Author:  AC Coordinator / AIUB/CODE

Rapid IGS Orbit Prediction Combination - Week 1087   Day: 4   (Nov 09, 2000)

Contacts: T.A. Springer (springer@aiub.unibe.ch)
          H. Bock (bock@aiub.unibe.ch), R. Dach (dach@aiub.unibe.ch)


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 11 days after the end of the GPS week.


REMARKS on IGS Rapid Orbit Prediction Combination:


1. Clock corrections found in the IGP sp3 orbit file are clock predictions 
   provided by COP. Users are reminded to use them with extreme caution.

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
                        -------+---------------
                         USP   |  19
                         SIP   |  19
                         EMP   |  19

3. The following orbit solutions were rejected from the combination due to
   lack of redundancy, i.e. not enough centres providing a solution
   (=> Minimum number of centres: 3):

                        Centre | PRN 
                        -------+-----
                         COP   |  19

_______________________________________________________________________________


Table 1: Daily transformation of each centre to the combined IGP orbit and
         clocks. 

         WRMS - RMS weighted by the centres SP3 header accuracy codes.
         STA  - Number of stations in the daily solutions.
         Units: meters, mas, ppb, nano-sec, nano-sec/day.

Table 1.1087.4   GPS week: 1087   Day: 4   MJD: 51857.0

CENT STA|  DX   DY   DZ    RX    RY    RZ  SCL  RMS WRMS |   TOFT  TDRFT    RMS
--------|------------------------------------------------|---------------------
cop  n/a|-.01 0.00-0.01 -0.50 -0.02  2.63 -0.1 0.15 0.14 |    0.0    0.0   0.00
emp  n/a|-.01 0.00 0.02  0.42 -0.30 -1.67 -0.1 0.20 0.22 |    0.0    0.0   0.00
gfp  n/a|0.00 0.01-0.03  1.33  0.44 -1.94  0.1 0.74 0.24 |    0.0    0.0   0.00
sip  n/a|0.00 0.03 0.03 -0.96  1.02 -3.24 -1.2 1.13 1.03 |    0.0    0.0   0.00
usp  n/a|-.01 0.01-0.01 -0.21  0.35 -0.61  0.5 0.43 0.33 |    0.0    0.0   0.00


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

         The last column gives the IGP resulting satellite accuracy measures 
         found in the IGP SP3 header. Eclipsing satellites are flagged with
         and "E" beside the PRN number.
         "MEDI" stands for median of the centre's satellite RMS.

         Units: cm.

Table 2.1087.4   GPS week: 1087   Day: 4   MJD: 51857.0

        Weighted Average
 PRN  | cop emp gfp sip usp  IGP |
------|--------------------------|
   1  |   6   7  10  48  27    8 | 
   2E |  15  66 155  46  39   31 | 
  X3  |  18   9  25 ---  40   12 | 
   4  |  34   3  10 278  12   30 | 
   5E |   6  18  82 109  34   18 | 
   6  |  18  22  32 168  60   23 | 
   7  |  15   4  37 213   5   22 | 
   8  |  16  19   7  99  33   14 | 
   9  |  10  12   5  24  14    6 | 
  10E |  29  10  79  79  62   21 | 
  11  |   8   5  31  25  29    8 | 
  13  |   5  12  15  37  11    6 | 
 X15  |  20  38 126  86 ---   30 | 
  17  |   7   6   9  50  10    6 | 
  20E |   9   9 106  67 102   27 | 
  21E |   9  28 199  66  40   31 | 
  22E |   3   8 143  39  67   25 | 
  24  |  13  32  42  51  86   22 | 
  25  |   7  14  24  33  22    8 | 
  26  |   6  15   7 108   6   12 | 
  27  |  11  10   8 122  20   14 | 
  28E |  18  13 106  44  22   18 | 
  29  |   5  10  16  76   5    9 | 
  30E |  17   9  17  79  47   14 | 
  31  |  19  11  19 223  25   24 | 
------|--------------------------|
 RMS  |  15  20  74 113  43      | 
 WRMS |  14  22  24 103  33      |
 MEDI |  11  11  25  72  28      |