GNSS Satellite (GIOVE-A)


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Monday, 4 January 2010

Galileo IOV Schedule

First of all a very happy and prosperous 2010 to all of you!

In 2009 saw very little concrete progress within the Galileo project. Behind the scenes a lot has happened, e.g., the cooperation between the EU and ESA has been improved and a lot of progress was made in the negotiations for the full orbit constellation (FOC) contracts. However, from a (scientific) user point of view this is not very concrete progress at all.

A significant issue with the Galileo project is the lack of an open communication principle. In 2009 I was really positively surprised about how open the GPS system has been regarding the issues with SVN-49. This is quite different from the way how the Galileo project is treating things. This is very surprising and even more so if one considers that GPS is still very much a military system whereas Galileo is a civil system. Thus one would expect much more open communications from Galileo!!

Secondly, also the data policy from the Galileo project is not really transparent. Since 2005 GIOVE-A has been in orbit and ESA has been gathering data from this satellite, and its brother GIOVE-B, using a network of 13 Galileo Experimental Sensor Stations (GESS). In principle this data is available to all ESA "trusted users", a status one can apply for on the ESA GIOVE web site. However, I know several institutes that have applied but never received this status. This is really disappointing, especially since a open data policy would most likely lead to much more interest, and consequently investigations and progress, from the scientific community. The currently employed "closed data policy" is very likely more harmful then helpful for the project. Several world leading scientist who would be interested in studying the Galileo, or rather GIOVE, data do not have access to the data. In this sense the Galileo project is very similiar to the Chinese COMPASS project.

So this brings us to the status of the Galileo IOV phase. In this phase 4 satellites will be launched in two launches. Both launches will be from Kourou using the the Russian Soyuz launcher. The four IOV satellites should, in principle be very similar to the final Galileo satellites. In Summer 2009 the IOV schedule foresaw that launch 1 would take place around September 2010 and launch 2 around February 2011. However, ever since the schedule has been slipping. Of course slipping schedules are quite normal in the space business but the lack of communications around it in the case of the Galileo project are untypical and make people wonder about the reasons for the delays. The latest rumours I have heard, and so far these rumours have always been true, is that launch 1 for the Galielo IOV is now scheduled for May 2011. The reason(s) for this (huge!) delay are completely unclear. But, we can speculate a bit about them....

Interesting is that in the FOC negotiations it seems that for building the satellites the consortium around OHB now seems to be winning against the "favourite" EADS consortium. The OHB consortium includes Surrey Satelite Technology Ltd which was responsible for the very successful GIOVE-A satellite. GIOVE-A was build on-time and within budget. And that was a truley great performance as time was the most critical factor in that case. The performance of EADS in building GIOVE-B was quite in constrast to the this with very significant delays and huge cost overruns. So if we put 1 and 1 together and start speculating a bit, it could very well be that the EU and ESA are a bit disappointed with the EADS performance both from GIOVE-B as well as now for the IOV satellites and are thus now favouring the OHB consortium for the FOC phase. It can also be just "politics" but the GIOVE-B and IOV satellites projects are certainly not one of the "best" we have seen. So there is some room for speculation here.....

Of course, in case the OHB consortium wins this will lead to a very inhomogeneous Galileo satellite constellation as the OHB satellites will most likely be quite different from the EADS IOV satellites. Also most likely the FOC constellation will be build in different phase with different generations of satellites. So when Galileo reaches FOC at least 3 different types of satellite will be in orbit.

In any case these are interesting times but before we see any real Galileo satellites in orbit my bet is that we will have to wait until 2011. So for 2010 the highlights we may expect will come from GPS and GLONASS. The GPS system is going to launch its, long overdue, first Block IIF satellite (currently scheduled for May) whereas the GLONASS system is going to launch its first GLONASS-K satellite (scheduled for the end of 2010).

Meanwhile I hope the Galileo project will become a bit more open both in its communication policy and, even more importantly, in its data policy.

