GNSS Resources in Louisiana

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GNSS Resources in Louisiana Present and Future

• J. Anthony Cavell, PLS, CFedS
• Louisiana State University, C4G

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Global Navigation Satellite System

• Currently GNSS's are GPS and GLONASS, Galileo is
  planned
• They supplant earlier systems
• Transit, STARFIX
• Omega, LORAN, Decca VOR, Del Norte, Motorola,
  Cubic, EDM
• Microwave (Autotape, MiniRanger, Microfix)
• Beacons, Lighthouses, Tape, Sextant, Transit,
  Compass, Clock

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Sextant Friends
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Resection
USACE
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Range-Azimuth
USACE
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Range - Range
USACE
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Dilution of Precision
USACE
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GNSS
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Augmentation Makes all the Difference
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Code (lt1m to 5m)

• Differential
• Two receivers and a reference
• Real-Time Differential
• Two receivers a reference and a radio
• National DGPS
• Coast Guard and Corps beacons
• WAAS adds to the mix
• Local networks add value

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Carrier (5mm to 5cm)

• Static baselines
• Two or more receivers
• Kinematic (poor performance)
• Post processing risky
• Real-Time Kinematic
• Add radio and reduce risk

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Enhanced Carrier

• Static baselines Kinematic
• CORS provide reliable tie to NSRS
• Real-Time Kinematic
• Local networks add precision
• Ties to NSRS add accuracy

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Real-Time Networks w/CORS

• CORS provide confident network tie to NSRS
• National CORS embedded in Network
• Network data supports numerous scientific,
  engineering and surveying endeavors
• Geology, Weather, Deformation, Construction

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High-Tech Louisiana

• A challenging environment for surveyors
• Towers used to extend surveys
• Radio ranging followed early-on
• Only private satellite navigation system,
  STARFIX
• NavBeacon use adopted early
• Static GPS brought survey control to the marsh
• Real-time kinematics methods enhanced topo,
  subsurface and boundary surveys
• Subsidence renders benchmarks unreliable!

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2001, An Important Year

• LSU C4G deploys GULFNet in cooperation with
  national CORS program
• NOAA/NGS reports that La. BMs unreliable.
• Seed planted to develop GULFNet Real-Time System
  (GRTS)

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LSU C4G GULFNetThe Hub of Progress

• C4G research provided crucial NOAA TR-50
• NGS used TR-50 to validate 80 BMs after
  Hurricanes Katrina and Rita
• By 2006 many more stations were added
• National Weather Service uses GULFNet data to
  improve forecasts
• In 2007 dream of LSU GRTS became reality
• 2008 LSU C4G, GULFNet and GRTS cover the borders
  of the state except offshore.

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The Future

• GULFNet provides better ties to the NSRS
• GRTS provides construction, topo, hydro and
  navigation with heretofore unheard of speed and
  accuracy
• The complex behavior of Louisiana geology will be
  measurable, reliably
• and much, much more.

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GULFNet
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Thank you for your attention.

• J. Anthony Cavell, PLS, CFedS
• LSU C4G