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Transition of the ORGNfrom
NAD 83(CORS96) epoch 2002.00to
NAD 83(2011) epoch 2010.00
Ken Bays, PLSLead Geodetic Surveyor
Oregon DOTMarch 2013
ODOT Surveyors Conference
Overview
Review of our overall plan to transition the ORGN to NAD 83(2011) epoch 2010.00
Changes ODOT made to GNSS Spider real-time network software
ORGN Real-time Products ORGN Post Processing Products (RINEX)
Where to find the new and superseded ORGN coordinates New ORGN Survey Mark Check-in web page
This is not a new datum!
– Reminder: Even though the new ORGN site coordinates are different, this is not a new datum.
It is a new realization of the NAD 83 datum Same reference ellipsoid (GRS80) as all other
realizations of NAD 83– Same origin– Same orientation– Same scale
NGS Guidelines for RTNs
Oregon DOT goal for positioning the ORGN to align with the NSRS:- follow NGS Guidelines for RTNs:- http://www.ngs.noaa.gov/PUBS_LIB/NGS.RTN.Public.v2.0.pdf
Oregon DOT’s written guidelines for positioning the ORGN closelyfollow the NGS guidelines.
Major Elements of ODOT’s Plan Minimum of 10% of the stations in the ORGN will be NGS
CORS Process/Adjust with NGS OPUS Projects (beta) online Process 5 days of data for all stations that were observed
during high pressure period over the state Fix NGS multi-year CORS sites in a least squares
adjustment– All fixed stations are NGS CORS sites that have
“computed velocities” – We did not fix NGS CORS sites in our adjustment that
only had “modeled velocities” Compare our adjustment results with other off-the-shelf
least squares adjustment software: Trimble Business Center.
Major Elements of ODOT’s Plan Compare our NAD 83(2011) epoch 2010.00 adjusted coordinates
with other coordinate sources– NGS CORS & NGS published OPUS-DB solutions, – WSRN: Also officially transitioned to NAD 83(2011) epoch
2010.00 on 8 March 2013. Note: The ODOT-adopted positions for stations in the ORGN may
vary slightly from the NGS-adopted position of some of the stations that are also NGS CORS stations. This is because the NGS has acknowledged that regional real-time GPS networks such as the ORGN may require tighter internal consistency than the NGS policy provides for. The NGS draft “Guidelines for Real-Time GNSS Networks”, v.2.0, March 2011, state that "For the sake of internal network consistency, the RTN administrator may want to adopt his/her adjusted values for the CORS coordinates rather than use the NGS-adopted values.“– ORGN coordinates agree at the centimeter level with NGS and
WSRN coordinates.
Major Elements of ODOT’s Plan
Seek NGS validation of our alignment of the ORGN to the NSRS– Fiducial (trustworthy check-in) survey marks to ensure
you’re your ORGN real-time correctors align with published survey mark positions.
ORGN Real-time Correctors after 8 March 2013 restart
with ORGN referenced to NAD 83(2011) epoch 2010.00
All ORGN RT Correctors are referenced to NAD 83(2011) epoch 2010.00.
We use NGS IGS08 absolute antenna calibrations in Spider. We continue to send out our RT correctors reduced to the
ellipsoid height at the Antenna Reference Point (ARP)
Rover Recommendationsafter 8 March 2013 ORGN restart
with ORGN referenced to NAD 83(2011) epoch 2010.00
Set the base receiver type as Unknown* Set the base antenna as ADVNULLANTENNA, none, or null*
– * depending on manufacturer Set the rover antenna to the IGS08 absolute antenna calibration
for your particular rover.– Work with your vendor/manufacturer to load IGS08 absolute
calibrations.– Be sure to include any vertical offset (in addition to the Phase
Center Variation calibration) of your antenna ARP, i.e., the Leica height hook = 0.36 m.
Use GEOID12A in the rover if you need NAVD88 ortho heights in the field, i.e., stakeout.– “GEOID12A is the only Geoid model that transforms between
NAD 83(2011) epoch 2010.00 ellipsoid heights and the NAVD88 vertical datum ortho heights.” (NGS)
ORGN Post Processing Products (RINEX) after 8 March 2013 restart
with ORGN referenced to NAD 83(2011) epoch 2010.00
All RINEX files generated by the ODOT Spider Software and posted to the ORGN FTP site now have the new NAD 83(2011) epoch 2010.00 positions (lat, long, and ellipsoid height) embedded in the RINEX files header.– Caution: RINEX files from our partner websites, may not
always be referenced to NAD 83(2011) epoch 2010.00. Always check with your RINEX file provider to see
what datum realization their coordinates are referenced to.
