This page contains all recent ILRS news. For those interested in news specific to satellite missions, please visit our Mission News page.
The GREAT experimentRelease Date: 04/27/2016
The unplanned eccentric orbit of Galileo-201 and -202 provides a unique opportunity to study the behavior of on-board clocks and the gravitational redshift predicted by General Relativity. The Galileo-201 and -202 satellites, the first two Fully Operational Capability (FOC) satellites, were launched on August 22, 2014. Due to technical problems with the launch, these satellites remain in an elliptical orbit, which is not useful for the Galileo operations.
Colleagues with the Galileo mission have proposed a one-year, ESA funded experiment, GREAT (Galileo gravitational Redshift Experiment with eccentric sATellites) during which the SLR will provide periods of intensive tracking on Galileo-201. The GREAT experiment will begin May 1, 2016. The stations in the ILRS network are asked to support this experiment.
The 20th International Workshop on Laser RangingRelease Date: 03/22/2016
The 20th International Workshop on Laser Ranging will be held at the Helmholtz Centre Potsdam/GFZ German Research Centre for Geosciences in Potsdam Germany on October 09-14, 2016. More information, including registration and abstraction submission deadlines, is available on the workshop’s website: http://iwslr2016.gfz-potsdam.de/international-workshop-on-laser-ranging/
Happy Birthday Vladimir Vasiliev!Release Date: 03/21/2016
The ILRS sends warmest wishes to our colleague Prof. Vladimir Vasiliev who celebrated his 85th birthday on March 18, 2016. He continues to actively contribute to various space projects, including those of interest to the ILRS. Prof. Vasiliev is a Doctor of Technical Science and Chief Research Scientist at JC «RPC «PSI». He is also the author of 5 monographs and more than 250 scientific papers. Happy Birthday Vladimir!
NASA Station Leads Way for Improved Measurements of Earth Orientation, ShapeRelease Date: 03/10/2016
NASA has demonstrated the success of advanced technology for making precise measurements of Earth’s orientation and rotation – information that helps provide a foundation for navigation of all space missions and for geophysical studies of our planet.
The technology includes a new class of radio antenna and electronics that provide broadband capabilities for Very Long Baseline Interferometry, or VLBI. This technique is used to make precise measurements of Earth in space and time.
VLBI measurements have been conducted for decades using a worldwide network of stations that carry out coordinated observations of very distant astronomical objects called quasars. To meet the demand for more precise measurements, a new global network of stations, called the VLBI Global Observing System, or VGOS, is being rolled out to replace the legacy network.
New version of the ILRS Mission Support Request form released Release Date: 03/09/2016
Under the direction of the ILRS Missions Standing Committee (Toshi Otsubo and Scott Wetzel) and the ILRS Central Bureau, a new version of the ILRS Mission Support Request form has been formulated and posted on the ILRS website:
This new form, available in Adobe PDF forms format, provides an improved method for obtaining the information required by the ILRS to support future missions. The form is easier to fill out and read; some additional questions have been added while obsolete, previously requested information has been removed. We encourage our mission colleagues to take a look at the new form and use it the next time support for a new mission is required!
Thanks to Toshi, Scott, the MSC, and the ILRS CB for their work on and reviews of the new MSR form.
The passing of Carroll AlleyRelease Date: 03/02/2016
The ILRS is sad to report that Carroll Alley, Professor Emeritus of physics at the University of Maryland College Park passed away on February 24, 2016. Dr. Alley was the Principal Investigator for the Lunar Laser Ranging Retroreflector experiment placed on the Moon in 1969 by the crew of Apollo 11. More information can be found at:
http://www.legacy.com/obituaries/name/carroll-alley-obituary?pid=1000000177892088. Carroll was a person of great vision and strength to the scientific community.
