Subject: [IGSMAIL-1388] Changes in EMR IGS Processing
From: Pierre Tetreault
Date: Mon, 15 Jul 1996 13:11:29 PDT

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IGS Electronic Mail      Mon Jul 15 13:11:29 PDT 1996      Message Number 1388
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Author: Pierre Tetreault
Subject: Changes in EMR IGS Processing

Subject: Changes in EMR IGS Processing

Dear IGS colleagues,

As of June 30, 1996 the EMR solutions submitted to IGS are performed in
agreement to the following IGS Silver Spring 1996 Workshop recommendations:

1)  ITFR94 coordinates and velocities used for the 13 IGS fiducial stations;
2)  Diurnal and semi-diurnal EOP terms (Ray model) are applied to the 
    observations and to the orbits but are not applied to the reported
    EOP's.  The reported EOP's are linear 24 hour averages.

In addition EMR has begun estimating and reporting Polar Motion (PM) rates
as of June 30, 1996.

The resulting discontinuities in EMR products have been estimated 
by processing Wk 859 both without and with the changes and are listed
in Table 1.

            Table 1:  June 30, 1996 Discontinuities in EMR Products 
                           (ITRF94 to ITRF93)
    
    Solution  T1(cm)  T2(cm) T3(cm) D(ppb)  R1(mas) R2(mas) R3(mas)
                                            (Ypol)  (Xpol) (-Ut1)   
    Stations  -2.0    -0.3   -0.4     .4   -1.41   -.84    -.72
    sigma       .1      .1     .1     .1     .05    .05     .03

    Orbits    -1.2     0.5   -0.2     .0   -1.36   -.80    -.81
    sigmas      .04     .04    .04    .04    .06    .08     .10
    
    EOP                                    -1.41   -.88    -.76       
    sigma                                    .05    .07     .21

Pierre Tetreault
-- 

EMR IGS Analysis Centre
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: [email-masked]

[Mailed From: Pierre Tetreault <[email-masked]>]