20 feb 2009 salt lake city, utacsm-marls-ucls-wfps conference 2009 geoid modeling, grav-d and height...
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20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009
Geoid Modeling, GRAV-D and Height Mod
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009
Why make a new vertical datum?
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009 2Courtesy of Dr. Dennis Milbert
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 200920 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009 3
Vertical Shift due the National Readjustment of 2007
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009
Hybrid Geoid Height Models (e.g., GEOID09), Gravimetric Geoid Height Models (e.g., USGG2009) and Conversion Surfaces using GPS on BM data
• Gravimetric Geoid systematic misfit to BM’s but best fits “true” heights• Hybrid Geoid “converted” to fit local BM’s, so best fits NAVD 88 heights• Conversion Surface model of systematic misfit derived from BM’s in IDB
Earth’s Surface
hh
h hh
HH
HH
H
NNNNN
Ellipsoid
Hybrid Geoid
Gravimetric Geoid Geoid
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 200920 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009 5
(Beta) GPSBM 2009 for CONUS
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009
USGG2009 (Beta)
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009 6
GEOID09 (Beta)
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009
Extent of Gravity Coverage Shown are the differences between NGSIDB value and EGM08 model
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009 7
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009
• Official NGS policy as of Nov 14, 2007– $38.5M over 10 years
• Airborne Gravity Snapshot– “Static Geoid”
• Absolute/Satellite Gravity Tracking– “Time Dependent Geoid”
• Re-define the Vertical Datum (using gravimetric geoid as reference surface) of the USA by 2017
GRAV-D: Gravity for the Redefinition of the American Vertical Datum
http://www.ngs.noaa.gov/GRAV-D/
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009
A North American Geoid
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009 9
20 FEB 2009 Salt Lake City, UT ACSM-MARLS-UCLS-WFPS Conference 2009
For a more thorough discussion,see the USGG2009/GEOID09 session
later today