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Wednesday, 2 December 2009


So it is time for an update on GLONASS.
As you may have noticed meanwhile the September has been canceled. There have been all sorts of speculations and it was difficult to get any hard facts. As far as we have been able to figure out the reason for canceling the launch lies in the fact that the GLONASS 726, in orbital slot 22, developed an unexpected problem and has consequently been unhealthy since quite some time. The problem seems to be with the signal generator on board of the satellite.

Now you may wonder, what does that have to do with the September launch. Well, as it turns out the three satellites scheduled for launch in September make use of the same signal generator. So as it is "better to be save then sorry" it was decided to send the satellites back to the factory to check, or more likely replace, the signal generators in all three satellites.

We originally thought that this would then also impair the December launch. However, we have been told that the satellites for the December launch used a different version of the signal generator and thus the December launch is "on track". In fact the last of the three Glonass-M navigation spacecraft intended for cluster 41 was delivered to Baikonur on November 27, 2009 by the JSC Academician M.F. Reshetnev Information Satellite Systems. The first two satellites were delivered to the spaceport on 17 and 23 November and are currently in preparation for launch. The launch date is set for December 18. A bit earlier then the normal "Christmas" launches around the 25 and 26 of December.

The September launch is now scheduled for February 2010.
If both of these launches work out as planned GLONASS will get very close to its full operational capabilities (FOC). The picuture gives the current GLONASS status which is already pretty good.

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Monday, 21 September 2009

GLONASS Launch Delay

*** UPDATE *** UPDATE ***
The GLONASS launched is delayed because of a problem with one of the three GLONASS-M satellites. The new launch data is October 29, 2009.
*** UPDATE *** UPDATE ***

The preparations for the next triplet GLONASS-M satellites scheduled for September 25, 2009, are progressing. Roscosmos is releasing interesting videos and pictures from the preparations. This is really exciting since this is, according to my knowledge, the first time that pictures like this are released officially by Roscosmos. A very good and positive development!

Furhtermore, last week the frequencies of two active GLONASS satellites were changed. For the two "antipodal" satellites in plane one, with GLONASS numbers 701 and 728, the frequency channel was changed from 1 to -4. This is an indication that the September launch will put 3 new satellites in plane 1. This is not surprising since it carries the two oldest satellites in the constellation, 701 from December 2003 and 712 from December 2004 with 701 being the first and therefore oldest GLONASS-M satellite. The "modernized" GLONASS satellites that live significantly longer then the first generation GLONASS satellites.

For those wondering what "antipodal" means. In GLONASS these are two satellites that fly in the same orbital plane but with an 180 degrees angle between them, meaning they are on opposite sides of the world. Several years ago the GLONASS system has been kind enough to have given back half of its frequency allocation because those frequencies were interfering with astronomical observations. However, for the GLONASS system, where the satellites are identified based on having different frequencies, this caused a small problem since there were no longer 24 different frequency channels available. However, since satellites on opposite ends of the Earth will not be observed simultaneously by an Earth bound observed the GLONASS system introduced the concept of using the same frequency channel for "antipodal" satellites.

Personally I am very much looking forward to the launch at the end this month as it will further improve the GLONASS performance and bring it very close to the GPS performance. In my "high accuracy" work (I deal with millimeters) we can now clearly see the benefit of using GPS and GLONASS compared to using just GPS.

Happy positioning and timing!

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Tuesday, 8 September 2009

GLONASS Launch Preparations

This is something really cool so I just had to put this link here for you all to see. This link shows the preparation of one of the GLONASS-M satellites that is being prepared for launch. The launch is scheduled for Septermber 25, see my earlier post.

This video has been posted on YouTube by Roscosmos, the Russian Space Agency.

Check it out is is really cool!

Personally I am very much looking forward to the launch at the end this month as it will further improve the GLONASS performance and bring it very close to the GPS performance. In my "high accuracy" work (I deal with millimeters) we can now clearly see the benefit of using GPS and GLONASS compared to using just GPS.

