International Laser Ranging Service

Recent News

This page contains all recent ILRS news. For those interested in news specific to satellite missions, please visit our Mission News page.

2023 Virtual International Workshop on Laser RangingRelease Date: 09/27/2023 The 2023 Virtual International Workshop on Laser Ranging will take place during the week of October 16th-20th, 2023. This year, due to unforeseen circumstances, we are not able to hold the Specialized International Workshop on Laser Raging in Arequipa, Peru as planned. However, we do think it will be advantageous to give the community an opportunity to get together to discuss updates on pertinent topics, and exchange ideas. Sessions are being organized primarily around invited talks, but presentations on new concepts and new technologies are welcome.

The Workshop's Theme is "New Developments in Satellite Laser Ranging", and it will be focused on new materials and new results.

Program Organizing Committee:
Michael Pearlman, ILRS Central Bureau Director
Claudia Carabajal, ILRS Central Bureau Secretary
Matt Wilkinson, Networks and Engineering Standing Committee Co-Chair
José Rodriguez, Missions Standing Committee Co-Chair
Robert Sherwood, Missions Standing Committee Co-Chair
Michael Steindorfer, Space Debris Study Group Chair
Emiliano Cordelli, European Space Agency (ESA) Space Debris Study Group
Clément Courde, LLR and Transponders Standing Committee Chair
Nicholas Colmenares, LLR and Transponders Standing Committee
Stephen Merkowitz, LLR and Transponders Standing Committee
Mathis Blossfeld, Analysis Standing Committee Co-Chair
David Sarrocco, Analysis Standing Committee
Frank Lemoine, NASA ILRS Central Bureau
Jeff Dorman, NASA Networks Manager

Program topics will include Missions & Applications, New technology/Systems and Operations, Analysis, including available analysis tools, error modeling, etc., Space Debris and Lunar Laser Ranging (LLR) and Transponders.

There are no registration fees.
Participants interested in presenting should register by September 29th, 2023.
Non-Presenters' Registrations will be accepted until October 6th, 2023.

Details on the Program will be published at a later date, as the sessions are being organized. Invitations for the Virtual Sessions using Microsoft Teams will be sent to registrants.

Visit the 2023 Virtual IWLR Website for updates: https://ilrs.gsfc.nasa.gov/lw23/index.html

Film titled "Terrestrial Reference Frames --- Connecting the World Through Geodesy" releasedRelease Date: 09/12/2023 The Global Geodetic Observing System (GGOS) Coordinating Office, together with the International Association of Geodesy (IAG) have released a new educational film, titled "Terrestrial Reference Frames --- Connecting the World Through Geodesy", which shows the great importance of the International Terrestrial Reference Frame (ITRF) for society. The film is available in English, Spanish, Portuguese, French, German, Japanese, Dutch and Bulgarian. Many colleagues of the geodetic services contributed to this video led by Zuheir Altamimi (IGN, France), Allison Craddock (NASA Jet Propulsion Laboratory, USA), & Martin Sehnal (Federal Office of Metrology and Surveying (BEV), Austria).

Terrestrial Reference Frames film - You Tube link: https://bit.ly/trf-film

Please share this video with your colleagues, friends and family and on social media to highlight the work of the geodetic services, including the International Laser Ranging Service (ILRS) on the definition of the International Terrestrial Reference Frame (ITRF).

IUGG/IAG NewsRelease Date: 08/01/2023 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 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

Journal article on ITRF2020 published by the Journal of Geodesy Release Date: 06/22/2023 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.

"The International Terrestrial Reference Frame (ITRF) is the result of a global collaboration of hundreds of institutions around the worlds: from the build-up of geodetic observatories, satellite missions, data collection, analysis and combination, to the ITRF generation, thanks to the investment of national mapping agencies, space agencies and universities. We are indebted to all Analysis and Combination Centers of the IAG Technique Services of the four techniques who constantly provide data for ITRF solutions which would not exist without their valuable contributions."

