improving ngs products ngs fall convocation holiday inn – silver spring, md. october 24-28, 2005
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Improving NGS Products NGS Fall Convocation Holiday Inn – Silver Spring, MD. October 24-28, 2005. Earl F. Burkholder, PS, PE New Mexico State University Las Cruces, NM 88003. Overview outline - 1. Introduction Mission of NGS History of interaction with NGS - PowerPoint PPT PresentationTRANSCRIPT
Improving NGS ProductsNGS Fall Convocation
Holiday Inn – Silver Spring, MD.October 24-28, 2005
Earl F. Burkholder, PS, PENew Mexico State University
Las Cruces, NM 88003
Overview outline - 1
• Introduction
• Mission of NGS
• History of interaction with NGS
• Current status: technology, profession
• Current projects at NMSU
• Spatial data arena
Overview outline - 2
• Relating NGS mission, spatial data arena
• NGS products and services include
• Forward looking opportunities
• Assumptions/consequences
• Thank you
• Questions/discussion
Introduction - EFB
• BS Univ. of Michigan 1973
• 5 years at Commonwealth Associates
• MS Purdue Univ. 1980
• 1980-1993 teach at Oregon Tech.
• Self employed for 5 years
• At NMSU since 1998
• On sabbatical, writing book on 3-D
Mission of NGS• As stated on web site:
“Deliver and evolve the Nation’s foundation of reference for latitude, longitude, height, velocity, (and other things). . .”
• Embraced by all team members?• Challenge for management is to establish
policies and provide leadership that minimizes default sabotage.
History of interaction with NGS
• At Commonwealth, I used NGS control.
• Oregon Tech, we got NGS support.
• Input from NGS for SEWRPC reports.
• At NMSU, work with Advisor Bill Stone.
• As ASCE Journal Editor, I relied upon NGS for reviews and articles.
• Now I’m promoting use of the GSDM.
Status of Science/Profession - 1
• Science/instrumentation, digital and 3-D.• Surveying profession – who are the players?
- ACSM, diversity and reorganization.
- ASCE, focus on engineering applications.
- ASPRS, imaging & spatial info society.
- FIG, international voice for surveying prof’n.
- GITA, represents spatial data users.
- IAG, international voice for geodesy.
Status of Science/Profession - 2
• Surveying program at NMSU:
- Started in 1990 by Dr. James P. Reilly.
- Three faculty; Frank, Wurm, Burkholder.
- Undergrad only, about 40 students.
- Graduates get good jobs; NM & elsewhere
- BLM support is vital. NMSU looking for more.
- Vendors have been very good to program.
(Leica loaned us $240K equipment for a year)
Status of Science/Profession - 3
• Work being done by NGS:
- Readjusting the spatial network.
- Supporting height modernization.
- Coordinating use of CORS.
- Refining services available using OPUS.
- Outreach through state advisors.
- Many others
3-D Projects at NMSU
• NMSU GPS HARN-based network (illustrates network & local accuracy).
• NAVD88 elevation on HARN Station “Reilly” from nearby first-order BMs.
• Support of Texas/NM GPS survey of boundary defined by Rio Grande River
NMSU GPS Network August 2005
Schematic OnlyNo Scale
Crucesair
Reilly
Bromilow
Pseudo
USPA
USPB
1
3
7
5
6
4
2
Description of network adjustment posted at www.zianet.com/globalcogo/magicls.pdf
NAVD88 Elevation on HARN Station “Reilly”
Station "Reilly"A-order HARN
First-order BMStation H-245
First-order BMStation A-245
0 1 km 2 km
Full article can be viewed at www.zianet.com/globalcogo/ReilElev.pdf
Rio Grande River Boundary Area
State Boundary Example
• State boundary between NM and Texas follows Rio Grande River for 25 miles.
• River meanders but boundary was “fixed” by U.S. Supreme Court in 1930 on basis of 1929 survey reconstructing 1852 lines.
• 105 monuments set in distance of 25 miles.• Current project is to GPS the line.• Horizontal record data are NAD27, Vertical
data are NGVD29 (mean sea level).
