Frames for the Future New Datum Definitions for Modernization of the U.S. National Spatial Reference System

Size: px
Start display at page:

Download "Frames for the Future New Datum Definitions for Modernization of the U.S. National Spatial Reference System"

Transcription

1

2 Figure 10. Horizontal position differences (in meters) between NAD 83 and ITRF 08 at time (January 1, 2022). Positional differences are shown for the North American and Pacific tectonic plates. The difference for the US territories Guam and the Commonwealth of the Northern Mariana Islands (CNMI) on the Mariana tectonic plate (not shown) is about 1.3 m. Note that stations located on the Caribbean tectonic plate are reference to the North American plate. Frames for the Future New Datum Definitions for Modernization of the U.S. National Spatial Reference System Replacing NAD 83 (Part 4 of 4) The Need for a New Geometric Datum To support improved GNSS positioning a new geometric datum is required. An excerpt from the aforementioned NGS 10-Year plan states NGS [will redefine] the national horizontal datum to remove gross disagreements with the ITRF (the ITRF is defined below). While the benefit from aligning NGD to ITRF is significant, the deployment of NVD requires a new geometric datum. The geoid is one of an infinite series of progressively enveloped (essentially parallel) non-intersecting gravity geopotential surfaces, whose limit in the minimum is Earth s mass center. >> By David H. Minkel and Michael L. Dennis

3 Figure 11. ITRF 2005 horizontal velocities with respect to NAD 83 (from Craymer, et al., 2007). To use a geometric datum that is not accurately referenced to the Earth s mass center for ellipsoid heights, such as NAD 83, reduces the effectiveness of NVD (being geoid-based) and will continue to introduce error in the determination of orthometric heights with GNSS technology. To best implement and utilize the NVD, the NGD origin must be at the best estimate of the Earth s mass center. Otherwise an ellipsoid height transformation will be required. Note that the NGD datum will not be another realization of NAD 83, e.g. NAD 83(2022), but rather an entirely new datum. In the early 1980 s, when the NAD 83 and WGS 84 datums were originally defined, our knowledge of the location of the Earth s mass center was at an uncertainty of about one to two meters. Since then improved technology (e.g., more artificial satellites and more accurate tracking of those satellites) has allowed a refined estimate of the position of the Earth s mass center. The offset between the location adopted for NAD 83 and the most accurate contemporary location is 2.2 meter (as defined by ITRF 08, or the International Terrestrial Reference Frame of 2008). The magnitude of the position shift between NAD 83 and the ITRF 08 at time (January 1, 2022) is shown in Figure 10. Note that this shift does not necessarily indicate the final horizontal position difference(s) between NAD 83 horizontal positions and NGD horizontal positions, but it does indicate the impact of changing the origin to the current best estimate of Earth s mass center. Other factors, such as crustal motion or a change in the definition of ITRF, will affect the magnitude of the horizontal shift from NAD 83 to NGD. Additional information on ITRF in particular (and global reference systems in general) can be obtained from the International Earth Rotation and Reference System (IERS) at org, and from the International GNSS Service (IGS) at igscb.jpl.nasa.gov/. Since ITRF is a truly global reference system that is entirely compatible with GNSS, there is great benefit from minimizing the differences between the ITRF and a contemporary national geometric datum. Because of this, NGD will be defined to be as coincident as practicable with a modern realization of ITRF. However, there is a complication. ITRF is fixed with respect to the overall Earth (using a no-net-rotation condition with regards to horizontal tectonic motions over the whole Earth), rather than to any specific tectonic plate. Because of this, tectonic movement of the North American plate causes ITRF coordinates to constantly change throughout the conterminous United States and Alaska, not just in locally tectonically active areas, such as western California. Similar issues exist for Hawaii and American Samoa (on the Pacific plate) and Guam and the Commonwealth of the Northern Mariana Islands (on the Mariana plate). Clearly there are significant advantages to a national datum whose coordinates do not constantly change. Because of this issue, there is currently a debate as to whether or not NGD will be fixed to the North American plate (also referred to as the Stable North American Reference Frame, or SNARF), so that most locations within the United States would not be subject to constantly changing coordinates (note that the horizontal rate of change of current ITRF coordinates within the stable part of the U.S., i.e. the part located on the North American

4 plate rather than the Pacific plate, is about 2 cm/year). Another option to avoid continuously changing coordinates is to define NGD with respect to a specific date or epoch of ITRF. To help visualize this coordinate change, Figure 11 (Craymer, et al., 2007) depicts the velocities, due to plate motion with respect to ITRF 2005, at stations in North America. The velocity vectors shown are a good indication of the rate of coordinate change one would expect if NGD were fixed to ITRF, rather than the SNARF or a specific ITRF epoch. Note that locations, such as portions of California located west of the San Andreas fault system, that are not on the North American plate will still see coordinate changes due to relative plate motion even if NGD is fixed to the SNARF. Two benefits from aligning the origin of NGD to that of ITRF are improved GNSS positioning and a better definition of NGD. Because GNSS orbits are global, GNSS orbits are determined within ITRF, or a frame closely aligned and consistent with ITRF, such as that defined by the International GNSS Service (IGS) for precise orbits. Currently, high-accuracy GNSS surveying in the U.S. requires the vector processing and determination of differential station positions be done in ITRF/IGS. Once the vector processing is completed, a transformation and adjustment are performed to convert the ITRF/IGS station coordinates to NAD 83. ITRF is defined and monitored by use of GNSS as well as other independent space geodesy techniques such as Very Long Baseline Interferometry (VLBI), Satellite Laser Ranging (SLR), and Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS). Therefore, if NGD is precisely aligned with ITRF, the relationship of NGD to all space-based systems is precisely monitored and maintained with minimal cost and error. Figure 12 shows the difference in ellipsoid heights between NAD 83 and ITRF 08 (as ITRF 08 minus NAD 83). Note that while the new geometric system will change a station s ellipsoid height as shown in Figure 12, this change will not cause a significant difference in its orthometric height (as shown in Part 3 of this series) since the vertical reference surface, i.e. the adopted reference geoid, will also shift along with the NGD ellipsoid. In its 10-year plan, NGS states it will provide a transformation tool between the contemporary realization of NAD 83 and NGD (contemporary at the time of adoption of NGD). Note that there is not currently an NGSsanctioned transformation between the NAD 83 High Accuracy Reference Network (HARN) realizations and the NAD 83(NSRS2007) realization (although such a transformation is currently under development by NGS). Therefore, at present, to reliably transform high-accuracy geospatial data based on realizations prior to NAD 83(NSRS2007) to NGD, the user must first migrate those data to NAD 83(NSRS2007) through processes that will, most likely, require additional survey work (or readjustment of existing GNSS vectors). For those facing this problem, the NGS utility OPUS (Online Positioning User Service, www. ngs.noaa.gov/opus/) could be an extremely cost-effective part of their solution until NGS releases the new transformation tool in mid Much work on improving NAD 83 itself remains to be done long before Figure 12. Difference in ellipsoid heights (in meters) between NAD 83 and ITRF 08 at time (January 1, 2022), as ITRF 08 minus NAD 83. The height differences are with respect to the North American tectonic plate. However, large-scale tectonic plate motion is nearly entirely horizontal, so the change in ellipsoid height is essentially independent of plate motion, as indicated in the figure. The difference for the US territories Guam and CNMI on the Mariana tectonic plate (not shown) is about +2.0 meters.

