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CDDIS

Crustal Dynamics Data Information System

NASA's Crustal Dynamics Data Information System (CDDIS), one of NASA's Distributed Active Archive Centers (DAACs), provides data and information to support the international space geodesy and geodynamics community. CDDIS is part of the Earth Sciences Division at NASA's Goddard Space Flight Center in Greenbelt, MD, and serves as one of the core components for the geometric services established under the International Association of Geodesy (IAG), an organization that promotes scientific cooperation and research in geodesy on a global scale. 

CDDIS provides continuous, long term, public access to the data and derived products from a global network of observing stations equipped with one or more of the following measurement techniques:

  • Global Navigation Satellite System (GNSS)
  • Satellite Laser Ranging (SLR)
  • Very Long Baseline Interferometry (VLBI)
  • Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS)

CDDIS also archives International Earth Rotation and Reference Systems Service (IERS) products.

CDDIS Data and Services

Visit the CDDIS website to learn more about data and services. CDDIS content is currently migrating over to the Earthdata website; some of the pages are already redirecting from cddis.nasa.gov to earthdata.nasa.gov. 

Location

Greenbelt, MD

Manager

Rivers Lamb (Interim)
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Founded

1982

CDDIS was established in 1982 as a dedicated data bank to archive and distribute space geodesy-related data sets. Today, CDDIS archives and distributes GNSS (primarily Global Positioning System GPS and GLObal NAvigation Satellite System GLONASS), laser ranging (both to artificial satellites, SLR, and lunar, LLR), VLBI, and DORIS data for an ever-increasing user community of geophysists.

CDDIS was initially developed to provide a central data bank for NASA's Crustal Dynamics Project (CDP), a historic proejct developed by the science community and NASA in the late 1970s. The system continues to support the space geodesy and geodynamics community through NASA's Space Geodesy Project as well as NASA's Earth Observing System Data and Information System (EOSDIS). 

CDDIS has served as a global data center for the International GNSS Service (IGS) since 1992. CDDIS also supports the International Laser Ranging Service (ILRS), the International VLBI Service for Geodesy and Astrometry (IVS), the International DORIS Service (IDS), and the International Earth Rotation Service (IERS) as a global data center.

The International Association of Geodesy (IAG)

The International Association of Geodesy (IAG) is a scientific organization in the field of geodesy. The mission of the IAG is the advancement of geodesy and thus the association promotes scientific cooperation and research in geodesy on a global scale and contributes to it through its various research bodies. It is an active member of the International Association of Geodesy and Geophysics (IUGG) which itself is a member of the International Council for Science (ICSU). Key components of the IAG are its Services. In particular, the geometric services are dedicated to providing data and products relevant for geodesy and broader scientific applications:

Services function as cooperating federations dedicated to a particular type of data. They provide data and products on an operational basis to geodesy analysts as well as a broader scientific community. The services are examples of a successful model of community management where they develop standards, are self-regulating, monitor performance, and define and deliver products using pre-determined schedules. The IAG services are a excellent example of successful operation through cooperation of many international organizations who leverage their respective limited resources to all levels of service functionality.

The CDDIS is the principle data center supporting four geometric services created under the IAG and make up the primary user community for CDDIS archive.

Space Geodesy Project (SGP)

NASA's Space Geodesy Project (SGP) is an initiative that started in the fall of 2011. SGP is part of the Earth Science Decadal and the National Research Council study "Precise Geodetic Infrastructure." It is a Goddard/JPL partnership with participation from the Smithsonian Astrophysical Observatory and the University of Maryland.

The long-range goal of the Space Geodesy Project is to build, deploy and operate a next generation NASA Space Geodetic Network (NSGN) of integrated, multi-technique next generation space geodetic observing systems, along with a system that provides for accurate vector ties between them. This new NSGN will serve as NASA’s core contribution to a global network designed to produce the higher quality observational data required to maintain the Terrestrial Reference Frame and provide other data necessary for fully realizing the measurement potential of the current and coming generation of Earth Observing spacecraft.

The primary goals of the SGP are to:

  • Contribute to the maintenance and improvement of a stable Terrestrial Reference Frame (TRF) that meets the needs of NASA's Earth orbiting missions, Earth Surface and Interior Focus Area, and deep space navigation
  • Contribute to measurements of Earth orientation parameters (EOP) that meet the needs of NASA's Earth orbiting missions, Earth Surface and Interior Focus Area, and deep space navigation
  • Contribute to determining accurate precision orbits to meet the needs of NASA's geodetic, Earth observation, navigation and space science missions

From: SGP website

International Earth Rotation and Reference Systems Service (IERS)

The International Earth Rotation and Reference Systems Service (IERS) was created in 1988 by the International Union of Geodesy and Geophysics (IUGG) and the International Astronomical Union (IAU). It replaced the Earth rotation section of the Bureau International de l'Heure (BIH), and the International Polar Motion Service (IPMS). It is a member of the Federation of Astronomical and Geophysical Data Analysis Services.

According to its Terms of Reference, the mission of the IERS is to provide timely and accurate data on the Earth's rotation for current use and long-term studies. For this purpose it has established and maintains an international terrestrial reference frame and an international celestial reference frame and it regularly monitors the relative motion of these two frames by analysing observational data from a variety of techniques, including Very Long Baseline Interferometry (VLBI), Lunar Laser Ranging (LLR) and satellite-geodetic techniques such as Global Navigation Satellite Systems (GNSS), Satellite Laser Ranging (SLR), and Doppler Orbitography and Radio-Positioning by Integrated Satellite (DORIS).

The IERS techniques have strengths that are used in a complementary way, keeping enough redundancy for ensuring the permanence of the service over decades and maintaining close operational interaction with other global astronomical and geophysical programs. The maintenance of the consistency and accuracy of IERS products requires a careful organisation and management of the contributions of the major techniques used in space navigation, space geodesy and astrometry.

The IERS is an interdisciplinary service that maintains key connections between astronomy, geodesy and geophysics.

