Airborne suborbital science: Platforms and sensors

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Airborne (suborbital) science Platforms and
sensors
12 in attendance Scott Ollinger (co-chair)
Dar Roberts (co-chair) Collective Expertise
LIDAR, Interferometric radar imaging
spectroscopy, UAV development and testing (NASA
and USDA), rapid response systems, fire
detection, thermal imagery, sensor webs, Several
new NSF initiatives (CUAHSI, NCALM, HAIPER)
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• 1. What are the Terrestrial Ecology,
  Biodiversity, and Applied Sciences Communitys
  current and future needs for suborbital
  observations?
• Important contributions of aircraft remote
  sensing
• Sensor test bed (Provides a platform for sensor
  testing and algorithm development
• Unique sensors (HF imaging spectrometers, small
  foot print LIDAR, LVIS, FLIR, FLEX, P-band SAR,
  ATLAS)
• Control over timing of data acquisition
  (critical)
• Improved cloud avoidance (data acquisition under
  or around clouds)
• Multiple times of day (e.g. target specific tidal
  stage, sun angle or plant stress level)
• Rapid deployment following disturbance (fires,
  floods, insect outbreaks)
• Extended periods of data collection
• Multiple sensor altitude - Variable (Scalable)
  spatial resolution (lt1m to 20 m)
• High Informational Resolution (Spectral,
  polarimetric and vertical)
• Fine spectral resolution (Imaging Spectrometers)
  - Discrimination of species, chemistry and
  physiological function.
• Multi-frequency, fully polarimetric radar
  (Penetration depth, soil moisture flood status,
  vegetation structure). Frequency allocation and
  band width issues limit capacity in space.
• Control over Sun-Earth-Sensor geometry (timing,
  flight trajectory, BDRF)
• Multisensor integration Many sensor combinations
  possible at multiple scales
• Data quality/Sensor evolution - Opportunities for
  repeat calibration, repair and upgrade.
• Cost/Development cycle Aircraft missions can
  be quick and cost effective as compared to
  satellite missions.

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• 1b. Limitations/Challenges with Aircraft Data
• Limited spatial temporal coverage
• Difficult Georectification
• Intractability to many users
• Perception (sometimes real unavoidable) of data
  being difficult to access and work with.
• Perception (sometimes real, but avoidable) of
  aircraft remote sensing being a hard community to
  break into.
• No (or limited) distribution of standard data
  products, restricts use by those lacking specific
  skills.

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• 2. Recognizing that the NASA Suborbital Science
  program is evolving and that repeated attempts to
  secure new funds for new airborne sensors have
  failed, how should our community respond, adjust
  and adapt?
• What should we do???
• We should know how many non-NASA sensors (i.e.
  University, private etc.) exist along with
  availability/quality?
• Education Airborne program can be taken for
  granted. Need to inform/remind scientists,
  management, congress, etc. of the value of the
  airborne program.
• Need for a review article on the contributions of
  aircraft remote sensing to ecological research.
  POSSIBLE JOURNALS BIOSCIENCES, FRONTIERS in
  ECOLOGY, ECOLOGICAL APPLICATIONS
• Improve dissemination and use of aircraft data
• Should NASA encourage development of data
  products from airborne sensors?
• Should there be an aircraft data DAAC or
  equivalent?
• Should NASA have specific calls for suborbital
  science product development?
• Interest in aircraft RS is growing in other
  agencies while resources at NASA remain flat.
  Provide feedback to program managers (at NASA and
  other agencies) where synergy exists with
  initiatives by other agencies

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• 3. What are the Terrestrial Ecology,
  Biodiversity, and Applied Sciences needs for
  unpiloted aerial vehicles (UAVs)?
• UAVs are appropriate for tasks that are Dull,
  Dirty or Dangerous
• Long duration, high altitude, plume dispersal
  fires, very low altitude
• Long duration eddy flux
• Fire dynamics
• Phytoplankton blooms
• Natural hazards requiring long duration, repeat
  passes
• UAV Attributes
• Cost
• Small UAVs can be cost effective and many are
  available
• Large UAVs are generally very expensive
  (cost/flight hour/pound payload UAVs 10x more
  than existing piloted aircraft.
• Medium-sized UAVs are presently lacking, but may
  be forthcoming
• Higher risk of crash
• Cannot fly over commercial airspace
• What UAVs are available? See
• http//uav.wff.nasa.gov/
• http//suborbital.nasa.gov/
• http//nirops.fs.fed.us/UASdemo/
• Payloads from 20 - 3000 kg