5 the NGD replaces it in Improved CORS coordinates in NAD 83 have been computed and issued in 2011, and a new set of passive control coordinates (based on GNSS technology and tied to CORS) will be published in June That is, there is a new realization of NAD 83 (identified as NAD 83(2011) epoch ) based in the improved CORS coordinates, and it is the basis of a new nationwide adjustment of passive control referred to as the National Adjustment of 2011 (NA2011). For more information on the NA2011 Project, see gov/web/surveys/na2011/. The NA2011 Project will keep the passive control consistent with a new realization of the CORS network, referenced to an epoch date of (this is the new Multi-Year CORS Solution, which is based on new orbits and absolute GNSS antenna models, among other improvements). Shortly after the new realization of NAD 83 is released, a tool will be developed to perform coordinate transformations between NAD 83(NSRS2007) and NAD 83(2011). This is in addition to the previously mentioned transformation under development by NGS between NAD 83(NSRS2007) and the various HARN realizations. To gauge the user community s ability to adapt to and adopt the new NVD and NGD, in May 2010, NGS hosted their first Federal Geospatial Summit on Improving the NSRS (Smith, 2010; NGS, 2011b); the next summit is in July 2012 (see gov/2012geospatialsummit/ for more information). One option presented at the 2010 Summit was to define and adopt NGD before NVD. Definition of a new geometric datum and transformation of NSRS coordinates to that datum are relatively easy to achieve, whereas the definition of NVD requires completion of the GRAV-D program. This would allow NGS, along with its customers and partners, to enjoy the benefits of a fully modern NGD geometric reference system without waiting until the completion of GRAV-D in 2022 (or later). Obviously, adoption of the NGD geometric datum prior to NVD would require generation of new hybrid geoid models to be used with NGD consistent with NAVD 88, since the NGD ellipsoid heights will, as shown in Figure 12, differ significantly from NAD 83 ellipsoid heights. For the purposes of minimizing impacts to the user community by going through two changes at different times, NGS has decided to reject this option and stick to the plan of a 2022 joint release. The State Plane Coordinate System The NAD 27 State Plane Coordinate System (SPCS) was first defined, at the request of and in collaboration with the user community, by NGS in the 1930s. Since the introduction, also by NGS, of the NAD 83 SPCS, advances in technology (e.g., computers with geospatial software that allow re-projection-onthe-fly ) have diminished the value of NGS support of the SPCS or any other general coverage projected coordinate system. This seems especially relevant since few (if any) practitioners use SPCS for the reason it was originally intended (to allow surveyors to perform geodetic surveys using plane trigonometry). SPCS is still used as a projection for Geographic Information Systems (GIS), other mapping products (such as USGS quadrangles), and by some government and private organizations for surveying and engineering projects. However, many users of SPCS for precise positioning (especially those in high elevation areas) use a modified version that is scaled to reduce map projection distortion (a practice which compromises accurate georeferencing of spatial data, among other problems). As such, it can be argued that the utility of SPCS is decreasing in many geographic areas, and therefore a new SPCS based on NGD may not be warranted, or at least as projected coordinate systems covering large geographic areas (with the accompanying relatively large linear distortion). The nominal distortion of SPCS is 1:10,000 (100 parts per million), but this is with respect to the reference ellipsoid (more-or-less at sea level ); much greater distortion occurs at high elevations (e.g., up to about 400 parts per million at an elevation of 6000 feet for SPCS). Given the evolution in user requirements and capabilities for projected coordinates (such as minimizing distortion), NGS has not yet determined how or whether an NGD version of SPCS will be developed. As with the implementation of an SPCS based on NAD 83, definition of a new SPCS as part of NGD, if done, would likely be based on new projection parameters. Doing so helps differentiate between SPCS based on the NGD, NAD 83, and NAD 27 datums by creating large differences in projected coordinates. Such an update of the SPCS will likely require changes in statute in many jurisdictions of the U.S. Invitation for Comment or Inquiry Readers who wish to comment on the definition and implementation of NGD are invited to send their comments, or questions, to: Joe.Evjen@noaa.gov. You are also invited to contact your nearest NGS Geodetic Advisor ( gov/advisors/advisorsindex.shtml) for more information or to comment on the new datum. References for this four-part series are available in the Exclusive Online-only Content area of amerisurv.com David Minkel is a geodesist in the Geodetic Services Division of the National Geodetic Survey. Formerly the NGS Geodetic Advisor to Arizona for 12 years, he has worked in NOAA s charting and geodetic services for the last 36 years. Michael Dennis is a geodesist at NGS and is currently manager of the National Adjustment of 2011 (NA2011) Project. He is also a licensed engineer and surveyor, including ownership of a consulting and surveying firm.