From: IERS web site

Global Geodetic Observing System (GGOS)

In mid-2003, the IAG established the Global Geodetic Observing System (GGOS) as a project to foster cooperation among the geometric services of the IAG and to promote outreach and education to a broad user community on the importance of the geodetic infrastructure to many Earth science applications. GGOS, a component of the IAG, works to integrate the geodetic techniques to ensure long-term monitoring of Earth processes, including global change research. Distribution of data and products for the generation of GGOS combination products will be accomplished through the data flow paths developed by the IAG services forming the underlying structure of GGOS. Access to data and products generated by these services will continue to be provided through the services, either directly or via a GGOS portal. This portal will facilitate access to GGOS products and provide a way to view the underlying, dedicated information systems developed by the IAG’s contributing services.

The CDDIS supports GGOS as an essential archive for the geometric services and will contribute to the GGOS portal by implementing systems to provide uniform access to a combined set of geodetic services’ information as well as technique-specific information systems.

From: GGOS web site

Earth Observing System Data and Information System (EOSDIS)

In late 2007, funding support for the CDDIS transitioned from the science research area within NASA to the Earth Observing System Data and Information System (EOSDIS). EOSDIS is a key core capability in NASA's Earth Science Data Systems Program. EOSDIS provides end-to-end capabilities for managing NASA’s Earth science data from various sources – satellites, aircraft, field measurements, and other programs. EOSDIS is responsible for the processing, archiving, and distribution of Earth science data sets, providing tools to facilitate use of these data, and ensuring that these data are available to the public to study Earth processes from space in order to meet the needs of the global community. In addition to managing the science systems, EOSDIS supports 12 Distributed Active Archive Centers (DAACs) in the U.S., each of which serves a specific Earth system science discipline. As one of these EOSDIS data centers, the CDDIS cooperates with other groups in support of NASA’s Earth science goals. This activity includes implementation of metadata standards that will eventually permit discovery of CDDIS archive content by researchers outside the existing user base. Thus, the CDDIS will have the opportunity to promote use of its data and products to a broader scientific community.

Solid Earth and Natural Hazards Research and Applications NRA

In 1996, the Solid Earth and Natural Hazards Research and Applications NASA Research Announcement (NRA) presented an opportunity for researchers to participate in the NASA research and development themes of Solid Earth and Natural Hazards Research and Applications. The research themes aim to develop and use NASA space geodetic and remote sensing technology to improve our understanding of the physical dynamics of the solid earth (including the interaction with atmosphere, ocean and fluid core) and to improve and demonstrate the capability of this technology in the assessment and mitigation of natural hazards.

From: Solid Earth and Natural Hazards Research and Applications NRA, August 1996

Crustal Dynamics Project (CDP)

The scientific objectives of the Crustal Dynamics Project (CDP) developed by the science community and NASA in the late 1970's were to improve our knowledge and understanding of:

  • Regional deformation and strain accumulation related to earthquakes at the plate boundary in the western United States
  • Contemporary relative plate tectonic motions of the North American, Pacific, South American, Eurasian, Australian, Nazca, and Caribbean plates
  • Internal deformation of lithospheric plates away from plate boundaries, with particular emphasis on North America
  • Polar motion and variations in Earth rotation and their possible correlation with earthquakes and other geophysical phenomena
  • Crustal motion and deformation occuring in other regions of high earthquake activity.

These objectives required the development of global geodetic systems that could measure distances with high accuracy. As a consequence, a major goal of NASA and solid Earth science in the 1970s was the development of satellite laser ranging (SLR) and very long baseline interferometry (VLBI) techniques to accuracy levels that would enable the scientific problems to be addressed. By the late 1970s, confidence in the viability of these measurement techniques justified initiation of an international, global program. This led to the formation of the NASA Crustal Dynamics Project (CDP) in 1979.

During the 1980s, the CDP and its international partners have made measurements of crustal motion between numerous sites around the world. One of the primary results of this work was to show that the current day motion of the major plates is close to the million year average motion vectors developed from geology. In addition, our knowledge of the distribution of crustal deformation occurring at both transform and subduction plate boundaries was significantly increased; and a new international effort was spawned to monitor the rotational dynamics of the Earth with unprecedented accuracy.

Through improvements in the tracking of satellites, our models of the Earth's gravity field and the ocean tides were dramatically improved.

From: Contributions of Space Geodesy to Geodynamics: Crustal Dynamics, Introduction, D.E. Smith and M. Baltuck

Dynamics of the Solid Earth (DOSE) Investigation

NASA's Solid Earth Sciences Branch identified broad scientific research objectives which required:

  • the improvement of our understanding of the interactions of the solid Earth with the oceans, ground water and atmosphere on time scales of hours to millions of years
  • the local changes in sea level resulting from changes in the Earth's climatic, hydrologic, and tectonic systems
  • the response of the lithosphere to local regional strain and loading and unloading phenomena such as post-seismic and glacial rebound; the evolving landscape as a record of tectonics, volcanism, and climate change during the last two million years
  • the motions and deformations of the lithosphere within the plates and across plate boundaries; the evolution of continents and the structure of the lithosphere
  • the dynamics of the mantle including the driving mechanisms of plate motion ; the dynamics of the core and the origin of the magnetic field
  • the origins and variability of the Earth's gravity field, and
  • the rotational dynamics and reference frames of the planet.

A major emphasis in Dynamics of the Solid Earth (DOSE) for the 1990s was NASA's contribution to the implementation and operation of an international global geophysical network for integrated, comprehensive measurements of many geophysical parameters. This fiducial network incorporates VLBI, SLR, and GPS (GNSS) systems which are operated on a permanent, continuous basis, and which will provide reference geodetic data to which regional studies occupying many sites on a short-term, temporary basis can anchor. Two or more different systems are co-located at many sites to provide strong reference frame ties, strengthen fiducial control, and allow intercomparison of the techniques. The two components of the system can be briefly characterized:

  • Fiducial Laboratories for an International Natural Science Network (FLINN) - a global permanent network of space geodetic stations with approximately 1000 km spacing which integrate GPS (GNSS), VLBI, SLR, and LLR technology to monitor plate motion and deformation, to monitor Earth rotation, and to define and maintain a terrestrial reference frame.
  • Densely Spaced Geodetic Systems (DSGS) - temporary or permanent regional and local monitoring networks deployed across tectonically active regions to measure and analyze motion and deformation over a broad range of spatial and temporal scales.

