Subject: Re: DORIS orbit comparisons
From: [email-masked]
To: Pascal Willis <[email-masked]>
Cc: Martine Feissel <[email-masked]>, Markus Rothacher <[email-masked]>, "John C. Ries" <[email-masked]>, [email-masked]
Date: Tue, 28 May 2002 18:54:23 +0100

Dear Pascal,

Indeed, I did indeed receive your first message but did not reply to it.
For the foreseen JASON orbit campaign I am expecting to get fairly wide
participation, considering that IGS LEO, IDS and CSTG are interested.
The announcement of this campaign is pending (a) a formal release of
the data (so that all interested groups can actually do JASON POD) and
(b) the identification of a suitable campaign period.

Most groups that are interested in participating are not involved with the
CALVAL process, and for that reason they do not have access to either
the tracking data or to the satellite models (antenna offsets etc).
An initial comparison at this point in time could only be organised among
the CalVal groups. ESOC is not one of those, even though I have
collected just about all information needed for JASON POD, thanks to
informal contacts with CNES. My JASON POD efforts are currently aimed
at identifying the best campaign period, rather than anything else.

If you would like to prepare something for the Biaritz meeting (...which I will
not attend, by the way) I would suggest that you also look into the most
suitable period for the campaign. From what I have seen so far, I mainly
derive the following requirements:
* about 30 days (3 cycles) with a minimum number of orbit events
* preferrably a period for which attitude quaternions are available
The data quality seems to be very homogeneous, but I have not yet
analysed all available data.

Perhaps we can simply release all required data through the various LEO
groups (IGS LEO, IDS, CSTG) but it would be more polite to wait for CNES
to do something like that. In fact, I expect that they will do so after
Biarritz.

Best regards,

Henno

Dear Henno,

could you please confirm that you got my previous message concerning
the availability of JASON orbit files (Gipsy-Oasis II JPL/IGN
solutions) by anonymous ftp on sideshow?

It would be quite easy for me to put orbit files for SPOT2, SPOT4 and
TOPEX for the same period of time 2002-JAN-16 to 2002-APR-24. Of
course, any other period of time would also be quite easy to provide
too.

Do you plan to do some early comparisons before Biarritz or do you
plan to use the Biarritz meeting to start the organization of a
campaign of comparisons?

Best regards
Pascal