GGOS is the Observing System of the International Association of Geodesy (IAG).
GGOS works with the IAG components to provide the geodetic infrastructure necessary for monitoring the Earth system and for global change research. It provides observations of the three fundamental geodetic observables and their variations, that is, the Earth's shape, the Earth's gravity field and the Earth's rotational motion.
GGOS integrates different geodetic techniques, different models, and different approaches in order to ensure a long-term, precise monitoring of the geodetic observables in agreement with the Integrated Global Observing Strategy (IGOS).
GGOS provides the observational basis to maintain a stable, accurate and global reference frame and in this function is crucial for all Earth observation and many practical applications (Fig. 1).
GGOS acts as the interface between the geodetic services and external users such as the Group on Earth Observation (GEO) and United Nations authorities.
Structure of GGOS
GGOS leadership is headed by a chair and vice-chair, who liaise with the GGOS Consortium, which serves as the steering and election committee. These are supported by the GGOS Coordinating Board (the decision-making body) and the GGOS Executive Committee (the management board). In turn, all of the aforementioned leadership elements work in concert with the IAG Scientific Services. The GGOS Coordinating Office supports outreach (including a provisional website ggosdays.com), internal and external coordination, and the daily management of GGOS.
At the heart of GGOS are its Bureaus, each containing working groups and other IAG support services. The Bureau of Networks and Observations (BNO) contains working groups on satellite missions, simulations, and data and information systems. Meanwhile, the Bureau of Products and Standards (BSC) oversees working groups on Earth system modelling and standards, and promoting the development of new geodetic products associated with the three GGOS Themes: Unified Height System, Geohazards Monitoring, and Sea Level Change.
Activities of GGOS
The GGOS components meet at least annually during the GGOS Days, while the Coordinating Board and the Bureaus meet at least semi-annually during the GGOS Days and the EGU General Assembly. The GGOS Executive Committee has a monthly teleconference to cover the current business. The different observing systems and the standard committees have their own meetings according to their needs.
The current activities focus on the following items:
· Unified Height Systems, covered by a special Focus Area
· Precision of observations towards 1 mm, common activities of all observations and the modelling groups within the Bureaus and the Science Panel
· Providing observations and models to understand and probably mitigate geohazards with a special Focus Area and all observations
· Generating standards and metadata for comparing observations and informations
The International Association of Geodesy (IAG) is organised into Commissions, Services, the Global Geodetic Observing System and Inter-Commission Committees. Currently, there is only the Inter-Commission Committee on Theory (ICCT) active within the IAG structure. ICCT was formally approved and established after the IUGG XXI Assembly in Sapporo, 2003, to succeed the former IAG Section IV on General Theory and Methodology as theories and methodologies matters to all IAG components. ICCT joint study groups interact actively and directly with IAG Commissions, Services and the Global Geodetic Observing System. In accordance with the IAG by-laws, the initial two periods were reviewed in 2011 at the IUGG XXIII Assembly in Melbourne where IAG approved the continuation of ICCT. At the IUGG XXIV Assembly in Prague, 2015, ICCT became a permanent entity within the IAG structure.
Recognizing that observing systems in all branches of geodesy have advanced to such an extent that geodetic measurements (i) are now of unprecedented accuracy and quality, can readily cover a region of any scale up to tens of thousands of kilometres, yield non-conventional data types and can be provided continuously; and (ii) consequently, demand advanced mathematical modelling in order to obtain the maximum benefit of such technological advance, ICCT (1) strongly encourages frontier mathematical and physical research, directly motivated by geodetic need and practice, as a contribution to science and engineering in general and theoretical foundations of geodesy in particular; (2) provides the channel of communication amongst different IAG commissions, services and GGOS on the ground of theory and methodology, and directly cooperates with and supports these entities in the topical work; (3) helps IAG in articulating mathematical and physical challenges of geodesy as a subject of science and in attracting young talents to geodesy. ICCT strives to attract and serve as home to all mathematically motivated and oriented geodesists as well as to applied mathematicians; and (4) encourages closer research ties with and gets directly involved in relevant areas of Earth sciences, bearing in mind that geodesy has always been playing an important role in understanding the physics of the Earth.
The overall objectives of the ICCT are to act as international focus of theoretical geodesy, encourage and initiate activities to advance theory in all branches of geodesy and to monitor developments in geodetic methodology. To achieve these objectives, ICCT interacts and collaborates with the IAG Commissions, Services and GGOS.