NASA Contributes to Global Standard for Navigation, Studies of EarthRelease Date: 02/25/2016
The surface of Earth is constantly being reshaped by earthquakes, volcanic eruptions, landslides, floods, changes in sea levels and ice sheets, and other processes. Since some of these changes amount to only millimeters per year, scientists must make very precise measurements of the landscape and ocean in space and time in order to study their evolution and help mitigate their impacts.
Working Groups now called "Standing Committees"Release Date: 02/24/2016
The IAG, which is the parent organization of the ILRS, has informed the ILRS that we can no longer use the term "Working Group" for our entities that have a lifetime longer than four years. Therefore, ILRS "Working Groups" (Analysis, Networks and Engineering, Data Formats and Procedures, Missions, and Transponders) will now be called "Standing Committees". Over time, high-level documentation and web material will be changed to reflect the new terminology, as must all new material being produced within the ILRS.
Satellite Laser Ranging Research Geophysicist Position at NASA/GSFCRelease Date: 01/13/2016
The Sciences & Exploration Directorate, Solar System Exploration Division, Laser Remote Sensing Laboratory (Code 694) at NASA Goddard Space Flight Center is seeking a research scientist to provide expertise in space geodesy and Satellite Laser Ranging (SLR) system development and operations. As a Research Geophysicist, the successful candidate will be responsible for conducting, managing, planning, and directing the research and development of NASA’s next generation SLR stations. Conceives and conducts instrument and systems development to increase fundamental knowledge and understanding of space geodesy via SLR. Serve as a technical leader for the implementation of new NASA SLR stations as part of the NASA Space Geodesy Network (NSGN), and ensure the operational NSGN produces the data required by NASA missions and the scientific community. Identify problems and requirements for making geodetic SLR observations to best achieve an improved understanding of Earth dynamic processes, and initiating new experiments and programs to address these problems. Responsible for the development of new and novel applications of the SLR technique. Participate in the writing and publication of significant scientific and technological findings in appropriate journals and other media. Give presentations at scientific and technical meetings, both nationally and internationally. Responsible for defining, articulating, advancing, and publicizing NASA's role in the worldwide SLR community and participating in the direction of international organizations using SLR results and supporting SLR activities. This includes leading and supporting activities of the International Satellite Laser Ranging Service (ILRS). Work closely with NASA and NASA partner mission owners to develop SLR related requirements on the mission, associated retroreflectors, and the operational SLR network to meet the mission's science requirements. Applicants should have experience in instrument design, research and development of precision laser ranging and related optical measurement systems (such as SLR, LIDAR, and laser interferometers) and their application to space geodesy, geoscience, and/or Earth observations. Further information about NASA’s Space Geodesy Project can be found at: http://space-geodesy.nasa.gov.
U.S. citizenship is required. To view the full vacancy announcement, which contains further information including qualification requirements and application instructions, go to (http://www.usajobs.gov/GetJob/ViewDetails/426383000). Applications must be received by February 29, 2016 via the USAJobs website. For additional questions, please contact Dr. Stephen M. Merkowitz at email@example.com.
NASA GSFC is an Equal Opportunity Employer.
Changes in NORAD and COSPAR IDs for COMPASS satellitesRelease Date: 01/06/2016 The COSPAR and NORAD numbers in the CPF files for Compass-MS1 and Compass-MS2 were incorrect (they did not correspond to the TLE data); the numbers were switched by the prediction provider starting with CPF 5041 (dated January 05, 2016) and now correspond to the TLE data. The SIC numbers did NOT change. The ILRS website has been updated as well.
- Compass-MS1: NORAD ID=40749/COSPAR ID=1503702/SIC=2007
- Compass-MS2: NORAD ID=40748/COSPAR ID=1503701/SIC=2008
Data archived before the change will be replaced at the data centers shortly.
Brief network outages at GSFC on December 19, 2015Release Date: 12/11/2015
Work will be performed on the NASA GSFC network infrastructure from 03:00 p.m. (20:00 UTC), Saturday, December 19, 2015 through 03:00 a.m. (08:00 UTC) on Sunday, December 20. Users can expect 10-15 minute interruptions during that time period.