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Tentative Paper Outline

• Title The unique role of aircraft remote
  sensing in ecological research
• Ecological Needs for Remote Sensing (broadly)
• Specific contributions of airborne sensors
• Types of ecological measurements
• Niche of Airborne Sensors relative to Spaceborne
  sensors
• Historical Role of Airborne Sensors
• Case studies
• Future Directions

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Additional Questions

• What other non-NASA programs exist that have a
  current or future need for aircraft remote
  sensing?
• How could NASA or the user community go about
  making the link between these agencies?
• NCALM University of Florida, UC Berkeley,
  Arizona
• NSF Consortium National Center for LIDAR
• LIDAR system
• Could this be a model we could use?
• Are there other NSF initiatives that could be
  used similar to NCALM?
• Yes HAIPER NCAR, gulf stream 5 jet, currently
  atmospheric focus, some interest in other
  sensors, routine data collection
• NSF program managers would like it to be broader
  (Bulletin American Meteorological Society BAMS)
  
• What unique measurements can be made that do not
  compete with private assets?
• How do you avoid competition with industry?
  Focus on research emphasis
• To what extent are aircraft missions useful
  beyond their service as a test bed for planned
  spaceborne missions?
• How will the suborbital program be impacted by
  and react to the decadal survey?
• What is the mechanism for downsizing sensors to
  fit on a UAV?
• What should the balance of funding be for PI
  sensors/Univ sensors vs facility sensors?
• Interdisciplinary nature of facility sensors
• What is the community preference?
• Availability of facility vs PI sensors

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Discussion Questions

• What are the Terrestrial Ecology, Biodiversity,
  and Applied Sciences Communitys current and
  future needs for suborbital observations?
• Alternative question How does the suborbital
  platform program contribute to TE, Biodiv and
  ASP?

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What might an Ecologist want to know?

• What is there (PFT, Species)?
• TE, Biodiversity, invasions, phytoplankton/algae,
  coral, submerged aquatic vegetation
• How much is there (plant cover)?
• TE, Biodiversity and invasions
• What is its physiological status?
• Vegetation health, chemistry, carbon exchange,
  LUE, NPP, etc.
• What is its structure, biophysical properties?
• Height, biomass, LAI, roughness, albedo,
  subcanopy
• What is the senesced biomass?
• How is it changing?
• Land-cover change, forest degradation,
  aforestation, invasion
• How do these properties vary with spatial,
  spectral and temporal scale?
• What are the geological/soil properties
  (chemistry, texture), soil exposure, erosion,
  soil moisture
• What are the atmospheric properties?
• What is its temperature and emissivity?
• For water, what is its depth, sediment
  concentration, current, waveheight, pigments

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Ecological Contributions of Airborne Platforms
(Part I)

• Fine to moderate spatial resolution (variable
  spatial resolution)
• For some applications, resolutions 3 m or less
  are needed
• Multiple sensor altitudes (atmospheric
  measurements, multibaseline)
• Fine spectral resolution (AVIRIS)
• Improves PFT or species discrimination, provides
  a suite of physiologically meaningful measures,
  improves biophysical retrievals, water vapor,
  trace gases and aerosols, chemical diversity
  (biodiversity)
• Multifrequency, fully polarimetric
• Frequency allocation issues limit capacity in
  space, P band in space, wide band width SAR not
  possible from space
• Penetration depth, soil moisture, flooded
  vegetation, structure (tree height, biomass
  classes)
• higher SNR
• Timing (critical)
• Provides improved cloud avoidance, data
  acquisition under clouds, flexibility to support
  field campaigns, meet timing requirements (ie,
  coastal tides)
• Provides non-sun synchronous acquisitions, night
  imaging
• Can explore variability in viewing vs solar
  geometry (scan angle, BRDF)\
• Trajectory control, relative overlap between
  flight lines etc.
• AIRMISR Multiangle along multiple trajectories
• Contributes timely data (ie, southern California
  fire storm)
• Hazards (earthquakes, floods, fires) need
  timely, immediate data acquisition following
  disturbance
• Insect outbreaks
• Persistence (dwelling over one spot for an
  extended period of time (fire monitoring,
  evapotranspiration, carbon release), daily repeat
  passes