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

Opening ceremony held at the SLR Station in Tsukuba, Japan (ID: 7306, Code: TKBL)Release Date: 04/06/2023 Shinichi Nakamura, the manager of the new JAXA Tsukuba SLR station reports that the development phase has been completed. The new SLR station is located in Tsukuba, southern Ibaraki Prefecture, about 50 km from central Tokyo. JAXA held the opening ceremony of the station on March 30, 2023. A total of 36 people attended the ceremony, including representatives of the Japanese Coast Guard, Hitotsubashi University, the University of Tokyo, the JAXA director, and many JAXA satellite project managers. Dr. Stephen Merkowitz, Chair of the ILRS Governing Board, gave a congratulatory speech on the opening of the station, which added to the festivities. With the guidance of the ILRS, the SLR Tsukuba station was assigned the station ID: 7306, and Code: TKBL. The JAXA Tsukuba station staff are proud that the new station will be a member of the ILRS network and look forward to contributing to space development and science through SLR operations. In April, 2023, trial operation will be held to familiarize JAXA staff and full operation is scheduled to start in May 2023.

The ILRS congratulates the JAXA team on the commissioning of this new SLR station.

Removal of Satellite Daily and Hourly Files older than 6 months - data holdings clean-upRelease Date: 03/31/2023 Dear ILRS Community,

The CDDIS has been working to provide clarity to new users of the archive and to reduce redundant data. With this effort, the CDDIS plans to take the following steps over the next few weeks:

1. Remove satellite daily and allsat hourly files older than 6 months. The data will still be available in satellite monthly and allsat daily files.
2. Move format transition data files to the quarantine directory. Specifically, CRD V1 data prior to May 1, 2012 and after August 1, 2022 will be moved to quarantine.
3. Removal of corrupt FRD Files; these files will be removed and not replaced:
   
   
   • allsat_20120510.frd
   • allsat_20120518.frd
   • allsat_20120528.frd
   • allsat_20150827.frd.gz
   • allsat_20151102.frd.gz
   • allsat_20151122.frd.gz
   • allsat_20151221.frd.gz
   • allsat_20151230.frd.gz
   • ajisai_20151130.frd.gz
   • ajisai_20151207.frd.gz

Please let us know if you have any questions about these changes. Thank you!

Justine Woo (she/her)
SLR Operations, Software Development
Crustal Dynamics Data Information System (CDDIS)
NASA GSFC, Code 61A
Greenbelt, MD 20771, USA
justine.y.woo@nasa.gov

22^nd International Workshop on Laser Ranging (IWLR) in Guadalajara, Spain - November 7-11, 2022 - Session Videos Available for viewingRelease Date: 03/03/2023 We are pleased to announce that the recordings for the 22^nd International Workshop on Laser Ranging (IWLR) held in Guadalajara, Spain, are available for viewing. This is the first time that a full ILRS workshop is made available in video. This, together with the ILRS Virtual World Tours 2020 and 2021, all the events organized by the ILRS in the last three years are publicly accessible to everyone.

The 22^nd IWLR was organized by the Observatory of Yebes, the National Geographic Institute of Spain (IGN/CNIG), and the ILRS. Over 170 delegates from 20 different countries participated in the conference, which took place on 7–11 November 2022. With the theme "Reconnecting the ILRS community", this event was for the first time in a hybrid in person/online format. The conference was a great opportunity for the experts in the various SLR-related fields to meet, discuss, and exchange ideas and new developments.

The video recordings of the conference include the talks from all the 10 Main Sessions; the presentations kindly given by the invited speakers; and the meetings of the ILRS Standing Committees on Data Formats & Proceedings, Networks & Engineering, and Missions. The Opening and Closing sessions, including the SLR Pioneers Awards, are all available for viewing as well.

You can access the recording here: https://www.youtube.com/@22ndIWLR

We thank the Local Organizing Committee for making and sharing the recordings of the conference possible.

"Leaders in Lidar" Video Series Release Date: 02/03/2023 For those interested in the Legacy of Goddard's lead role in laser altimetry, you can view the recently released "Leaders in Lidar" Series (All Episodes – Youtube).
"In this series, we dive into the legacy of Goddard's lead role in developing laser altimetry, which has revolutionized the way we map our planet, the Moon and other planets. Each chapter looks at the successes and failures of these lidar instruments, beginning with the Mars Observer Laser Altimeter in the late 1980s, through the current generation of laser altimeters on ICESat-2 and GEDI. Through dozens of interviews and archival footage, the history, challenges and legacy of lidar are uncovered."
https://www.youtube.com/watch?v=w06s8x-0smE

Announcing the 2023-2024 ILRS Governing BoardRelease Date: 02/03/2023 Elections for the 2023-2024 ILRS Governing Board (GB) concluded in December of 2022.
The new ILRS GB took office on January 01, 2023