A total of 54 investigations were selected in response to the DOSE NRA.

From: DOSE NRA, December 1990

2025

2026

  • ION Precise Time and Time Interval Meeting (PTTI), Anaheim, CA, USA, January 26-29
  • IAG International Symposium on Reference Frames for Applications in Geosciences (REFAG2026), Munich, Germany, March 2-4
  • GGOS/IERS Unified Analysis Workshop (UAW2026), Munich, Germany, March 5-6
  • ION Pacific Positioning, Navigation and Timing (PNT) Conference, Honolulu, Hawaii, USA, April 13-16
  • EGU General Assembly 2026, Vienna, Austria, May 3-6
  • FIG Congress 2026, Cape Town, South Africa, May 24-29
  • 46th COSPAR Scientific Assembly, Florence, Italy, August 1-9
  • AOGS 23rd Annual Meeting, Fukuoka, Japan, August 2-7
  • ION GNSS+ 2026, Orlando, FL, USA, September 14-18
  • Tracking and Investigating Geodynamics and Earth Rotation - TIGER Symposium in Geodesy (the 1st symposium of the IAG Commission 3 on Earth Rotation and Geodynamics, in cooperation with the Journees meeting series), Gaevle, Sweden, September 28 - October 1
  • GGOS Topical Meeting on Geohazards, Gaevle, Sweden, October 1-2
  • GGOS Days 2026, Gaevle, Sweden, October 5-7
  • 24th International Workshop on Laser Ranging, Buenos Aires, Argentina, October/November [exact dates TBD]
  • AGU 2026 Fall Meeting, San Francisco, CA, USA, December 7-11

2027

  • EGU General Assembly 2027, Vienna, Austria, April 4-9
  • European Navigation Conference 2025 (ENC 2025), Wroclaw, Poland, May 13-16
  • FIG Working Week 2027, Stavanger, Norway, May 23-27
  • IUGG General Assembly, June, South Korea
  • AOGS 24th Annual Meeting, Singapore, July 25-30
  • XXXIII IAU General Assembly, Rome, Italy, August 10-19
  • IAG Scientific Assembly, Rimini, Italy, September 1-9
  • International Data Week 2027, Cape Town, South Africa, September 20-23
  • ION GNSS+ 2027, Orlando, FL, USA, September 20-24
  • AGU 2027 Fall Meeting, Washington, DC, USA, December 13-17

2028

  • EGU General Assembly 2028, Vienna, Austria, April 23-28
  • FIG Working Week 2028: Celebrating FIG 150 Anniversary, Paris, May/June [exact dates TBD]
  • 47th COSPAR Scientific Assembly, Dubai, UAE, July 8-16
  • ION GNSS+ 2028, Dallas, TX, USA, September 11-15
  • AGU 2028 Fall Meeting, San Diego, CA, USA, December 11-15

2029

  • EGU General Assembly 2029, Vienna, Austria, April 8-13
  • ION GNSS+ 2029, Dallas, TX, USA, September 24-28
  • AGU 2029 Fall Meeting, San Francisco, CA, USA, December

2030

  • EGU General Assembly 2030, Vienna, Austria, April 28 - May 3
  • XXXIV IAU General Assembly, Santiago de Chile, Chile, August [exact dates TBD]
  • AGU 2030 Fall Meeting, December, [TBD]

2024

2023

  • ION Precise Time and Time Interval Meeting (PTTI), Long Beach, CA, USA, January 23-36
  • 2nd EOP Prediction Comparison Campaign Workshop No. 2, Alicante, Spain, March 1-3
  • Munich Satellite Navigation Summit 2023, Munich, Germany, March 13-15
  • EGU General Assembly 2023, Vienna, Austria, April 23-28
  • Twelfth IVS Technical Operations Workshop (TOW 2023), Westford, MA, USA, April 30 - May 4
  • 2023 Joint Conference of the IEEE International Frequency Control Symposium & European Frequency and Time Forum, Toyoma, Japan, May 15-19
  • EUREF 2023 Symposium, Gothenburg, Sweden, May 24-26
  • IEEE GNSS+R 2023, Boulder, CO, USA, May 24-26
  • Technical Seminar on Reference Frames in Practice, Orlando, FL, USA, May 27-28
  • FIG Working Week 2023, Orlando, FL, USA, May 28 - June 1
  • European Navigation Conference 2023 (ENC 2023), Noordwijk, The Netherlands, May 31 - June 2
  • 26th EVGA Working Meeting, Koetzting, Bavaria, Germany, June 11-15
  • 11th European Frequency and Time Seminar, Besancon, France, June 26-30
  • Gaia: The (TWO) Billion Star Galaxy Census: The Magic of Gaia DR3 - Symposium S3 at EAS Annual Meeting, Krakow, Poland, July 10-14
  • 28th IUGG General Assembly, Berlin, Germany, July 11-20
  • Thirteenth Session of the United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM), New York City, NY, USA, August 2-4
  • Journees 2023: Temps et Relativite Generale (Time and General Relativity), Nice, France, September 11-13
  • 2023 DiFX workshop, Socorro, NM, USA, September 11-15
  • ION GNSS+ 2023, Denver, CO, USA, September 11-25
  • First Lunar Laser Ranging Meeting 2023, Calern/Grasse (Alpes-Maritimes), France, September 14-15
  • GGOS Days 2023, Yebes, Spain, September 20-23
  • 17th Meeting of the International Committee on Global Navigation Satellite Systems (ICG-17), Madrid, Spain, October 15-20
  • 2023 GRACE-FO Science Team Meeting, USA, Boulder, CO, USA, October 16-18
  • 2023 ILRS Technical/Specialty Workshop, Arequipa, Peru, October 16-20
  • 20th WEGENER Assembly, Sousse, Tunisia, October 24-27
  • International Symposium on Satellite Navigation (ISSN 2023), Jiaozuo, Henan, China, November 20-22
  • ITU World Radiocommunication Conference 2023 (WRC-23), Dubai, United Arab Emirates, November 20 - December 15
  • DORIS Analysis Working Group Meeting, Saint-Mande, France, November 28-29
  • 2023 Fall Meeting of the American Geophysical Union, San Francisco, CA, USA and online, December 11-15