NGS and the Modernization of the National Spatial Reference System (NSRS)

NGS and the Modernization of the National Spatial Reference System (NSRS) NGS and the Modernization of the National Spatial Reference System (NSRS) Dr. Dana Caccamise Pacific Southwest Region (CA,NV) Geodetic Advisor dana.caccamise@noaa.gov NOAA s National Geodetic Survey geodesy.noaa.gov

More information

NATRF 2022 AND LDP OCTOBER 11, 2017

NATRF 2022 AND LDP OCTOBER 11, 2017 NATRF 2022 AND LDP OCTOBER 11, 2017 MODERNIZATION OF THE NSRS Why? Leaving passive control marks behind and relying solely on the CORS network for 3D positions: Older methodology relies on terrestrial

More information

MODERNIZATION OF THE NSRS

MODERNIZATION OF THE NSRS NATRF 2022 AND LDP SEPTEMBER 12, 2017 MODERNIZATION OF THE NSRS Why? Leaving passive control marks behind and relying solely on the CORS network for 3D positions: Older methodology relies on terrestrial

More information

Fusion of Geodesy and GIS at NOAA s National Geodetic Survey

Fusion of Geodesy and GIS at NOAA s National Geodetic Survey Fusion of Geodesy and GIS at NOAA s National Geodetic Survey Esri Survey Summit July 6-9, 2013 San Diego, CA Michael Dennis, RLS, PE michael.dennis@noaa.gov The Plan Background NGS Data Explorer New Datasheet

More information

The National Spatial Reference System of the Future

The National Spatial Reference System of the Future The National Spatial Reference System of the Future William Stone Southwest Region (AZ, NM, NV, UT) Geodetic Advisor william.stone@noaa.gov NOAA s National Geodetic Survey geodesy.noaa.gov Salt Lake City

More information

Positioning a nation for the future: Modernizing the United States National Spatial Reference System

Positioning a nation for the future: Modernizing the United States National Spatial Reference System Positioning a nation for the future: Modernizing the United States National Spatial Reference System Dr. Dana Caccamise USA Representative Pacific Southwest Region Geodetic Advisor dana.caccamise@noaa.gov

More information

Modernization of the National Spatial Reference System 2022 Datum. Jacksonville Chapter July 2018

Modernization of the National Spatial Reference System 2022 Datum. Jacksonville Chapter July 2018 Modernization of the National Spatial Reference System 2022 Datum Jacksonville Chapter July 2018 Randy Tompkins, PSM, PLS Geomatics Project Manager Surveyor, Hydrographer, & Geodesist DRMP, Inc. Jacksonville,

More information

Making Sense of Evolving Reference Frames for North America

Making Sense of Evolving Reference Frames for North America Making Sense of Evolving Reference Frames for North America Mike Craymer Geodetic Survey Division, Natural Resources Canada Giovanni Sella U.S. National Geodesy Survey American Geophysical Union 2007 Joint

More information

The U.S. National Spatial Reference System in 2022

The U.S. National Spatial Reference System in 2022 Presented at the, May 29 - June 2, 2017 in The U.S. National Spatial Reference System in 2022 Daniel R. Roman, (Chief Geodesist) NOAA s National Geodetic Survey 1 Why change? Outline Naming conventions

More information

Positioning the Pacific: NOAA s Geospatial Activities. Juliana Blackwell, Director NOAA s National Geodetic Survey March 6, 2012

Positioning the Pacific: NOAA s Geospatial Activities. Juliana Blackwell, Director NOAA s National Geodetic Survey March 6, 2012 Positioning the Pacific: NOAA s Geospatial Activities Juliana Blackwell, Director NOAA s National Geodetic Survey March 6, 2012 A Common Problem of the Early 19 th Century 1807 President Thomas Jefferson

More information

NGS is Scheduled to Replace NAVD 88 and NAD 83 In 2022

NGS is Scheduled to Replace NAVD 88 and NAD 83 In 2022 NGS is Scheduled to Replace NAVD 88 and NAD 83 In 2022 Indiana Society of Professional Land Surveyors Conference January 2017 John Ellingson NGS Geodetic Advisor john.ellingson@noaa.gov 202-306-6904 1

More information

New Datums: Replacing NAVD 88 and NAD 83

New Datums: Replacing NAVD 88 and NAD 83 New Datums: Replacing NAVD 88 and NAD 83 By Dave Zenk PE, LS National Geodetic Survey Northern Plains Regional Advisor 1735 Lake Drive West Chanhassen, MN 55317-8581 952-368-2548 office 612-414-9522 mobile

More information

MSGIC Spring Mtg Denton April 23, 2014

MSGIC Spring Mtg Denton April 23, 2014 Modernization of the National Spatial Reference System Keeping Pace with Changes in Positioning Technology and User Expectations in a Dynamic World MSGIC Spring Mtg Denton April 23, 2014 Dave Doyle Base

More information

U.S. Datums: Where We ve Been,

U.S. Datums: Where We ve Been, U.S. Datums: Where We ve Been, Where We re Going Modernizing the National Spatial Reference System Matt Wellslager RFA, South Carolina Geodetic Survey Presentation Outline 1. - Introductions. 2. - National

More information

Vertical Reference Frame Pacific

Vertical Reference Frame Pacific Vertical Reference Frame Pacific Andrick Lal SPC Geoscience Division GIS&RS User Conference 29 th November 2016 USP, Fiji. What does it mean? All buildings and features have a height. But what is it relative

More information

Changes are coming NGS NSRS Modernization Are you Ready?

Changes are coming NGS NSRS Modernization Are you Ready? Changes are coming NGS 2022 - NSRS Modernization Are you Ready? Pam Fromhertz Rocky Mountain Regional Advisor Pamela.Fromhertz@noaa.gov 240-988-6363 John Hunter CO State Geomatics Coordinator DRCOG March

More information

BUILDING AN ACCURATE GIS

BUILDING AN ACCURATE GIS BUILDING AN ACCURATE GIS 2006 GIS in the Rockies Denver, Colorado September 13, 2006 William E. Linzey United States Department of Commerce National Oceanic and Atmospheric Administration National Geodetic

More information

Achieving Great Height with GNSS

Achieving Great Height with GNSS Achieving Great Height with GNSS Oregon GPS Users Group 2015 Annual Meeting January 23, 2015 Salem, Oregon Salem Convention Center Michael Dennis, RLS, PE Oregon State University National Geodetic Survey

More information

The U.S. National Spatial Reference System in 2022

The U.S. National Spatial Reference System in 2022 The U.S. National Spatial Reference System in 2022 Daniel ROMAN, U.S.A. Key words: Capacity Building; GNSS/GPS; Legislation; Positioning; Reference Frames; Reference Systems; Standards SUMMARY In 2022,

More information

The 3-D Global Spatial Data Model: Geometrical Foundation of the Global Spatial Data Infrastructure