These are the eighteen members of the Board

Newly elected ILRS GB Chairperson: Stephen Merkowitz (NASA/GSFC, USA)

Four ex-officio/appointed members of the Board:
Director of the Central Bureau - Mike Pearlman (Harvard U., USA)
Secretary of the Central Bureau - Claudia Carabajal (SSAI @ NASA/GSFC, USA)
Representative of IAG Commission - Urs Hugentobler (TUM, Germany)
IERS Representative - Daniela Thaller (BKG, Germany)

Twelve elected members of the Board:
EUROLAS Network Representatives - Sven Bauer (DIGOS, Germany), Jose Rodriquez (Yebes Observatory, IGN, Spain)
NASA Network Representatives - Evan Hoffman (NASA/GSFC, USA), Stephen Merkowitz (NASA/GSFC, USA)
WPLTN Representatives - James Bennett (EOS Space Systems Pty. Ltd., Australia), Zhang Zhongping (SHAO, China)
Data Center Representative – Justine Woo (SSAI @ NASA/GSFC, USA)
LLR Representative – Clément Courde (Geoazur, France)
Analysis Representatives – Vincenza Luceri (E-GOST, Italy), Mathis Blossfeld (TUM, Germany)
At-Large Representatives – Matthew Wilkinson (NERC/NSGF, UK), Christian Schwatke (TUM, Germany)

Two appointed At-Large Representatives of the Board:
Randall Carman (Geoscience Australia), Takehiro Matsumoto (JAXA, Japan)

Congratulations to all those elected!

We thank Toshimichi Otsubo for his dedication as the ILRS GB Chair for the 2021-2022 term.
We also thank all previous members of the ILRS GB for your service to the ILRS.
We look forward to your continued participation on ILRS activities and Workshops, Standing Committees and Study Groups.

Data centers ceased accepting CRD and CPF Format V1 files January 1, 2023Release Date: 01/25/2023 The ILRS DF&PSC announced at the International Workshop on Laser Ranging (IWLR) that the data centers would cease accepting CRD and CPF Format V1 files beginning January 1, 2023. The CPF files transitioned from version 1 to version 2 on March 1, 2022 and CRD files transitioned from version 1 to version 2 on August 1, 2022. If you have not had the chance to change over your scripts, please find the new files available at:

NASA Delivers First Flight Hardware to ESA for Lunar PathfinderRelease Date: 12/02/2022 NASA delivered the first flight hardware for the Lunar Pathfinder mission to ESA (European Space Agency), which formally accepted the instrument on Nov. 4. NASA's Goddard Space Flight Center in Greenbelt, Maryland, developed the instrument, a laser retroreflector array, which will test new navigation techniques for lunar missions.

NASA and ESA plan to launch Lunar Pathfinder via a future Commercial Lunar Payload Services delivery. In addition to testing navigation capabilities, Lunar Pathfinder will operate as a commercial communications relay satellite and provide communications services for exploration missions on the lunar surface.

The Lunar Pathfinder mission is led by Surrey Satellite Technology Ltd (SSTL), and ESA arranged for the mission to provide communications services to NASA. NASA Space Geodesy Project Manager Stephen Merkowitz, along with teams from ESA and SSTL, completed inspections when the laser retroreflector array arrived at SSTL's facility in Guildford, U.K., where it will be installed in the satellite.

Read more on nasa.gov

Pioneer Awards presented at the 22^nd IWLR in Guadalajara, SpainRelease Date: 12/02/2022

Ron Noomen - "In recognition of his pioneering scientific achievements ranging from the WEGENER campaign to the first ILRS combination products"

Dr. Jean-Marie Torre - "In recognition of his achievements and efforts in enhancing the productivity of precise lunar laser ranging and contributions to challenging space missions"

Dr. Graham Appleby - "In recognition of his pursuit of the single-photon regime to improve measurement accuracy and geodetic parameters"

22^nd International Workshop on Laser Ranging (IWLR): Reconnecting the ILRS CommunityRelease Date: 12/02/2022