2022

  • ION PTTI Meeting, Long Beach, California, USA, January 24- 27
  • Tour de l'IGS 3rd Stop: GNSS processing based on IGS products, Virtual, February 17
  • Munich Satellite Navigation Summit 2022 - hybrid, Munich, Germany, March 7-9
  • 4th VLBI Training School, Helsinki, Finland, March 24-26
  • 12th IVS General Meeting - virtual, Helsinki, Finland, 27 March - 1 April
  • ION Pacific Positioning, Navigation and Timing (PNT) Conference - virtual, April 12-14
  • EFTF-IFCS 2022: European Frequency and Time Forum and IEEE International Frequency Control Symposium, Paris, France, April 24-28
  • Tour de l'IGS 4th Stop - virtual, April 25-29
  • EGU General Assembly 2022, Hybrid, Vienna, Austria, May 23-27
  • EUREF 2022 Symposium, Zagreb, Croatia, May 31-June 3
  • AOGS 19th Annual Meeting, Honolulu, Hawaii, USA, June 5-10
  • X Hotine-Marussi Symposium on Mathematical Geodesy, Milan, Italy, June 13-June 17
  • International Data Week 2022 - hybrid, Seoul, South Korea, June 20-23
  • Symposium S12 "Gaia: The (TWO) Billion Star Galaxy Census: The Dawn of Gaia DR3" at EAS 2022, Valencia, Spain, June 27-28
  • IGS Workshop 2022, Virtual, Boulder, Colorado, USA, June 27 - July 1
  • 10th European Frequency and Time Seminar (2022 EFTS), Besancon, France, July 4-8
  • 15th European VLBI Network (EVN) Symposium and Users Meeting, Cork, Ireland, July 11-15
  • 44th COSPAR Scientific Assembly, Athens, Greece, July 16-24
  • ESA/JRC International Summerschool on GNSS, Krakow, Poland, July 18-29
  • AOGS 19th Annual Meeting, Virtual, August 1-5
  • IAU XXXI General Assembly, Hybrid, Busan, Repuplic of Korea, August 2-11
  • Astrometry for 21st Century Astronomy (Focus Meeting 7 at IAU GA XXXI), Busan, Republic of Korea, August 10-11
  • Twelfth Session of the United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM), New York City, USA, August 3-5
  • International Association of Geodesy (IAG): 2nd International Symposium of IAG Commission 4 - Positioning and Applications, Potsdam, Germany, September 5-9
  • Technical Seminar on Reference Frames in Practice, Warsaw, Poland, September 10-11
  • FIG XXVII Congress and General Assembly, Warsaw, Poland, September 11-15
  • 8th International Colloquium on Scientific and Fundamental Aspects of GNSS, Sofia, Bulgaria, September 14-16
  • 9th European Radio Interferometry School (ERIS), Dwingeloo, The Netherlands, September 19-23
  • ION GNSS+ 2022, Denver, CO, USA, September 19-23
  • 16th Meeting of the International Committee on Global Navigation Satellite Systems (ICG-16), Abu Dhabi, United Arab Emirates, October 9-14
  • 2022 GRACE-FO Science Team Meeting, Potsdam, Germany, October 17-21
  • IAG Commission 1 Symposium (REFAG 2022), Thessaloniki, Greece, October 17-21
  • GGOS/IERS Unified Analysis Workshop (UAW) 2022, Thessaloniki, Greece, October 22-25
  • IDS Workshop, Hybrid, Venice, Italy, October 31 - November 2
  • 22nd International Workshop on Laser Ranging, Guadalajara (near Yebes), Spain and Online (Hybrid), November 7-11
  • GGOS Days 2022, Munich, Germany, November 14-18
  • AGU Fall Meeting 2022, Chicago, IL, USA, December 12-16

2021

  • COSPAR 2021, hybrid, 43rd Scientific Assembly, Sydney, Australia, Jan 28 - Feb 04, 2021
  • EGU General Assembly 2021, Vienna, Austria, April 25 - 30, 2021
  • FIG Working Week 2021, Utrecht, Netherlands, June 20 - 24, 2021
  • AOGS 18th Annual Meeting, Singapore, August 01-06, 2021
  • European Navigation Conference 2021 (ENC 2021), Edinburgh, Scotland, UK, November 15 - 18, 2021

2020

  • Chapman Conference on Distributed Volcanism and Distributed Volcanic Hazards, Flagstaff, Arizona, USA, March 16 - 20, 2020
  • GGOS Days 2020, October 5 - 7, Virtual
  • ILRS Virtual World Tour 2020, November 2 -6, 2020
  • AGU 2020 Fall Meeting, San Francisco, CA, December 7 - 11, Virtual

2019

  • ION Precise Time and Time Interval Meeting (PTTI), Reston, VA, USA, January 28-31
  • 24th Working Meeting of the European VLBI Group for Geodesy and Astrometry (EVGA), March 17-19, Las Palmas (Gran Canaria), Spain
  • IDS Analysis Working Group Meeting, Munich, Germany, April 04
  • EGU General Assembly, Vienna, Austria, April 07-12
    • ILRS Analysis Standing Committee meeting, April 6
  • ION Pacific Positioning, Navigation and Timing (PNT) Conference, Honolulu, Hawaii, USA, April 08-11
  • ESLAB #53 Symposium: Gaia, Noordwijk, The Netherlands, April 08-12
  • IGS 2019 Analysis Workshop, Pottsdam, Germany, April 15-17
  • FIG Working Week 2019, Hanoi, Vietnam, April 22-26
  • ESA Living Planet Symposium, Milan, Italy, May 13-17
  • The First LARES 2 and Fourth LARES International Science Workshop in conjunction with The second International GRM Workshop, Rome, Italy, July 01-05
  • 27th IUGG General Assembly, Montreal, Canada, July 08-18
  • AOGS 16th Annual Meeting, Singapore, July 28 - August 02
  • 7th International Colloquium on Scientific and Fundamental Aspects of GNSS, Zurich, Switzerland, September 04-06
  • Unified Analysis Workshop, Paris, France, October 02-04
    • ILRS Analysis Standing Committee (ASC) meeting, Oct. 01
  • Journées 2019: Astrometry, Earth rotation and Reference systems in the Gaia era [On occasion of the centenary of the IAU commission on Earth rotation], Paris, France, October 07-09
  • GRACE-FO Science team Meeting, Pasadena, California, USA, October 08-10
  • 2019 ILRS Technical Workshop, "Laser ranging: To improve economy, performance, and adoption for new applications", Stuttgart, Germany, Oct 21-25
  • OSTST Meeting (Jason 2-3), Chicago, Illinois, USA, Oct 21-25
  • 4th Symposium of the Committee on Space Research (COSPAR), Herzliya, Israel, November 04-08
  • GGOS Days, Rio de Janeiro, Brazil, November 11-14
  • AGU 2019 Fall Meeting, San Francisco, CA, USA, December 09-13

