Subject: [IGSMAIL-186] JPL Epoch '92 Re-analysis
From: James F Zumberge
Date: 28 Jan 1993 00:00:00

From:     James F Zumberge
Subject:  JPL Epoch '92 Re-analysis
-----------------------------------

Submitted by

J F Zumberge, G Blewitt, M B Heflin, D C Jefferson, F H Webb

all at the Jet Propulsion Laboratory, California Institute of Technology, 
Pasadena, CA  91109.

The following files have been posted on BODHI (for access to BODHI contact
[email-masked]):

______________________________________________________________________________
filename               contents
______________________________________________________________________________
jplepoch92.sum           This text file.
jplepoch92.erp           Earth rotation parameters for Epoch '92.
jplepoch92.sp1           GPS ephemerides for Epoch '92, sp1 format.
jplepoch92.sp3            "       "       "    "    " , sp3   "   .
______________________________________________________________________________

These files contain the results of our re-analysis of the Epoch '92
period, 1992 Jul 26 through 1992 Aug 07, with our most recent analysis
strategy.  Because of AS, the days of Aug 1, Aug 2, and Aug 8 were not
analyzed.

This submission resembles a normal weekly one.  In the UTPM table,
the UT1R-UTC column contains the assumed nominal values from IERS Bulletin-B
finals (_not_ predicts).

The new polar motion estimates differ from the original "near-real-time"
values as indicated in the following table:

          delta X (mas)   delta Y (mas)

average        0.07           -0.43
st deviation   0.40            0.30

Shown below is a comparison of the new ephemerides with the original
ones.  Actually, the comparison is with the cleansed originals (refer to
IGS Message Nos.  127 and 164), and explains the absence of an entry for
prn 15 on Jul 26.  Each entry in the table represents, for the
indicated prn and day, the 3d rss difference over 24 hours between the
current Epoch '92 analysis and the original analysis.

The ~3.5-m 3d-rss difference for Jul 26-30 changes abruptly to ~1.1 m on
Jul 31, because of a change in the nominal earth-orientation values in
the original processing (caused by an update in the IERS B predicts),
and because the original processing used the nominal (not solved-for)
earth orientation in the transformation from inertial to earth-fixed
coordinates.  The values used on Jul 31 and later for the original
analysis are very close to the IERSB Final values used in the current
re-analysis.

The ~1.1-m comparison for Jul 31 and later (with some exceptions, to be
discussed), is due mainly to the change in convention from referring to
the antenna phase center (our original convention) to the spacecraft
center of mass (the current convention).

The comparison for Monday, Aug 3 shows mixed results.  Because A-S was
in effect for the first 10 hours of this day, cross-correlated data from
Block-II satellites were not used, as reflected in the data availability
tables at the end of this file.  Because the comparisons are over a
24-hr period, some of the Block-II results come from extrapolations.
For example, the value of 9.2 m for prn 25 becomes 1.3 m if differences
before 10 am are excluded.

Finally, the outlier of 26.6 m from prn 15 on Aug 6 is a result of
our deweighting data from that prn and day in our original submission.
It is modeled perfectly well with the current estimation strategy.

COMPARISON OF EPOCH '92 ORBITS WITH ORIGINAL "NEAR-REAL-TIME" ORBITS
      92  7 26   92  7 27   92  7 28   92  7 29   92  7 30   92  7 31
prn   3d rss (m)
  2       3.6        3.6        3.6        3.6        3.7        1.1 
  3       3.4        3.6        3.6        3.6        3.8        1.0 
 11       3.5        3.5        3.7        3.8        3.8        1.0 
 12       3.7        3.7        3.7        3.8        3.9        1.0 
 13       3.6        3.4        3.7        3.8        3.8        1.0 
 14       3.4        3.6        3.6        3.7        3.8        1.1 
 15                  3.5        3.7        3.9        3.8        1.0 
 16       3.5        3.6        3.6        3.8        3.8        1.1 
 17       3.2        3.3        3.3        3.4        3.5        1.1 
 18       3.4        3.5        3.5        3.6        3.7        1.1 
 19       3.4        3.4        3.5        3.6        3.6        1.0 
 20       3.5        3.6        3.6        3.7        3.8        1.2 
 21       3.5        3.4        3.4        3.6        3.7        1.1 
 23       3.5        3.5        3.6        3.7        3.7        1.1 
 24       3.3        3.3        3.4        3.5        3.6        1.0 
 25       3.4        3.5        3.5        3.7        3.8        1.0 
 28       3.5        3.5        3.6        3.7        3.8        1.1 
                 92  8  3   92  8  4   92  8  5   92  8  6   92  8  7
prn    
  2                  2.4        1.1        1.1        1.1        1.1 
  3                  0.9        0.9        0.9        1.0        0.9 
 11                  1.0        1.0        1.0        1.0        1.0 
 12                  1.0        1.0        1.0        1.0        1.0 
 13                  1.0        1.0        1.0        1.0        1.0 
 14                  1.1        1.0        1.1        1.1        1.1 
 15                  1.1        1.1        1.1       26.6        1.1 
 16                  4.6        1.0        1.0        1.0        1.1 
 17                  1.8        1.1        1.1        1.1        1.1 
 18                  1.1        1.1        1.2        1.1        1.2 
 19                  1.1        1.1        1.1        1.1        1.1 
 20                  5.5        1.1        1.1        1.2        1.2 
 21                  4.0        1.1        1.1        1.1        1.0 
 23                  3.6        1.1        1.1        1.2        1.1 
 24                  1.6        1.2        1.2        1.1        1.1 
 25                  9.2        1.0        1.1        1.1        1.1 
 28                  5.2        1.1        1.1        1.1        1.1 
END COMPARISON OF EPOCH '92 ORBITS WITH ORIGINAL "NEAR-REAL-TIME" ORBITS

