Latest IGU Summary

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Latest IGU summary

This file is the latest summary produced in the IGS UltraRapid orbit generation, which provides a quick look into the most recent IGS analysis of the GPS satellites. 

The "REMARKS" section will note if any satellites were not included in the combined solution, due to too few analysis centers providing a solution. Any satellites which have no prediction provided due to a maneuver will also be listed.

Table 2 shows which satellites were eclipsing, the sp3 orbit accuracy code for each PRN, and whether any analysis centers did not provide a solution for any satellites.

This page is designed for humans to read, to check on how the latest UltraRapid analysis went. To obtain UltraRapid products for operational and/or automated use, please see the IGS product table.


Author:  AC Coordinator / NOAA NGS

sum-file Version 2.0
Ultra Rapid IGS Orbit Combination - Week 1847  Day: 2  Hour: 12  (Jun 02, 2015)

Contacts: igs.acc@noaa.gov


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

igu18472_12.sp3   IGU GPS ephemeris in SP3 format.
igu18472_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.
igu18472_12.sum   Combination summary report.

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

 1. The following centre clock solutions, which provide broadcast and/or 
    predicted broadcast clock corrections, were excluded from the combination
    but kept in the combination statistics:
    
             -> Broadcast Centre: GOU COU 
    
    The reference time scale is based on a linear alignment to the clocks
    of a particular centre, which is normally pre-aligned to broadcast GPS
    time.  The reference centre is chosen from the following list, in order
    of availability, and is indicated by 0 TOFT, 0 TDRFT, and non-zero RMS
    in Table 1:
    
             -> Reference Centre: EMU USU ESU GFU
    
    Starting on 1-Jul-2009 (GPS Week 1538, day 3, hour 12; MJD 55013.5),
    clock predictions are excluded for satellites set unhealthy due to MX
    or UNUSUFN NANU events.  The centre clock statistics in Table 1 do not
    include the excluded satellites; however, these are included in the later
    IGU center comparison statistics with the IGS Rapid clocks.
    
    Starting 3-Feb-2012 (GPS Week 1673, day 5, hour 00; MJD 55959.0), a new
    solution from Wuhan University (WHU) is included for comparison only. Starting
    27-Feb-2012 (GPS Week 1677, day 1, hour 12; MJD 55984.5), a new solution
    from NOAA/National Geodetic Survey (NGU) is included for comparison only.
    
    Two changes were made to the IGU starting 8-Aug-2012 (GPS Week 1700, day 3,
    hour 12; 56147.5). The WHU and NGU orbits are now included with full weight,
    and any AC contribution with orbital frame rotations larger than 300 uas will
    be excluded. This threshold is consistent with those used in the IGR rapid
    combination.

 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
               --------+---------------
                  GOU  |   8

 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  |   8 

 4. Starting 5-Nov-2006 (GPS Week 1400, day 0, MJD 54044) until 16-Apr-2011
    (GPS Week 1631, day 6, MJD 55667) all IGS products, including the IGS
    combined orbits, are based on the IGS realization of the ITRF2005 reference
    frame (IGS05).   For more information see IGSMAIL #5447.  The IGS05 frame is
    also the basis for the homogeneously reprocessed IGS products from GPS Weeks
    730 to 1459 (1994-2007); see IGSMAIL #6136.
    
    Starting 17-Apr-2011 (GPS Week 1632, day 0, MJD 55668) all IGS products,
    are based on the IGS realization of the ITRF2008 reference frame (IGS08).
    For more information see IGSMAIL #6354.
    
    Starting 07-Oct-2012 (GPS Week 1709, day 0, MJD 56207) all IGS products,
    are based on the updated IGS08 frame (IGb08). 
    For more information see IGSMAIL #6663.

 5. Starting 5-Nov-2006 (GPS Week 1400, day 0, MJD 54044) until 16-Apr-2011
    (GPS Week 1631, day 6, MJD 55667) the absolute antenna model is introduced
    (IGSMAIL #5438). The antenna phase center offsets and phase center variations
    are given in the file:
        ftp://igs.org/igscb/station/general/igs05.atx
    These antenna calibrations are also used in the homogeneously reprocessed IGS
    products from GPS Weeks 730 to 1459 (1994-2007); see IGSMAIL #6136.
    
    Starting 17-Apr-2011 (GPS Week 1632, day 0, MJD 55668) the absolute antenna
    model is updated (IGSMAIL #6255 & #6374) as given in the file:
        ftp://igs.org/igscb/station/general/igs08.atx
    
    Starting 07-Oct-2012 (GPS Week 1709, day 0, MJD 56207) the igs08.atx absolute
    antenna model file gives updated (IGSMAIL #6662) values for the JPSREGANT_DD
    and JPSREGANT_SD antennas, plus updates for GPS IIF transmit antennas. This
    updated file should be used in conjunction with IGb08. Though, igs08.atx is
    also still consistent with IGS08.


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

Table 1: 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.
   