2018

  • 2018 ESIP Winter Meeting, Bethesda, MD, USA, January 9-11
  • ION Precise Time and Time Interval Meeting (PTTI), Reston, VA, USA, January 29 - February 01
  • IGNSS2018, Sydney, Australia, February 07-09
  • European Geosciences Union General Assembly 2018, Vienna, Austria, April 08-13
  • FIG XXVI Congress and General Assembly, Istanbul, Turkey, May 06-11
  • European Navigation Conference, Gothenburg, Sweden, May 14-17
  • AOGS 15th Annual Meeting, Hawaii, USA, June 03-08
  • 0th IVS General Assembly, Longyearbyen, Spitsbergen, Norway, June 03-09
  • IDS AWG meeting, Toulouse, France, June 11
  • Sentinel-3A POD Quality Working Group, Toulouse, France, June 12
  • IDS Governing Board meeting, Toulouse, France, June 13
  • 42nd COSPAR Scientific Assembly, Pasadena, CA, USA, July 14-22
  • 2018 ESIP Summer Meeting, Scripps, Tucson, AZ, USA, July 17-July 20
  • IX International Symposium: "Metrology of Time and Space", September 12-14
  • "25 years of Progress in Radar Altimetry" Symposium, Ponta Delgada, São Miguel Island, Azores Archipelago (Portugal), September 24-29
    • IDS workshop 2018, September 26-28
  • GGOS Days 2018 - Tsukuba, Japan, October 02-04
  • IGS 2018 Workshop, Wuhan, China, October 29 - November 02
  • 21st International Workshop on Laser Ranging, Canberra, Australia, November 04-09
  • AGU 2018 Fall Meeting, Washington, D.C., USA, December 10-14

2017

  • ION Precise Time and Time Interval Meeting (PTTI), Monterey, CA, USA, January 30 - February 02
  • Munich Satellite Navigation Summit 2017, Munich, Germany, March 14-16
  • CryoSat and SWARM Science and Geodetic Missions Workshop, Banff, Alberta, Canada, March 20-24
  • EGU 2017 General Assembly, Vienna, Austria, April 23-28
  • IAU Symposium 330 "Astrometry and Astrophysics in the Gaia sky", Nice, France, April 24-28
  • Ninth IVS Technical Operations Workshop, Westford, MA, USA, April 30 - May 04, 2017
  • European Navigation Conference 2017 (ENC 2017), Lausanne, Switzerland, May 09-12
  • 23rd Working Meeting of the European VLBI Group for Geodesy and Astrometry (EVGA), Gothenburg, Sweden, May 15-19
  • EUREF 2017 Symposium, Wroclaw, Poland, May 17-19
  • Joint JpGU-AGU meeting 2017, Chiba, Japan, May 20-25
  • IDS AWG meeting, London, England, May 22-24
  • Extended Workshop on Space Weather Effects on GNSS Operations, Trieste, Italy, May 22 - June 02
  • FIG Working Week and General Assembly, Helsinki, Finland, May 29 - June 02
  • 21st Meeting of the Consultative Committee for Time and Frequency (CCTF), Sèvres, France, June 06-09
  • 4th IEEE International Workshop on Metrology for Aerospace (MetroAeroSpace 2017), Padua, Italy, June 21-23
  • IGS Workshop 2017, Paris, France, July 03-07
  • IFCS-EFTF 2017: IEEE Frequency Control Symposium and European Frequency, Besancon, France, July 09-13
  • IAG/GGOS/IERS Unified Analysis Workshop (UAW), Paris, France, July 10-12
  • FIG/UN-GGIM-AP/IAG/JFS Technical Seminar on Reference Frames in Practice, Kobe, Japan, July 29-30
  • IAG and IASPEI Joint Scientific Assembly, Kobe, Japan, July 30 - August 04
  • Seventh Session of UN-GGIM, New York City, NY, USA, August 02-04
  • AOGS 14th Annual Meeting, Singapore, August 06-11
  • 2017 International Symposium of Asia-Pacific Space Geodynamics (APSG) Project: From Space Geodesy to Astro-Geodynamics, Shanghai, China, August 15-18
  • URSI General Assembly & Scientific Symposium, Montreal, Canada, August 19-26
  • The science of Gaia and future challenges, Lund, Sweden, August 30 - September 01
  • Journees des Systemes de Reference et de la Rotation Terrestre, Alicante, Spain, September 25-27
  • ION GNSS+ 2017, Portland, OR, USA, September 25-29
  • 2017 ILRS Technical Workshop, Riga, Latvia, October 02-05
  • Jason-2 and -3 Ocean Surface Topography Science Team Meeting, Miami, FL, USA, October 23-27
  • 6th International Colloquium on Scientific and Fundamental Aspects of GNSS / Galileo, Valencia, Spain, October 25-27
  • GGOS Days 2017, Vienna, Austria, October 31-November 02
  • SIRGAS2017 Symposium, Mendoza, Argentina, November 22-December 01
  • Fifth UN-GGIM High Level Forum, Mexico City, Mexico, November 28-30
  • AGU 2017 Fall Meeting, New Orleans, LA, USA, December 11-15