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Ecological Contributions of Airborne Platforms
(Part II)

• Unique sensors
• HF Imaging Spectrometry (AVIRIS), Small footprint
  LIDAR, LVIS, FLIR, Fluorescence (FLEX),
  polarimetric (P band), no single pass
  interferometer, multispectral high spatial
  resolution thermal (ATLAS, MASTER, Autonomous
  Modular Sensor (AMS)), eddy covariance
• Data continuity at an appropriate spatial scale
• Long term sampling (ie, long term resampling of a
  site with the same or similar sensors)
• Improved data continuity by persistence
• Multisensor integration
• An imaging spectrometer can be used to simulate
  other sensors
• Critical for scaling between ground and space
• Synergistic use of sensors (combination of two or
  more sensors) Need good validation from an
  airborne program
• Sensor Test bed
• Provides a platform for testing out sensor
  concepts, technology components and measurement
  strategies
• Provides a platform for algorithm development and
  testing, evaluating potential sensor web
  configurations
• Calibration/Validation of spaceborne sensors
• Sensor repair
• Data Quality (can be improved between flight
  seasons)
• Quality of calibration, daily calibration
• Many commercial sources do not provide science
  quality data
• Sensor evolution
• Sensors can be improved over multiple flight
  seasons (AVIRIS, AIRSAR)

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Advantages and Limitations of Spaceborne Sensors
for Ecology

• Advantages
• Global sampling, global access
• Variable swaths, local (ASTER) to continental
  (MODIS)
• Repeat sampling (high frequency, daily,
  multi-day, monthly)
• Well understood surface tracks, illumination and
  viewing geometry
• Sensor legacy (ie, Landsat Continuity)
• Reduced geometric distortion
• No airspace restrictions
• Very high national and international contribution
  to agencies, research, education
• Prestige, public awareness
• Limitations
• Spatial/spectral resolution tradeoffs
• Fixed spatial scales
• Band width limitations
• Inflexible acquisition times
• Inflexible orbits
• High sensor and launch costs, long development
  cycle
• Limited sensor availability (ie, LIDAR, P-band
  SAR, hi-fidelity imaging spectrometry)
• Limited sensor evolution, difficulty to repair
  (ie, Landsat ETM)

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Limitations and Advantages of Spaceborne Sensors
for Ecology
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Question 2 Part 1

• Recognizing that the NASA Suborbital Science
  program is evolving and that repeated attempts to
  secure new funds for new airborne sensors have
  failed, how should our community
  respond/adjust/adapt?
• There should be consideration of other programs,
  such as NSF/NEON (Scott Ollinger)
• NSF calls for sensor development (MREFC) NEON
  400-500 million dollars, CLEANER (Collaborative
  Large Scale Engineering Analysis Network for
  Environmental Research) hydrology eng water
  quality), CUAHSI (Consortium of Universities for
  Advancement of Hydrological Science Incorporated)
  hydrology, environmental engineering Water
  supply)
• NSF 6 million central NEON office (call, 2 years
  ago, Bruce Hayden NEON Inc).
• 7 out of 8 groups considered aircraft remote
  sensing as a core set of requirements for a NEON
  network (Imaging Spectrometry and LIDAR).
• Partnerships with NASA and other agencies, where
  one could develop it, the other deploy
• Concern Advice given in design consortium did
  not acknowledge potential contribution of NASA,
  no representatives from NASA (NEON project
  implementation committee).
• Concern NASA/NSF should coordinate on
  compatibility (je, an instrument that can fly on
  many platforms)
• What can we do as a community to push these
  things through?
• Other programs
• SBIR, Naval Postgraduate School, EPA, NOAA, DOE
• Recommendation What kinds of sensors could be
  developed through an SBIR?
• NASA should be encouraged to partner or
  facilitate agreements with NSF to aid NEON
• NASA must be encouraged to understand the
  advantageous of a partnership with NSF
• NEON/NSF needs to agree to support NASA efforts
  with its ground based observations
• NASA should support NSF/NEON in the development
  of sensors that complement NASA capabilities
• NSF needs feedback from the science community of
  the importance of NASA technology to their
  program
• University/Institutional efforts
• ie, Carnegie waveform small foot print LIDAR,
  Imaging Spectrometry

