Coherent Lidar Activities at NASA Langley Research Center

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Coherent Lidar Activities at NASA Langley
Research Center

• Michael J. Kavaya
• NASA Langley Research Centermichael.j.kavaya_at_nasa
  .gov

14th Coherent Laser Radar Conference Snowmass,
Colorado USA 8-13 July 2007
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Current Projects Involving Coherent Lidar
LRRP Laser Risk Reduction Program GWOS Global
Wind Observation System IIP-DAWN Instrument
Incubator Program-Doppler Aerosol WiNd Lidar
ALHAT Autonomous precision Landing and Hazard
detection and Avoidance Technology
Skywalker VALIDAR VALIDation LIDAR LIF Lidar
Intercomparison Facility
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Types of Research vs. Coherent Lidar Projects
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Laser Risk Reduction Program(LRRP)
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NASAs Laser Risk Reduction Program
2 Lasers, 4 Techniques, 6 Priority Measurements
Pulsed Laser Development
2.05 micron
DIAL CO2
Backscatter Lidar Aerosols/Clouds
2 MICRON
2.05 micron
Atmosphere Lower Upper
Coherent Winds
Doppler Lidar

Key Technologies in Common Laser Diodes Laser
Induced Damage Frequency Control Electrical
Efficiency Heat Removal Ruggedness
Lifetime Contamination Tolerance
Coherent
High Accuracy High Resolution Lower Trop. Clouds
Hybrid Lidar Winds
Noncoherent Winds
Direct
Global Coverage Medium Resolution Medium
Accuracy Mid/Upper Atmosphere
0.355 micron
X3
1 MICRON
X2
Altimetry
DIAL Ozone
Surface Mapping, Oceanography
1.06 micron
Backscatter Lidar Aerosols/Clouds
X2
0.30-0.32 micron
0.532 micron
OPO
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Laser Risk Reduction ProgramCoherent Lidar
Accomplishments2-Micron Pulsed Laser

• Demonstrated over 1.2 Joule pulse energy (single
  pulse, 12/05) at 2 microns 1.5 J (double pulse,
  2/05) (both 2 Hz)
• Exceeds requirement for active wind measurement
  from space
• Advanced both oscillator and amplifier design
• Advanced material from HoTmYLF to HoTmLuLiF
• Advanced cooling method from all liquid to
  partially conductive (pump laser diode arrays,
  LDAs) to all conductively cooled (LDAs and laser
  rod)
• Advanced LDA pumping more LDAs around
  circumference, light guidance into rod, heat
  removal, A to AA package
• Maintained beam quality and electrical
  efficiency
• Advanced from lab table to compact, engineered
  design

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Laser Risk Reduction ProgramCoherent Lidar
AccomplishmentsPump Laser Diode
ArraysCharacterization, Advancement, Life Testing

• Developed sophisticated LDA Characterization
  Facility
• Developed 16-station LDA Lifetime Test Facility
• Improved LDA heat removal with novel diamond
  substrate
• Began development of lifetime theory
• Assisted ICESAT CALIPSO flight missions

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Global Wind Observing System(GWOS)
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Global Wind Observing SystemGWOS

• NASA HQ Anticipated NRC Earth Science Decadal
  Survey
• In Aug. 2006 HQ requested 8 mission studies
  including GWOS
• Study teams requested to define
• Science requirements
• Instrument and mission concepts
• Cost vs. performance
• GWOS study by GSFC and LaRC
• Used GSFC ISAL and IMDC instrument and mission
  design teams
• Measurement requirements very close to NASA-NOAA
  Demo Req.
• Scanners eliminated in favor of 4 fixed
  telescopes shared by coherent and direct
  detection lidars, 0.5 m each

