Date: Wed, 14 Jun 2000 17:38:24 -0700 (PDT)
From: Robert F Meyer <rfm@cobra.jpl.nasa.gov>
Message-Id: <200006150038.RAA04768@kalman.jpl.nasa.gov>
To: IGSREPORT@IGSCB.JPL.NASA.GOV, SCIGN@IGSCB.JPL.NASA.GOV
Subject: [IGSREPORT-7263] JPL GNAAC Analysis Report: New Format and <7 ACs
Sender: owner-igsreport
Precedence: bulk

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IGS Electronic Report   14 Jun 17:38:25 PDT 2000      Message Number 7263
******************************************************************************

Author: R F Meyer

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NEW GNAAC COMPARISON FROM JPL FOR GPS WEEK(S)  1062, 1063, 1064++ 14-JUNE-2000 
******************************************************************************

R F Meyer (Raytheon, Pasadena, CA); M B Heflin, J F Zumberge, D C Jefferson,
M M Watkins, F H Webb (Jet Propulsion Laboratory, California Institute of
Technology, Pasadena, CA)

**NOTE: 

     1) Only 6 of the 7 Analysis Centers [AC] are available. SIO is missing.
        Solutions in SINEX format, if available, are obtained from:

               COD, EMR, ESA, GFZ, JPL, NGS, SIO.  

        For weeks: 1062, 1063, 1064, the SIO SINEX solutions were not available.
        This is reflected in the tabular output and typically results in less 
        sites in common.

     2) For weeks 1062 and later, a new output format is reported.
        The format now includes one more significant figure for each of
        the North, East and Vertical WRMS values (NEV) in millimeters [mm].

        The tabular format is now three lines per AC. The first line is 
        WRMS N [mm] and WRMS E [mm]. The second, WRMS V [mm] and the third
        line indicates the number of sites in common for the combined 
        or site-wise pair. [an example for GPS week 1062 is shown].

Each center was compared to each other center by estimating a 7-parameter
Helmert transformation to minimize the least-squares coordinate residuals.

The following table summarizes comparison results.  The North, East, and
Vertical WRMS values are given in mm for each pair.  The number of common sites
is given directly underneath the values for WRMS.  The number underneath each
center's name is the scale factor applied to the formal errors from that
center.  Transformation parameters for each pair are given at the end of the
report.

We also compute a free-network combination of solutions from all centers.  Each
solution is scaled and edited according to the results of pairwise comparisons.
Then all free-network solutions are rigorously combined using their full
covariance matrices.  Sites common to all solutions are used to compare
individual solutions with the combination and residuals are given in the first
row of the comparison table.


Example: Week 1062

   N [mm.m] E [mm.m]
       V [mm.m]
     common sites


TABLE OF COMPARISON RESIDUALS (N E V in mm)
-----------+---------+---------+---------+---------+---------+
     cod       emr       esa       gfz       jpl       ngs    
c+---------+---------+---------+---------+---------+---------+
o| 2.1  2.0| 2.6  3.0| 2.4  3.6| 1.5  1.7| 1.1  1.6| 3.9  5.5|
m|    9.2  |    4.1  |   10.2  |    4.0  |    4.5  |    6.7  |
b+    13   |    13   |    13   |    13   |    13   |    13   |
++---------+---------+---------+---------+---------+---------+
     cod   | 6.0  4.4| 2.4  3.9| 3.8  3.5| 3.9  3.2| 5.6  6.2|
           |   11.5  |   12.6  |   12.2  |   13.3  |   11.2  |
    15.0   |    35   |    42   |    55   |    58   |    58   |
           +---------+---------+---------+---------+---------+
               emr   | 5.9  6.3| 3.4  5.4| 3.0  4.3| 5.4  8.2|
                     |   12.2  |    6.6  |    5.1  |    9.3  |
               5.0   |    28   |    26   |    32   |    32   |
                     +---------+---------+---------+---------+
                         esa   | 4.5  4.2| 3.6  4.6| 6.7  7.3|
                               |    7.1  |   11.1  |   13.4  |
                         8.0   |    31   |    36   |    45   |
                               +---------+---------+---------+
                                   gfz   | 2.1  2.3| 5.0  7.3|
                                         |    7.5  |    8.9  |
                                  14.0   |    42   |    46   |
                                         +---------+---------+
                                             jpl   | 5.4  7.1|
                                                   |    8.7  |
                                             4.0   |    46   |
                                                   +---------+
                                                       ngs    
  
                                                      13.0