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Question 2 Part 2

• Recognizing that the NASA Suborbital Science
  program is evolving and that repeated attempts to
  secure new funds for new airborne sensors have
  failed, how should our community
  respond/adjust/adapt?
• We should know how many non-NASA sensors (ie,
  University etc) exist?
• We should have a table of existing sensors
• What exists and how accessible is it and what is
  its quality?
• NASA should set minimum data quality standards
• Perhaps the Instrument Incubator Program could be
  used
• NASA has invested considerable funds in UAV SAR
  how might this engineering model be adapted for
  use with a different sensor package or support a
  different science objective (ie, canopy height)
• Outreach/education why do management, congress,
  scientists etc. not perceive the value of the
  airborne program?
• How do we change perceptions?
• The data are difficult to work with
• The data are only accessible to a small club
• There are no standard data products
• Should there be an AIRCRAFT DAAC for Data or
  example data?
• Should PIs be required to provide examples of
  their work
• Location of data sets should be reported
• Data should be made more accessible to the user
  community
• Difficulty in getting data when you needed it
• Difficulty in processing data
• The community may not perceive what the airborne
  program and the individuals involved contribute
  to the success of a mission

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Question 3 Part IWeb sites http//uav.wff.nasa.
gov/http//suborbital.nasa.gov/platforms/platform
s.html

• What are the TE, Biodiv, and ASP needs for
  unpiloted aerial vehicles (UAVs)? How should we
  take advantage of current investments in UAV
  technology?
• When is a UAV appropriate (the cost of UAVs is
  really high, so you need a good justification)
• Justification Tasks that are Dull, Dirty or
  Dangerous
• Long duration, high altitude, autonomy (ie,
  guided by sensor input to tell it where the
  optimal flight lines are through a sensor web),
  volcanic plumes, smoke (dirty), too dangerous
  (fire, or very low altitude such as eddy
  covariance over tree tops), Boreas (flux tower
  repeat flights)
• What UAVs are available? (see http//uav.wff.nasa.
  gov/ for a more complete list, that is still out
  of date)
• http//nirops.fs.fed.us/UASdemo/ (see
  photogallery at bottom 20 lbs)
• Ikhana (predator)
• Aerosonde (leased from AAI)
• Sierra (AMES)
• Altair (Lease arrangement with General Atomics)
• Proteus (normally piloted) leased from Scaled
  Composites
• What does NASA have now?
• Sierra (still under construction at NASA Ames)
• 100 lbs
• Predator B (ikhana) Delivery in Fall 06
• Global Hawks (Dryden) possession in 2007,
  control later

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Question 3 Part IIWeb sites http//uav.wff.nasa
.gov/http//suborbital.nasa.gov/platforms/platfor
ms.html

