2020-09-25

SC 1.3: Regional Reference Frames

Chair: Carine Bruyninx (Belgium)

Terms of Reference

Sub-commission 1.3 deals with the definitions and realizations of regional reference frames and their connection to the global International Terrestrial Reference Frame (ITRF) and International Height Reference Frame (IHRF). It offers a home for service-like activities addressing theoretical and technical key common issues of interest to regional organisations.

Objectives

In addition to the specific objectives of each regional Sub-commission, the main objectives of SC1.3 as a whole are to:

  • Coordinate the activities of the regional Sub-commissions focusing on exchange of data, competences and results;
  • Promote operation of permanent GNSS stations, in connection with IGS whenever appropriate, as the basis for the long-term maintenance of regional reference frames;
  • Promote open access to the GNSS data from permanent GNSS stations used for the maintenance of regional reference frames and scientific applications;
  • Develop specifications for the definition and realization of regional reference frames, including the vertical component;
  • Encourage and stimulate the development of the AFREF project in close cooperation with IGS and other interested organizations;
  • Encourage and assist countries, within each regional Sub-commission, to re-define and modernize their national geodetic systems, compatible with the ITRF;
  • Support the efforts of the United Nations Initiative on Global Geospatial Information Management
  • (UN-GGIM) towards a sustainable Global Geodetic Reference Frame (GGRF).

Program of Activities

  • Provide a forum for addressing activities, results and key issues of common interest to the regional Sub-commissions;
  • Develop analysis strategies and compare methods for the implementation of the regional reference frames and their expression in the ITRF, in full interaction with the IGS;
  • Consider developing tectonic deformation models that will enable transformation of locations within a defined reference frame between different epochs;

SC 1.3a: Europe

Chair: Martin Lidberg (Sweden)
Secretary: Karin Kollo (Estonia)

Terms of Reference

EUREF, the Regional Reference Frame Sub-commission for Europe, deals with the definition, realization and maintenance of the European Reference Frames. EUREF is focusing on both the spatial and the vertical components in close cooperation with the pertinent IAG components (Services, Commissions, and Inter-commission projects). For more information, see www.euref.eu .

Objectives

  • The definition, realization and maintenance of the European Geodetic Reference Systems;
  • The promotion and assistance of the adoption and use of European Terrestrial Reference
  • System (ETRS89) and European Vertical Reference System (EVRS) in our partner countries;
  • The development and maintenance of the EUREF GNSS Permanent Network (EPN) which is the ground based GNSS infrastructure for scientific and practical applications in positioning and navigation (Global Geodetic Observing System - GGOS, IGS Real-time Service);
  • The development of strategies and technologies for the realization of geodetic reference systems.

Structure

EUREF is composed of representatives from European IAG member countries. The Governing Board (GB) is composed of members elected by the EUREF plenary, members in charge of special tasks and ex-officio members. The current Chair of GB is Wolfgang Söhne (Germany).

In addition, several Working Groups have been set up:

  • Working group on "European Dense Velocities"
    Chair: Elmar Brockmann (Switzerland)
  • Working group on "EPN Densification"
    Chair: Ambrus Kenyeres (Hungary)
  • Working group on "Deformation models"
    Chair: Martin Lidberg (Sweden)
  • Working Group on “Multi GNSS”
    Chair: Elmar Brockmann (Switzerland)
  • Working group on "EPN Reprocessing"
    Chair: Christof Völksen (Germany)