The structure of ICCT is specified in IAG by-laws. The ICCT steering committee for the period 2015-19 consists of the President (P. Novák, Czech Republic), the Vice-President (M. Crespi, Italy), the Past-President (N. Sneeuw, Germany) and representatives from IAG Commissions, Services and GGOS. ICCT activities are undertaken by its study groups. By the inter-commission nature of ICCT, the study groups are joint study groups, affiliated to one or more of Commissions, Services and/or to GGOS.
In the structure of ICCT for the 2015-19 period, there are 13 joint study groups:
1. High-rate GNSS (M. Crespi, Italy)
2. Multiresolutional aspects of potential field theory (D. Tsoulis, Greece)
3. Advanced computational methods for recovery of high-resolution gravity field models (R. Čunderlík, Slovakia)
4. Integral equations of potential theory for continuation and transformation of classical and new gravitational observables (M. Šprlák, Australia)
5. Fusion of multi-technique satellite geodetic data (K. Sośnica, Poland)
6. Regional geoid/quasi-geoid modelling – theoretical framework for the sub-centimetre accuracy (J. Huang, Canada)
7. Earth’s inner structure from combined geodetic and geophysical sources (R. Tenzer, China)
8. Multi-GNSS theory and algorithms (A. Khodabandeh, Australia)
9. High resolution harmonic analysis and synthesis of potential fields (S. Claessens, Australia)
10. Time series analysis in geodesy (W. Kosek, Poland)
11. Space weather and ionosphere (K. Börger, Germany)
12. Geophysical modelling of time variations in deformation and gravity (Y. Tanaka, Japan)
13. Definition of next generation terrestrial reference frames (C. Kotsakis, Greece)
ICCT's activities include participating as conveners of geodesy sessions at major international geoscientific conferences such as IAG, IUGG, EGU and AGU, organizing regular Hotine-Marussi symposia on mathematical geodesy, initiating summer schools on theoretical geodesy and maintaining a website for dissemination of ICCT related information (http://icct.kma.zcu.cz).
ICCT will participate at a number of sessions at the upcoming IAG Scientific Assembly to be held in Kobe, Japan, 31 July – 4 August 2017 jointly with the International Association of Seismology and Physics of the Earth's Interior (IASPEI). However, next ICCT activities will be focused on organizing the IX. Hotine-Marussi Symposium on Mathematical Geodesy in 2018. This will be the next symposium in a series which started back in 1954 since there were international symposia promoted by Antonio Marussi and organized under the umbrella of IAG like Hotine Symposia on Mathematical Geodesy in memory of the well-known English Geodesist Martine Hotine. At these symposia theoretical problems of geodesy and advances in geodetic knowledge, research and technology were discussed. After the death of Marussi these meetings are named Hotine-Marussi Symposia on Mathematical Geodesy.
The International Association of Geodesy (IAG) holds its Scientific Assemblies traditionally midterm between two IUGG-IAG General Assemblies. The next one will be held middle of the General Assemblies 2015 (Prague, Czech Republic) and 2019 (Montreal, Canada) together with the International Association of Seismology and Physics of the Earth (IASPEI) in Kobe, Japan, from July 30 to August 4, 2017. There will be nine joint symposia of IAG and IASPEI, and seven IAG specific symposia. The titles are:
J01 Monitoring of the cryosphere
J02 Recent large and destructive earthquakes
J03 Deformation of the lithosphere: Integrating seismology and geodesy through modelling
J04 Geohazard early warning systems
J05 Crustal dynamics: Multidisciplinary approach to seismogenesis
J06 The spectrum of fault-zone deformation processes (from slow slip to earthquake)
J07 Tracking the sea floor in motion
J08 Imaging and interpreting lithospheric structures using seismic and geodetic approaches
J09 Geodesy and seismology general contributions
G01 Reference frames
G02 Static gravity field
G03 Time variable gravity field
G04 Earth rotation and geodynamics
G05 Multi-signal positioning: Theory and applications
G06 Geodetic remote sensing
G07 Global Geodetic Observing System (GGOS) and Earth monitoring services
Most important dates for contributions to the symposium are:
December 7, 2016: Abstract submission and registration open;
February 8, 2017: Deadline for abstract submission and travel support application;
April 5, 2017: Notification of acceptance;
May 10, 2017: Closure of early bird registration;
July 7, 2017: Closure of pre-registration.