The 3-D Global Spatial Data Model: Geometrical Foundation of the Global Spatial Data Infrastructure The 3-D Global Spatial Data Model: Geometrical Foundation of the Global Spatial Data Infrastructure Earl F. Burkholder, PS, PE Annotated Table of Contents July 8,2006 I. The Global Spatial Data Model (GSDM)

More information

New Datums: Replacing NAVD 88 and NAD 83

New Datums: Replacing NAVD 88 and NAD 83 New Datums: Replacing NAVD 88 and NAD 83 Professional Surveyors Association of Nebraska Winter Seminar Dave Zenk NGS Advisor February 9, 2018 Kearney, NE February 9, 2018 Professional Surveyors Association

More information

Working Group 1. Geodetic Reference Frame. Activity Report. for. The UN-GGIM-AP Plenary Meeting

Working Group 1. Geodetic Reference Frame. Activity Report. for. The UN-GGIM-AP Plenary Meeting Regional Committee of United Nations Global Geospatial Information Management for Asia and the Pacific (UN-GGIM-AP) Established by a United Nations Resolution Working Group 1 Geodetic Reference Frame Activity

More information

United States NSRS 2022: Terrestrial Reference Frames

United States NSRS 2022: Terrestrial Reference Frames United States NSRS 2022: Terrestrial Reference Frames Daniel ROMAN, U.S.A. Key words: Capacity building; Positioning; Reference frames; Reference systems, Cadastre SUMMARY In 2022, the United States will

More information

Next Generation Australian Datum. Permanent Committee on Geodesy, ICSM

Next Generation Australian Datum. Permanent Committee on Geodesy, ICSM Next Generation Australian Datum Permanent Committee on Geodesy, ICSM 2 Presentation: Next Generation Australian Datum Trends in the geospatial sector The Geocentric Datum of Australia 1994 (GDA94) Progress

More information

From Global to National Geodetic Reference Frames: how are they connected and why are they needed?

From Global to National Geodetic Reference Frames: how are they connected and why are they needed? From Global to National Geodetic Reference Frames: how are they connected and why are they needed? Zuheir ALTAMIMI Institut National de l Information Géographique et Forestière, France Vice-President,

More information

Positioning in the Pacific Islands

Positioning in the Pacific Islands Positioning in the Pacific Islands Andrick Lal United Nations/Nepal Workshop on the Applications of Global Navigation Satellite Systems Kathmandu - Nepal 15 th December 2016 Presentation Outline Introduction

More information

Control Surveys and Coordinate Systems

Control Surveys and Coordinate Systems Control Surveys and Coordinate Systems The Earth is Round Basic Shape of the Earth: Oblate Spheroid of Revolution The length of the equatorial axis is approximately 27 miles greater than the polar axis.

More information

Ground Truth Annual Conference. Design and Documentation of Low Distortion Projections for Surveying and GIS

Ground Truth Annual Conference. Design and Documentation of Low Distortion Projections for Surveying and GIS Professional Land Surveyors of Oregon 15 Annual Conference Ground Truth Design and Documentation of Low Distortion Projections for Surveying and GIS Michael L Dennis, RLS, PE v. (rev 1), January 15, Design

More information

Ground Truth Annual Conference. Optimized Design of Low Distortion Projections. Michael L. Dennis, RLS, PE

Ground Truth Annual Conference. Optimized Design of Low Distortion Projections. Michael L. Dennis, RLS, PE Arizona Professional Land Surveyors Association 016 Annual Conference Ground Truth Optimized Design of Low Distortion Projections Michael L. Dennis, RLS, PE Version 3 (rev 1), May 016 Design and metadata

More information

SIRGAS: Basis for Geosciences, Geodata, and Navigation in Latin America

SIRGAS: Basis for Geosciences, Geodata, and Navigation in Latin America SIRGAS: Basis for Geosciences, Geodata, and Navigation in Latin America Claudio Brunini President of SIRGAS Universidad Nacional de La Plata, Argentina María Virginia Mackern President of SIRGAS/WG-I:

More information

Geospatial Data Standards Considerations for the delivery of 2D and 3D spatial data February 2019

Geospatial Data Standards Considerations for the delivery of 2D and 3D spatial data February 2019 Geospatial Data Standards Considerations for the delivery of 2D and 3D spatial data February 2019 Prepared by: GRCA Geomatics Version Date Summary of Changes Changes Made By: 1.00 March 16, 2018 Version

More information

VT State Plane. Daniel J. Martin National Geodetic Survey VT Geodetic Advisor. VSLS Conference Rutland VT April 11, 2008

VT State Plane. Daniel J. Martin National Geodetic Survey VT Geodetic Advisor. VSLS Conference Rutland VT April 11, 2008 VT State Plane Daniel J. Martin National Geodetic Survey VT Geodetic Advisor VSLS Conference Rutland VT April 11, 2008 Today s Outline Define the problem Review of VT State Plane System Relationship

More information

4 Survey Datums. 4.1 Horizontal Datum Policy SURVEY DATUMS SEPTEMBER 2006

4 Survey Datums. 4.1 Horizontal Datum Policy SURVEY DATUMS SEPTEMBER 2006 4 Survey Datums Today s multi-organizational Project Development efforts require the use of common, accurate horizontal and vertical survey datums and consistent, precise control-survey procedures to ensure

More information

Georeferencing, Map Projections, Cartographic Concepts. -Coordinate Systems -Datum

Georeferencing, Map Projections, Cartographic Concepts. -Coordinate Systems -Datum Georeferencing, Map Projections, Cartographic Concepts -Map Projections -Coordinate Systems -Datum Map projection is "the process of systematically transforming positions on the Earth's spherical surface

More information

Town of Chino Valley. Survey Control Network Report. mgfneerhg mc N. Willow Creek Road Prescott AZ

Town of Chino Valley. Survey Control Network Report. mgfneerhg mc N. Willow Creek Road Prescott AZ Town of Chino Valley Survey Control Network Report mgfneerhg mc. 2050 N. Willow Creek Road Prescott AZ 86301 928-771-2376 Page 1 of 70 Table of Contents Town of Chino Valley Survey Datum Outline A short

More information

Lecture 2 Measurement Systems. GEOS 655 Tectonic Geodesy

Lecture 2 Measurement Systems. GEOS 655 Tectonic Geodesy Lecture 2 Measurement Systems GEOS 655 Tectonic Geodesy VLBI and SLR VLBI Very Long Baseline Interferometry SLR Satellite Laser Ranging Very Long Baseline Interferometry VLBI Geometric Delay δg S Baseline