The 22^nd International Workshop on Laser Ranging took place in Guadalajara, Spain, November 7-11, 2022, hosted by the Yebes Observatory, the National Geographic Institute of Spain (IGN), with the support of National Centre for Geographic Information (CNIG), and in collaboration with the International Laser Ranging Service (ILRS). Being the first in-person ILRS meeting since the start of the COVID-19 pandemic, the theme of the meeting was "Reconnecting the ILRS community". In person and online attendees participated in an exciting program, which included sessions on ILRS Contributions to Earth Orientation Parameters (EOP); Laser Ranging Applications to Precision Orbit Determination (POD); Science Applications of Satellite Laser Ranging (SLR); Errors in SLR detection, mitigation, and modeling; Current and Future Missions; Ground Networks and Operations; Space Debris, Technology and Developments, and New Applications; and Lunar Laser Ranging and Deep Space. Participation in the workshop included 170 delegates from 20 different countries, and approximately 30-40 persons attending online each day from throughout the world, with 77 oral talks and 32 posters presented. Invited talks were given by Dr. Nick Brown (Geosciences Australia), Dr. Pablo de Vicente (Yebes Observatory, IGN/CNIG, Spain), Dr. Rüdiger Haas (University of Technology, Onsala Space Observatory, Sweden), and Dr. Tim Flohrer (ESOC, European Space Agency). The program included a visit to Yebes Observatory with a tour of the facilities, including the new Satellite Laser Ranging (SLR) station at Yebes, set to become operational in 2023. Ron Noomen (TU Delft, The Netherlands), Jean-Marie Torre (Observatoire de la Côte d'Azur, France) and Graham Appleby (Herstmonceux Geodetic Observatory, U.K.) were presented with ILRS Pioneer Awards. Stephen Merkowitz (NASA Goddard Space Flight Center, U.S.A.) was elected as the Chairperson of the ILRS Governing Board (GB) for the period 2023-2024.

Splinter meetings for the ILRS Governing Board, Analysis, Missions, Networks and Engineering Special Committees, the Transponders & Lunar Laser Ranging and Space Debris Study Groups were also held, and reports presented.

https://congreso-yebes.ign.es/web/portal/home

22^nd International Workshop on Laser Ranging, Guadalajara, Spain, November 7-11, 2022. (Photos credit: 22nd IWLR Local Organizing Committee, Claudia Carabajal, SSAI/NASA.)

22^nd International Workshop on Laser Ranging, Guadalajara, Spain, November 7-11, 2022. Visit to the Yebes Observatory, Spain. (Photos credit: Claudia Carabajal, SSAI/NASA)

50-year anniversary of Wettzell ObservatoryRelease Date: 10/14/2022 Since 1972, various stages of geodetic instrumentation have been introduced to Wettzell (Germany) which is today regarded as the best-equipped geodetic observatory in the world. BKG and TUM jointly celebrated their 50 years milestone on 7 Oct 2022, with about 100 attendees from Germany and foreign countries. A series of welcome notes and talks were presented by the hosts, the local politicians, government representatives and the IAG Services. Congratulations!

Transition to CRD V2 formatRelease Date: 08/16/2022 The ILRS CB and ILRS DF&PSC announced in June that the transition from the Consolidated laser Ranging Data (CRD) format version 1 to version 2 was to occur on August 1, 2022. This transition has occurred and CRD v2 data can be downloaded from the desired data center:

NASA CDDIS:

Users who have not transitioned should do so immediately. Although we have requested that stations continue to provide data in the old and new formats for a limited time longer, we cannot guarantee their compliance.

Successful Launch of LARES-2 – 13 July 2022 at 13:13:17 UTCRelease Date: 07/15/2022 LARES-2 was successfully launched from Kourou, FR Guiana, on July 13, 2022, at 13:13 UTC on the inaugural VEGA-C launch VV21. It was inserted in the designed orbit (without spin!) about an hour and a half later. Following the lucky tradition set by LARES in 2012, the launch date was picked again to be the 13th of the month! The release was done over Yarragadee; as soon as ESA provides initial elements, CPF prediction files will be generated and delivered to ILRS. Following that we will wait to hear which of our systems will get it first!

https://www.nasaspaceflight.com/2022/07/vega-c-debut-launch/

For those who missed the launch, you can see the entire program on ESA WEB YouTube channel:

English: https://www.youtube.com/watch?v=sJTm-3QxDQc

French: https://www.youtube.com/watch?v=XnijRbDBxZE

Below is a picture of the moment LARES-2 is released:

The Second LARES 2 and fifth LARES International Science WorkshopRelease Date: 05/26/2022 Rome, Italy, May 31 –June 3 , 2022
General Relativity, Time and Time Travel in General Relativity, Space Research and John Archibald Wheeler.
Preliminary list of invited speakers: Kip Thorne (Caltech), Roger Penrose (Oxford University) and Igor Novikov (Lebedev Institute)

View program.

