[IGSMAIL-5986]: AGU2009 Session G12: Challenges and Opportunities in Combining Multiple GNSS Observations

[Tim.Springer at esa.int]

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IGS Electronic Mail      19 Aug 04:51:27 PDT 2009      Message Number 5986
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Author: Tim Springer and Yoaz Bar-Sever


Dear IGS Colleagues,

We would like to draw your attention to our GNSS session (G12) at the 
AGU2009 meeting.
The detailed session description is attached below. 

AGU abstract deadline is: September 3

Many greetings,
Tim and Yoaz


G12: Challenges and Opportunities in Combining Multiple GNSS Observations 
The availability of modernized GPS, a revitalized GLONASS, and the 
upcoming Compass and Galileo will offer many challenges but also exciting 
opportunities in the next decade. Mixing different GNSS today brings about 
significant complications like intersystem biases and because of different 
modulations, e.g. CDMA for GPS versus FDMA for GLONASS, also frequency 
dependent biases. The addition of new signals on existing frequencies as 
well as additional frequencies will further complicate matters. Today we 
are already suffering issues with this with GPS alone. The new available 
civil code measurements on the L2 frequency has lead to an inhomogeneous 
set of observations from different receivers. Some receivers now deliver 
only C1 and C2 whereas others provide only P1 and P2. The combination of 
observations of such receivers is problematic because of the biases 
present in each of these observations. Thinking about the future with 
Galileo offering 5 different measurement types on E1, 9 different 
measurement types on E5, and 5 different measurement types on E6 (see 
RINEX 3.00) the myriad of different observation combinations and biases 
becomes mind-boggling! And things get even more complicated if we think 
about GLONASS moving from FDMA to CDMA and the new Compass system. Despite 
all these challenges we are convinced that the new and improved signals, 
as well as the new and additional satellites in different orbit 
configurations do present some very exciting opportunities. This is 
especially true considering that the planned GNSS systems promise to 
increase the number of satellites by a factor of 4 and to improve the 
accuracy of the (code) measurements by a factor of 10 (from 1 to 0.1 
meters). With this session we would like to invite presentations 
addressing not only the challenges but also presentations highlighting the 
opportunities offered by the new signals and systems. We therefore would 
appreciate contributions which focus on ensuring that we will in fact be 
able to combine the observations from all different systems observed by 
many different receivers. Here contributions from the hard- and soft-ware 
receiver side are especially welcome. Furthermore we solicit contributions 
focusing on the scientific opportunities offered by true GNSS solutions, 
e.g. GPS + GLONASS, COMPASS, and/or Galileo, both today as well as in the 
(near) future.