Should the CDDIS be unaccessible, users can access one of the other data centers supporting the services:
- IGS: http://www.igs.org/about/data-centers
http://ilrs.gsfc.nasa.gov/data_and_products/data_centers/index.html (check before December 19!)
- IVS: http://ivscc.gsfc.nasa.gov/about/org/components/dc-list.html
- IDS: http://ids-doris.org/data-products/info.html
New "Site Requirements for GGOS Core Sites" document releasedRelease Date: 12/02/2015 Version 2 of the document Site Requirements for GGOS Core Sites has been issued.
ILRS Resolutions from the 2015 Technical WorkshopRelease Date: 11/18/2015 The 2015 ILRS Technical Workshop was held in Matera Italy, October 24 through 30. The theme of the workshop was "Network Performance and Future Expectations for ILRS Support of GNSS (Global Navigation Satellite Systems), Time Transfer, and Space Debris Tracking." Representatives from various global GNSS, such as the U.S. GPS, Russia's GLONASS, Europe's Galileo, and China's Beidou, presented their requirements for and satisfaction with the ILRS network's laser ranging support of their systems. The ILRS will use this information to better set satellite tracking priorities and develop tracking strategies. Several presentations reviewed capabilities established at select ILRS stations for using laser ranging to track and model space debris, where testing capabilities ranging to decommissioned satellites with retroreflector arrays is underway. The last main session reviewed ways the ILRS can monitor data quality through characterizing biases (timing, range, etc.) in laser systems that have adverse effects on the data analysis products. The week included a tour of the nearby Matera Space Geodesy Center, which is home to an SLR system, VLBI antenna, GNSS receiver, and gravimeter; the station also provides downlink and data processing capabilities for Europe's Copernicus program. Several resolutions were put forward at the conclusion of a very successful week of presentations, discussion, and splinter meetings. A website with links to abstracts, presentations, posters, and papers will be available soon.
2015 ILRS Pass Performance Standard releasedRelease Date: 11/17/2015 At its meeting during the 2015 ILRS Technical Workshop in Matera Italy, the ILRS Governing Board agreed to modify the ILRS Pass Performance Standard, which reflects our evolving technologies, improved procedures, increased ranging experience, and increased number of targets and users.
2015 Leap second report releasedRelease Date: 10/08/2015 A report from a survey of the ILRS stations' experiences during the 2015 leap second event has been published.
Michael Pearlman awarded the 2014 Golden Medal of MeritRelease Date: 08/28/2015 In April 2015, Michael Pearlman, Director of the ILRS Central Bureau, was awarded the 2014 Golden Medal of Merit by the Scientific Board of the Institute of Applied Astronomy of the Russian Academy of Sciences in recognition of his achievements and contributions in laser ranging and international scientific programs. The citation for the award read: "For outstanding contribution to the development of space geodesy and for promoting the IAA RAS role in creation and enhancement of GGOS." Mike visited the Institute of Applied Astronomy in Saint Petersburg in April and accepted the award during a ceremony in conjunction with the 6th All-Russian Meeting "Fundamental and Applied Positioning, Navigation and Timing" (PNT-2015). Mike also participated in the conference and gave a talk titled, "The Global Geodetic Observing System (GGOS) and the Important Role played by the Institute of Applied Astronomy, ROSCOSMOS, and other Russian Participants."
Third GNSS Tracking CampaignRelease Date: 08/05/2015 The third SLR GNSS Tracking Campaign will run from August 10 through October 16 (10 weeks). The focus will be on the following GNSS satellites:
- GLONASS-123, -125, -128, -129, -133, and -134
- Galileo-101, -102, -103, and -104
The revised priority list reflecting these changes for the third campaign is now available on the ILRS website at: http://ilrs.gsfc.nasa.gov/missions/mission_operations/priorities/index.html. The results from this campaign will be a topic of discussion at the upcoming ILRS Technical Workshop to be held October 26 - 30 in Matera (http://geodaf.mt.asi.it/2015_ILRS_TW/index.html).