The GNSS future looks bright!

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Wednesday, 26 August 2009

GLONASS Launch Schedule Update

As in 2008 the GLONASS schedule promises again two triplet launches this year. The first one to take place on September 25, just like in 2008. The second is planned for the meanwhile "traditional" Christmas launch around the end of December. The first satellite for the September launch has been shipped to the Baikonur spacedrome and launch pad in Uzbekhistan. The two other satellites will follow in late August and early September.

Currently there are 18 healthy dual frequency GLONASS satellites. With the two triplet launches of this year the constellation should reach the "magical" number of 24 satellites which is the amount of satellites needed to reach to so-called "full orbit constellation" (FOC). However, for FOC each of the three orbital planes of the GLONASS system will need 8 satellites. Currently the planes have 5, 5, and 8 respecitively. So most likely the launch in September will be used to populated plane I which has the oldest satellites. The December launch will then repopulate plane II.

Plane I has two rather old satellites, by GLONASS standards, one from 2003 (SVN-701 in slot 6) and one form 2004 (SVN-712 in slot 7). These might die before the end of this year. The offical planned FOC data is by the end of 2010. In 2010 two more triplet launches are planned again in September and December.

The really exiting part of that will be the launch of the the new platform, the GLONASS-K satellite. One of the 3 satellites to be launched in December 2010 will be a GLONASS-K satellite. The most important features of this new GLONASS satellite generation are:
  • Longer life time, design life time of 10 years
  • Much lighter satellites reducing launch costs and enabling launches with Soyus rather then with the huge and costly Proton launcher
  • Addition of GPS-like CDMA signals.

The addition of CDMA, in paralel to the GLONASS original FDMA signals, will make GLONASS interoperable with GPS (and Galileo). This will enhance the interest and usage of GLONASS even further then its already rapidly spreading usage.

The GNSS future looks very interesting and very bright!

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Monday, 10 August 2009

Last launch of GPS Block IIR Satellite

On August 17 the last GPS Block IIR satellite will be launched. It will be named SVN50/PRN21. This launch is the end of the aera of the Block IIR, "replenishment", satelites. The next satellite generation to be launched will be the Block IIF, "future", satellites. Of course the lifetime of 10 years will mean that we will use GPS Block IIR satellites for the next decade.

SVN50 will be placed into orbital plane/slot E3, replacing SVN40, a Block IIA satellite launched in July 1996 that is past its design life but still working well. SVN40 will be moved a little further along the orbital path. Successful launch and activation of the new satellite will bring the constellation to 31 operational satellites, not counting SVN49 which is still set unhealthy due to its signal anomaly.

Here it is important to note that SVN50 will not have any payload connected to the J2 auxiliary payload port that proved problematical with the L5 demonstration payload on SVN49, and possibly on other Block IIR/IIRMs.

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Wednesday, 25 March 2009

Innovative GPS Satellite Launched

On March 24, 2009, a next GPS Block IIR-M satellite was succesfully launched. This satellite carries an interesting innovative payload that is capable of sending signals on the new L5 civil frequency. It was launched successfully with a Delta II rocket from Cape Canaveral Air Force Station in Florida.

Follow-on generations of GPS spacecraft will include an operational L5 signal to improve the accuracy and performance capabilities of the system, in particular for civil users. This new satellite, designated GPS IIR-20(M), will demonstrate this new civil signal located on the L5 frequency (1176.45MHz). The signal will comply with international radio frequency spectrum requirements.

GPS world quotes
Don DeGryse, Lockheed Martin's vice president of Navigation Systems “Working closely with our Air Force partner, and building upon the design capabilities of the IIR-M space vehicle, the team has developed an innovative, low-risk, low-cost demonstration payload that will pave the way for the new operational third civil signal. We look forward to a successful demonstration of this critical capability and setting another modernized GPS spacecraft into operations as quickly as possible.”

