[IGSMAIL-5439]: IGS Ultra Combination (IGU): 1396 2 12 (Resubmission)

Gerd Gendt3 igsacc at gfz-potsdam.de
Tue Oct 10 08:39:01 PDT 2006


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IGS Electronic Mail      10 Oct 08:39:07 PDT 2006      Message Number 5439
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Author:  AC Coordinator / GFZ Potsdam

Ultra Rapid IGS Orbit Combination - Week 1396  Day: 2  Hour: 12  (Oct 10, 2006)

Contacts:  G.  Gendt  (gendt at gfz-potsdam.de),
          Th. Nischan ( nisn at gfz-potsdam.de)


COMBINATION STRATEGY:
---------------------

For a complete description of the combination strategy along with all tables 
and statistics, please refer to the IGS Final Combination reports posted on 
CDDIS within 13 days after the end of the GPS week.


PRODUCT FILES:
--------------

The Rapid Orbit files generated and uploaded into CDDIS @ NASA/GSFC are:

igu13962_12.sp3   IGR GPS ephemeris in SP3 format.
igu13962_12.erp   Earth Rotation Parameters (ERP) and their rates as well as
                  Universal Time (UT1-UTC) and Length Of Day (LOD) associated 
                  with IGS ephemerides.
igu13962_12.sum   Combination summary report.

    
REMARKS concerning the IGU Orbit Combination:                                  
---------------------------------------------

 1. The following centre clock solutions, which provide broadcast and/or 
    predicted clock corrections, were excluded from the combination but kept 
    in the combination statistics:
    
             -> Centre: GOU COU 

 2. The following orbit solutions were excluded from the combination because
    they were biasing the weighted average. They were still used for statistics
    computation unless all centres were excluded for the problem satellites in 
    which case they were simply eliminated from the combination and statistics.
    The following table lists the exclusions:
    
                Centre | PRN list
               --------+---------------
                  EMU  |  29
                  GFU  |  29

 3. The following orbit solutions were excluded from the combination because
    less than 3 ACs have submitted results for given satellite(s).
    The following table lists the exclusions:
    
                Centre | PRN list
               --------+---------------
                  COU  |  31 
                  GOU  |  29 

 4. Starting on 02-Dec-2001 (GPS Week 1143-0, MJD 52245) all IGS products,
    including the IGS combined orbits, are based on the  IGS realization of
    the ITRF2000 reference frame (IGb00).
    For more information see IGSMAIL #3605.


    
ORBIT COMBINATION AND EVALUATION STATISTICS:                                    
--------------------------------------------                                    

Table 1: Daily transformation of each centre to the combined IGU orbit
         and clocks. 
         
         WRMS - RMS weighted by the centres SP3 header accuracy codes.
         STA  - Number of stations in the daily solutions.
         Units: mas, ppb, meters, nano-sec, nano-sec/day.
   
Table 1.1396.2   GPS week: 1396   Day: 2   MJD: 54018.500                            

CENT STA|  DX   DY   DZ    RX    RY    RZ  SCL  RMS WRMS |   TOFT  TDRFT    RMS
--------+------------------------------------------------+---------------------
cou   74| .00 -.00  .00   .00  -.02  -.47  -.1  .06  .04 |     .1   -1.2   7.54
emu   54| .00 -.00 -.00   .14  -.02   .05   .0  .06  .05 |  -17.0   -5.9    .68
gfu   61|-.00  .00  .00  -.10  -.25   .55  -.1  .10  .04 |     .6    -.2   4.46
gou   41| .00  .00 -.01   .19   .01   .05  -.0  .06  .06 |    -.0     .0  11.84
siu   42|-.00  .00  .03  -.47   .78  -.09   .4  .17  .12 |     .0     .0    .0 
usu   34| .00 -.00  .00  -.32   .04  -.03   .1  .14  .12 |    2.6  -13.6   3.22



Table 2: Daily fit for each satellite and each centre resulting from weighted
         average combination. 

         The last column gives the IGU resulting satellite accuracy measures 
         found in the IGS SP3 header. Eclipsing satellites are flagged with 
         "E" (or "M" for moon) beside the PRN number. "X" stands for excluded
         from RMS,  WRMS and MEDI-combination statistics but included in IGU

         Units: cm.