2016

  • ION Precise Time and Time Interval Meeting (PTTI), Monterey, CA, USA, January 25-27
  • IGS Workshop "GNSS Futures", Sydney, NSW, Australia, February 08–12
  • Munich Satellite Navigation Summit 2016, Munich, Germany, March 01-03
  • 2nd IVS Training School for the Next Generation Geodetic and Astrometric VLBI, Hartebeesthoek Radio Observatory, South Africa, March 09-12
  • 9th International VLBI Service for Geodesy and Astrometry (IVS) General Meeting, Ekudeni in Muldersdrift (near Johannesburg), South Africa, March 13-19
  • European Geosciences Union General Assembly 2016, Vienna, Austria, April 17–22
  • Living Planet Symposium 2016, Prague, Czech Republic, May 09-13
  • Celebrating 40 Years of LAGEOS, NASA Goddard Space Flight Center, Greenbelt, MD, USA, May 11
  • EUREF Symposium 2016, San Sebastian, Spain, May 25-27
  • IDS Analysis Working Group meeting, Delft, The Netherlands, May 26-27
  • 2016 European Navigation Conference, Helsinki, Finland, May 30 - June 02
  • European Space Solutions, The Hague, The Netherlands, May 30 - June 03
  • The Science of Time: Time in Astronomy & Astronomy, Past, Present, and Future, Cambridge, MA, USA, June 05-09
  • 18th International Symposium on Geodynamics and Earth Tides, Trieste, Italy, June 05-09
  • 3rd IEEE International Workshop on Metrology for Aerospace (MetroAeroSpace 2016), Florence, Italy, June 22-23
  • On the Threshold of 1st Gaia Data - the Gaia Research for European Astronomy Training (GREAT) Network Science Symposium, Athens, Greece, July 04-06
  • Geodesy, Astronomy and Geophysics in Earth Rotation (GAGER2016) - A Joint IAU/IAG/IERS Symposium, Wuhan, Hubei, China, July 18-23
  • International Symposium on Geodesy and Geodynamics (ISGG 2016), Tianjin, China, July 22-26
  • IAG/CPGPS 1st International Conference on GNSS+ (ICG+2016), Shanghai, China, July 27-30
  • AOGS 13th Annual Meeting, Beijing, China, July 31 - August 05
  • 6th Session of UN-GGIM, New York, NY, USA, August 01-05
  • CODATA-RDA School of Research Data Science, Trieste, Italy, August 01-12
  • IAG Commission 4 "Positioning and Applications" Symposium, Wroclaw, Poland, September 04-07
  • WDS Members' Forum, Denver, Colorado, USA, September 11
  • 18th General Assembly of WEGENER, Ponta Delgada, Portugal, September 12-15
  • IAG Workshop: "Understanding the Earth core and nutation.", Brussels, Belgium, September 19-21
  • International Symposium on Gravity, Geoid and Height Systems 2016 (GGHS2016), Thessaloniki, Greece September 19-23
  • 13th European VLBI Network (EVN) Symposium and Users' Meeting, St. Petersburg, Russia, September 20-23
  • 3rd UN-GGIM Europe Plenary meeting, Budapest, Hungary, October 05
  • First International Workshop on VLBI Observations of Near-field Targets, Bonn, Germany, October 05-06
  • GRACE Science Team Meeting, Potsdam Germany, October 05-07
  • 20th International Workshop on Laser Ranging, Potsdam Germany, October 09-14
  • 5th International VLBI Technology Workshop, Haystack Observatory, Westford, MA, USA, October 12-14
  • Fifth UN-GGIM Asia and the Pacific Plenary Meeting, Kuala Lumpur, Malaysia, October 16-20
  • GGOS Days 2016, Cambridge MA, USA, October 24-28
  • 10th DiFX Users and Developers Meeting, Shanghai, China, October 30 - November 3
  • Ocean Surface Topography Science Team (OSTST) Meeting, La Rochelle, France, October 31 - November 04
  • Gaia 2016 Data Release #1 Workshop, Madrid, Spain, November 02-04
  • 11th Meeting of the International Committee on Global Navigation Satellite Systems (ICG), Sochi, Russia, November 06-11
  • International Navigation Conference (INC2016), Glasgow, United Kingdom, November 08-10
  • SIRGAS Symposium 2016, Quito, Ecuador, November 16-18
  • Gaia Data Workshop, Heidelberg, Germany, November 21-24
  • ISGNSS 2016: International Symposium on GNSS, Tainan, Taiwan, December 05-07
  • International Global Navigation Satellite Systems (IGNSS) 2016, Sydney, Australia, December 06-08
  • 7th Gaia Science Alerts Workshop 2016, Utrecht, The Netherlands, December 07-09
  • 2016 American Geophysical Union Fall meeting, San Francisco, CA, USA, December 12-16

2015

  • 2015 EGU General Assembly, Vienna, Austria, April 12-17
  • GNSS+R 2015 Workshop, Potsdam, Germany, May 11-13
  • European Lunar Symposium, Frascati, Italy, May 12-14
  • 22nd Meeting of the European VLBI Group for Geodesy and Astrometry (EVGA), Sao Miguel, Azores, May 17-21
  • IDS AWG, Toulouse, France, May 28-29, 2015
  • The Third International LARES Science Workshop, Rome, Italy, June 15-17
  • 26th IUGG General Assembly, Prague, Czech Republic, June 22 to July 2
    • IAG Symposium on Reference Frames
  • 1st DEMETRA Workshop, Prague, Czech Republic, July 17, 2015.
  • Fifth Session of the United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM), New York, NY, USA, August 03-07
  • ESA/JRC International Summer School on GNSS, Barcelona, Spain, August 31 - September 10
  • Sixth 2015 European Radio Interferometry School (ERIS2015), Garching, Germany on September 06-10
  • VI International Time Scale Algorithms Symposium and Tutorials, Sevres, France, September 09-11
  • GRACE Science Team Meeting, Austin, Texas, USA, September 21-23
  • IDS DORIS Analysis Working Group meeting, Greenbelt, Maryland, October 15-16
  • OSTST (Jason2-3 Ocean Surface Topography Science Team Meeting), Reston, VA, October 18-23
  • 2015 ILRS Technical Workshop, Matera Italy, October 24-30
  • COSPAR Capacity Building Workshop, Planetary data mission analysis, Guaratinguetá, Brazil, October 26 - November 06
  • 5th International Colloquium on Scientific and Fundamental Aspects of the Galileo Programme, Braunschweig, Germany, October 27 - 29
  • 10th Meeting of the International Committee on Global Navigation Satellite Systems (ICG-10), Boulder, CO, USA, November 01-06
  • 6th Gaia Science Alerts Workshop, November 10-13, Liverpool, UK
  • International Symposium on GNSS (IS-GNSS), Kyoto Japan, November 16-19
  • Simposio SIRGA 2015 y VII Escuela SIRGAS es Sistemas de Referencia, November 16-20, Santo Domingo, Dominican Republic
  • 4th International VLBI Technology Workshop, Auckland, New Zealand, November 23-25
  • International Committee on Global Navigation Satellite Systems, Experts Meeting: Global Navigation Satellite Systems Services, Vienna, Austria, December 15-18
  • 2015 American Geophysical Union Fall Meeting, San Francisco, CA, USA, December 14-18,

