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Satellite Status / Space Weather Update 03 May 2008, GPSWeek 1477 31 healthy GPS Satellites: (GPS/UTC offset is 14 seconds) Mission planning is strongly encouraged for your GPS operations as even with 31 satellites there remain some periods of high DoP and reduced availability in some regions when using an elevation mask of 10 degrees or higher. You can have high DOP even with 6 satellites if the geometry is poor. I have attached the latest CONUS and worldwide max Dop Plots for your review. ftp://ftp.trimble.com/pub/eph/almanac.alm (Latest combined GPS/GLONASS Almanac) GPS Launch Update: IIRM 19, SVN48 PRN 07 was launched 15 March. Next launch is due 30 June (IIRM 20, SVN49 – with demo L5 payload) followed by 11 September (IIRM 21, SVN 50). In any event, 2SOPS intends to try to launch the remaining 2RM GPS satellites by the end of FY 2008, replacing older, high maintenance satellites. Updated GPS Interference Testing notice, 17 April 2008 WAAS GEO (correction source) Satellite Status GLONASS Status 15 (of 16) Satellites healthy Launch Update: Expect two launches of 3 satellites each, in September and December 2008. Modernization Update: The Russian Government moved GLONASS to the equivalent of ITRF this September 20 (PZ90.02). It looks like they have improved the orbit determination process significantly since the reference system upgrade. Other planned modernizations, which include improved clock stability, monitoring station extensions and timekeeping enhancements, are planned to provide 'GPS like' performance by 2009. Galileo Update from around the EU: GIOVE-B was placed in a medium earth orbit (MEO) by a Soyuz/Fregat rocket from Baikonur, Kazakhstan. Lift-off was at 0416 local time on 27 April (2216 UTC on 26 April). Some 3 h 45 m later the Fregat upper stage had reached a circular orbit at 23,200 km, inclined at 56 degrees to the equator. GIOVE-B was then released - its 2 solar panels deployed correctly and were operational by 0328 UTC. GIOVE-B carries:
The 500 kg satellite was built by a European industrial team led by Astrium GmbH, with Thales Alenia Space performing integration and testing. It is now under the control of Telespazio's spacecraft operations centre in Fucino, Italy. GIOVE-B will take over GIOVE-A's mission to secure the Galileo frequencies, as that first Galileo demonstration satellite - built by SSTL in UK and launched in December 2005 - has exceeded its operational life, although it is still working perfectly. The next step in the Galileo programme will be the launch of 4 operational satellites - to validate the Galileo space and ground segments - by 2010. Full Operational Capability (FOC), with a constellation of 30 satellites, is due by 2013. More at: http://www.esa.int/esaCP/SEM9GD2QGFF_index_0.html Iono Status and Geomagnetic Forecast: Current Space weather Conditions: NOAA’s Space Environment center has seen a small reverse polarity sunspot, the second since January, indicating that we are in solar cycle 24. The sun remains remarkably quiet as we are certainly at the bottom of the cycle. The consensus opinion on the upcoming solar cycle 24 is split: The experts differ as to the maximum size of cycle 24...one group says it will peak at 140 (w/peak date October 2011) with the other group predicting 90 (w/peak date August 2012). Cycle 23 peaked with an average of sunspot number of 120 mid 2001. Even at the bottom of the solar cycle there can be very strong solar activity as seen with the Dec 06 2006 Radio Burst Event. The following link has a nice plot comparing the differing solar cycle predictions:
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