Program of Activities

  • Continue to develop the EPN in close cooperation with IGS (International GNSS Service), for the maintenance of the European Terrestrial Reference Frame (ETRF), as a contribution to the ITRF and as an infrastructure to support practical applications for precise positioning and referencing geo-information;
  • Extend the Unified European Levelling Network (UELN) in order to include as many countries as possible in the current realization of the European Vertical Reference System (EVRS), and further continue the long-term maintenance of the European Vertical Reference Frame (EVRF) applying a kinematic approach;
  • Closely follow and contribute to the developments regarding the International Height Reference System (IHRS) and its realizations in International Height Reference Frames (IHRF), and when appropriate establish the precise relation between IHRF and EVRF;
  • Promote efforts on regional geoid models in Europe as the link between the ETRF and the EVRF;
  • Support new developments in reference frame realization and applications by introducing new technologies like real-time GNSS data transfer and products, as well as Galileo for precise positioning;
  • Realize a dense and homogeneous position and velocity product for Europe;
  • Establish a dense velocity field model in Europe for the long-term maintenance of the European reference frame;
  • Provide GNSS tropospheric estimates at the EPN stations in support of climate research;
  • Contribute to the IAG Programme GGOS using the installed infrastructures managed by the EUREF members;
  • Promote the adoption of the reference systems defined by EUREF (ETRS89 - European Terrestrial Reference System 1989 and EVRS - European Vertical Reference System) in the European countries and European-wide initiatives related to geo-referencing activities like INSPIRE;
  • Cooperate with European political and scientific organisations and projects, e.g. EuroGeographics, EUMETNET, CEGRN (Central European GPS Geodynamic Reference Network), EPOS (European Plate Observing System), UN-GGIM: Europe, etc.;
  • Organize annual symposia addressing activities carried out at national and Europe-wide levels related to the global work and objectives of EUREF.

Members of the EUREF Governing Board

The members of the Governing Board in the fall of 2019 are as follows. However, some new members are foreseen to be elected at the symposium in May 2020. An up to date list is available at www.euref.eu.

Carine Bruyninx (Belgium)
Elmar Brockmann (Switzerland)
Rolf Dach (Switzerland)
Ambrus Kenyeres (Hungary)
Karin Kollo (Estonia)
Juliette Legrand (Belgium)
Martin Lidberg (Sweden)
Tomasz Liwosz (Poland)
Rosa Pacione (Italy)
Martina Sacher (Germany)
Wolfgang Söhne (Germany, Chair of GB)
Christof Völksen (Germany)
Active honorary members:
Zuheir Altamimi (France)
Alessandro Caporali (Italy)
Markku Poutanen (Finland)
João Agria Torres (Portugal)

SC 1.3b: South and Central America

Chair: José Antonio Tarrio (Chile)
Vice-Chair: Demián Gomez (US)

Terms of Reference

Sub-commission 1.3b (South and Central America) encom­passes the activities developed by the “Geocentric Refer­ence System for the Americas” (SIRGAS). As such, it is concerned with the definition, realization and maintenance of a modern geodetic reference infrastructure for South and Central America and the Caribbean. This includes a geo­metric reference frame consistent with ITRS/ITRF and a gravity field-related vertical reference system, defined and realized globally. SIRGAS WG-1 coordinates the functioning and analysis of the SIRGAS Continuously Operating Network (SIRGAS-CON).  SIRGAS WG-1 also promotes the installation of the analysis centres for SIRGAS, under the responsibility of American institutions and the use of SIRGAS observations for atmospheric (ionosphere and troposphere) studies.  SIRGAS WG-2 is responsible for promoting and supporting the adoption of SIRGAS realization through continuous operating GNSS stations.


Objectives

  • To determine, maintain and make available a geocentric reference frame (a set of stations with high-precise geo­centric positions and their variation with time) as a regional densification of the global ITRF;
  • To support the SIRGAS countries in the establishment and maintenance of national geodetic reference networks as local densifications of SIRGAS in order to guarantee accessibility to the global ITRF at national and local levels;
  • To establish a unified vertical reference system supporting the determination and precise combination of physical and geometric heights as well as their variations with time;
  • To support the IAG Sub-Commission 2.4b (Gravity and Geoid in South America) in the activities related to gravity densifications in order to improve the distribution of gravity information and to establish a new Absolute Gravity Network in South America;
  • To contribute to the GGOS program by developing and implementing state-of-the-art products based on the SIRGAS observational infrastructure;
  • To promote, support, and coordinate the efforts of the American and Caribbean countries to achieve these objectives. 

