Author:  AC Coordinator / NRCan GSDivision

Rapid IGS Orbit Prediction Combination - Week 0914   Day: 2   (Jul 15, 1997)

Contacts: J. Kouba (kouba@geod.emr.ca), Y. Mireault (mireault@geod.emr.ca)


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
                        -------+---------------
                         EMP   |  23
                         SIP   |  ALL (high Rotations - See Table 1)

_______________________________________________________________________________


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 1.0914.2   GPS week: 0914   Day: 2   MJD: 50644.0

CENT STA|  DX   DY   DZ    RX    RY    RZ  SCL  RMS WRMS |   TOFT  TDRFT    RMS
--------|------------------------------------------------|---------------------
cop  n/a| .00  .00 -.08  -.64   .89 -3.16  -.1  .65  .47 |     .0     .0     .0
emp  n/a| .00 -.01  .05   .99  1.13  2.73  -.2 6.74  .84 |     .0     .0     .0
esp  n/a|-.01 -.01  .00  1.14  -.34 -3.99   .6  .96  .19 |     .0     .0     .0
gfp  n/a| .00  .00 -.02 -1.17 -1.86 -1.21  -.3  .48  .30 |     .0     .0     .0
jpp  n/a| .01  .00 -.02   .24   .66  4.07   .5  .46  .28 |     .0     .0     .0
sip  n/a| .01 -.02  .07  -.69   .53-19.46 -1.3  .95  .95 |     .0     .0     .0


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. 
         "MEDI" stands for median of the centre's satellite RMS.

         Units: cm.

Table 2.0914.2   GPS week: 0914   Day: 2   MJD: 50644.0

               Weighted Average
 PRN  | cop emp esp gfp jpp sip  IGP |
------|------------------------------|
   1  |  45  23  26  18  19  24   13 | 
   2  |  43  37  17  17  30  22   15 | 
   3  |  16  14  11  56  52  52   20 | 
   4  |  61  19  17  24  24  31   16 | 
   5  |  90  13  22  44   9  31   22 | 
   6  |  24  28  17  33  42  27   16 | 
   7  |  16  26   8   8  27  38   10 | 
   9  |  11  62  18  46  11  46   18 | 
  10  |  38 100 263 ---  68  56   77 | 
  14  |  78 330 200 ---  60  43  110 | 
  15  |  68  15  18   5  28  24   16 | 
  16  |  75  45  57 ---  63 ---   35 | 
  17  |  36  16   9  15  34  26   12 | 
  18  |  23  26  19  12  18  18   10 | 
  19  |  14  27  16  12  21  37    9 | 
  21  |  25  84  99 168 151  56   63 | 
  22  |  18  15   9  25  12  86    9 | 
  23  | 216 >>> 316  82 --- 417  145 | 
  24  | 115  30  26  35  49  39   29 | 
  25  |  52  23  22  28  41  69   18 | 
  26  |  18  21  24  30  28  31   13 | 
  27  |  13  48  30  12  31  59   15 | 
  29  |   8  15  11  15  18  20    7 | 
  30  |  64  14  10  33  11  52   16 | 
  31  |  19  60  21  37  15  29   17 | 
------|------------------------------|
 RMS  |  65 674  96  48  46  95      | 
 WRMS |  47  84  19  30  28  95      |
 MEDI |  36  26  19  27  28  38      |