Mon #90 to Mon #93: Mark to
∆X m ∆Y m ∆Z m Mark Dist.
Record 1241.591 -
430.521 -95.970 1,317.614 m
Observed 1241.509 -
430.477 -96.031 1,317.527 m Diff = -0.087 m or 1:15,144 ∆e m ∆n m ∆u m Hor Dist. Geodetic (3-D) Azi.
Record 1312.820 -
112.287 -1.048 1,317.614 m 94 53 19.26
Observed 1312.729 -
112.329 -1.096 1,317.526 m 94 53 27.03 Diff = 0.048 -0.088 m 7.77 Mon #93 to Mon #94: Mark to
∆X m ∆Y m ∆Z m Mark Dist.
Record 57.258 11.743 44.772 73.627 m Observed 57.096 11.740 44.772 73.501 m Diff = -0.126 m or 1:584 ∆e m ∆n m ∆u m Hor Dist. Geodetic (3-D) Azi. Record 51.533 52.586 0.163 73.627 m 44 25 13.42 Observed 51.379 52.560 0.204 73.501 m 44 20 55.54 Diff = 0.041 -0.126 m -4 17.88
What About Record Accuracy?
• Supreme Court Report values: - Horizontal given to .001 seconds (0.03 m) - Vertical given to 0.001 feet (0.0003 m)• Use those as standard deviations• Input into BURKORD9 • Inverse between points for: - Distance = 73.627 m +/- 0.042 m - Azimuth = 44-25-13.42 +/- 118.9 sec.
Spatial Data Arena is Huge
• ASPRS 10 yr forecast for remote sensing.
• ASPRS Panel Report to USGS on National Orthoimagery Program – comments due by October 24, 2005. see www.zianet.com/globalcogo/asprs-comments.pdf
• Global Spatial Data Infrastructure (GSDI) purpose is international cooperation and collaboration.
Relate NGS Mission to Arena
• Define and support National Spatial Reference System.
• Develop and promote standards.
• Clearing house for implementation of new technology.
NGS Services/Products Include
• CORS – 3D positions and velocities.• OPUS – Automated processing for users.• Height Modernization – geoid modeling.• Standards – Network and local accuracy.• Outreach to: - Other federal agencies - State and local agencies - Professional organizations
Forward Looking Opportunity - 1
• Height – If data from all satellites are used on a deformable Earth, then vertical may turn out to be the strongest component.
- Involves interpolation in radial direction.
- Requires simultaneous data from all GPS satellites to worldwide network.
- GSDM provides appropriate computational environment to do it.
Forward Looking Opportunity - 2
• Ellipsoid height is adopted as elevation.
- Reduces the need for geoid modeling.
- Hydraulic head is not given by orthometric heights.
- Use time analogy with local noon.
• ACSM articles on heights.
• www.zianet.com/globalcogo/elevgsdm.pdf
Forward Looking Opportunity - 3
• Orthophoto map is produced by plotting local differences with respect to origin selected by the user.
- Presumes each pixel has ECEF coordinates and covariance.
- That means raster file is converted to a vector file?
- Totally impractical due to storage req’d?
Assumptions
• Spatial data are digital and 3-D.
• There must be a single origin for 3-D data.
• ECEF geocentric system is foundation.
• Spatial data are obtained from physical observations reduced to components.
• Strict hierarchy for primary/derived data.
• Spatial data accuracy is given by standard deviations – component by component.
Consequences
• Need to make distinction between measurement and observation.
• Need to understand and honor difference between direct & indirect measurements.
• Some spatial data are relative and some are absolute. It makes a difference.
• Local & network accuracy are both legitimate. Local accuracy is based upon storing and using correlation.
Thank you!
• Truly grateful for opportunity to share.
• Sabbatical is going well. Lots yet to do.
• Windows-based BURKORD™ software is coming along. Will be gratis with book.
• Publisher not yet chosen.
• Back in classroom August 2006.
• www.zianet.com/globalcogo/status.html .