More information

Practical considerations for determining Euler Pole Parameters for the terrestrial reference frames in the United States

Practical considerations for determining Euler Pole Parameters for the terrestrial reference frames in the United States Practical considerations for determining Euler Pole Parameters for the terrestrial reference frames in the United States Jacob M. HECK and Dru A. SMITH, United States Key words: GNSS/GPS, Positioning,

More information

Geographic Information Systems class # 1 February 19, Coordinate reference systems in GIS: geodetic coordinates

Geographic Information Systems class # 1 February 19, Coordinate reference systems in GIS: geodetic coordinates Geographic Information Systems class # 1 February 19, 2013 Coordinate reference systems in GIS: geodetic coordinates Manuel Campagnolo ISA Manuel Campagnolo (ISA) GIS/SIG 2012 2013 February 19, 2013 1

More information

GEOIDS FAQ. November

GEOIDS FAQ. November GEOIDS FAQ 1. What is a geoid? A geoid is a representation of the equipotential surface of the Earth s gravity field. It can be thought of as a surface coinciding with the undisturbed mean sea level extended

More information

Beyond GEOID12: Implementing a New Vertical Datum for North America

Beyond GEOID12: Implementing a New Vertical Datum for North America Daniel R. ROMAN, Neil D. WESTON, UNITED STATES Key words: Positioning, Heights, GPS/Leveling, Geoid, Vertical Datum SUMMARY The National Geodetic Survey (NGS) is responsible for maintaining both the horizontal

More information

A Strategic Plan for Geodesy in Sweden. Mikael Lilje Lars E. Engberg Geodesy Department Lantmäteriet Sweden

A Strategic Plan for Geodesy in Sweden. Mikael Lilje Lars E. Engberg Geodesy Department Lantmäteriet Sweden A Strategic Plan for Geodesy in Sweden Mikael Lilje Lars E. Engberg Geodesy Department Lantmäteriet Sweden Our vision is to be able to meet Swedish society s needs for a homogeneous, sustainable geodetic

More information

Intro to GIS Fall 2010 Georeferencing & Map Projections

Intro to GIS Fall 2010 Georeferencing & Map Projections Intro to GIS Fall 2010 Georeferencing & Map Projections SHAPE OF THE EARTH Earth's Shape Geoid: shape of earth minus topographic features (irregular due to local variations in gravity) Ellipsoid: elongated

More information

Height Modernization Program in the United States: Implementing a Vertical Datum Referenced to a Gravimetric Geoid Model

Height Modernization Program in the United States: Implementing a Vertical Datum Referenced to a Gravimetric Geoid Model Height Modernization Program in the United States: Implementing a Vertical Datum Referenced to a Gravimetric Geoid Renee Shields, Christine Gallagher, USA Key words: GNSS, orthometric height, elevation,

More information

Reference frames and positioning

Reference frames and positioning The APREF Project: an Improved Geodetic Infrastructure for Asia and the Pacific (4861) John Dawson (Australia), Graeme Blick (New Zealand), Manoj Deo, Guorong Hu and Gary Johnston (Australia) Reference

More information

The International Terrestrial Reference System and ETRS89: Part II : ITRS & ETRS89 relationship

The International Terrestrial Reference System and ETRS89: Part II : ITRS & ETRS89 relationship The International Terrestrial Reference System and ETRS89: Part II : ITRS & ETRS89 relationship Zuheir ALTAMIMI Laboratoire de Recherche en Géodésie Institut national de l information géographique et forestière

More information

Session description and objectives

Session description and objectives Journey to the Moving Center of the Earth The Evolution of the National Spatial Reference System NJSPLS SurvCon 2018 January 31, 2018 Dan Martin Northeast Regional Geodetic Advisor ME, NH, VT, MA, CT,

More information

Report for 15th PCGIAP Meeting at 18th UNRCC-AP Working Group 1 Regional Geodesy

Report for 15th PCGIAP Meeting at 18th UNRCC-AP Working Group 1 Regional Geodesy Report for 15th PCGIAP Meeting at 18th UNRCC-AP Working Group 1 Regional Geodesy Chairman Shigeru Matsuzaka, Japan - shigeru@gsi.go.jp Vice Chairman Prof. Pengfei Cheng, China - chengpf@casm.ac.cn John

More information

This week s topics. Week 6. FE 257. GIS and Forest Engineering Applications. Week 6

This week s topics. Week 6. FE 257. GIS and Forest Engineering Applications. Week 6 FE 257. GIS and Forest Engineering Applications Week 6 Week 6 Last week Chapter 8 Combining and splitting landscape features and merging GIS databases Chapter 11 Overlay processes Questions? Next week

More information

GISC3325 Spring 2011 Final Exam

GISC3325 Spring 2011 Final Exam GISC3325 Spring 2011 Final Exam Name: Carefully read each question. Identify the important elements and the question being asked. Show your work for partial credit. No credit for undocumented wrong answers.

More information

LEADS. The Essential Elements of a 3-D Geographic Coordinate

LEADS. The Essential Elements of a 3-D Geographic Coordinate The Essential Elements of a 3-D Geographic Coordinate John W. Dix 13 September 2005 ESRI Homeland Security GIS Summit - Denver, CO John.W.Dix@nga.mil NATIONAL GEOSPATIAL-INTELLIGENCE AGENCY Overview is

More information

REGIONAL REFERENCE FRAMES: THE IAG PERSPECTIVE

REGIONAL REFERENCE FRAMES: THE IAG PERSPECTIVE REGIONAL REFERENCE FRAMES: THE IAG PERSPECTIVE João Agria Torres SPUIAGG IAG Sub-commission 1.3: Regional Reference Frames jatorres@iol.pt 1. About the IAG CONTENT 2. Objectives and organization of SC

More information

Publ. Astron. Obs. Belgrade No. 91 (2012), REALIZATION OF ETRF2000 AS A NEW TERRESTRIAL REFERENCE FRAME IN REPUBLIC OF SERBIA

Publ. Astron. Obs. Belgrade No. 91 (2012), REALIZATION OF ETRF2000 AS A NEW TERRESTRIAL REFERENCE FRAME IN REPUBLIC OF SERBIA Publ. Astron. Obs. Belgrade No. 91 (2012), 199-206 Contributed paper REALIZATION OF ETRF2000 AS A NEW TERRESTRIAL REFERENCE FRAME IN REPUBLIC OF SERBIA D. BLAGOJEVIĆ and V. VASILIĆ Faculty of Civil Engineering,

More information

Inclusion of Leveling with GNSS Observations in a Single, 3-D Geodetic Survey Network Adjustment. Daniel GILLINS, U.S.A., and Michael DENNIS, U.S.A.

