Date: Fri, 15 Nov 2002 13:24:16 -0800
From: Pascal Willis <Pascal.R.Willis@jpl.nasa.gov>
To: Jean-Paul Berthias <jean-paul.berthias@cnes.fr>
Cc: "John C. Ries" <ries@csr.utexas.edu>,
    Bruce J Haines <bjh@cobra.jpl.nasa.gov>,
    Yoaz Bar-Sever <Yoaz.Bar-Sever@jpl.nasa.gov>,
    nzelensk@geodesy.gsfc.nasa.gov, sluthcke@xyz.gsfc.nasa.gov,
    krchoi@csr.utexas.edu, Martine Feissel <feissel@ensg.ign.fr>
Subject: better DORIS "dynamic" solutions ?

Hello Jean-Paul,

I have compared my new DORIS/JASON orbit solutions for the first 20 
cycles (usual modelling + 1/day R_OFF + X_OFF + Y_OFF parameter).

The agreement with the JPL/GPS reduced solution is much better: when 
looking at daily RMS over 29 hours, the median value is now 1.8 cm 
(instead of 3.7 cm before)

I think it is a significant improvement.

In the previous solutions (real dynamic runs), there was a better 
agreement between DORIS dynamic runs and GPS dynamic runs in January 
(where my estimated R_OFF value was small) and in July, when using 
the new preprocessed cycle 20.

I will now try to see if we can adopt a simple model (fix R_OFF in 
the daily dynamic runs to a conventional value) to see if it also 
improve the solution.

My guess is that the laser residuals should also be better as they 
agreed quite well with the GPS reduced dynamic, but it still needs to 
be tested.

Best regards
Pascal