[IGSMAIL-4219]: 3 New GLONASS Satellites Launched

[Slater, James A.]

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IGS Electronic Mail      26 Dec 11:34:33 PST 2002      Message Number 4219
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Author: Jim Slater
Season's Greetings from IGLOS!!! 
(Some of you will have already seen this message from IGLOSmail, so I
apologize for the duplication.  
Jim Ray also sent an IGSmail message with the GLONASS launch news.)

On 25 December 2002, three new GLONASS satellites were launched into slots
21, 22 and 23 in orbit plane 3.  These are designated as GLONASS numbers
792, 791 and 793, respectively.   If they are all successfully placed into
operation, there will be 10 operational GLONASS satellites.

The IGS's IGLOS tracking network now consists of about 45 worldwide tracking
stations with dual-frequency receivers.  These data are integrated into the
IGS Global Data Center archives.  BKG and ESA in Germany and the Mission
Control Center in Russia continue to compute precise orbits for all the
satellites.  These individual orbits are combined by the IGLOS Analysis
Coordinator to produce combined orbits for each GLONASS satellite.  (We are
still looking for one or more additional analysis centers to compute GLONASS
orbits in order to strengthen the quality of the combined orbits.)

We have noticed that many organizations have been downloading the precise
orbits.  We would very much like to know what the orbits and tracking data
are being used for.  PLEASE SEND ME INFORMATION ABOUT WHAT APPLICATIONS AND
USES YOU HAVE FOR THE GLONASS DATA AND ORBITS. There is a considerable
amount of effort being made by all the organizations that run the tracking
stations, and by the Analysis Centers and other individuals to maintain the
IGLOS project.  The IGS needs to understand what people are using these data
for and whether it is worthwhile to maintain the GLONASS service.  We will
be evaluating this during the next few months.  

The 10-satellite GLONASS constellation when added to the GPS constellation
of 28 satellites means that the user community will have 38 navigation
satellites available.  The extra satellites can provide positional accuracy
benefits in areas with obstructed visibility at lower elevation angles.
They can also add a significant amount of data for certain ionospheric and
atmospheric applications that currently exploit the microwave signals from
GPS.  Integration of GLONASS and GPS data into existing software and
applications has been a good test case for the interoperability and
compatibility issues that will be encountered when trying to do the same
thing with the European Galileo system in the future.

Best Wishes for the coming year!

Jim Slater, Chair
IGLOS Pilot Project


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JIM SLATER     (301)227-4549     Fax: (301)227-2837     E-mail:
slaterj at nima.mil
NIMA, PPSC, MS D-68, 4600 Sangamore Rd., Bethesda, MD 20816-5003, U.S.A.
"...skate to where the puck is going to be, not where it has been." -Wayne
Gretzky