All interested persons are invited to submit abstracts for oral presentations or posters. For more details of the assembly please visit the Homepage http://www.iag-iaspei-2017.jp.
Hermann Drewes, IAG Secretary General
Dear ITRF Users and Colleagues,
The ITRS Center at IGN has the pleasure to announce to the community the availability of an IERS Technical Note describing the analysis and results of the ITRF2014 solution, available at the following link:
The ITRF2014 Technical Note includes the summary descriptions of the contributions of the four Technique Services (IDS, IGS, ILRS IVS), to be acknowledged here for their enormous efforts in providing their reprocessed solutions.
Also appended to the Technical Note the full open access article on ITRF2014 that can be retrieved here:
Many thanks to colleagues at the IERS Central Bureau at BKG for their efficient assistance and cooperation in finalizing the ITRF2014 Technical Note.
Head, ITRS Center
Source: IERS Message No. 329
We cordially invite you to the 5th La Plata International School on Astronomy and Geophysics (LAPIS): "Space geodesy applied to geodynamics and atmospheric research" to be held on October 29th - November 04th, 2017, in the Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, in the city of La Plata, Argentina.
· addresses post-graduate and doctoral students in Geodesy, Astronomy, Geophysics, Engineering and related disciplines of Geosciences and Atmospheric science; advanced graduate students may also be admitted.
· comprises lectures and exercices which familiarize the participants with the geometrical space-geodetic observation techniques (GNSS, SLR, VLBI) as data sources for research related to geodynamics and the atmosphere.
· is free of charge for the particpants. Course language is English.
Each participant has to bring an own notebook.
The pre-inscription is open until May 31, 2017, the number of participants is limited. Pre-inscription and further information are available at:
LAPIS 2017 Local Organizing Committee
Facultad de Ciencias Astronomicas y Geofisicas
Universidad Nacional de La Plata, Argentina
Source: IERS Message No. 330
April 30 – May 4 , 2017, Westford, MA, USA
May 9-12, 2017, Lausanne, Switzerland
May 15-19 , 2017, Gothenburg, Sweden
May 17 – 19, 2017, Wroclaw, Poland
May 20 – 25, 2017, Makuhari Messe, Chiba, Japan
May 22 – 24, 2017, London, United Kingom
May 29 – June 2, 2017, Helsinki, Finland
June 21 – 23, 2017, Gdynia, Poland
June 22 – 25, 2017, Gdańsk, Poland
July 2 – 7, 2017, Washington, DC, USA
July 3 – 7, 2017, Paris, France
July 3 – 5, 2017, Berlin, Germany
July 10 – 12, 2017, Paris, France
July 10 – 14, 2017, New York, USA
July 30 – August 4, 2017, Kobe, Japan
August 6-11, 2017, Singapore, Singapore
August 21-25, 2017, KTH, Stockholm
September 4-6, 2017, Brussels, Belgium
September 4-15, 2017, Longyearbyen, Svalbard-Spitzbergen, Norway
September 5-7, 2017, Reykjavik, Iceland
September 11-15, 2017, Potstdam, Germany
September 18-22, 2017, Jeju Island, South Korea
3rd Symposium of the Committee on Space Research (COSPAR): Small Satellites for Space Research
September 19-21, 2017, Bonn, Germany
September 25-27, 2017, University of Alicante, Spain
September 25-29, 2017, Portland, Oregon, USA
September 26-28, 2017, Berlin, Germany
October 4-7, 2017, Riga, Latvia
October 10-11, 2017, IHB, Monaco
October 16-18, 2017, Strasbourg, France
October 23-27, 2017, Miami, FL, USA
October 25-27, 2017, Valencia, Spain,
October 29 – November 4, 2017, La Plata, Argentina
December 11-15, 2017, New Orleans, LA, USA
January 15-17 , 2018, Zurich, Switzerland
April 8-13 , 2018, Vienna, Austria
June 3-8, 2018, Hawaii, USA
June 3-8, 2018, Longyearbyen, Spitsbergen, Norway
July 14-22, 2018, Pasadena, CA, USA
August 20-31, 2018, Vienna, Austria
October 27-31, 2018, Canberra, Australia
December 10-14, 2018, Washington, D.C., USA
April 7-12 , 2019, Vienna, Austria
July 8 – 17, 2019, Montreal, Canada
July 28 – August 2, 2019, Singapore, Singapore
Bernard Guinot, honorary astronomer of the Observatoire de Paris, died on March 6, 2017, aged 91. He was Correspondent of the French Académie des sciences, Honorary Member of the Bureau des longitudes and Member of the Academia Europaea.