• What are the TE, Biodiv, and ASP needs for
  unpiloted aerial vehicles (UAVs)? How should we
  take advantage of current investments in UAV
  technology?
• UAV Attributes
• What is the cost?
• Altair Currently cost prohibitive (hugely
  expensive compared to manned assets)
• Ikhana Actual cost unknown, likely to be costly
  but when assessed by flight hour might match
  manned assets
• Global Hawk unkbnown costs
• Metric cost/flight hour/pound payload UAVs 10x
  more pricey
• What are the flight attributes? (ie, speed,
  elevation, stability)
• Altair up to 36 hours continuous flight,
  altitude 52,000 feet, up to 1000 lbs (depends on
  sensor pod limitations)
• What is the payload?
• Altair 1000 lbs, same as Ikhana
• Global Hawk 2-3000 lbs
• Flight limitations/liability
• Can your sensor be adapted to work with a UAV?
• NASA is currently heavily invested in UAVs. How
  might this capability be used?
• UAVs are not the answer to all problems (Scott)
• How much do you care about your sensor?
• UAVs crash more often
• Which smaller UAVs exist

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Additional Questions

• What other non-NASA programs exist that have a
  current or future need for aircraft remote
  sensing?
• How could NASA or the user community go about
  making the link between these agencies?
• What unique measurements can be made that do not
  compete with private assets?
• To what extent are aircraft missions useful
  beyond their service as a test bed for planned
  spaceborne missions?
• How will the suborbital program be impacted by
  and react to the decadal survey?
• What is the mechanism for downsizing sensors to
  fit on a UAV?

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Additional Questions

• What are the mission concepts that could take
  advantage of the unique attributes of UAVs?
• Long duration flights either required for diurnal
  studies or long range acquisition (ie, southern
  Ocean)
• CO2 sniffer for validation of OCO and towers
  (remote areas) Small package (NOAA, modified
  LICOR 7550 IRGA)
• Night time fluxes
• Coastal blooms (need for continuous measurements)
• Forest fire emissions and dynamics (spread,
  intensity)
• Fires, dwelling (time series), perimeters
• Circumnavigation of ice sheets (antarctic)
• Real-time data acquisition at fine spatial
  resolution
• UAV often has a high band width satellite link
  that can be taken advantage of. This is also more
  cost effective than a satellite for onboard
  processing
• How much might we gain from this type of
  real-time potential?
• Example, plant fluorescence
• Potential of continental scale mapping made
  possible by long duration capabilities of UAV
  using an active sensor (ie, LIDAR power various
  with square of distance, so this translates to a
  lower power need for a laser)
• Ideal platform for testing out microsat
  constellation

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Action Items

• Journal Article on Ecological Advantages of
  airborne platforms?
• Target Bioscience, Frontiers in Ecology,
  Ecological Applications, Summary in EOS
• Participants
• Jeff Luvall (thermal), Matt Fladeland (UAV, past
  flight requests, historical program), Scott
  Ollinger (imaging spectrometry), Dar Roberts
  (imaging spectrometry), Michelle Hofton (LIDAR),
  Susan Ustin, Greg Asner, Robert Green
• Map of US showing where aircraft sensors have
  been flown, existing archives

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Key bullets Day 1

• We identified a number of benefits of aircraft
  remote sensing that cannot be replaced by
  satellites
• Summarize this list (or for example)
• Outreach
• Knowledge of benefits of suborbital science
  program is poor in important components of the
  scientific community
• We need a paper that summarizes the ecological
  strengths of an airborne program
• Working with non-NASA programs that have needs
  for aircraft remote sensing (NEON) or taking
  advantage of existing non-NASA, public resource
• UAVs
• To date there is no evidence that they are likely
  to be an effective replacement of current
  aircraft, but could enhance or complement these
  programs (cost prohibitive)
• There are unique ecological questions that
  probably can only be addressed using an UAV (long
  duration requirements, dangerous acquisitions)
• Excellent UAV information exists

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Airborne (suborbital) science Day 2 Platforms
and sensors

• Scott Ollinger, Dar Roberts
• 10 in attendance
• Rob Sohlberg (UAV, rapid response, sensor webs))
• Robert Green (AVIRIS)
• Cheryl Yuhas (Suborptical management)
• Matt Fladeland (Suborbital, UAV etc)
• Emily Wilson (NASA Goddard)
• Nicholas Coops
• Paul Siqueira (JPL
• Amy Neuenschwander (U Texas)
• Greg Asner (Carnegie)
• Susan Ustin (UC Davis)