Structure

The structure of the Sub-commission 1.3b is based on the functioning SIRGAS Working Groups. There are currently three Working Groups:

  • SC1.3b-WG 1: Reference System
    Chair : José Antonio Tarrio (Chile)
  • SC1.3b-WG 2: SIRGAS at National Level
    Chair: Demián Gomez (US)
  • SC1.3b-WG 3: Vertical Datum
    Chair : Gabriel do Nascimento Guimarães (Brazil)

The SIRGAS Executive Committee (as it is named in the SIRGAS statutes) is composed of:

  •     Chair : Sonia María Alves Costa (Brasil, IAG member-at-large).
  •     Vice-Chair : Diego Alejandro Piñón (Argentina) 
  •     IAG SC1.3b WG1 Chair : José Antonio Tarrio (Chile)
  •     IAG SC1.3b WG2 Chair : Demián Gomez (US)
  •     IAG SC1.3b WG3 Chair : Gabriel do Nascimento Guimarães (Brazil)

Program of Activities

Since the SIRGAS countries are improving their national reference frames by installing an increasing number of continuously operating GNSS stations, it is necessary to outline the best strategy for the appropriate integration of those frames into the continental frame. This includes:

  • Promotion of the IGS and IERS standards within the SIRGAS countries to ensure the adequate installation, maintenance, and analysis of continuously operating GNSS stations;
  • Establishment of a SIRGAS National Processing Centre in all the member countries;
  • Refinement of the SIRGAS station hierarchy. At present, two classes are considered: core and densification stations (the establishment of other categories is under considera­tion);
  • Promotion of the adequate usage of SIRGAS as a refer­ence frame by means of capacity building activities. This comprises SIRGAS schools on reference frames, scien­tific processing of GNSS data, atmospheric analysis based on the SIRGAS infrastructure, etc.;
  • Promotion and implementation of real-time services based on the SIRGAS infrastructure to make available the reference frame to more users;
  • The kinematics of the SIRGAS frame, up to now, have been represented by linear station movements (i.e. con­stant velocities). This representation is not sufficiently precise due to existing seasonal variations in the station position time series and due to discontinuities caused by the frequent occurrence of seismic events in the SIRGAS region.

According to this, it is necessary:

  •  To model non-linear station movements within the refer­ence frame computation;
  •  To implement a methodology aiming at a precise transfor­mation between different epochs and, in general, between pre-seismic and post-seismic reference frame realizations in particular;
  •  To evaluate the feasibility of computing and using near-real time reference frames instead of those based on epoch station positions and constant velocities.

The establishment of a unified vertical reference system continues to be a big challenge of SIRGAS. The related activities concentrate on:

  •  Continental adjustment of the national vertical networks in terms of geo-potential numbers;
  •  Combined analysis of tide gauge registrations, GNSS posi­tioning and satellite altimetry observations to deter­mine the dynamic ocean topography at the classical vertical datums;
  •  Determination of potential differences between the refer­ence tide gauges and the global reference surface;
  •  Stronger cooperation with the Sub-Commission 2.4b (Gravity and Geoid in South and Central America - GGSCA) to promote national initiatives regarding the modernization of the gravity reference networks and the computation of geoid models of high resolution. 

Hourly SIRGAS ionospheric models (vTEC) based on the GNSS SIRGAS stations have been generated since 2003 to 2015. The SIRGAS ionospheric model is being upgraded to include a better distribution of the electron density based on the assimilation of ground- and space-based GNSS observations. In addition, SIRGAS is developing a service for estimate hourly tropospheric Zenith Total Delay (ZTD) based on the operational SIRGAS processing. The ZTD estimates allow inferring Integrated Water Vapour (IWV) values with high accuracy. 