Table 1.1847.2   GPS week: 1847   Day: 2   MJD: 57175.500                            

CENT STA|   DX    DY    DZ    RX    RY    RZ   SCL  RMS  WRMS|    TOFT   TDRFT   SDEV    RMS
        |  [mm]  [mm]  [mm] [uas] [uas] [uas] [ppb] [mm] [mm]|    [ps]  [ps/d]   [ps]   [ps]
--------+----------------------------------------------------+------------------------------
cou  131|    0     0    -4   -23   -33    28   .17   23   18 |    -174    1113    ---  11250
emu   94|    0     0     2    39    25    -4   .08   13   11 |       0       0    ---  11010
esu  109|    0     0     0   -36   -29   -43  -.18   20   18 |  -39920   59030    ---  68550
gfu   98|    0    -3     6    -4    -9     3   .08   26   26 |    -925    1231    ---  11200
gou   94|    0     0   -11   -67    39    36  -.61   40   35 |    -370     151    ---  13910
siu  n/a|    0     0    -2    67    22 -1610   .06   61   59 |       0       0    ---      0
usu   29|   -1    -1     9   185   447  -232  -.11   48   46 |    -816     557    ---   9037
whu  111|    0    -1     7    91   265   192  -.59   65   52 |    3499   -5724    ---  11400



Table 2: 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: mm

Table 2.1847.2   GPS week: 1847   Day: 2   MJD: 57175.500                            

        Weighted Average                             
 PRN  |  cou  emu  esu  gfu  gou  siu  usu  whu  IGU |
------+----------------------------------------------+
   1  |   24   10   13   15   29  114   29   35    8 |
   2  |   14   12   18   16   68   45   35   34   11 |
   3  |    9    4   14   25   30   41   34   29    7 |
   4  |   12    6   11   15   30   52   31   46    6 |
   5  |   17    8   29   14   32   53   42   27    9 |
   6  |   12    7   17   18   27   32   35   45    7 |
   7  |   12    9   17   25   27   29   32   37    8 |
  X8  | ----  ---  ---  ---  ---  ---  ---  ---    0 |
   9E |   13    9   21   15   22  114   91   54    7 |
  10  |   15   18   16   25   32   33   52   26   10 |
  11  |   17   11   19   15   26   48   30   45    8 |
  12  |   17    4   21   22   31   57   28   51    8 |
  13E |   13   19    9   34   33   26   29   28   10 |
  14E |   15   27   20   30   20   83   58   43   12 |
  15  |   78   12   34   56   29   51   66  261   23 |
  16  |   14    9   16   25   86  104   36   32   14 |
  17  |   20   17   46   35   47   30   68  131   15 |
  18  |   19   17   17   34   38   48   46   24   11 |
  19  |    9    9   21   28   41   24   46   35    9 |
  20  |   21   14   18   25   25   59   31   26    9 |
  21  |   32   10   18   11   67   28   72   36   13 |
  22  |   17   17   16   27   22   22   44   27    9 |
  23E |   20   18   19   21   37   32   30   45   10 |
 X24  |   24   15   21   29  ---   80   42   30   12 |
  25  |   10    9   14   19   38   29   67   35    8 |
  26  |   18    6   27   17   70  107   49   39   12 |
  27E |   25   27   16   35   33   24  ---   50   13 |
  28  |   10    5   12   23   37   71   39   31    8 |
  29  |   11   10   18   26   47   44   29   69   10 |
  30  |    7    6   16   21   30   56   38   36    7 |
  31  |   40    6   19   31   33  113   83   33   12 |
  32  |   24   11   13   24   37   19   35   31   10 |
------+----------------------------------------------+
 RMS  |   23   13   20   26   40   61   48   65      |
 WRMS |   18   11   18   26   35   59   46   52      |
 MEDI |   17   10   18   25   32   48   38   35      |



Table 3: Earth Orientation Parameters daily summary.                           
                                                                              
         Centre ERP, ERP Rates and LOD differences with respect to       
         IGU combined values.                                                  
                                                                              
         Xpole,Xrt: x pole and x pole rate                            
         Ypole,Yrt: y pole and y pole rate                        
         LOD: Length Of Day                                                
                                                                              
         AC LOD BIAS:  7-day mean LOD bias with respect to Bulletin A      
         AC LOD BIAS RMS: RMS of AC LOD BIAS                               
                                                                              
         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: Until 1766_2_06, COU submit ERP-products for 00 and 12 UT
                 only, for 06 and 18 UT extrapolations made by the
                 combination processes were used. Starting 1766_2_12, COU
                 provides ERP-products for all combinations.


Table 3.1847.2   GPS week: 1847   Day: 2   MJD: 57175.000
                                                         AC LOD  AC LOD
CENT  FLAG  |   Xpole   Ypole     Xrt     Yrt    LOD |    BIAS  BIAS RMS
            |   [uas]   [uas]   [uas/d] [uas/d]  [us]|    [us]    [us]
------------+----------------------------------------+------------------
cou   uuuuu |      15      22      22      19      1 |      -1     11
emu   uuuuu |     -25     -37     -32     -30      7 |      -5     10
esu   uuuuu |      -8      18      63      15      1 |      -1     11
gfu   uuuuu |      20      -7     -70      -7    -12 |      -6     10
gou   uuuuu |      58      82      68      62      3 |      -1     11
ngu   xxxxx |      39      70    -144     -19     -9 |      18     36
usu   xxxxx |    -314    -183    -216     -11     -2 |     -14     21
whu   xxxxx |     -20    -142     334      53     17 |     -24     33

Table 3.1847.3   GPS week: 1847   Day: 3   MJD: 57176.000
                                                         AC LOD  AC LOD
CENT  FLAG  |   Xpole   Ypole     Xrt     Yrt    LOD |    BIAS  BIAS RMS
            |   [uas]   [uas]   [uas/d] [uas/d]  [us]|    [us]    [us]
------------+----------------------------------------+------------------
cou   uuuuu |      63      47      47      25      3 |      -1     11
emu   uuuuu |     -31     -60      -7     -24      5 |      -5     10
esu   uuuuu |      81      39      88      21      6 |      -1     11
gfu   uuuuu |     -24      -8     -45      -1    -11 |      -6     10
gou   uuuuu |    -178      74    -237      -8     -3 |      -1     11
ngu   xxxxx |    -306      61    -442     175    -66 |      18     36
usu   xxxxx |    -587    -164    -231      15   -108 |     -14     21
whu   xxxxx |    -608      19     370      95      0 |     -24     33

 

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