Goals and instructions
Results from Second GNSS Tracking CampaignRelease Date: 07/31/2015
The second GNSS Tracking Campaign was held November 28, 2014 through February 28, 2015.
Justine Woo from Excelis has compiled a broad range of information on the campaign. To keep the document at a manageable size, it focuses on the 14 most productive sites in this campaign: Yarragadee, Mt. Stromlo, Changchun, Altay, Komsomolsk, Shanghai, Graz, Herstmonceux, Matera, Monument Peak, Zelenchukskaya, GSFC, Arkhyz, and Wettzell. The report can be accessed on the activities link in the LARGE Study Group section of the ILRS website at: http://ilrs.gsfc.nasa.gov/docs/2015/GNSScampaign2_statisticreport_20150630.pdf.
Even though the results are for only 14 stations, they should be of interest to all of the sites. This document was created with the intent of assessing the success of the campaign and planning our path forward in addressing our user requirements. It is rather extensive, but take a look and see what some of the stations were able to do.
Mark Torrence has also provided additional charts on the time distribution of data over the day (24 hours) for the same period. We selected the GLONASS satellites GLONASS-123, -125, -129, -130, -131, and -132 from the campaign as an example. Performance on Galileo and Compass-M was similar. This report is also available on the ILRS website at: http://ilrs.gsfc.nasa.gov/docs/2015/GNSScampaign2_localtimereport_20150730.pdf.
Conclusions from the campaign:
- We need more sectors covered for the 6 higher priority GLONASS satellites and Galileo and M class Compass satellites. It is more important to get 2 and 3 sectors of data in the higher priority GLONASS satellites than to track the lower priority GLONASS satellites.
- We need more data in daylight, or at least around sunrise and sunset.
- Figures 1-3: Number of normal points, pass sectors, and passed by station for each of the constellations and how often they got 1, 2 and 3 sectors in a pass. This distribution is very important. We recognize that some stations have the advantage of good weather and several shifts of operation.
- Figures 4-7: Number of Sectors (Beginning, Middle, End of the pass) that data was taken for each station and on each constellation. Some stations were able to achieve 2 and 3 sector coverage during some passes.
- Figures 8-21: Mean and maximum number of normal points per satellites per pass. We can see that some stations have higher priorities for some satellites.
- Figures 22-35: Show pie charts showing the percentage of the passes tracked that included one, two, and three segments by constellation, and the distribution of the these segments with in the passes (B - beginning, M - middle, E - end). Again, some stations were able to track 2 and 3 segments in some passes. The charts also show that some stations are tracking with their own tracking preferences.
- Figures 36-63: Show a sample in time of the satellites tracked by each stations.
- Figures 64-67: Show tracking campaign - GNSS satellites vs non-campaign-GNSS satellites.
First quantum data communication performed to an Earth-orbiting satellite (Lares)Release Date: 07/28/2015
For the first time, a quantum data communication was performed to an Earth-orbiting satellite (at 1,700 km). The experiment, published in the journal Physical Review Letters was a collaboration between the Center of Space Geodesy of the Italian Space Agency (ASI) and University of Padova.
Data were 'bundled' into light particles and sent from the ASI station in Matera up to the Lares satellite, launched by ASI in 2012, whose surface is covered with retroreflectors. Once caught by the light beam, the mirrors reflected the signal back to the Matera station. It "a decisive step" that approaches quantum communications, a mode that is impossible to intercept, since interception automatically destroy them.
Quantum communication of the letter "E" over a distance of 1,700 km was a first said ASI president, Roberto Battiston. Quantum communication over land has been attempted, but over distances ten times shorter.
