GNSS Satellite (GIOVE-A)


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Thursday, 24 December 2009

GNSS Year in Review 2009

So what happened in the GNSS world in 2009!?

Well....not as much as we hoped for but some progress was made. Most progress was made "behind the scenes".


The most exiting and most "visible" was the launch of the GPS satellite SVN-49. This satellite brought new signals to the GPS system as it carries an experimental payload that allows the transmission of the new (future) GPS signals on the L5 band. The L5 experiment was bitterly needed because of the significant delays in getting the GPS IIF (F for Future) satellites ready. Thus the GPS system was at risk of loosing the L5 frequency allocation if they would not get a satellite up and "beeping" on the L5 frequency. The European Galileo system faced, and still faces, a similar challenge for which the launched the Giove-A and Giove-B experimental satellites. Unfortunately, the experimental character of the SVN-49 satellite actually caused some unexpected ill effects on the satellite on which we reported in our BLOG. This is the reason the satellite is still unhealthy although it is planned to turn the satellite healthy soon. However, the satellite will never perform as good as the other GPS satellites due to its anomaly. Besides SVN-49 also SVN-50 was launched marking the last GPS Block IIR-M satellite launch. The next GPS satellite to be launched will be the of the Block IIF type, currently scheduled for May 2010. An other "sad" event in 2009 was that SVN-35 was taken out of service. This satellite was special as it was one of only two GPS satellites that carries a Satellite Laser Ranging reflector array. The loss of this satellite is a grave loss for the scientific world especially because currently no SLR reflector arrays are foreseen on the GPS Block IIF nor on the first batch of the GPS Block III satellites. Hopefully the second batch of GPS Block III satellites will correct this "oversight" of the GPS system.


The most solid progress was made by the GLONASS system. Firstly, one of the three satellites launched in December 2008, GLO-729, is carrying a brand new SLR reflector array design which is 1.5 times better then the previous arrays. This is very exiting because it allows daylight tracking of this satellite which is an absolute "first" in the GNSS world. So far GNSS satellites could only be tracked by the SLR stations during the night. Furhtermore, an other successful triplet launch took place on December 14, 2009. However, also the GLONASS system did have its problems this year. One of the new satellites launched in 2008, GLO-726, developed a problem with its signal generator. As the satellites planned for launch in September 2009 used signal generators from the same batch as this faulty satellite the September launched was cancelled in order to check the satellites and replace the signal generators. The satellites are now scheduled for launch in February 2010. Nevertheless, the progress of GLONASS remains remarkable and they have managed to stick to the schedule that was laid out in 2005! In the space business that is an really astonishing accomplishment!


On the Galileo front things have been very quiet. Giove-A and Giove-B remain to operate which especially for Giove-A is a great accomplishment as it is well past its design life time. However, the schedule of the In Orbit Validation (IOV) seems to remain a "running target". In June the first launch was planned for September 2010. Meanwhile, rumours say the launch has been postponed until May 2011. The reasons for these delays are completely unclear and a more open communication policy would do the project a lot of good. The same holds for the data policy. Since 2005 Giove data has been gathered but the data is only available to ESA "trusted users". Unfortunately, it is practically impossible to obtain a trusted user status with ESA. So the Giove data is only accessible to a very limited number of institutes and thus limits the scientific analysis of the data. Under the surface a lot of things are happening in the Galileo project. The cooperation between ESA and the EU has been improved although it is certainly still not optimal. And a lot of progress has been made for awarding the contracts. The contracts should have been awarded early in 2009 but the process has, not unexpectedly, taken longer then planned. So also for 2010 visibly nothing much will be happening with Galileo. We will have to wait until 2011, at least.


Some progress was made for the COMPASS/Beidou system but since no data is publicly available I can not say too much about it. To my understanding there is still only 1 MEO satellite (MEO is the typical GNSS orbit) and a couple of GEO satellites. One additional GEO satellite was launched but also one was lost and was drifting through the GEO orbit causing quite some concerns for other GEO satellite operators (GEO is the orbits used for most telecommunication satellites). A "wild" satellite in this orbit is very dangerous and can cause a lot of damage.

The Japanese regional QZSS system is making good progress. The signal generator is currently undergoing in space testing as it is being flown on a GEO satellite. The first satellite will be launched in 2010. In principle three satellites are planned but currently funding for only 1 satellite exists.

The only thing remaing to be said is....
Merry Christmas

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