Dear Markus,

for your information, there is now a fourth DORIS Analysis Center 
that has recently submitted one year (2004) of DORIS weekly 
solutions with the same level of precision of the three previous 
group: NASA/CDDIS (Frank Lemoine). It is extremely important for 
DORIS, because it brings a new software and a slightly different 
analysis strategy into the picture.

Concerning the meeting itself, I don't think that my presentation is 
required. Let Martine Feissel describe the whole DORIS context as 
Analysis Coordinator. I will participate in the discussion when 
needed.

In my opinion, we should also spend more time about the 
objectives of the working group: what products are we supposed to 
obtain, from what data (weekly solutions or the full time series, 
using or not geodetic local ties or not, individual ACs solutions or 
combined intra-techniques solutions or both,...). We just started 
some initial discussion in Napa but we could not follow it to the 
end. We need to discuss the goal first before discussing very 
technical issues.

Following a suggestion from Jim Ray, I would also like that the 
leadership of this group could be addressed during our meeting in 
Vienna. Asfar as I know, no combination is currently available from 
this experiment since its begining. We can't just continue forever to 
discuss about what COULD be done, at some point we need to DO 
some type of combination, otherwise we should just stop this 
working group as it could be too premature at this point. The 
groups doing some combinations should could also consider 
distributing some information on a regualr basis using the Bulletin 
Board that you set up.

Concerning "IERS products" I think that the whole discussion is 
totally premature. To follow some  wise procedurex used by IGS for 
years, we first need the working group to provide some results, 
then we need to test if the products can be done efficiently and in a 
defined timetable at a certain precision and only then we can 
discuss of accepting a new products. Let us show first that it is 
feasible, that some groups are willing to do that on a regular basis 
and that, in a operational mode, it can achieved some predefined 
precision. In my opinion, we are far from there! The only thing that 
has changed in the past year is that the techniques have evolved to 
provide sinex products (combined or not) on a regular basis. The 
combination part seems to be at the same level or operationality 
and results. I would welcome all type of discussion before Vienna 
on this Bulletin Board instead of seing "preliminary results" every 6 
months at some meetings.

My personnal suggestion for this whole group (that is for me done 
in parallel with the ITRF2004 realization and not identical to it) is 
that we can provide before summer 2005 some combination 
products at the ftp site that you created. Otherwise, in September 
2005,  I would be in favor to close this whole acitivity and to 
reopen it later on in the future when we can effectively do it instead 
of just talking about it. I don't think that it is a good strategy for 
IAG in general and for IERS in, particular to keep non-active groups 
over long periods of time.

Looking forward your anwer or answers from other members of 
this group

See you all in Vienna
Pascal

----- Original Message -----
From: Markus Rothacher <Markus.Rothacher@bv.tu-
muenchen.de>
Date: Sunday, April 17, 2005 11:41 pm
Subject: Agenda of the IERS Combination WG Meeting in Vienna

> Dear Colleagues,
> 
> please find attached the draft agenda of the
> IERS Combination WG Meeting. If you have a short
> presentation relevant for one of the topics,
> please let me know, so that it can be included in the agenda.
> The focus should be, however, on topic 5, the
> "Next Steps and Future IERS Products", where we should
> allow much time for a thorough discussion of the next steps,
> the strategies and goals (including ITRF2004 and IERS CPP),
> based mainly on the draft document "Steps Toward Future IERS
> Products" that I will send out Tuesday or Wednesday this
> week as a priori information.
> 
> I would also like to mention that a third DORIS long time series
> has been submitted by LEGOS-CLS (LCA). It will be available
> in the IERS database soon.
> At present, we are still missing the IVS combined solution.
> 
> Hope to see you all in Vienna.
> With best regards,
>                          Markus Rothacher
> 
>