JPL LODR TABLE                                  Epoch '92 (1992 Jul 26 - Aug 07)
  MJD       LODR     +/-
          (ms/day)
 48829.5    1.54     0.05
 48830.5    1.55     0.05
 48831.5    1.52     0.05
 48832.5    1.24     0.05
 48833.5    1.42     0.05
 48834.5    1.44     0.05
 48837.5    1.44     0.07
 48838.5    1.86     0.05
 48839.5    1.89     0.05
 48840.5    1.90     0.05
 48841.5    1.75     0.05
END LODR TABLE

NOTE: In the following table, UT1R-UTC are the assumed nominal values from
IERS Bulletin-B finals; estimated LODR values are given in the previous
table. See IGS Mail Message 97 for details.

JPL UTPM TABLE                                  Epoch '92 (1992 Jul 26 - Aug 07)
  MJD       X        Y       UT1R-UTC XSIG    YSIG   UTSIG  RMS  XYC STA SAT
           ''        ''        sec     ''     ''      sec
 48829.5  -.09972   .43566   .40824  .00013  .00015  .00000  .0  .00  29 18
 48830.5  -.09792   .43761   .40681  .00013  .00014  .00000  .0  .01  29 18
 48831.5  -.09581   .43903   .40540  .00014  .00015  .00000  .0 -.03  29 18
 48832.5  -.09443   .44105   .40398  .00014  .00014  .00000  .0  .01  28 18
 48833.5  -.09255   .44300   .40254  .00013  .00014  .00000  .0  .03  29 18
 48834.5  -.09007   .44511   .40105  .00013  .00014  .00000  .0  .04  29 18
 48837.5  -.08291   .45154   .39646  .00028  .00031  .00000  .0 -.04  29 18
 48838.5  -.08187   .45416   .39489  .00013  .00014  .00000  .0  .01  29 18
 48839.5  -.08015   .45586   .39329  .00014  .00015  .00000  .0 -.03  29 18
 48840.5  -.07820   .45779   .39166  .00014  .00015  .00000  .0  .01  28 18
 48841.5  -.07643   .45993   .39001  .00015  .00017  .00000  .0  .03  28 18
END UTPM TABLE

The following table indicates the "3-dimensional orbit repeatability", as 
defined in IGS Mail Message 37, for the Epoch '92 period, 1992 Jul 26 - Aug 07:
["3d rss" = sqrt(xrms**2 + yrms**2 + zrms**2)]

JPL ORBIT REPEATABILITY TABLE                   Epoch '92 (1992 Jul 26 - Aug 07)
      92  7 26   92  7 27   92  7 28   92  7 29   92  7 30   92  7 31
prn   3d rss (m)
  2       0.3        0.20       0.57       0.51       0.35       0.4 
  3       0.2        0.28       0.45       0.42       0.48       0.5 
 11       0.3        0.30       0.64       0.46       0.30       0.2 
 12       0.2        0.33       0.47       0.43       0.27       0.1 
 13       0.3        0.33       0.35       0.39       0.24       0.2 
 14       0.3        0.47       0.41       0.36       0.32       0.3 
 15       0.9        0.54       0.87       0.86       0.69       0.4 
 16       0.1        0.21       0.21       0.25       0.26       0.3 
 17       0.2        0.15       0.26       0.20       0.32       0.3 
 18       0.3        0.34       0.41       0.40       0.53       0.4 
 19       0.3        0.23       0.38       0.57       0.22       0.3 
 20       0.2        0.27       0.24       0.28       0.29       0.4 
 21       0.3        0.39       0.69       0.27       0.20       0.1 
 23       0.3        0.31       0.37       0.37       0.26       0.3 
 24       0.3        0.28       0.20       0.26       0.40       0.3 
 25       0.2        0.30       0.31       0.62       0.76       0.6 
 26       0.6        0.28       0.40       0.43       0.44       0.3 
 28       0.2        0.30       0.29       0.27       0.28       0.2 