2014

  • 8th IVS General Meeting "VGOS: The New VLBI Network", Shanghai, China, March 02-07
  • IDS AWG meeting, CNES HQ, Paris France, March 26-27
  • EGU General Assembly, Vienna Austria, April 28 - May 02
    • IAG Service Review, Technical University of Vienna, April 25
    • GGOS Coordinating Board Meeting, Technical University of Vienna, April 26
    • IGS Governing Board Business Meeting, Technical University of Vienna, April 27
    • ILRS Analysis Working Group Meeting, Technical University of Vienna, April 28
    • ILRS LARGE Study Group Meeting, Technical University of Vienna, April 28
    • GGOS Networks and Communications Bureau Meeting, Technical University of Vienna, April 30
    • GGOS PLATO Working Group Meeting, EGU Splinter Meeting R9, May 01 at GIAC Meeting, Technical University of Vienna, May 01
  • XXV FIG Congress and General Assembly, Kuala Lumpur, Malaysia, June 16-21
  • IGS 20th Anniversary Workshop, Pasadena CA, USA, June 23 - 27
  • International Symposium on Geodesy for Earthquake and Natural Hazards, Matsushima, Japan, July 22-26
  • 40th COSPAR Scientific Assembly, Moscow, Russia, August 02-10
  • European VLBI Network (EVN) Symposium, Cagliari, Sardinia (Italy), October 07-10, 2014
  • IAG Commission 1 Symposium 2014 on Reference Frames for Applications in Geosciences (REFAG2014), Luxembourg, October 13-17
  • SARAL/AltiKa Workshop, Lake Constance, Germany, October 27
  • IDS workshop 2014, Lake Constance, Germany, October 27-28
  • 2014 Ocean Surface Topography Science Team (OSTST) meeting, Lake Constance, Germany, October 28-31
  • 19th International Workshop on Laser Ranging "Celebrating 50 Years of SLR: Looking Back and Planning Forward", Greenbelt, MD, USA, October 27-31
  • Third International VLBI Technology Workshop, Groningen, the Netherlands, November 10-13.
  • Precise Time and Time Interval Conference, Boston , MA, USA, December 01-04
  • AGU Fall Meeting, San Francisco CA, December 15-19
    • GGOS Consortium, December 13, 08:00-12:00
    • GGOS Coordinating Board, December 13, 13:00-18:00
    • IGS Governing Board, December 14, 13:00-18:00
    • IERS, December 14, 08:00-13:00
    • GIAC, December 14, 08:00-12:00
    • GGOS Bureau of Networks and Observations, December 17, 13:00-16:00

2013

  • IVS EGU Training School for VLBI in Geodesy and Astrometry, Helsinki, Finland, March 02-05
  • 21st EVGA Meeting, Helsinki, Finland, March 06-08
  • EGU General Assembly Vienna, Austria, April 07-12
    • ILRS Analysis Working Group Meeting, April 07
  • AGU Meeting of the Americas, Cancun, Mexico, May 14-17
  • Geoscience Union (JpGU) Meeting, Chiba-city, Japan, May 19-24
  • IERS Workshop on Local Surveys and Co-locations, Paris France, May 21-22
  • AOGS 10th Annual Meeting, Brisbane, Australia, June 24-28
  • 2013 Beacon Satellite Symposium, Assembly Rooms, Bath, UK, July 8-12
  • IAG Scientific Assembly, Potsdam, Germany, September 01-06
    • ILRS Analysis Working Group Meeting, September 01
  • ITU/BIPM Workshop on the Future of the International Time Scale, Geneva, September 19-20
  • 2nd International VLBI Technology Workshop, Seogwipo, Jeju Island of South Korea, October 10-12
  • 18th International Workshop on Laser Ranging, Fujiyoshida, Japan, November 11-15
  • AGU Fall Meeting, San Francisco CA, December 09-13

EGM96 is a geopotential model of Earth consisting of spherical harmonic coefficients complete to degree and order 360. It is a composite solution, consisting of: a combination solution to degree and order 70; a block diagonal solution from degree 71 to 359; and the quadrature solution at degree 360. The EGM96 model is the result of a collaboration between the National Geospatial Intelligence Agency (NGA, formerly known as the National Imagery and Mapping Agency/NIMA), NASA's Goddard Space Flight Center, and the Ohio State University.

The major reference for this model is NASA/TP-1998-206861.

How to Cite EGM96

Please use the following citation when referencing EGM96:

The Development of the Joint NASA GSFC and NIMA Geopotential Model EGM96, F. G. Lemoine, S. C. Kenyon, J. K. Factor, R.G. Trimmer, N. K. Pavlis, D. S. Chinn, C. M. Cox, S. M. Klosko, S. B. Luthcke, M. H. Torrence, Y. M. Wang, R. G. Williamson, E. C. Pavlis, R. H. Rapp and T. R. Olson, NASA Goddard Space Flight Center, Greenbelt, Maryland, 20771 USA, July 1998.