Authors of the jPR Letters are Paolo Villoresi, University of Padova, and Giuseppe Bianco, of the Centre for Geodesy ASI Matera. The Matera station, noted Battiston, is one of the fundamental global benchmarks in the international space geodesy network that provides precise measurements of the position of the moon and satellites with pinpoint accuracy. Battiston said that this is a great achievement that puts Italy at the forefront in a sector with important science and industrial applications.
CDDIS Earthdata webinarRelease Date: 07/22/2015 The CDDIS held an Earthdata webinar titled, "Distributing Real-Time GNSS Data and Derived Products at the CDDIS". This webinar provides an overview of the Global Navigation Satellite System (GNSS), the International GNSS Service (IGS), Real-time GNSS, the CDDIS real-time data caster and protocol, the registration process before accessing the real-time data, and several demonstrations on configuring and using the client software.
The passing of Suriya Kerimovna TatevianRelease Date: 07/20/2015
Author: INASAN Administration Staff
The Institute of Astronomy regrets to announce that Suriya Kerimovna Tatevian, Doctor of Technical Sciences and a leading researcher at the Institute of Astronomy of the Russian Academy of Sciences (RAS), died suddenly on July 16, 2015; she was 79 years old.
Suriya was known as an expert in the field of space geodesy and space geodynamics. In 1962, two years after the end of her studies at MIIGAiK, Suriya started working at the Astronomical Council of the USSR, which was later transformed into the Institute of Astronomy. She progressed from a research assistant to the head of the department. For more than half a century, Suriya devoted all her strength, talent and energy to the establishment and development of a new scientific direction in the field of space geodesy and geodynamics. Suriya made significant contributions to the organization of high-precision laser observations of satellites, as well as many international cooperative programs. Up until her passing, Suriya Tatevyan continued scientific and organizational activities with her continued passion and enthusiasm.
Employees of the Institute of Astronomy mourn the loss of their colleague and express their condolences to the families and friends of Suriya Kerimovna Tatevian.
ILRS Technical Workshop (26-30 October 2015, Matera, Italy) Abstract SubmissionRelease Date: 07/20/2015
Author: Cinzia Luceri/Giuseppe Bianco
At the next ILRS Technical Workshop (26-30 October 2015, Matera, Italy) session chairs will designate key people to present position papers to introduce topics and set the scene for discussion. Abstracts for these position papers must be submitted through the abstract submission process. Other abstracts may be submitted for oral and poster presentations. Oral presentations must be relevant to a particular session and address some of the key questions identified in the session description. Oral presentations will go through an approval process by session chairs so they can plan an orderly program including sufficient time for discussion. Presentations should be short and informative. All presentations not accepted for oral talks may be given as posters. We view posters as a very important part of the meeting; they provide one-on-one opportunity for discussion on key features of the papers. Participants are welcome to submit abstracts for any or all sessions.
We need broad participation in the session discussions. In addition to the scheduled talks, participants are encouraged to bring one or two charts to stress or support particular points and issues in the discussion. Look carefully at the questions listed for each session. These charts will be uploaded before each session but do not require a submitted abstract. The Session Chairs will coordinate this activity. All charts will be included in the workshop proceedings.
The opportunity to submit abstracts is now open, deadline September 30th, 2015.
Please, use the conference website
NASA Explains Why June 30 Will Get Extra SecondRelease Date: 06/26/2015
The day will officially be a bit longer than usual on Tuesday, June 30, 2015, because an extra second, or "leap" second, will be added.
"Earth's rotation is gradually slowing down a bit, so leap seconds are a way to account for that," said Daniel MacMillan of NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
Strictly speaking, a day lasts 86,400 seconds. That is the case, according to the time standard that people use in their daily lives – Coordinated Universal Time, or UTC. UTC is "atomic time" – the duration of one second is based on extremely predictable electromagnetic transitions in atoms of cesium. These transitions are so reliable that the cesium clock is accurate to one second in 1,400,000 years.