Inclusion of Leveling with GNSS Observations in a Single, 3-D Geodetic Survey Network Adjustment. Daniel GILLINS, U.S.A., and Michael DENNIS, U.S.A. Inclusion of Leveling with GNSS Observations in a Single, 3-D Geodetic Survey Network Adjustment Daniel GILLINS, U.S.A., and Michael DENNIS, U.S.A. Key words: Leveling, Integrated Geodesy, Geoid Accuracy,

More information

Modernization of National Geodetic Datum in China *

Modernization of National Geodetic Datum in China * UNITED NATIONS E/CONF.102/IP.16 ECONOMIC AND SOCIAL COUNCIL Nineteenth United Nations Regional Cartographic Conference for Asia and the Pacific Bangkok, 29 October 1 November 2012 Item 6(b) of the provisional

More information

TOWARDS ROBUST LOCALIZATION OF RTK-GPS TOPOGRAPHIC SURVEYS 23

TOWARDS ROBUST LOCALIZATION OF RTK-GPS TOPOGRAPHIC SURVEYS 23 TOWARDS ROBUST LOCALIZATION OF RTK-GPS TOPOGRAPHIC SURVEYS Jerry W. Nave, North Carolina A&T University; Tarig A. Ali, American University of Sharjah Abstract Localization is performed to fit the observed

More information

Understanding Projections for GIS

Understanding Projections for GIS Presented by John Schaeffer Juniper GIS Services, Inc. This PowerPoint is available at JuniperGIS.com Presentation Objectives To understand basic concepts on projections and coordinate systems for the

More information

This presentation covers the following areas

This presentation covers the following areas Geodetic Datums and Coordinate Systems for Surveying and Mapping in Hong Kong FIG Working Week 2012 Rome, Italy 6-10 May Simon KWOK Hong Kong, China 1 This presentation covers the following areas Explains

More information

Spatial Data Collection using GPS: BEST PRACTICES

Spatial Data Collection using GPS: BEST PRACTICES Spatial Data Collection using GPS: BEST PRACTICES - 2007 Page 1 of 10 Best practices for GPS & Spatial Data Collection, Storage and Documentation These Best Practices are designed to maximize positional

More information

Boolean Operators and Topological OVERLAY FUNCTIONS IN GIS

Boolean Operators and Topological OVERLAY FUNCTIONS IN GIS Boolean Operators and Topological OVERLAY FUNCTIONS IN GIS Query asking a question of the attribute data Standard Query Language (SQL) is used to query the data There are 4 basic statements used to get

More information

The Future of SPCS in Charles Chuck Ghilani, Ph.D. Professor Emeritus Pennsylvania State University

The Future of SPCS in Charles Chuck Ghilani, Ph.D. Professor Emeritus Pennsylvania State University The Future of SPCS in 2022 Charles Chuck Ghilani, Ph.D. Professor Emeritus Pennsylvania State University Class Etiquette Turn off all cell phones Or set them to vibrate Go out of the room to answer any

More information

CORS Network and Datum Harmonisation in the Asia-Pacific Region. Richard Stanaway and Craig Roberts

CORS Network and Datum Harmonisation in the Asia-Pacific Region. Richard Stanaway and Craig Roberts CORS Network and Datum Harmonisation in the Asia-Pacific Region Richard Stanaway and Craig Roberts School of Surveying and Spatial Information Systems University of New South Wales CORS Networks in the

More information

Shape of the Earth. Data Output by the Receiver

Shape of the Earth. Data Output by the Receiver It is quite common for confusion to arise about the process used during a hydrographic survey when GPS-derived water surface elevation is incorporated into the data as an RTK Tide correction. This article

More information

Modernising the Northern Territory s GRS

Modernising the Northern Territory s GRS Modernising the Northern Territory s GRS Geospatial & GNSS CORS Forum Kuala Lumpur, Malaysia Amy Peterson; Rob Sarib DIPL Land Information Survey Services Sunday 16 October 2016 Presentation Outline Our

More information

REFERENCING COORDINATE SYSTEMS MAP PROJECTIONS GEOREFERENCING

REFERENCING COORDINATE SYSTEMS MAP PROJECTIONS GEOREFERENCING GIS in Ecology SPATIAL REFERENCING COORDINATE SYSTEMS MAP PROJECTIONS GEOREFERENCING : :1 Where on earth? Early mapmakers recognized the need for a system that could locate features on the earth's surface.

More information

ESTIMATES OF HORIZONTAL DISPLACEMENTS ASSOCIATED WITH THE 1999 TAIWAN EARTHQUAKE

ESTIMATES OF HORIZONTAL DISPLACEMENTS ASSOCIATED WITH THE 1999 TAIWAN EARTHQUAKE ESTIMATES OF HORIZONTAL DISPLACEMENTS ASSOCIATED WITH THE 1999 TAIWAN EARTHQUAKE C. C. Chang Department of Surveying and Mapping Engineering Chung Cheng Institute of Technology, Taiwan, ROC ABSTRACT A

More information

GEODETIC NETWORK OF SAUDI ARABIA AND FIDUCIAL STATIONS. GFN OF Saudi Arabia in Based on ITRF2000 Datum

GEODETIC NETWORK OF SAUDI ARABIA AND FIDUCIAL STATIONS. GFN OF Saudi Arabia in Based on ITRF2000 Datum STUDIES OF TECTONIC MOVEMENTS IN SAUDI ARABIA USING CORS M. Al Rajhi, Ali Al Omar, R. Yanar, F. Kartal, K. Eren, SUBJECT TO TALKS BACKGROUND GEODETIC NETWORK OF SAUDI ARABIA AND FIDUCIAL STATIONS GFN OF

More information

Height systems. Rudi Gens Alaska Satellite Facility

Height systems. Rudi Gens Alaska Satellite Facility Rudi Gens Alaska Satellite Facility Outline Why bother about height systems? Relevant terms Coordinate systems Reference surfaces Geopotential number 2 Why bother about height systems? give a meaning to