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1998

Journal Articles

2019

  • Pearlman, M., Noll C., Pavlis E., Lemoine F., Combrink L., Degnan J., Kirchner G., Schreiber U., The ILRS: approaching twenty years and planning for the future, Journal of Geodesy, 2019, DOI: https://doi.org/10.1007/s00190-019-01241-1
  • Noll, C.E., Ricklefs, R., Horvath, J. et al., Information Resources Supporting Scientific Research for the International Laser Ranging Service, J Geod (2018). https://doi.org/10.1007/s00190-018-1207-2

2018

  • McGarry, J.F., Hoffman, E.D., Degnan, J.J. et al., NASA’s satellite laser ranging systems for the twenty-first century, J Geod (2018). doi: https://doi.org/10.1007/s00190-018-1191-6
  • Merkowitz, S.M., Bolotin, S., Elosegui, P. et al., Modernizing and expanding the NASA Space Geodesy Network to meet future geodetic requirements, J Geod (2018), doi: https://doi.org/10.1007/s00190-018-1204-5
  • Noll, C., Ricklefs, R., Horvath, J., Mueller, H., Schwatke, C., Torrence, M., Information resources supporting scientific research for the international laser ranging service, Journal of Geodesy, 2018, DOI: https://doi.org/10.1007/s00190-018-1207-2

2017

  • O. Montenbruck, P. Steigenberger, L. Prange, Z. Deng, Q. Zhao, F. Perosanz, I. Romero, C. Noll, A. Stürze, G. Weber, R. Schmid, K. MacLeod, S. Schaer, The Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS) – Achievements, Prospects and Challenges, Advances in Space Research, Available online 17 January 2017, DOI: 10.1016/j.asr.2017.01.011

2010

2009

2007

2006

Technical Papers

2016

2015

  • A. Nothnagel, International VLBI Service for Geodesy and Astrometry (IVS); 2015: The IVS data input to ITRF2014. International VLBI Service for Geodesy and Astrometry, GFZ Data Services. http://doi.org/10.5880/GFZ.1.1.2015.002

2014

2007

  • C. Noll, Pearlman, M. (Eds.). International Laser Ranging Service 2005-2006 Report. NASA Technical Paper NASA/TP-2007-214153. Washington, D.C : National Aeronautics and Space Administration, 2007.
  • M. Pearlman, C. Noll, W. Gurtner, and R. Noomen, The International Laser Ranging Service and its Support for GGOS, Dynamic Planet - Monitoring and Understanding a Dynamic Planet with Geodetic and Oceanographic Tools. Rizos, C., Tregoning, P. (Eds.), IAG Symposia 130, ISBN: 978-3-540-49349-5, 2007.
  • M. Pearlman, Z. Altamimi, N. Beck, R. Forsberg, W. Gurtner, S. Kenyon, D. Behrend, F.G. Lemoine, C. Ma, C.E. Noll, E.C. Pavlis, Z. Malkin, A.W. Moore, F.H. Webb, R.E. Neilan, J.C. Ries, M. Rothacher, and P. Willis, GGOS Working Group on Networks, Communication, and Infrastructure, Dynamic Planet - Monitoring and Understanding a Dynamic Planet with Geodetic and Oceanographic Tools. Rizos, C., Tregoning, P. (Eds.) , IAG Symposia 130, ISBN: 978-3-540-49349-5, 2007.

2006

  • C. Noll, CDDIS Brochure, 2006.
  • A. Moore, C. Bruyninx, C. Noll, M. Scharber, "IGS Network & Data Center Position Paper, Darmstadt Workshop – May 2006" (PDF paper | .3 MB), at IGS 2006 Workshop, Darmstadt, Germany, May, 2006.

2005

  • M. Pearlman, C. Noll, W. Gurtner, R. Noomen, "The International Laser Ranging Service and its Support for GGOS" (PDF paper .4 MB), at Dynamic Planet 2005, Cairns Australia, August 2005.
  • M. Pearlman, et al, "GGOS Working Group on Ground Networks and Communication" (PDF paper .4 MB), at Dynamic Planet 2005, Cairns Australia, August 2005.

2002

2000

  • "Current Status of and Backup Plans for Flow of IGS Data and Products" (PDF paper), at IGS Network Workshop, Oslo, Norway, July 2000.
  • "The IGS Global Data Center at the CDDIS -- An Update" (PDF paper), at IGS Network Workshop, Oslo, Norway, July 2000.
  • "DORIS Data Center at the CDDIS" (PDFpaper), in DORIS Days 2000, Toulouse, France, May 2000.

1999

  • "IGEX-98 Data Flow" (PDF paper) in Proceedings from IGEX-98 Workshop, Nashville, TN, September, 1999.
  • "The IGEX Data Center at the CDDIS" (PDF paper) in Proceedings from IGEX-98 Workshop, Nashville, TN, September, 1999.

1998

  • "Data Center Issues", (PDF) position paper in Proceedings from IGS Network Systems Workshop
  • "Recent Enhancements of the CDDIS" (PDF summary) in Proceedings from IGS Network Systems Workshop

1997

  • "Flow of GPS Data and Products for the IGS, (PDF) presented at the IGS-PSMSL Workshop on Methods for Monitoring Sea Level, March 1997.

1996

  • "Flow, Archiving, and Distribution of Global GPS Data and Products for the IGS and the Role of the Crustal Dynamics Data Information System (CDDIS)" (PDF paper), presented at the Workshop on Improving the DGPS Infrastructure for Earth and Atmospheric Science Applications, March 1996.

1995

Technical Reports/Other

2018

  • "CDDIS Global Data Center Technical Report 2019" (PDF) in 2019 IGS Technical Report

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

  • "IDS Data Flow Coordination and CDDIS Data Center Report" (PDF) in 2005 IDS Annual Report
  • "CDDIS Data Center Summary for the 2005 IVS Annual Report" (PDF), in 2005 IVS Annual Report.

2004

2003

  • "CDDIS Data Center Summary for the 2003 IVS Annual Report" (PDF), in 2003 IVS Annual Report
  • "CDDIS Summary for the 2003 LTP Annual Report" (PDF), in 2003 LTP Annual Report

2002

  • "CDDIS Data Center Summary for the 2002 IVS Annual Report" (PDF), in 2002 IVS Annual Report
  • "CDDIS Global Data Center Report" (PDF), submitted to 2002 IGS Technical Report
  • "IGS Data Center Report" (PDF), in 2002 IGS Annual Report
  • "CDDIS Summary for the 2002 LTP Annual Report" (PDF), in 2002 LTP Annual Report

2001

2000

1999

1998

1997

1996

  • "CDDIS Global Data Center Report" (PDF), in 1996 IGS Technical Reports

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