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dorismail               05-Jun-2012 08:47:59 Message No 0826
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Author: "Capdeville Hugues" <hcapdeville@cls.fr>
Subject: Corrective model for jason1 updated


This is a multi-part message in MIME format.

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Dear colleagues,

Since May 3th 2012, the satellite Jason-1 has been moved to a geodetic
orbit. The corrective model for Jason-1 has been updated to take into
account the new orbit of Jason-1.=20

The main change is that we cannot any more consider the Topex mean
ground track (determined over a 7-year period) after the maneuvers
performed to move Jason-1 on the geodetic orbit.=20

For the new orbit, since it is drifting, we had to add another
capability in the model.=20

We can use an external orbit in a sp3 format.=20

So, before the orbit change, we can use Topex mean ground track or sp3
orbit files, and after change only sp3 files.=20

=20

The new version of software is online on the IDS ftp site with the
following upgrades:

- a new input file called < orbit_sp3 > in ANNEXE/ORBITE which contains
orbit file in sp3 format

- 6 new routines to convert the orbit to a ground track=20

- 4 routines modified to consider the new feature with sp3 files=20

=20

A regular update of the model is also done by considering the news DORIS
data since the last update.

By using data between February 20th 2009 and January 6th 2012, we
determine the recent evolution of the model parameters.

The amplitude parameter has changed and the model has been modified in
consequently.

=20

The corrective model for Jason-1 DORIS Doppler data designed by CNES is
available on the CB ftp site under:=20

=20

ftp://ftp.ids-doris.org/pub/ids/satellites/CORRECTIVE_MODEL_JASON1

=20

This model was optimized and documented in order to be able to deliver
an operational module (software) that will be used by the processing
centers of DORIS data.

You can get this model and the technical note which gives the principle
of the model and allow its implementation and its use.

=20

Please, read the Readme.txt file before getting the model.

And for those who had already installed a previous version, we recommend
to proceed to the complete installation of the new version.

=20

Best regards,

=20

H. Capdeville