Members

SIRGAS Executive committee
Sonia María Alves Costa , Chair (Brasil). 
Diego Alejandro Piñón, Vice-Chair (Argentina) 
José Antonio Tarrio, SIRGAS-WG1 Chair (Chile)
Demián Gomez, SIRGAS-WG2 Chair (US)
Gabriel do Nascimento Guimarães, SIRGAS-WG3 Chair (Brazil)

SIRGAS Directing council
Hermann Drewes, Representative of IAG
Hector Carlos Rovera Di Landro, Representative of PAIGH
Juan Francisco Moirano; Demian Gómez (Argentina)
Arturo Echalar Rivera; Mario Sandoval Nava (Bolivia)
Luiz Paulo Souto Fortes; Sonia Maria Alves Costa (Brazil)
Juan Pedro Harms; Sergio Rozas Bornes (Chile)
Jose Ricardo Guevara Lima; Francisco Javier Mora Torres (Colombia)
Max Lobo Hernández; Álvaro Álvarez Calderón (Costa Rica)
Alejandro Jiménez Reyes; José Leandro Santos (Dominican Republic)
Edgar Fernando Parra Cárdenas; Jose Luis Carrión (Ecuador)
Carlos Enrique Figueroa; Wilfredo Amaya Zelaya (El Salvador)
Óscar Cruz Ramos; Fernando Oroxan Sandoval (Guatemala)
Rene Duesbury; Hilton Cheong (Guyana)
Bruno Garayt; Alain Harmel (French Guyana)
Luis Alberto Cruz (Honduras)
Enrique Muñoz Goncen, Francisco Medina (Mexico)
Wilmer Medrano Silva, Ramón Aviles Aburto (Nicaragua)
Javier Cornejo, Melquiades Dominguez (Panama)
Daniel Ariar, Joel Roque Trinidad (Paraguay)
Julio Enrique Llanos Alberca, Julio Sáenz Acuña (Peru)
Daniel Piriz (Uruguay)
Dana J. Caccamise II, Daniel R. Roman (USA)
Jose Napoleón Hernández, Melvin Jesús Hoyer Romero (Venezuela)

SIRGAS Scientific Council
Luiz Paulo Souto Fortes (Brazil)
Laura Sanchez (Germany)
Claudio Brunini (Argentina)
María Virginia Mackern (Argentina)

SC1.3c: North America (NAREF)

Co-Chairs:
Michael Craymer (Canada)
Dan Roman (USA)

Terms of Reference

To provide international focus and cooperation for issues involving the horizontal, vertical, and three- dimensional geodetic control networks of North America, including Central America, the Caribbean and Greenland (Denmark). For more information, see www.naref.org.

Objectives

In collaboration with the IAG community, its service organisations, and the national geodetic organizations of North America, the aims and objectives of this regional Sub-commission are to provide international focus and cooperation for issues involving the horizontal, vertical and three dimensional geodetic control networks of North America. Some of these issues include:

  • Densification of the ITRF reference frame in North America and the promotion of its use;
  • Definition, maintenance and future evolution of plate-fixed geometric reference frames for North America, including the North American Datum of 1983 (NAD83) and the forthcoming North American Terrestrial Reference Frame of 2022 (NATRF2022).
  • Effects of crustal motion, including post-glacial rebound and tectonic motions along, e.g., the western coast of North America and in the Caribbean;
  • Standards for the accuracy of geodetic positions;
  • Coordination of efforts with neighbouring SC1.3b South America (SIRGAS) to ensure strong ties between each other’s reference frames;
  • Outreach to the general public through focused symposia, articles, workshops and lectures, and technology transfer to other groups.

Structure

  • Co-Chairs: Michael Craymer (Canada), Dan Roman (USA)
  • Steering committee: Michael Craymer (Canada), Dan Roman (USA), Bo Finn Madsen (Denmark)

Working Groups of Sub-Commission 1.3c

WG 1.3c.1: North American Reference Frame Densification (NAREF)
Chair: Michael Craymer (Canada)

WG 1.3c.2: Plate-Fixed North American Terrestrial Reference Frame of 2022 (NATRF2022)
Chair: Dan Roman (USA)

WG 1.3c.3: Reference Frame Transformations in North America
Chair: Michael Craymer (Canada)

SC 1.3d: Africa


Chair: Elifuraha Saria (Tanzania)

Terms of Reference

Sub-commission 1.3d (Africa) is concerned with the definition and realization of a unified continental reference frame (AFREF) for Africa, which will be consistent and homogeneous with the global International Terrestrial Reference Frame (ITRF).