Table 2.1396.2   GPS week: 1396   Day: 2   MJD: 54018.500                            

        Weighted Average              
 PRN  | cou emu gfu gou siu usu  IGU |
------+------------------------------+
   1E |   3   9  15   4   8  15    4 |
   2  |   5   4   7   3   9  30    5 |
   3E |   4   6   6  11  30  11    5 |
   4  |   5   3   3   4  14  17    3 |
   5  |   5   6   3   6  12  10    3 |
   6E |  10   3  17   9  11  26    6 |
  X7E |   4   3 ---   7  19  14    4 |
   8  |   3   3   3   3  12  14    3 |
   9  |   3   3   4   7   6   8    2 |
  10  |   2   4   6   4  12  16    3 |
  11  |   4   4   4   5  22   6    3 |
  13E |   4   5   5   5   5   9    2 |
  14E |   3  16  14   6   9  11    5 |
  15  |   4   6  10   5   7  14    3 |
  16  |   5   3   4   4  49  12    6 |
  17E |  11   7  24   6  20   7    6 |
  18  |   2   5   4   2   8   9    2 |
  19E |  15  15  17   9  12  15    6 |
  20  |   5   6   4   6  14   7    3 |
  21  |   3   4   3   5  13  15    3 |
  22  |   3   3   3   4  11   9    2 |
  23E |   4   7  13   6  10   7    4 |
  24  |   4   3   3   4   6  16    3 |
  25  |   5   5   3   3  30   9    4 |
  26E |   8   6  25   4  11   7    5 |
  27  |   2   2   3   3  19  15    3 |
  28  |   4   6   4   7  19  12    3 |
 X29E |---- --- --- --- --- ---    0 |
  30  |   3   5   4  12  19  11    4 |
 X31  |---- --- --- --- --- ---    0 |
------+------------------------------+
 RMS  |   6   6  10   6  17  14      |
 WRMS |   4   5   4   6  12  12      |
 MEDI |   4   5   4   5  12  11      |



Table 3: Earth Orientation Parameters daily summary.                           
                                                                              
         Daily Centre ERP, ERP Rates and LOD differences with respect to       
         IGU combined values.                                                  
                                                                              
         Xpole,Xrt: x pole and x pole rate (10**-5")                           
         Ypole,Yrt: y pole and y pole rate (10**-5"/day)                       
         LOD: Length Of Day (us)                                               
                                                                              
         AC LOD BIAS: 21-day mean LOD bias with respect to Bulletin A (us)     
         AC LOD BIAS RMS: RMS of AC LOD BIAS (us)                              
                                                                              
         FLAG: "u" (used), "x" (excluded), "-" (no submission)                 
               for Xpole, Ypole, Xrt, Yrt and LOD                              
                                                                              
         A star ("*") beside the AC name indicates that AC LOD values were     
         derived from AC UT1-UTC values.                                       
                                                                              
         Remark: COU submits ERP-products for 00 and 12 UT only,               
                 for 06 and 18 UT extrapolations are used.                            


Table 3.1396.2   GPS week: 1396   Day: 2   MJD: 54018.000
                                                     AC LOD   AC LOD
CENT  FLAG  |  Xpole  Ypole    Xrt    Yrt    LOD |    BIAS  BIAS RMS
------------+------------------------------------+------------------
cou   uuuuu |      2    -17     -4     -3    -15 |      -1     15
emu   uuuuu |     -4    -11      3     -6     23 |       0     17
gfu   uuuuu |      8     20      6     -6      1 |      26     33
gou   uuuuu |      0    -10     11     10    -22 |      -2     31
siu   xuuuu |    -87     51    -56      1     12 |      31     90
usu   uuuuu |    -10     30      0      8     -1 |      16     23

Table 3.1396.3   GPS week: 1396   Day: 3   MJD: 54019.000
                                                     AC LOD   AC LOD
CENT  FLAG  |  Xpole  Ypole    Xrt    Yrt    LOD |    BIAS  BIAS RMS
------------+------------------------------------+------------------
cou   uuuuu |     -5     14     -7      7    115 |      -1     15
emu   uuuuu |     -4    -17     -1      9    -55 |       0     17
gfu   uuuuu |     38      8     44     -7     77 |      26     33
gou   uuuuu |    -18    -36     -3    -21     45 |      -2     31
siu   xuuuu |   -114     51     -8      7    108 |      31     90
usu   uuuuu |     -2     34    -40     13   -224 |      16     23



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