Date: Tue, 28 May 2002 18:54:23 +0100 From: Henno.Boomkamp@esa.int To: Pascal Willis Cc: Martine Feissel , Markus Rothacher , "John C. Ries" , John.Dow@esa.int Subject: Re: DORIS orbit comparisons 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