Objectives

In collaboration with the IAG community and its services, regional organisations, and the National and Regional Mapping Organizations of Africa, the objectives of Sub-commission 1.3d (Africa) are:

  • Coordinate the activities of the regional organisations focusing on exchange of data, competences and results;
  • Promote operation of permanent GNSS stations, in connection with IGS whenever appropriate, as the basis for the long-term maintenance of regional reference frames;
  • Promote open access to the GNSS data from permanent GNSS stations used for the maintenance of regional reference frames and scientific applications;
  • Develop specifications for the definition and realization of regional reference frames, including the vertical component;
  • Encourage and stimulate the development of the AFREF project in close cooperation with IGS and other interested organizations;
  • Encourage and assist countries, within each regional organisation, to re-define and modernize their national geodetic systems, compatible with the ITRF;
  • Support the efforts of the United Nations Initiative on Global Geospatial Information Management (UN-GGIM) towards a sustainable Global Geodetic Reference Frame (GGRF).

Structure

  • Chair: Elifuraha Saria (Tanzania)
  • Governing Board (see list of members below)

Program of Activities

  • Provide a forum for addressing activities, results and key issues of common interest to the regional organisations;
  • Develop analysis strategies and compare methods for the implementation of the regional reference frames and their expression in the ITRF, in full interaction with the IGS;
  • Consider developing tectonic deformation models that will enable transformation of locations within a defined reference frame between different epochs.

Members

The members of the AFREF Governing Board are as follows.
Elifuraha Saria (Tanzania), Chair
Emanuel Nkurunziza (Kenya)
Joseph Dodo (Nigeria)
Salah Mahmud (Egypt)
Cesare Mbaria (Kenya)
Prosper Ulotu (Tanzania)
Andre Nonguierma (Burkina Faso)
Akingbade O (Nigeria)
Moha El-Ayachi (Morocco)
Elias Lewi (Ethiopia)
Patrick Vorster (South Africa)
Prof. Kamal Labbassi (Morocco)

Active honorary members:

Richard Wonnacott (South Africa)
Hussein Farah (Kenya)
Olajide Kufoniyi (Nigeria)

Some additional members are foreseen to be elected at the AFREF meeting in 2020.

SC 1.3e: Asia-Pacific

Chair: Basara Miyahara (Japan)

Terms of Reference

Sub-commission 1.3e aims to improve regional cooperation that supports the realization and densification of the ITRF. This activity will be carried out in close collaboration with the Geodetic Reference Framework for Sustainable Development Working Group of the United Nations Global Geospatial Information Management for Asia and the Pacific (UN-GGIM-AP). For more details about UN-GGIM-AP WG1, see http://www.un-ggim-ap.org/workinggroups/geodetic.

Objectives

  • The densification of the ITRF and promotion of its use in the Asia Pacific region;
  • To encourage the sharing of GNSS data from Continuously Operating Reference Stations (CORS) in the region;
  • To develop a better understanding of crustal motion in the region;
  • To promote the collocation of different measurement techniques, such as GNSS, VLBI, SLR, DORIS and tide gauges, and the maintenance of precise local geodetic ties at these sites; and
  • To outreach to developing countries through symposia, workshops, training courses, and technology transfer activities.

Program of Activities

The activities of Asia-Pacific Sub-commission will principally be those of the Asia-Pacific Reference Frame (APREF) project. The APREF project consists of a Central Bureau, Network operators, Data centers, and Analysis centers. The Central Bureau, within Geoscience Australia, functions as the 'day-to-day' APREF coordinating body. Specifically, the Central Bureau ensures that APREF products are made available to the global geodetic community. Furthermore, they are the combination center responsible for analyzing, combining and validating the individual solutions of the contributing Analysis Centers, and for expressing the combined solution in the ITRF. Following APREF data and products are provided with an open access data policy via the internet following the practice of the IGS. They consist of daily GNSS RINEX data, station log files, weekly coordinate estimates in SINEX format, and APREF network and time-series plots.