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GWOS Simulated Space-Based Performance
Direct 0.8/0.36 J, 100 Hz, 0.5 m
Coherent 0.25 J, 5 Hz, 0.5 m
400 km 45 deg nadir 4 azimuths
Coherent
Direct
GWOS with background aerosol mode
GWOS with enhanced aerosol mode
Coherent
Direct
Courtesy Simpson Weather Assoc
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Dual Lidars Hybrid are Complementary
GWOS with background aerosol mode
Dual sampling with the coherent and direct
detection molecular Global Wind Observing Sounder
(GWOS)
GWOS with enhanced aerosol mode
Green represents percentage of sampled volumes
when coherent subsystem provides the
most accurate LOS measurement Yellow is for
direct detection Gray is when neither system
provides an observation that meets data
requirements
Courtesy Simpson Weather Assoc
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Dual Lidars Hybrid are Synergistic
Background aerosol mode
Enhanced aerosol mode
Green both perspectives from coherent
system Yellow both perspectives from direct
molecular Blue one perspective coherent one
perspective direct
Courtesy Simpson Weather Assoc
When two perspectives are possible
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Instrument Incubator ProgramDoppler Aerosol WiNd
lidar(IIP-DAWN)
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Instrument Incubator ProgramDoppler Aerosol WiNd
lidarIIP-DAWN
ABSTRACT The state-of-the-art pulsed 2-micron
HoTmLuLiF coherent Doppler wind lidar
breadboard developed at NASA/LaRC will be
engineered and compactly packaged consistent with
future aircraft flights. The packaged transceiver
will be integrated into an existing coherent
Doppler wind lidar system test bed at LaRC
VALIDAR (VALIDation LIDAR). Atmospheric wind
measurements will be made to validate the
engineered, packaged technology. LEVERAGE DAWN
will consider the lessons learned from the LRRP
Compact Laser Task and incorporate them into an
improved compact transceiver
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Global Tropospheric Wind Profiling Roadmap
NOW
2-Micron Coherent Doppler Lidar
High Energy Technology 1997
2 micron laser 1988
Conductive Cooling Techn. 1999
Diode Pump Technology 1993
Inj. Seeding Technology 1996
Compact Packaging 2005
Packaged Lidar Ground Demo. 2006
Pre-Launch Validation
Autonomous Oper. Technol.
Lifetime Validation
3-Yr. Lifetime Validation
Space Qualif.
Aircraft Operation
Threshold, 400 km
Demo, NPOESS
UAV Operation
Autonomous Oper. Technol.
3-Yr. Lifetime Validation
Space Qualif.
Pre-Launch Validation
Lifetime Validation
1 micron laser
Diode Pump Technology
Inj. Seeding Technology
Compact Packaging 2006
Packaged Lidar Ground Demo. 2006
Conductive Cooling Techn.
High Energy Technology
0.355-Micron Direct Doppler Lidar
Lidar Perf. Simulations
OSSEs
Past Funding
Laser Risk Reduction Program
1 micron altimetry space missions
2 micron Doppler wind aircraft flights
Pump Laser Diode Advancement
Dual Wavelength Telescope Scanner
Ground-Based Risk Reduction (IPO)
IIP-2004 Projects
Optional
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DAWN Part of Global Winds Roadmap
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Scope
Lasers and Optics
Lidar Transceiver (DAWN)
Transmitter Laser
l/4 Plate
Pol. BS
Large Optics (telescope, scanner)
Receiver
T/R Switch
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LRRP Packaged TransceiverTransmitter Side
11.5 x 26.5 inches
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Autonomous precision Landing and Hazard detection
and Avoidance Technology(ALHAT)
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Autonomous precision Landing and Hazard detection
and Avoidance Technology

• ALHAT Objectives
• Autonomous Precision Lunar Landing Descent and
  landing systems for crewed and non-crewed lunar
  missions capable of landing within 10s of meters
  of predefined surface features or previously
  deployed assets.
• Autonomous Hazard Avoidance Ability to reach
  landing sites which may lie in areas containing
  hazardous terrain features such as craters,
  slopes, and rocks.

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Precision Landing and Hazard Avoidance Lunar
Landing Scenario
Powered Descent Ignition Altitude 20 km
Begin pitch over and Throttle down Altitude 1-
4 km
Acquire altitude data for updating IMU and
reducing position errors
Begin Vertical Descent Altitude 100- 500 m
Acquire terrain maps to perform Terrain Relative
Navigation (TRN)
Acquire elevation maps of the landing site to
identify hazardous features and define safe
landing location (HDA)
Acquire velocity data for Controlling the vehicle
powered descent and touchdown
x
Touch down
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All-Fiber Altimeter/Velocimeter Lidar (Coherent
Doppler Lidar)
Transmitter Single-mode Er fiber
amplifier Wavelength 1.5 micron Seed Laser
Single-mode external cavity diode laser
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Skywalker
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Skywalker

• DARPA funded
• Take advantage of updrafts to extend UAV range
  and duration aloft
• SWA/Emmitt

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VALIDation LIDAR(VALIDAR)
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VALIDation LIDAR(VALIDAR)

• System testbed for advanced high-energy lasers,
  optical components, receiver components, data
  processing software
• Serve as ground-based system testbed for future
  airborne and spaceborne lidar measurements
• Atmospheric data collection

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Lidar Intercomparison Facility(LIF)
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Lidar Intercomparison Facility

• Up to 4 Doppler lidars
• Surveyed for parallel beams
• 6.1 degrees
• Target lights at 677 m

• VALIDAR TODWL agreed to
• 0.42 m/s RMS (7/28/03)

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Concluding Remarks

• Strong coherent lidar portfolio at NASA LaRC
• Great team of civil servants and contractors
• We appreciate the support and funding from the
• NASA Science Mission Directorate (SMD)
• NASA Exploration Systems Mission Directorate
  (ESMD)
• NPOESS Integrated Program Office (IPO)
• DARPA

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Back Up
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Laser Risk Reduction Program Coherent Lidar
Accomplishments2-Micron Coherent Receiver

• Met and surpassed the bandwidth goal of 500 MHZ
• (demonstrated 1 GHz bandwidth)
• Will work on a diode laser version for the LO
  laser

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Laser Risk Reduction ProgramCoherent Lidar
AccomplishmentsCompact Electronics
AFTER
BEFORE
19 rack-mount enclosure, 1.75 inches high
8 separate electronic boxes
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Laser Risk Reduction Program

• Recommended to NASA by 2000 External Review
  Panel
• Steven B. Alejandro Air Force Research
  Laboratory
• Ralph Burnham Fibertek Inc.
• T.Y. Fan MIT Lincoln Laboratory
• Michael Hardesty NOAA
• Thomas Wilkerson Utah State University
• Develop laser technology before mission
  approval to reduce mission risk and cost
• Langley-Goddard joint program
• Started in FY02 scheduled through FY08
• Langley 2 micron laser UV Goddard 1
  micron laser UV
• Langley work both coherent and direct detection

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Location of Coherent Lidar Efforts at NASA LaRC
Langley Research Center
Systems Engineering Directorate
Science Directorate
Laser Remote Sensing Branch
Remote Sensing Flight Systems Branch
Mechanical Systems Branch
Electronic Systems Branch