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The International Laser Ranging Service (ILRS) provides global satellite and lunar laser ranging data and their related products to support geodetic and geophysical research activities as well as IERS products important to the maintenance of an accurate International Terrestrial Reference Frame (ITRF). The service develops the necessary global standards/specifications and encourages international adherence to its conventions. The ILRS is one of the space geodetic services of the International Association of Geodesy (IAG).

The ILRS collects, merges, archives and distributes Satellite Laser Ranging (SLR) and Lunar Laser Ranging (LLR) observation data sets of sufficient accuracy to satisfy the objectives of a wide range of scientific, engineering, and operational applications and experimentation. These data sets are used by the ILRS to generate a number of scientific and operational data products including:

Earth orientation parameters (polar motion and length of day)
Station coordinates and velocities of the ILRS tracking systems
Time-varying geocenter coordinates
Static and time-varying coefficients of the Earth's gravity field
Centimeter accuracy satellite ephemerides
Fundamental physical constants
Lunar ephemerides and librations
Lunar orientation parameters

The accuracy of SLR/LLR data products is sufficient to support a variety of scientific and operational applications including:

Realization of global accessibility to and the improvement of the International Terrestrial Reference Frame (ITRF)
Monitoring three dimensional deformations of the solid Earth
Monitoring Earth rotation and polar motion
Support the monitoring of variations in the topography and volume of the liquid Earth (ocean circulation, mean sea level, ice sheet thickness, wave heights, etc.)
Tidally generated variations in atmospheric mass distribution
Calibration of microwave tracking techniques
Picosecond global time transfer experiments
Astrometric observations including determination of the dynamic equinox, obliquity of the ecliptic, and the precession constant
Gravitational and general relativistic studies including Einstein's Equivalence Principle, the Robertson-Walker b parameter, and time rate of change of the gravitational constant
Lunar physics including the dissipation of rotational energy, shape of the core-mantle boundary (Love Number k2), and free librations and stimulating mechanisms
Solar System ties to the International Celestial Reference Frame (ICRF)

Recent News

The Second LARES 2 and fifth LARES International Science Workshop - The Second LARES 2 and fifth LARES International Science Workshop will take place in Rome, Italy, May 31 - June 3. 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).

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ESA Lunar Pathfinder mission to include Lunar Laser Ranging - The European Space Agency (ESA) announced that a test version of a 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 in orbit around the Moon. In addition the Lunar Pathfinder spacecraft will carry a laser retroreflector array for lunar laser ranging, and an X-Band radio transponder for ranging and communications.

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GGOS Coordinating Office Develops Film to Promote Geodesy - 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. Check out the videos on YouTube:

https://www.youtube.com/watch?v=Jwqz097N2IY&list=PLIIfsJS7iAuxXGqq0YLAUO_m_06za9vqr

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The IERS ITRS Center at the IGN (Institut Géographique National, France) announced the availability of the ITRF2020 solution - 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.

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.

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New ILRS Station Izaña (7701, IZ1L) in Tenerife (Canary Islands, Spain) is now Operational - 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 Satellites - From April 17- 30, 2022 at the request of ISRO (Indian Space Research Organization), the ILRS Central Bureau is organizing a tracking campaign for IRNSS, the 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.

During the current campaign (April 17- 30, 2022) 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. The IRNSS tracking data from the campaigns will be used to assess the performance of these IRNSS satellites, in a similar way to that used to validate the performance of other GNSS constellations such as Galileo.

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Definitions of Pass, Pass-Segment, and Session - 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 is defined as all tracking that lasts less than a full satellite period. For geosynchronous satellites, the duration is capped at 24 hours; this is the standard product.
A pass-segment is another term for a session (interval of continuous data) which is a reflection of how the data was taken at the station and submitted to the data centers. A single pass-segment/session is counted from one H1 to H8.

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 - 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:

June 20, 2022 (Abstract deadline)
July 25, 2022 (Early registration deadline)

For more information, check the URL for the meeting: www.refag2022.org

CPF v1 format discontinued - 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 Ukraine - The International Association of Geodesy, a parent organization of the IVS/ILRS, has posted a statement on Ukraine. Read the statement.

Meetings

EUREF 2022 Symposium, Zagreb, Croatia, May 31-June 3, 2022

The Second LARES 2 and fifth LARES International Science Workshop, Rome, Italy, May 31 - June 3

AOGS 19th Annual Meeting, Honolulu, Hawaii, USA, June 5-10, 2022

Publications

2016-2019 ILRS Report

Proceedings from the 19th International Workshop on Laser Ranging

International Laser Ranging Service

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