Be sure you use the correct coordinates for each site, whether the superseded or new.
Be sure you don’t mix coordinate datum realizations on a project.
Post Processing after 8 March 2013 restart
with ORGN referenced to NAD 83(2011) epoch 2010.00
Geoid models for Post Processing:– Use only GEOID12A in your post-processing software if
you are processing your project in NAD 83(2011) epoch 2010.00.
“GEOID12A is the only Geoid model that transforms between NAD 83(2011) epoch 2010.00 ellipsoid heights and the NAVD vertical datum ortho heights.” NGS
– If you are processing your project in the superseded NAD 83(CORS96) epoch 2002.00, you should use GEOID03 or GEOID09 in your post-processing software
NGS Antenna Calibration Page: www.ngs.noaa.gov\ANTCAL– Only (IGS08) Absolute Antenna Calibration values should
be used when processing data with NAD 83(2011) epoch 2010.00 coordinates.
ORGN Coordinates Web Page www.TheORGN.net/orgn_coordinates.html
Link to the superseded NAD 83 (CORS 96) epoch 2002.00 coordinates
Link to the new NAD 83(2011) epoch 2010.00 coordinates for each ORGN site
Info about the ORGN transition– Background on the transition– ORGN real-time and RINEX product changes – Transition plan– Antenna Info– Geoid Model Info– Project Management Info
Link to new ORGN Check-In Survey Mark page Link to Presentations from the 4 March 2013 webinar:
“ORGN2011”
ORGN Check-In Survey Mark Web Page
www.TheORGN.net/ORGN_check-in_mark.html Link to the new survey mark check-in form Info about check-in survey marks Benefits of check-in marks to ORGN users
– Validation that user is aligned to the NSRS Info about benefits of publishing the position of a
mark to OPUS-Database (OPUS Published Solutions)
Oregon Real-time GPS Networkwww.TheORGN.net
Ken Bays, PLSODOT Lead Geodetic [email protected]
Ron Singh, PLSODOT Chief of Surveys, [email protected]
Randy Oberg, PLSODOT Geodetic Surveyor
Mark Armstrong, PLSNGS State Geodetic [email protected]
Back up slides
Agricultural users in eastern Oregon are the least affected by the change to ORGN coordinates. Positions on the ground may only change 1 inch or so which may not require updating your land coordinate system. Agricultural users on the Oregon coast may or may not want to make changes depending how they use their GPS system. Updating your land coordinate system may be accomplished similarly to how surveyors will update their project coordinates in the next few slides.
Agricultural Users
Surveying/Engineering Projects Starting a new project in NAD 83(2011) epoch 2010.00 Transitioning an existing NAD 83(CORS96) epoch 2002.00
to NAD 83(2011) epoch 2010.00 Keeping an existing NAD 83(CORS96) epoch 2002.00
project in NAD 83(CORS96) epoch 2002.00
Always document the datum realization of your project in your project meta data.
ODOT will issue policy procedures for ODOT projects to ODOT land surveyors and ODOT consultants.
Starting a New Project in NAD 83(2011) epoch 2010.00
Post processing:– Use the new NAD 83(2011) epoch2010.00 coordinates
for ORGN sites. ORGN coordinates are available at: www.TheORGN.net/orgn_coordinates.html
– Use GEOID12A– “GEOID12A is the only Geoid model that
transforms between NAD 83(2011) epoch 2010.00 ellipsoid heights and the NAVD88 vertical datum ortho heights.” (NGS)
Rover using ORGN Real-time Correctors– As always: Don’t use a transformation from WGS84 to
NAD 83 in your rover because the ORGN RT correctors are already referenced to NAD 83.
Keeping a current project in NAD 83(CORS96) epoch 2002.00
Perform a localization on your project after occupying your project control points with GPS while receiving ORGN RT correctors that are now referenced to NAD 83(2011) epoch 2010.00.
or alternatively : Set up your own local RTK Base Station on your project
using the superseded coordinates in your base and broadcast correctors to your rover in NAD 83(CORS96) epoch 2002.00.
Use the superseded ORGN coordinates and either GEOID03 or GEOID09 for post-processing your project.
Transitioning an existing NAD 83(CORS96) epoch 2002.00 project
to NAD 83(2011) epoch 2010.00
Perform a localization on our project to the new coordinate system.
or Reprocess your static data: Do a new network adjustment
fixing the new coordinates on your control stations.
