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Overview

Satellite Laser Ranging (SLR) and Lunar Laser Ranging (LLR) use short-pulse lasers and state-of-the-art optical receivers and timing electronics to measure the two-way time of flight (and hence distance) from ground stations to retroreflector arrays on Earth orbiting satellites and the Moon. Scientific products derived using SLR and LLR data include precise geocentric positions and motions of ground stations, satellite orbits, components of Earth’s gravity field and their temporal variations, Earth Orientation Parameters (EOP), precise lunar ephemerides and information about the internal structure of the Moon. Laser ranging systems are already measuring the one-way distance to remote optical receivers in space and can perform very accurate time transfer between sites far apart. Laser ranging activities are organized under the International Laser Ranging Service (ILRS) which provides global satellite and lunar laser ranging data and their derived data products to support research in geodesy, geophysics, Lunar science, and fundamental constants. This includes data products that are fundamental to the International Terrestrial Reference Frame (ITRF), which is established and maintained by the International Earth Rotation and Reference Systems Service (IERS). The ILRS develops the necessary global standards/specifications for laser ranging activities and encourages international adherence to its conventions.

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Highlights

The SLR-tailored version of ITRF2020, the SLRF2020, has been released to the publicRelease Date: 07/25/2023 The long-awaited SLR-tailored version of ITRF2020, the SLRF2020, has been released to the public, along with the associated Data Handling File required for proper and accurate reduction of SLR data. Both files contain notes that are important to users, especially to those requiring the highest quality results in their work; it is imperative that users read these notes before implementing the new TRF in their production lines.

The two files can be accessed from the ILRS website pages:

https://ilrs.gsfc.nasa.gov/science/dataAnalysisResources/index.html
https://ilrs.gsfc.nasa.gov/network/site_information/index.html

CDDIS Landing pages with the appropriate DOIs are here:

https://cddis.nasa.gov/Data_and_Derived_Products/SLR/slrf_2020.html
https://cddis.nasa.gov/Data_and_Derived_Products/SLR/slrf_2020_DHF.html

First Lunar Laser Ranging (LLR) Meeting, September 14^th and 15^th, 2023, Pole Astronomie Géoazur, Observatoire de la Côte d'Azur (OCA), CNRS - INSU, Université Côte d'Azur (UCA), France Release Date: 05/10/2023 The first LLR meeting wishes to bring both the producers, the users and the science behind lunar laser ranging together in order to join efforts and resources, to define goals and enhance the visibility for a LLR community, and to identify synergies and to plan for the future. The goal is to encourage every group to help and form a visible global community.

Clément Courde
courde@geoazur.unice.fr

Julien Chabé
chabe@geoazur.unice.fr

SLR & DORIS Support the Discovery of 19,000 Undersea Volcanos Using Satellite AltimetryRelease Date: 04/21/2023

A team of scientists has published a new catalog of undersea volcanos, or seamounts, that are derived using ocean radar altimetry data from the satellites Jason-1, Envisat CryoSat-2, and Saral/AltiKa. The altimeter data for this study were obtained primarily from the geodetic missions for these satellites. In the geodetic missions, the satellites flew so that successive ground tracks were aligned close together. This facilitated the mapping of the ocean geoid.The data from these most recent satellite missions have improved the ability to find previously undetected seamounts, from how the mass of the seamounts perturbs the shape of the ocean surface.

The new map will aid studies of marine tectonics, geology, ecology and ocean mixing.

This discovery was supported by Precise Orbit Determination (POD), including Satellite Laser Ranging (SLR), and DORIS for Jason-1, Envisat, CryoSat-2, and Saral/ALtiKa whose altimeter data contributed to the results of this new study.

More information:
Overview article in Science magazine, April 19, 2023:
https://www.science.org/content/article/it-s-just-mind-boggling-more-19-000-undersea-volcanoes-discovered

Scientific publication, published March 20, 2023:
Gevorgian J., Sandwell D., Yu Y., Kim S.-S. and Wessel P. (2023). "Global distribution and morphology of small seamounts". Earth and Space Science, 10, e2022EA002331.
https://doi.org/10.1029/2022EA002331

Updated list of Conferences and workshops related to earth rotation, reference frames, geophysical fluids, GNSS, SLR, VLBI, DORIS, etc. posted by the IERS

More news...

Recent News

IUGG/IAG News - During the recent International Union of Geodesy and Geophysics (IUGG) held in Berlin, Germany, at the International Association of Geodesy (IAG) Closing Session, Dr. Graham Appleby and Dr. Toshimichi Otsubo, both former ILRS GB Chairs, were inducted as 2023 Fellows of the IAG.

Dr. Vincenza Luceri, Chair of the ILRS Analysis Center Standing Committee, was elected as a member of the IAG Executive Committee for the 2023-2027 Term.

Our congratulations to all three, and our thanks for their continued contribution to the IAG and the geodetic community.

The SLR-tailored version of ITRF2020, the SLRF2020, has been released to the public - The long-awaited SLR-tailored version of ITRF2020, the SLRF2020, has been released to the public, along with the associated Data Handling File required for proper and accurate reduction of SLR data. Both files contain notes that are important to users, especially to those requiring the highest quality results in their work; it is imperative that users read these notes before implementing the new TRF in their production lines.

The two files can be accessed from the ILRS website pages:

https://ilrs.gsfc.nasa.gov/science/dataAnalysisResources/index.html
https://ilrs.gsfc.nasa.gov/network/site_information/index.html

CDDIS Landing pages with the appropriate DOIs are here:

https://cddis.nasa.gov/Data_and_Derived_Products/SLR/slrf_2020.html
https://cddis.nasa.gov/Data_and_Derived_Products/SLR/slrf_2020_DHF.html

Journal article on ITRF2020 published by the Journal of Geodesy -

The journal article full citation is:

Altamimi, Z., Rebischung, P., Collilieux, X., Métivier L., Chanard K. (2023). "ITRF2020: an augmented reference frame refining the modeling of nonlinear station motions". Journal of Geodesy, 97, 47. https://doi.org/10.1007/s00190-023-01738-w

The SLR contribution to ITRF2020 consists of 244 fortnightly SINEX solutions for 1983.0—1993.0, based on LAGEOS-1, and 1459 weekly solutions afterwards based on the LAGEOS 1 & 2 and ETALON 1 & 2 satellites. The paper acknowledges the contributions of the Geodetic Observatories and stations, the funding agencies, mapping agencies and space agencies that support space geodesy, and the IAG technique services (including the ILRS) for their contributions.

Read more...

First Lunar Laser Ranging (LLR) Meeting, September 14^th and 15^th, 2023, Pole Astronomie Géoazur, Observatoire de la Côte d'Azur (OCA), CNRS - INSU, Université Côte d'Azur (UCA), France - The first LLR meeting wishes to bring both the producers, the users and the science behind lunar laser ranging together in order to join efforts and resources, to define goals and enhance the visibility for a LLR community, and to identify synergies and to plan for the future. The goal is to encourage every group to help and form a visible global community.

Clément Courde
courde@geoazur.unice.fr

Julien Chabé
chabe@geoazur.unice.fr

Meetings

Journees 2023: Temps et Relativite Generale (Time and General Relativity), Nice, France, September 11-13, 2023

2023 DiFX workshop, Socorro, NM, USA, September 11-15, 2023

ION GNSS+ 2023, Denver, CO, USA, September 11-25, 2023

Publications

2016-2019 ILRS Report

Proceedings from the 19th International Workshop on Laser Ranging

International Laser Ranging Service

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