ESA Lunar Pathfinder mission to include Lunar Laser RangingRelease Date: 04/28/2022 The European Space Agency (ESA) announced that a test version of unique satellite navigation receiver has been delivered for the Lunar Pathfinder spacecraft, scheduled for launch in 2024. The receiver will receive GNSS-signals from the Galileo and GPS constellations for position, navigation and timing around the Moon. The Lunar Pathfinder spacecraft will also carry a laser retroreflector array for lunar laser ranging, and an X-Band transponder for ranging and communications using conventional deep space tracking facilities.

The laser retroreflector array on Lunar Pathfinder will be an evolution of the retroreflector array designed for NASA's Lunar Reconnaissance Orbiter (LRO). The LRO retroreflector array is a 15 × 18 × 5 cm, 650-g array of twelve 32-mm diameter solid corner cubes mounted on the LRO anti-nadir deck. In 2020, NASA scientists and colleagues from the ILRS station at Grasse, France, conducted successful two-way laser ranging to the LRO spacecraft.

Lunar Pathfinder will relay signals from lunar orbital and lunar surface missions, and provide navigation information for lunar orbiting and surface assets. The Lunar Pathfinder spacecraft is being built by SSTL (Surrey Satellite Technology Limited) in the U.K.

Link for ESA news story: https://www.esa.int/Applications/Navigation/The_Moon_where_no_satnav_has_gone_before

Description of Lunar Laser Ranging to NASA's Lunar Reconnaissance Orbiter (LRO)
Mazarico E., Sun X., Torre JM. et al (2020). "First two-way laser ranging to a lunar orbiter: infrared observations from the Grasse station to LRO's retro-reflector array". Earth Planets Space 72, 113. doi:10.1186/s40623-020-01243-w

GGOS Coordinating Office Develops Film to Promote GeodesyRelease Date: 04/28/2022 The Global Geodetic Observing System (GGOS) Coordinating Office has helped to organize a general ∼8 minute video that explains geodesy, the geodetic observations and products that are available from the different IAG services, and the benefits of geodesy to science and society.

The GGOS video so far is available in English, Spanish, German, French & Japanese.

Contributors included Allison Craddock (IGS, NASA/JPL, USA), Detlef Angermann (GGOS, TU München, Germany), Basara Miyahara (GGOS, Geospatial Information Authority of Japan), Laura Sánchez (GGOS, TU München, Germany), Martin Sehnal (GGOS, BEV Federal Office of Metrology and Surveying, Austria), Michael Pearlman (ILRS, Harvard Center for Astrophysics, USA), Riccardo Barzaghi (IAG, Politecnico di Milano, Italy), Adrian Jäggi (IAG, AIUB, Switzerland), Zuheir Altamimi (IAG, Institut Géographique National, France), Richard Gross (GGOS, NASA/JPL, USA), Kosuke Heki (GGOS, Hokkaido University, Japan), Toshimichi Otsubo (ILRS, Hitotsubashi University, Japan), Laurent Soudarin (IDS, CLS, France), Alexandre Couhert (IDS, CNES, France), Pascale Ferrage (IDS, CNES, France), Frank Lemoine (IDS & ILRS, NASA GSFC, USA), Kayako Hori, Shinobu Kurihara, William Martínez, and Katharina Sehnal.

Check out the videos on YouTube:

English: https://www.youtube.com/watch?v=Jwqz097N2IY

Spanish: https://www.youtube.com/watch?v=biqkQ8Iy5rI

French: https://www.youtube.com/watch?v=9CLlDXIl_aI

German: https://www.youtube.com/watch?v=6sjp4cGbKT8

Japanese: https://www.youtube.com/watch?v=SQ6k64IkQ1g

Please share the video(s) in your home institutes and on social media.

If you would like to contribute to GGOS by translating the video into another language, please contact the GGOS Coordinating Office (email: co AT ggos.org).

