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