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dorisreport             04-Aug-2020 15:40:39 Message No 5096
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Author: "Lemoine, Frank G. (GSFC-61A0)" <frank.g.lemoine@nasa.gov>
Subject: Submission of gscwd40 SINEX series to the IDS Data Centers.


Authors:
F.G. Lemoine (Frank.G.Lemoine@nasa.gov)
D.S. Chinn   (Douglas.S.Chinn@nasa.gov)
N.P. Zelensky (nzelensk@umd.edu)
Alexandre Belli (Alexandre.Belli@nasa.gov)

 We have submitted a new SINEX series, gscwd40, to the
 IDS Data centers.  This series represents a complete reprocessing of all
DORIS data from November 1992 to May 2020, and represents
another step in developing a NASA GSFC reprocessed DORIS
contribution for ITRF2020.

This delivery includes 1438 weekly SINEX files
(Earth Orientation Parmeters and Station Coordinates)
from 1992-DOY0285 (Oct. 11, 1992)
  to    2019-DOY0363 (Apr. 26, 2020)

The following satellites were processed:
 SPOT-2, SPOT-3, SPOT-4, SPOT-5,
 TOPEX/Poseidon, Jason-1, Jason-2, Jason-3,
 Envisat, HY-2A, Cryosat-2, Saral.

This series builds on gscwd35 series and introduces
the following changes:

1. The SPOT-5 radial offset is adjusted weekly over the duration
   of the SPOT-5 mission.
2. We used 3.5day arcs from 1999 to 2003, instead of 7.0 day
   arcs in the previous series, for SPOT-2, SPOT-4, SPOT-5, and Envisat.
   In addition, when the solar flux was very high (> 180), we adjusted
   empirical accelerations for the along and cross track components
   every 6 hrs and with a correlation time constraint of 6 hrs as well.
   (This was tested in the series gscwd39).
3. We have lowered the elevation cutoff on the data to 7.0 degrees
   instead of 10.0 degrees.
4. We have introduced an elevation-dependent weighting function.
   We apply 1/sqrt(sin(elevation)) as the weighting factor on the
   DORIS data.
5. Since the weighting function on average downweights the DORIS data,
   we have changed the data sigma used in GEODYN from 2 mm/s to 1.25 mm/s
   for data after 2003. For data prior to 2003, which already had a higher
   RMS of fit
   (cf. Fagard, 2006, J. Geodesy, Lemoine et al., 2010, Adv Space Res),
   we have not changed the GEODYN-applied data sigma.
   The data sigma in combination with the
   weighting factor will propagate through to the formal standard
   deviations for the estimated parameters.

For other details in the modelling, the reader is referred
to the description file for the gscwd35 series at the
IDS data centers (gswd35.snx.dsc) and
 to DORISReport No: 4992 :
   "Submission of gscwd35 solution to the IDS Data Centers",
    dated Mon, 23 Mar 2020 19:51:34.


Please do not reply directly to this message, but send 
comments and suggestions to IDS.central.bureau@cls.fr