Being at first an officer in the shipping department, he become an astronomer at the Paris Observatory in 1952, where André Danjon, then Director, associated him with his research on the astrolabe named after him. B. Guinot was actively involved in the further development of this instrument and of its scientific applications. In 1958, he obtained his doctoral thesis on this subject. In 1965 he became Director of the Bureau International de l’Heure (BIH), a position he held until 1985 at the Paris Observatory, in the Department of Fundamental Astronomy (now SYRTE). In this context, he devised new algorithms for the calculation of Universal Time UT1 and pole coordinates; he developed methods for the transition from optical measurements to space geodesy techniques and created a rapid service for the needs of space research. In 1979, he proposed the definition of a new equatorial origin which was adopted at the international level in 2000.
In 1980, he proposed the use of space geodesy observatories contributing to the measurement of Earth's rotation for the maintenance of the global geodetic reference system. He is thus the instigator of the geodetic reference system used worldwide - in particular by the space positioning systems - which gave birth to the current International Terrestrial Reference System (ITRS). This work was developed within the framework of a co-operation which he proposed to the IGN, which produced the publication of a first realization of this system in 1985, and later, in 1988, the creation of the International Earth Rotation and Reference System Service (IERS). In June 2015, he had the opportunity to present the genesis of this work during the scientific colloquium (Bureau des Longitudes, IGN, Observatoire de Paris), which celebrated the 30th anniversary of this system and its role in geodynamics, oceanography, climate and relativity.
As Director of the BIH, he was one of the most active authors of the transition from the astronomical measurement of time to its quantum measurement and one of the major players in the organization of world time metrology. He was strongly involved in the establishment of the global coordination of Coordinated Universal Time (UTC), the current basis of legal time. He created and developed the algorithm for the construction of the International Atomic Time (TAI) and made the TAI recognized as the unique and official basis for time and frequencies measurements. He improved its construction in order to make it the best approximation of the ideal time of physics. In 1985, he joined the International Bureau of Weights and Measures (BIPM) as a principal physicist, then as a consultant. He officially transferred the BIH activity on TAI to the BIPM in 1988 at the creation of the IERS, which replaced the IPMS and the earth-rotation section of the BIH. In addition to his activities on time scales, he devoted himself to the problem of the relativistic definitions of space-time references of which he assured the recognition by the IAU in 2000.
During the course of his career, he has been given many national and international responsibilities. At Paris Observatory, he was in charge of the Astrolabe Service (1962-1968) and the Service de l'Heure (1964-1976) and director of the Primary Time and Frequency Laboratory (LPTF, 1976-1979). He was also a member of the board of directors of the Bureau national de métrologie (BNM, 1972-1984), scientific and then executive director of the Groupe de recherche de géodésie spatiale (GRGS, 1979-1985), and President of the Bureau des longitudes (1984-1986). At the international level, he was President of Commission 19 (Rotation of the Earth) of the International Astronomical Union (IAU, 1961-1967), of the Scientific Council of the International Polar Motion Service (IPMS, 1962-1970), of the Federation of the Astronomical and Geophysical data analysis Services (FAGS, 1970-1973) and of the Consultative Committee for the Definition of the Second (CCDS, 1978-1984; now CCTF) and was also a Member of the International Committee of Weights and Measures (CIPM). In all these responsibilities, his competence, his rigor and his scientific authority have always been unanimously recognized.
B. Guinot wrote a large number of authoritative publications on space and time references, among which “La méthode des hauteurs égales en astronomie” with Suzanne Débarbat (Gordon & Breach 1970), and “Les fondements de la mesure du temps”, with Claude Audoin (Masson 1998; English translation, Gordon & Breach 1981). He strongly emphasized the book "Les références de temps et d’espace”, edited by the Bureau des longitudes, to appear in May 2017, which is dedicated to his memory.
The great scientific rigor and innovative concepts that Bernard Guinot has shown during his sixty years of scientific activity have allowed him to make astronomy and time measurements best benefit from the gain of precision brought by space geodesy and atomic clocks. We have lost with him a prominent personality and a great scientist.
Nicole Capitaine, Felicitas Arias, Claude Boucher
and Colleagues from the Observatoire de Paris, Bureau des longitudes and Bureau international des poids et mesures
This document has been provided by the Communicational and Outreach Branch of the International Association of Geodesy.