More information

Height Modernization 2013 A New Canadian Vertical Datum

Height Modernization 2013 A New Canadian Vertical Datum Height Modernization 2013 A New Canadian Vertical Datum What is Height Modernization? The Height Reference System Modernization is a project at the Geodetic Survey Division (GSD) of Natural Resources Canada

More information

Torsten Mayer-Gürr Institute of Geodesy, NAWI Graz Technische Universität Graz

Torsten Mayer-Gürr Institute of Geodesy, NAWI Graz Technische Universität Graz GGOS and Reference Systems Introduction 2015-10-12 Torsten Mayer-Gürr Institute of Geodesy, NAWI Graz Technische Universität Graz Torsten Mayer-Gürr 1 Course and exam Lecture Monday 14:00 16:00, A111 (ST01044)

More information

Tectonics of the terrestrial litosphere in spherical harmonics

Tectonics of the terrestrial litosphere in spherical harmonics Journal of Physics: Conference Series PAPER OPEN ACCESS Tectonics of the terrestrial litosphere in spherical harmonics To cite this article: A V Mokhnatkin et al 2016 J. Phys.: Conf. Ser. 769 012007 View

More information

A PRIMER ON COORDINATE SYSTEMS Commonly Used in Michigan

A PRIMER ON COORDINATE SYSTEMS Commonly Used in Michigan A PRIMER ON COORDINATE SYSTEMS Commonly Used in Michigan David P. Lusch, Ph.D., GISP Department of Geography Remote Sensing & GIS Research and Outreach Services Group Michigan State University September,

More information

Lab 9: Satellite Geodesy (35 points)

Lab 9: Satellite Geodesy (35 points) Lab 9: Satellite Geodesy (35 points) Here you will work with GPS Time Series data to explore plate motion and deformation in California. This lab modifies an exercise found here: http://www.unavco.org:8080/cws/pbonucleus/draftresources/sanandreas/

More information

EnvSci360 Computer and Analytical Cartography

EnvSci360 Computer and Analytical Cartography EnvSci360 Computer and Analytical Cartography Lecture 3 Geodesy Map Projections, Datums, and Coordinate Systems 1 Geodesy The science of measuring and representing the shape and size of the earth, and

More information

GGOS Bureau for Standards and Conventions

GGOS Bureau for Standards and Conventions GGOS D. Angermann (1), T. Gruber (2), J. Bouman (1), M. Gerstl (1), R. Heinkelmann (1), U. Hugentobler (2), L. Sánchez (1), P. Steigenberger (2) (1) Deutsches Geodätisches Forschungsinstitut (DGFI), München

More information

Geographic coordinate systems

Geographic coordinate systems 1 Geographic coordinate systems In this chapter you ll learn about longitude and latitude. You ll also learn about the parts that comprise a geographic coordinate system including Spheres and spheroids

More information

GEOGRAPHIC COORDINATE SYSTEMS

GEOGRAPHIC COORDINATE SYSTEMS GEOGRAPHIC COORDINATE SYSTEMS Introduction to GIS Winter 2015 What is Georeferencing? Used to establish a location on the Earth s surface 1 st order polynomial transformation Georeferencing toolbar What

More information

Semi-Dynamic Datum of Indonesia

Semi-Dynamic Datum of Indonesia Technical Seminar Reference Frame in Practice, Semi-Dynamic Datum of Indonesia H.Z. Abidin, A.B. Wijanarto, S.T. Wibowo, Susilo, J. Efendi Geospatial Information Agency, Indonesia (BIG) Sponsors: Page

More information

WHERE ARE YOU? Maps & Geospatial Concepts Fall 2015

WHERE ARE YOU? Maps & Geospatial Concepts Fall 2015 WHERE ARE YOU? Maps & Geospatial Concepts Fall 2015 Where are you? Relative location I m at school Absolute Location 45 26 18.07 122 43 50.78 Where is Boston? Introducing Geodesy, Ellipsoids & Geoids Geodesy

More information

Proceedings of the First International Conference on Civil Engineering, Assiut University, Volume 2, pp , October 7-8.

Proceedings of the First International Conference on Civil Engineering, Assiut University, Volume 2, pp , October 7-8. Proceedings of the First International Conference on Civil Engineering, Assiut University, Volume 2, pp. 246-253, October 7-8. PRODUCTIVE GPS TOPOGRAPHIC MAPPING FOR NATIONAL DEVELOPMENT PROJECTS IN EGYPT

More information

How GNSS CORS in Japan works for geodetic control and disaster mitigations

How GNSS CORS in Japan works for geodetic control and disaster mitigations ICG Working Group D Reference Frames, Timing and Applications How GNSS CORS in Japan works for geodetic control and disaster mitigations ICG11, Nov. 7-11, 2016, Sochi, Russia Hiromichi TSUJI Geodetic Observation

More information

A Unique Reference Frame: Basis of the Global Geodetic Observing System (GGOS) for Geodynamics and Global Change

A Unique Reference Frame: Basis of the Global Geodetic Observing System (GGOS) for Geodynamics and Global Change SRTM (InSAR) A Unique Reference Frame: Basis of the Global Geodetic Observing System (GGOS) for Geodynamics and Global Change Hermann Drewes President IAG Commission 1 Reference Frames Deutsches Geodätisches

More information

WHERE ARE YOU? Maps & Geospatial Concepts Fall 2012

WHERE ARE YOU? Maps & Geospatial Concepts Fall 2012 WHERE ARE YOU? Maps & Geospatial Concepts Fall 2012 Where are you? Relative location I m at school Absolute Location 45 26 18.07 122 43 50.78 Datums Datums A reference surface of the Earth Used as the

More information

Ellipsoid Hydro Datum Geoid Errors

Ellipsoid Hydro Datum Geoid Errors Ellipsoid Hydro Datum Geoid Errors Jack L. Riley Office of Coast Survey Hydrographic Systems & Technology Branch Geoid Errors via Ellipsoid Hydrography? Per datum hydro Traditional & ellipsoid referenced

More information

The Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG)

The Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG) The Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG) Hermann Drewes Representative of the International Union of Geodesy and Geophysics (IUGG) to the Cartographic

More information

Case Study of Australia

Case Study of Australia Case Study of Australia John Dawson, Geoscience Australia 1 Australia s Geodetic eco-system Geocentric Coordinates Observing Infrastructure Height Datum Geoid Models Tools Services Standards 2 Australia