The original plan was to demonstrate the new L5 signals on the first Block IIF GPS satellite generation. However, the L5 frequency band was assigned to the GPS system under the condition that it would use the frequency before the end of 2009. Due to significant delays in building the new IIF generation of satellites it became impossible to launch those satellites before 2010. Therefore a special experiment was designed and implemented on this block IIR satellite.

So on this satellite the L5 signals are only an experiment and, to my understanding, the L5 experimental transmitter will only be on "occasonaly" and not permanently. Furthermore, it is unclear whether there are any receivers capable of tracking these new signals when they are transmitted. So although a very interesting innovation it is not something that will widely be used. However, if any L5 data from these satellites becomes available it will be very interesting to have a detailed look at it just as at the Giove-A and Giove-B signals.

Let us wait and see when we get the first L5 "beebs".

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Thursday, 25 December 2008

Successfull GLONASS Launch

The GLONASS launch planned for today, December 25, 2008, was successfull! Launches around Christmas are by now a tradition for GLONASS. Since several years the Christmas time is used to make "triplet" launches. This launch was the second triplet launch this year and will bring the number of active GLONASS satelites to 20!

A very nice Christmas present from Russia to the GNSS world! These satellites further enhance the GLONASS constellation and bring it yet again a step closer to completion. More interestingly, the combination of GPS and GLONASS is also profiting from a ever increasing GLONASS constellation.

According to the orbiter-forum the spacecrafts have been given the designations Melchior-2447, Gaspar-2448 and Baltasar-2449.

Last but not least I wish all my readers that they will find their direction(s) in 2009!

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Wednesday, 17 December 2008

GLONASS Launch Schedule Update

The GLONASS schedule promised two triplet launches this year. The first one took place on September 25. The second is planned for December 25.

All three satellites of the September launch were succesfully taken into serve, in fact in record time! Unfortunately some older GLONASS satellites were decomissioned in the September/October timeframe. So the current GLONASS constellation consists out of 16 active and healthy GLONASS satellites.

The launch in December should bring to total number of satellites up to 19. With the oldest satellites being from 2004. This great number of satellites together with the ever growing size of the GNSS station tracking network makes GLONASS a very interesting addition, and even independent alternative, to GPS. Within the International GNSS Service there are two Analysis Centres that do a full fledged GNSS analysis, i.e., a processing of the combination of GPS and GLONASS observations to estimate the satellite orbits but also Earth Orientation parameters, station coordinates, and atmospheric influences. These two Analysis Centres should start seeing a significant benefit from the combination of the two systems (but more on that in a next post).

The next big step for GLONASS will be the new platform, the GLONASS-K satellites. That will increase the lifetime of the satellites and, more importantly, should move GLONASS from the FDMA technique to the CDMA technique used by GPS and Galileo. That will make all three systems interoperable and will keep the end-user equipment simple and therefore cheap!

Last but not least: Merry Christmas!

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Thursday, 18 September 2008

GNSS Launch Schedule

Since my earlier post this year several things have changed so it is time for a short GNSS launch update.


Galileo has kept its "promise" and successfully launched the Giove-B satellite on April 27, 2008. The real special of this satellite is its extremely stable on board clock, a hydrogen maser clock. This is the first time a clock like that is flown on a GNSS satellite and it seems to be performing really well. The next step in the Galileo project will be the IOV phase (In Orbit Validation). For the IOV 4 satellites will be launched in a constellation that will allow the simultaneous visibility of all 4 satellites for a limited amount of time each day. This is similar to what was done with GPS in its early days. The IOV phase is currently scheduled for 2010, but with this project one never knows. Galileo FOC (Full Orbit Constellation) is scheduled for 2014 although it would be saver to say 201x (if not 20xx).


