ICESat LITHO (.pdf)
• Environmental Assessment for ICESat (.pdf)
• National Environmental Policy Act (.pdf)

Images and info from http//icesat.gsfc.nasa.gov/