The IERS ITRS Center at the IGN (Institut Géographique National, France) announced the availability of the ITRF2020 solution Release Date: 04/21/2022 On April 15, 2022, the IERS ITRS Center at the IGN (Institut Géographique National, France) announced the availability of the ITRF2020 solution at their dedicated web site:

https://itrf.ign.fr/en/solutions/ITRF2020

The new reference frame realization includes the contributions of all the IAG Geodetic Services (IVS, ILRS, IDS, IGS) and their Analysis Centers and Combination Centers. The ILRS contribution was based on a reprocessing of SLR data to the LAGEOS, LAGEOS-2 & the two Etalon satellites from 1993.0 to 2020.0 and to LAGEOS only from 1983.0 to 1993.0. As part of the reprocessing, the ILRS Analysis Standing Committee (ASC) conducted a 5-year effort of systematic analysis, to determine systematic errors in the SLR data. The reanalysis incorporated an improved "target signature" model (CoG) for better separation of true systematic errors from errors in describing the target's signature (Rodriguez et al., 2019; Pavlis et al., 2021). A major result is that the scale difference with VLBI in ITRF2020 is ~1.4 mm (0.23 ppb) compared to ITRF2014 where the SLR-VLBI scale difference was ~8.8 mm (1.37 ppb). While SLR defines the origin of the ITRF, both SLR & VLBI are used to define the scale of the ITRF. We show the characteristics of the ILRS contribution to ITRF2020 in the figure below, with the ITRF2020 SLR scale in blue and the ITRF2014 SLR scale in red (Pavlis et al., 2021).

The ILRS ASC is working on an ILRS extended version, the SLRF2020, which will include the SLR stations that were not part of the ITRF2020 solution and will provide instructions on how to get the highest accuracy results when implementing this extended model in SLR data analysis.

In the meantime, users should visit the ITRF website to update their procedures with the new files and software that have been released with the ITRF2020, and should implement the new Post-Seismic Displacement model and other related enhancements.

The ITRS solutions by the other ITRS centers, DTRF2020 from DGFI-TUM (Deutsches Geodätisches Forschungsinstitut, Technische Universität München), and JTRF2020 from JPL (the NASA Jet Propulsion Laboratory), are being finalized and should be available in the near future (e.g. Glomsda et al., 2021).

References:
Glomsda M., Seitz M., Bloßfeld M. et al. (2021). "DTRF2020: the ITRS2020 realization of DGFI-TUM", Frontiers of Geodetic Science (virtual meeting, Sept. 22, 2021). (https://mediatum.ub.tum.de/doc/1625232/1625232.pdf)

Pavlis E., Luceri V., Basoni A. et al. (2021). "ITRF2020: The International Laser Ranging Service (ILRS) Contribution, AGU 2021 Fall Meeting , 13-17 December 2021, doi:10.1002/essoar.10509208.1

Rodriguez, J., Appleby, G., Otsubo, T. (2019). "Upgraded modelling for the determination of centre of mass corrections of geodetic SLR satellites: impact on key parameters of the terrestrial reference frame", J. Geodesy, 93(12), 2553-2568, doi:10.1007/s00190-019-01315-0.

New ILRS Station Izaña (7701, IZ1L) in Tenerife (Canary Islands, Spain) is now OperationalRelease Date: 04/14/2022 Izaña (7701) has completed the requirements to be an operational station in the ILRS network and its data has been released from quarantine. The Analysis Standing Committee has approved the release of data collected since 2021-11-28.

We thank our station colleagues Andrea Di Mira, Jens Steinborn for their efforts, and congratulate them on this achievement!

ILRS Stations Participate in Tracking Campaign for the IRNSS SatellitesRelease Date: 04/12/2022 From April 17-30, 2022 at the request of ISRO (Indian Space Research Organization), the ILRS Central Bureau is organizing a tracking campaign for the IRNSS Indian constellation of GNSS satellites. The objective is for the network to provide an even distribution of SLR normal points around the orbit, for the satellites that are the focus of the campaign. The IRNSS satellites are located in geosynchronous (24-hr) orbits over the Indian Ocean region and their ground track makes a 'figure-8' on the surface of the Earth.

Seven satellites (IRNSS-1A,1B,1C,1D,1E,1F and IRNSS-1I) make up the IRNSS constellation, and are on the ILRS tracking roster. The distance to the geosynchronous orbit altitude (35786 km) makes these satellites challenging objects to track for the ILRS stations. Each IRNSS satellite is equipped with a retroreflector array consisting of 40 corner cubes, where each cube is 29.7 mm in height and 38 mm in diameter. These cubes were designed, manufactured and tested in India. The retroreflector arrays underwent thermo-optical characterization at the National Institute of Nuclear Physics/National Laboratory of Frascati facility in Italy (Porcelli et al., 2017). The current tracking campaign is a follow-on to an earlier ILRS campaign in 2018.