For more details, see http://www.ga.gov.au/scientific-topics/positioning-navigation/geodesy/asia-pacific-reference-frame.

Members

The members of the Asia-Pacific Sub-commission are national geodetic representatives from the UN-GGIM-AP member nations and APREF participating organisations.

UN-GGIM-AP WG1 (Geodetic Reference Frame)
Basara Miyahara (Japan), Chair
John Dawson (Australia), vice-Chair
Yamin Dang (China)
S. K. Singh (India)
Mohd Yunus (Malaysia)
Dalkhaa Munkhtsetseg (Mongolia)
Graeme Blick (New Zealand)
Sangoh Yi (South Korea)

APREF Analysis Group
Guorong Hu (Australia)
Alex Woods (Australia)
Yunbin Yuan (China)
Basara Miyahara (Japan)

SC 1.3f: Antarctica

Chair: Martin Horwath (Germany)

Terms of Reference

Sub-commission 1.3f focuses on the realization and densification of a unified reference frame for Antarctica, which will be consistent with the global International Terrestrial Reference Frame (ITRF). The Sub-commission shares objectives and activities of the Scientific Committee on Antarctic Research (SCAR), namely of the SCAR Expert Group Geodetic Infrastructure of Antarctica (GIANT). The Sub-commission closely links IAG and SCAR activities by embedding identical activities, with identical persons where indicated, into the two complementary organisational structures.

Objectives

  • Maintenance and densification of the precise geodetic reference network in Antarctica by permanent observations and GNSS campaigns;
  • Realization of a unified vertical datum including GNSS ties of tide gauges;
  • Providing unified reference for further GNSS applications like airborne gravimetry, ground truthing for satellite missions, geodynamics and glaciology;
  • Develop technologies for remote geodetic observatories;
  • Stimulate and coordinate international collaboration on the above fields, under the unique political conditions of Antarctic research given by the Antarctic Treaty, in order to make optimum use of logistics and infrastructure.

Program of Activities

  • Organization of GNSS campaigns in Antarctica;
  • Extend activities for the operation of remote permanent GNSS stations;
  • Maintenance of the data archive (SCAR GNSS data base) to collect Antarctic GNSS data and provide them to the scientific community;
  • Data analysis and determination of the Antarctic GNSS network as a regional densification of ITRF;
  • Provide homogeneous site velocities for e.g. glacial isostatic adjustment determination;
  • Support airborne surveys and satellite missions with precise terrestrial reference;
  • Collaborate with IAG Sub-Commission 3.4 (Cryospheric Deformation) and the SCAR Scientific Research Programme Solid Earth Response and Influence on Cryosphere Evolution (SERCE) and subsequent programmes, respectively
  • Organize special workshop(s) on the consistent analysis of GNSS data and realization of ITRF
  • Organize meetings/sessions at conferences like IAG, IUGG, SCAR Open Science Conference.

Members

Martin Horwath (Germany), Chair
Alessandro Capra (Italy)
Mirko Scheinert (Germany)
Manuel Berrocoso (Spain)
Graeme Blick (New Zealand)
Jan Cisak (Poland)
Koishiro Doi (Japan)
Rene Forsberg (Denmark)
Thomas James (Canada)
Aspurah Kamburov (Bulgaria)
Matt King (Australia)
Kenichi Matsuoka (Norway)
Alexey Matveev (Russia)
Gennadi Milinevsky (Ukraine)
Elizabeth Petrie (United Kingdom)
Markku Poutanen (Finland)
Goncalo Prates (Portugal)
Lars Sjoberg (Sweden)
Norbertino Suarez (Uruguay)
Terry Wilson (USA)
Andres Zakrajsek (Argentina)

Working Groups of Sub-Commission 1.3

WG 1.3.1: Time-dependent transformations between reference frames in deforming regions
Chair: Richard Stanaway (Australia)

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