However, the mean solar day – the average length of a day, based on how long it takes Earth to rotate – is about 86,400.002 seconds long. That's because Earth's rotation is gradually slowing down a bit, due to a kind of braking force caused by the gravitational tug of war between Earth, the moon and the sun. Scientists estimate that the mean solar day hasn't been 86,400 seconds long since the year 1820 or so.
This difference of 2 milliseconds, or two thousandths of a second – far less than the blink of an eye – hardly seems noticeable at first. But if this small discrepancy were repeated every day for an entire year, it would add up to almost a second. In reality, that's not quite what happens. Although Earth's rotation is slowing down on average, the length of each individual day varies in an unpredictable way.
The passing of Dr. Bob SchutzRelease Date: 06/11/2015We are sad to announce that our colleague and friend, Dr. Bob Schutz, University of Texas at Austin/Center for Space Research (CSR) passed away on June 7, 2015, surrounded by family.
Bob was a member of the faculty at the University of Texas since 1969. His research interests included space geodesy and its applications, space geodetic instrumentation, precise orbit determination, orbital mechanics, mission planning and computational techniques. He was the science team leader for NASA's Geoscience Laser Altimeter System (GLAS), an instrument used to measure topography, especially the changes in Antarctic and Greenland ice sheets, that operated on the Ice, Cloud, and land Elevation Satellite (ICESat) in Earth's orbit for seven years.
Bob was recently elected a member of the National Academy of Engineering (NAE), and he was a fellow of the American Institute of Aeronautics and Astronautics, the American Geophysical Union, and the American Astronautical Society. Most recently, he held the Joe J. King Chair in Engineering and the FSX Professorship in Space Applications and Exploration at the University of Texas at Austin. Bob was also a special friend of the IAG Services, participating in many activities over the years and giving advice both in the early days and through recent years. His IAG contributions including being a co-founder of the International Laser Ranging Service (ILRS), and being closely involved in the IGS (International GPS Service, now the International GNSS Service) since its inception in the early 1990s, serving most recently on the ILRS Governing Board.
Bob was a cherished colleague, a Ph.d advisor, mentor and a fine gentleman. His legacy will be appreciated for many years to come. We wish to pass on our condolences to Bob’s family, friends, and colleagues around the world. We will truly miss him.
Leap second to be introduced into UTC on June 30, 2015Release Date: 06/04/2015UTC must be adjusted to maintain its correlation to mean solar time due to irregularities in the Earth's rotation. Therefore, a leap second will be introduced into UTC on June 30, 2015 at 23:59:59 UTC. More information about the leap second and preparing for it is available from the following websites:
- USNO: http://tycho.usno.navy.mil/leapsec.html
- U.S. Department of Homeland Security, Navigation Center: http://www.navcen.uscg.gov/pdf/cgsic/Leap_Second_Best_Practices_20150526_Intrl_Version.pdf
NASA network connectivity outageRelease Date: 04/22/2015
Starting this Sunday, April 26, there will be a scheduled outage for NASA network connectivity, from April 26 17:00 UTC through April 27 05:00 UTC. We have been told that the NASA network will be unavailable during the first four hours; intermittent outages of several minutes can be expected after that time until the end of the period specified above. During the outage, the ILRS, CDDIS, and Space Geodesy Project websites will not be accessible.
While the CDDIS is unavailable, users can access one of the other data centers supporting the services:
IGS RTS: http://igs.org/rts/access
ILRS: http://ilrs.gsfc.nasa.gov/data_and_products/data_centers/index.html (consult prior to outage)
We regret any problems this outage may cause the user community.
2015 is the International Year of LightRelease Date: 04/10/2015
The International Year of Light, a UN initiative to raise public awareness of the importance of photonics on everyday life, was officially launched at a ceremony at UNESCO in Paris on January 19. Photonics is the science and technology of generating, controlling and detecting photons, or light particles. The Year is endorsed by the International Council for Science (ICSU) and the International Social Science Council (ISSC), as well as by a number of scientific unions.