There were four GPS launches planned for 2008; in March, June, August, and September. The launch in March took place, GPS-48 (PRN07), a Block IIRM (2R-19)satellite, was launched successfully. The launch from June (2R-20) has been postponed and is now scheduled for November 7. The launch of the first Block IIF, (Future) satellite which was planned for August, has been moved to 2009. The third launch (2R-21) is currently TBD (to be determined) sometime in 2009. Although this slippage of the launch schedule looks bad it is not. There are currently 30 active satellites so there is no dire need for fresh new satellites. Unfortunately, GPS-35 (PRN05) is at its end because all its clocks have gone bad. It is one of only two GPS satellites that were equipped with special Satellite Laser Ranging (SLR) refelectors. Currently, none of the future GPS satellites are scheduled to carry such an equipment which is really a big loss for the scientific community. Fortunately, all GLONASS and Galileo satellites will carry SLR reflectors!


The GLONASS schedule promises two triplet launches this year. The first one no September 27, the second on December 25. Currently there are 16 GLONASS satellites although only 14 have been usable in the last weeks. If we assume that all the GLONASS satellites launched before 2005 are decomissioned the GLONASS constellation will still grow to 17 active satellites. Since we can savely assume that some of the 2003 and 2004 satellites will remain active we should see a GLONASS constellation of more then 18 satellites. That would be a very good achievement for the GLONASS system and will make it really usable! The next big step for GLONASS will be the new platform, the GLONASS-K satellites. That will increase the lifetime of the satellites and, more importantly, should move GLONASS from the FDMA technique to the CDMA technique used by GPS and Galileo. That would make all three systems interoperable and will keep the end-user equipment simple and therefore cheap!

Stay on track!

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Saturday, 26 January 2008

2008 An interesting year for GNSS!

The year 2008 promises to become a very interesting year for the Global Navigation Satellite Systemss (GNSS). You say why? Well let me explain.

Lets first have look at the dominating global satellite navigation system, the American NAVSTAR GPS (Global Positioning System). What makes 2008 special for 2008!? Well there are four launches planned. Most of them are really needed to ensure that the system remains complete. Currently there are 32 GPS satellite operational. This is actually the maximum number of PRN codes that were originally envisioned for GPS. However, from the 32 satellites 14 are relatively old Block IIA satellites. Most (if not all) of them have passed their design life time and thus they may fail any day. Therefore launching new satellites is not really a luxury but actually a most. The interesting part is that with the new launches the L2C capacity in orbit is enhanced and will allow a thorough use of it. Thus it will allow us to evaluate how much this signal can help to improve the quality of using GPS. The real highlight is that one of the launches will be the launch of the new GPS Block IIF satellite. This will be really interesting since it will be the first GPS satellite which emits signals on three frequencies. This will open up a whole new "world" to the users of the GPS constellation. I am really looking forward to working with the first data from this satellite and analyse the quality of the new signalis. The triple frequency will offer an exiting field for new usage of the GPS signal. The launch of this satellite is currently scheduled for August 2008. The other GPS launches are planned for March, June, and September.

Now to the Russian based system GLONASS. By the way the abreviation GLONASS comes from the Russion "Global'naya Navigatsionnaya Sputnikovaya Sistema" which may be translated as "Global Navigation Satellite System". Also for GLONASS 2008 holds quite some promise. After the two successful "triplet" launches in October and December 2007 the GLONASS system currently has 16 active satellites. The launch schedule for 2008 is not 100% clear (it is still difficult to get reliable information out of Russia). However, at least one additional triplet launch is planned but there are also indication that there will be two. The first triplet launch is scheduled for September. The second may be, as is almost a GLONASS tradition, around Christmas 2008. The most interesting fact for GLONASS is the planned launch of the first new GLONASS-K satellites. The GLONASS-K, is an entirely new model based on the non-pressurized platform, standardized to the specifications of the previous models' platform, Express-1000. Its main difference with the previous GLONASS satellites is that is much lighter (about half the weight!). This allows them to be launched (two at a time) with the Soyuz launcher which is much cheaper than the Proton launcher currently used (even if it launches three satellites at the same time). Furhtermore the design lifetime of the GLONASS-K satellites is much longer. There are rumours that the GLONASS-K will also transmit on three frequencies. But this is not very clear at the moment. In any case it will be interesting to see if Russia can keep up with their very ambitious plan of restoring GLONASS to full orbit constellation (FOC) by 2009. So far they have been doing very well and I am convinced that they will manage this. The only real threath to this goal would be significant politcal changes is Russia. Given the fact that Putin seems to have all well under control this threath does not seem to be very large. In any case it will be very interesting to receive the first GNSS data from this completely new satellite and see how both the data and the satellite will behave.