During the current campaign ILRS stations in the Eastern Region of the Indian Ocean (Asia, Australia) will track IRNSS 1C plus IRNSS -1D. ILRS stations in the Western Region of the Indian Ocean (Europe, Africa) will track IRNSS 1C plus IRNSS- 1I. While stations may try to track in the daytime, but it is expected that most data will be obtained during nighttime passes.

The IRNSS tracking data from the campaign will be used to assess the performance of these IRNSS satellites, in a similar way to how SLR data are used to validate the performance of other GNSS constellations such as Galileo.

References:

IRNSS constellation home page: https://www.isro.gov.in/irnss-programme

Kogure S., Ganeshan A.S., and Montenbruck O. (2017). "Regional systems", in Springer Handbook of Global Navigation Satellite Systems, pp. 305-337, I Teunissen, P.J., Montenbruck, O. (eds). Springer-Verlag, Cham. doi:10.1007/978-3-319-42928-1_11.

Porcelli, L., et al. (2017). "Thermo-optical vacuum testing of IRNSS laser retroreflector array qualification model", Adv. Space Res., 60(5), 1054-1061, doi: 10.1016/j.asr.2017.05.012.

Sen J.R., Lakshimi K.T. Mukundun M. et al. (2020). "IRNSS information for beginners", Remote Sensing of Clouds and the Atmosphere XXV, Proceedings of SPIE, 11531, 115310O, doi: 10.1117/12.2575993.

Definitions of Pass, Pass-Segment, and SessionRelease Date: 04/11/2022 The CDDIS, EDC, and NASA DOC provide statistics for the ILRS community including the monthly report cards, verification counts, and statistics for presentations and reports. These groups have worked together to standardize their definitions of a pass and a pass-segment.

The following definitions have been agreed to:

A pass includes all data taken on a satellite during one transit over the station. The pass-segment is just a magnification of how the data was taken and submitted.

Call for Papers for IAG REFAG2022 Meeting Release Date: 04/04/2022 The primary scope of REFAG 2022 is to address today's theoretical concepts of reference systems and their practical implementation by space geodetic techniques and their combination. Contributions for the meeting may include, global reference frames by individual space geodetic techniques and their combination; space geodetic measurements and mitigation of their systematic errors; geocenter motion and non-tidal loading effects; terrestrial and space geodetic ties for multi-technique combination; regional reference frames and related applications; Celestial reference frames; comparison and combination of Earth Orientation parameters; and use and challenges of geodetic reference frames for Earth science applications. The scientific program of the symposium will also cover initiatives and projects that endorse the role of geodetic reference frames for scientific exploration, sustainable development, climate monitoring, and satellite navigation.

Key Dates:

New ILRS Station (Izaña, IZ1L) in Tenerife (Canary Islands, Spain) undergoing acceptance testingRelease Date: 03/28/2022 The new SLR station Izaña (IZ1L, Tenerife, Canary Islands, Spain) is undergoing acceptance testing. The station is providing tracking data to LAGEOS-1, LAGEOS-2 and LARES which are being analyzed by the ILRS Analysis Standing Committee (ASC) to verify the performance prior to its acceptance as an operational station of the ILRS. The station Izaña (IZ1L) is built for the European Space Agency (ESA) by a consortium of European companies and institutes under the lead of DiGOS Potsdam GmbH (Germany). A recent article in the online space news periodical "spaceref.com" provides news of and a description of the station. (URL: http://spaceref.com/commercial-space/new-laser-station-lights-the-way-to-space-debris-reduction.html)

CPF v1 format discontinuedRelease Date: 03/10/2022 On March 1, 2022, the ILRS officially discontinued predictions in the CPF v1 format and have switched to the CPF v2 format. Please find the most recent predictions available at https://cddis.nasa.gov/archive/slr/cpf_predicts_v2/current/

IAG Statement on UkraineRelease Date: 03/04/2022 The International Association of Geodesy, a parent organization of the IVS/ILRS, has posted a statement on Ukraine. Read the statement.

The Passing of Professopr George Veis (based on a bio written by Ivan Mueller)Release Date: 01/31/2022 It is with great sadness that we convey the passing of George Veis, scientist, teacher, and a good friend to all of us; truly one of the fathers of Space Geodesy.

