stone national spatial reference system heights
TRANSCRIPT
Grand Junc*on September 24, 2014
U.S. Department of Commerce Na*onal Oceanic & Atmospheric Administra*on
Na$onal Geode$c Survey Mission: To define, maintain & provide access to the
Na(onal Spa(al Reference System (NSRS) to meet our Na*on’s economic, social & environmental needs
Na$onal Spa$al Reference System
& their (me varia(ons
(& Na*onal Shoreline, etc.)
• Latitude • Longitude • Height
• Scale • Gravity • Orientation
National Geodetic Survey Geodetic Advisors
Geode*c Advisor Contact Info: hLp://geodesy.noaa.gov/ADVISORS/AdvisorsIndex.shtml
! SW Region (AZ, NV, NM, UT)
Bill Stone
! Colorado Pam Fromhertz
! Oregon Mark Armstrong
! Wyoming Mike Londe (BLM)
Establishing accurate eleva*ons (heights)…
1. is important
2. can be expensive
3. can be technically challenging
Con*nuously Opera*ng Reference Sta*ons (CORS)
! 2000 sites
(including 400 PBO)
! 225 organiza$ons
U.S. CORS Velocity Field -‐ NAD83(2011) epoch 2010.0
CORS 90-‐day Coordinate Plots
Heights “101”
GEOID12A
NAD 83(2011) epoch 2010.00
NORTH AMERICAL VERTICAL DATUM 1988 (NAVD88)
`
BM with Scaled Posi*on Datasheet
`
Scaled Orthometric Height
Datasheet
GPS-‐derived Orthometric Height
Datasheet
NEW Na*onal Geode*c Survey Ten-‐Year Plan
" By 2022, reduce all defini*onal & access-‐related errors in geometric reference frame to 1 cm when using 15 min of GNSS data
“Replace NAD83”
" By 2022, reduce all defini*onal & access-‐related errors in orthometric heights in geopoten*al reference frame to 2 cm when using 15 min of GNSS data
“Replace NAVD88”
NAD83 Shortcomings o 2.2 m offset –
NAD83 vs.
Interna$onal Terrestrial Reference Frame (ITRF)
o CORS & passive network inconsistency
vs.
Future Geometric (3-‐D) Datum # replace NAD83 with new geometric datum – by 2022
# CORS-‐based, accessed via GNSS observa$ons
# coordinates & veloci$es in ITRF & official US datum & rela$onship
(NAD83 replacement: plate-‐fixed or “ITRF-‐like”?)
# passive control $ed to new datum; not a component of new datum
# address user needs of datum coordinate constancy vs. accuracy
New geometric datum minus NAD 83 (horizontal)
New geometric datum minus NAD 83 (ellipsoid height)
NAVD88 Shortcomings o Cross-‐country errors (1-‐m $lt)
o 0.5 m bias in reference surface vs. global mean sea level geoid
o Subsidence, uplif, freeze/thaw invalidate BM eleva$ons
Approximate Geoid Mismatch in the NAVD88 H=0 surface
The Rela$onship of Heights
• $38.5M over 10 years
• Replace the na*onal ver*cal datum (NAVD88) by 2022 with a 1 cm accurate gravimetric geoid
• Orthometric heights accessed via GNSS accurate to 2 cm
• Thrusts of project:
– Airborne gravity survey of en*re
country and its holdings
– Long-‐term geoid change monitoring
– Partnership surveys
Gravity for the Redefini$on of the American Ver$cal Datum (GRAV-‐D)
Gravity and Heights are
inseparably connected
GRAV-D Status • 10 km spaced data lines • 70 km spaced cross lines • 20,000 m al*tude • 230 kt flight speed • 35% of US complete (Q1-‐2014)
GPS DoV
Leveling
Gravity
LIDAR/ Imagery
Geoid Slope Valida*on Surveys – 2011 & 2014
Future Geopoten*al (Ver*cal) Datum # replace NAVD88 – by 2022
# accessed by GNSS & gravimetric geoid
# monitor $me-‐varying nature of gravity field
# most accurate con$nental gravimetric geoid model, ever
Hybrid Geoid Model (GEOID12A) & Gravimetric Geoid Model (USGG2012) Conversion Surfaces using GPS on BM data
Earth’s Surface
h h
h h h
H H
H H
H
N N N N
N
Ellipsoid
Hybrid Geoid
H ~ h -‐ N
GEOID12A GPS on BMs
• upload L1/L2 GPS data # OPUS-‐RS (Rapid Sta*c) -‐-‐-‐-‐15 min to 2 hr (per CORS)
# OPUS-‐S (Sta*c) -‐-‐-‐-‐ 2 to 48 hr (anywhere) • solu*on via email -‐-‐-‐-‐ in minutes
• op*onal sharing (formerly “publishing”)
• OPUS-‐Projects (coming soon)
Online Posi$oning User Service (OPUS)
>>> fast, easy NSRS access
OPUS – Share (aka OPUS-‐DB)
! Sharing Criteria:
• NGS-calibrated antenna • > 4 hour data span • > 70% observations used • > 70% fixed ambiguities • < 0.04m H peak-to-peak • < 0.08m V peak-to-peak
! Uses:
• GPS on BMs
• PLSS / GCDB
• Data archive
• Data sharing
Shared OPUS Solu*ons
Height Modernization -faster -cheaper -more accessible
Height Modernization
Western Regional States
Height Moderniza*on Regions
Height Moderniza*on Program Page: Mee*ngs, Presenta*ons
NGS homepage: geodesy.noaa.gov
• Data access
• Geode*c Toolkit
• Publica*ons
• Height Moderniza*on
• Training opps
• Educa*on resources
• Presenta*ons
• CORS, OPUS, …
Accurate positioning begins with accurate coordinates
Sour
ce: Z
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h-A
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ican
Insu
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roup