Next to GPS and GLONASS there are also developments on the European "front". As you may know Europe is in the process of building up its own Global Satellite Navigation System, called Galileo. A first test satellite, called GIOVE-A, is in orbit since two years and performing very well. In 2008 its "larger brother", called GIOVE-B, is scheduled for launch in April. The real "special" GIOVE-B offers is its on board clock. The on-board clock is the single most important instrument of any GNSS satellite. Therefore, all GNSS satellite use atomic clocks since those are the only ones which offer the required clock stability. And since the clock is so imporant typically 3 or 4 clocks are on-board for redundancy purposes. The new thing on GIOVE-B is that besides atomic clocks it will also have what is called a Hydrogen Maser on board. A H-maser on the long term is not as stable as an atomic clock but on the short term (12-48 hours) it is extremely stable. Thus the behavior of a H-maser clock can be predicted much betten than an atomic clock. And since the navigation messages as broadcasted by all GNSS systems are based on predictions the use of H-masers offers a significant accuracy improvement for the end-users (e.g. you and me with our cars navigation systems). So it will be very thrilling to see the behaviour of the H-maser in orbit. This is the first time such a clock is flown on a GNSS satellite! Furthermore, it will be very interesting to observe the GIOVE-B signals and validate if they can uphold the European Galileo promise of much improved signal quality compare to GPS and GLONASS. Furhtermore, there is also some rumour that the GIOVE-A2, a copy of the GIOVE-A, will be launched in November 2008. However, I believe that this will only happen if the GIOVE-B fails.

Furthermore, 2008 will certainly also show some new developments on the Chinese side of the GNSS world. The Chinese are quickly expanding their Beidou/Compass system. Currently I have very little knowledge on this system. I will dig into that during the year and "blog" about that later.

So I hope that you agree with me that 2008 holds a lot of GNSS promises! Maybe not all promises will be kept, but nevertheless even if 1 or 2 of these exiting events will come true the year will be very interesting!!

More on GNSS next month (or sooner if I can find the time).

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Wednesday, 2 January 2008

GNSS Blog Introduction

So the new year, 2008, is there and I start this year with my first BLOG site. The idea is to write things about GNSS on this BLOG. I have a very modest aim of writing one article each month on this site. So I should manage to write 12 articles this year but not counting this one! I will set the end of the month as deadline for my montly articles.

However, in this first article I would like to inform you about two recent GNSS launch events. One GPS launch and one GLONASS launch.

The GPS launch took place on 20-December 2007 at 20:04 GMT a Delta II rocket holding the newest GPS satellite, IIR-18(M) was launched successfully from Cape Canaveral, FL. This GPS satellite, IIR-18(M), is planned to be stationed in GPS orbital slot C1. This satellite has been assigned the Space Vehicle Number 57 (SVN-57) and it will use the Pseudo Random Noise code 29 (PRN-29). This new GPS satellite is expected to be set healthy for use in early January 2008.

Click here for detailed information on the GPS constellation status.

The GLONASS launch took place on 25-December-2007 three more GLONASS satellites were launched successfully. This second successful launch in 2007 will bring the GLONASS constellation up to 16 satellites. With this the GLONASS system remains well on track to reach full orbit constellation and full availability in 2009.

Click here for more information regarding the GLONASS launch.

Click here for detailed information on the GLONASS constellation status.

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