More information

Global vertical datum unification based on the combination of the fixed gravimetric and the scalar free geodetic boundary value problems

Global vertical datum unification based on the combination of the fixed gravimetric and the scalar free geodetic boundary value problems Global vertical datum unification based on the combination of the fixed gravimetric and the scalar free geodetic boundary value problems Laura Sánchez contribution to the IAG-IC.: Vertical Reference Frames

More information

GEOID UNDULATIONS OF SUDAN USING ORTHOMETRIC HEIGHTS COMPARED WITH THE EGM96 ANG EGM2008

GEOID UNDULATIONS OF SUDAN USING ORTHOMETRIC HEIGHTS COMPARED WITH THE EGM96 ANG EGM2008 GEOID UNDULATIONS OF SUDAN USING ORTHOMETRIC HEIGHTS COMPARED Dr. Abdelrahim Elgizouli Mohamed Ahmed* WITH THE EGM96 ANG EGM2008 Abstract: Positioning by satellite system determine the normal height above

More information

Georeferencing. Place names Postal addresses Postal codes Coordinate systems (lat/long, UTM, etc.)

Georeferencing. Place names Postal addresses Postal codes Coordinate systems (lat/long, UTM, etc.) Georeferencing Georeferencing Used to describe the act of assigning locations to data or information Certain requirements include that they are: unique, have shared meaning, and are persistent through

More information

What is a Map Projection?

What is a Map Projection? What is a Map Projection? It is how we represent a three dimensional Earth on a flat piece of paper However The process of transferring information from the Earth to a map causes every projection to distort

More information

Low Distortion Projections Part 2 Ground versus Grid

Low Distortion Projections Part 2 Ground versus Grid Blue Marble Geographic Calculator provides an incredible variety of tools for working with an infinite combination of datums and projections. Shown here, I ve entered the parameters for a Low Distortion

More information

GRAV-D. Gravity for the Re-definition of the American Vertical Datum

GRAV-D. Gravity for the Re-definition of the American Vertical Datum GRAV-D Gravity for the Re-definition of the American Vertical Datum Why this briefing? NGS recently acquired a new airborne gravimeter Intended to support GRAV-D GRAV-D is an ambitious new plan for NGS

More information

ERTH 455 / GEOP 555 Geodetic Methods. Lecture 04: GPS Overview, Coordinate Systems

ERTH 455 / GEOP 555 Geodetic Methods. Lecture 04: GPS Overview, Coordinate Systems ERTH 455 / GEOP 555 Geodetic Methods Lecture 04: GPS Overview, Coordinate Systems Ronni Grapenthin rg@nmt.edu MSEC 356 x5924 August 30, 2017 1 / 22 2 / 22 GPS Overview 1973: Architecture approved 1978:

More information

Geodesy on the move. Craig Allinson. Dealing with dynamic coordinate reference systems. IOGP Geodesy Subcommittee. EPUG London, November 2017

Geodesy on the move. Craig Allinson. Dealing with dynamic coordinate reference systems. IOGP Geodesy Subcommittee. EPUG London, November 2017 Geodesy on the move Dealing with dynamic coordinate reference systems Craig Allinson IOGP Geodesy Subcommittee EPUG London, November 2017 Why the concern? A bridge too far Historic geodesy mental image

More information

GGOS INFORMATION MODELS: ANALYSIS OF INTERRELATIONS BETWEEN OBSERVATION TECHNIQUES AND THE EARTH GRAVITY FIELD

GGOS INFORMATION MODELS: ANALYSIS OF INTERRELATIONS BETWEEN OBSERVATION TECHNIQUES AND THE EARTH GRAVITY FIELD GGOS INFORMATION MODELS: ANALYSIS OF INTERRELATIONS BETWEEN OBSERVATION TECHNIQUES AND THE EARTH GRAVITY FIELD Wojciech Pachelski 1) Małgorzata Paśnicka-Pawłowska 2) Karolina Szafranek 3) Agnieszka Zwirowicz

More information

The Canadian Height Modernization Initiative. Information for British Columbia Stakeholders / Clients

The Canadian Height Modernization Initiative. Information for British Columbia Stakeholders / Clients The Canadian Height Modernization Initiative Information for British Columbia Stakeholders / Clients Introduction A modern society requires the ability to measure elevations relative to mean sea level

More information

EUREF Technical Note 1: Relationship and Transformation between the International and the European Terrestrial Reference Systems

EUREF Technical Note 1: Relationship and Transformation between the International and the European Terrestrial Reference Systems EUREF Technical Note 1: Relationship and Transformation between the International and the European Terrestrial Reference Systems Zuheir Altamimi Institut National de l Information Géographique et Forestière

More information

Memo : Specifications for reference frame fixing in the analysis of a EUREF GPS campaign

Memo : Specifications for reference frame fixing in the analysis of a EUREF GPS campaign ' ' 7 7 7 6 6 ' Memo : Specifications for reference frame fixing in the analysis of a EUREF GPS campaign Version 1 : 30-09-1993 Version 2 : 07-03-1995 Version 3 : 10-02-1997 Version 4 : 0-01-199 Version

More information

HORIZONTAL PROJECTION PARAMETERS: DANE COUNTY COORDINATES

HORIZONTAL PROJECTION PARAMETERS: DANE COUNTY COORDINATES Recommended RTK GPS Configuration Parameters for the City of Madison, WI Base Station Compiled by: Dan Rodman RLS, City of Madison (608)266-6674 drodman@cityofmadison.com For base station information see

More information

System of Geodetic Parameters Parametry Zemli 1990 PZ-90.11

System of Geodetic Parameters Parametry Zemli 1990 PZ-90.11 System of Geodetic Parameters Parametry Zemli 1990 PZ-90.11 Authors: PhD Anastasiya N. Zueva, PhD Evgeniy V. Novikov, Dr. Dmitriy I. Pleshakov, PhD Igor V. Gusev Speaker: Igor Gusev 9 th Mee'ng of the

More information

New satellite mission for improving the Terrestrial Reference Frame: means and impacts

New satellite mission for improving the Terrestrial Reference Frame: means and impacts Fourth Swarm science meeting and geodetic missions workshop ESA, 20-24 March 2017, Banff, Alberta, Canada New satellite mission for improving the Terrestrial Reference Frame: means and impacts Richard

More information