George was born in Athens in 1929. In 1951 he graduated in Surveying Engineering from the National Technical University of Athens (NTUA). In 1955 he was the recipient of a Greek state fellowship for advanced studies in Paris at the Sorbonne and the Ecole Nationale des Sciences Geographiques. He then spent some time at the Observatoire de Paris and the Bureau Gravimetrique International. Starting in 1957 he continued his postgraduate studies at the Ohio State University, where he was awarded with his PhD in 1958, after defending his famous dissertation on the "Geodetic Applications of Observations of the Moon, Artificial Satellites and Rockets".

George was one of the framers of the early Satellite Geodesy Program at the Smithsonian Astrophysical Observatory, which itself was a fundamental element of the early NASA Space Geodesy Activity.

George joined the Smithsonian Astrophysical Observatory (SAO), (later the Harvard Smithsonian Center for Astrophysics) in 1959 at the beginning of satellite geodesy era and the deployment of the Baker Nunn Satellite Tracking Cameras for geodetic and other scientific research. Over two decades as principal scientific consultant at SAO, he helped guide activities as the satellite geodesy program evolved with the Baker Nunn Camera and the emergence of Satellite Laser Ranging (SLR). He worked with the engineers on the design of the SAO SLR systems and the retroreflectors on satellites.

While at SAO, George contributed the early concept and evolution of the Differential Orbit Improvement (DOI) Program, which became the main analysis tool for satellite tracking, geopotential estimation, station coordinate determination, and satellite drag research. He defined the fundamental reference system used for many years, which now forms the basis of modern models of earth rotation, precession, and nutation. He also initiated the SAO Star Catalogue project, which provided a uniform all-sky catalogue for precision camera observations, and was used for many years all over the world.

Keeping his connection with SAO, George returned to NTUA, where he was elected Professor of Surveying (renamed later Higher Geodesy and Cartography) to develop satellite geodesy in Greece.

In 1969 he established the tracking station at Dionysos, installed a Baker-Nunn camera there, and began developing a laser ranging system. He had the vision of a complete geophysical observatory with, of course, satellite tracking, a meteorological observatory, earth tide monitoring, strain gauges, etc. He also developed surveys based on Transit Doppler measurements and GPS when the equipment became available. As an early mobile SLR deployment, George transported the Dionysos laser system to the remote island of Othoni, north of Corfu, Greece, and used it in October of 1973 to measure the distance to an Italian target at Specchia, Cristi at the tip of the boot. This measurement enabled for the first time the accurate connection of the Greek geodetic network with main Europe (Balodimos D., Geodetic Connection between Greece and Italy, Anno xxxvi, Bollettino di Geodesia e scienze Affini, 1977).

George's department at NTUA was a major source of young geodesists for the global community.

The Dionysos station contributed to the MERIT, MEDLAS, WEGENER and other programs. Between 1965 and 1984 George also organised the famous series of international symposia, in Lagonissi and Athens, on the "Use of Artificial Satellites for Geodesy and Geodynamics". The five volumes of the proceedings of these symposia document a great part of 20 years of geodetic history.

George's career as a science-administrator was also rich. As a member of the NTUA's senate and the Dean of the Faculty of Surveying Engineering, he suffered a short, but painful imprisonment by the military dictatorship in Greece, because of his proper academic comportment during students protest which caused the furious reaction of the regime. He was the Secretary General of the Hellenic Committee for Geodesy and Geophysics, its President from 1982 to 1990. He was President of the Board of the Athens National Observatory and the President of the Observatory's Scientific Council. He was the President of the Cadastre and Mapping Organization of Greece and the President of the National Consultative Council for Research. He also presided over several IAG/IUGG and COSPAR organizations. George retired from the NTUA in 1997. The ETH of Zurich honored him with an Honorary Doctor's degree.

George continued to be active in a key position as the President of the important Supreme Council for Personnel Selection, a state authority responsible for the selection of personnel for the public administration in Greece. George was awarded the Levallois Medal in 2003 in recognition of his distinguished service to the science of geodesy.

George Veis continued to be endlessly creative, engaging, seducing, elegant, modern and forever young scientist, who shared his ideas with enthusiasm, and helped everyone with whom he had contact. He witnessed the birth of space geodesy, its evolution from many meters to mm's, and continued to think about its future until his death. He had celebrated his 92nd birthday last September 8th, 2021.

George is survived by his wife Katerina, and children Konstandinos, Alexandros, Ino, Nico and Maria, and his grandchildren. His funeral is set for January 31, at noon.

May his memory be an abiding blessing.

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