       92  8  3   92  8  4   92  8  5   92  8  6   92  8  7
prn 
  2        0.4        0.22       0.19       0.22       0.2 
  3        0.1        0.24       0.31       0.37       0.2 
 11        0.2        0.27       0.17       0.15       0.1 
 12        0.4        0.41       0.38       0.37       0.5 
 13        0.3        0.32       0.33       0.31       0.3 
 14        0.3        0.32       0.31       0.22       0.3 
 15        0.4        0.89       0.60       0.31       0.3 
 16        0.2        0.30       0.12       0.26       0.3 
 17        0.2        0.21       0.15       0.28       0.2 
 18        0.5        0.47       0.43       0.56       0.6 
 19        0.5        0.48       0.37       0.42       0.2 
 20        0.4        0.51       0.23       0.36       0.3 
 21        0.3        0.32       0.23       0.23       0.1 
 23        0.2        0.34       0.34       0.31       0.2 
 24        0.2        0.29       0.27       0.26       0.3 
 25        0.1        0.52       0.46       0.25       0.3 
 26        0.4        0.38       0.26       0.48       0.4 
 28        0.2        0.28       0.26       0.29       0.2 
END ORBIT REPEATABILITY TABLE

As described in IGS Mail Message 37, the following table compares the JPL
precise ephemerides with those from the broadcast ephemeris:

JPL COMPARISON OF BROADCAST NAVIGATION MESSAGE WITH PRECISE EPHEMERIDES
      92  7 26   92  7 27   92  7 28   92  7 29   92  7 30   92  7 31
prn   3d rss (m)
  2       4.3        4.7        3.5        3.7        4.0        3.7 
  3      10.1       10.1        9.8        9.7        9.6        9.5 
 11       7.4        4.6        3.7        8.8       10.1        5.7 
 12      10.0        8.4        8.5       10.7       13.3       14.2 
 13       8.69       8.1        6.7        5.97      10.3        6.6 
 14       4.5        7.2        8.1        4.4        4.4        5.9 
 15       6.1        8.9        9.7        9.8        9.7        5.8 
 16       8.0       10.7        8.8        6.7        7.3        7.1 
 17       4.6        5.4        9.2        7.3        7.9        6.1 
 18       4.5        4.7        4.8        4.7        5.1        4.1 
 19       6.5        4.8        2.9        2.5        4.5        5.0 
 20       3.7        3.5        4.5        3.7        5.2        4.9 
 21       5.3        5.4        4.0        5.3        7.3        6.4 
 23      11.9       10.4        5.8        3.7        3.4        4.4 
 24      14.4       14.5       14.9       16.1       15.9       14.3 
 25       7.0        7.4        9.8       14.7       14.3        8.9 
 26      24.5       22.5       20.3       20.0       14.2       20.0 
 28       3.3        2.9        3.4        3.5        3.0        3.7 

      92  8  3   92  8  4   92  8  5   92  8  6   92  8  7
prn 
  2       3.6        3.8        4.8        5.3        5.3 
  3       8.1       12.9        8.4        9.7       13.3 
 11       8.1        9.5        8.7        7.6        7.8 
 12       8.1       13.1        7.5       22.0        7.8 
 13       6.6        7.1        6.0        8.3        9.8 
 14       8.2        8.1        7.5        6.5        7.1 
 15       8.0        7.5        6.2        5.3        5.6 
 16       7.0        8.5        8.2       11.3        9.4 
 17       6.1        8.4        6.5        6.0        5.5 
 18       3.5        4.5        5.0        6.3        9.5 
 19       3.7        3.5        4.1        3.7        3.8 
 20       3.6        3.6        4.4        6.0        3.3 
 21       8.2        8.3        6.9        5.4        4.1 
 23       3.3        7.4        9.5        8.2        7.3 
 24      11.4       10.8       10.6       11.1       12.3 
 25       7.6       11.7       12.0        9.3        9.9 
 26       9.3        8.1        7.6        9.1        5.3 
 28       2.6        3.1        4.0        2.8        2.9 
END COMPARISON OF BROADCAST NAVIGATION MESSAGE WITH PRECISE EPHEMERIDES

The following table, as explained in IGS Report No. 99, indicates the
amount of data from each tracking site used in the Epoch '92 analysis:

JPL GROUND STATION INCLUSION TABLEs             Epoch '92 (1992 Jul 26 - Aug 07)
      92  7 26   92  7 27   92  7 28   92  7 29   92  7 30   92  7 31
ALBH        93         95         92         93         95         89
ALGO*       97         94         86         79         78         82
CANB        69         93         93         93         94         93
FAIR*       98         98         92         90         98         99
GOLD        78         87          0         89         92         88
HART*       91         92         76         91         92         88
HERS        82         83         81         82         82         77
JPLM        92         94         91         90         98         93
KOKB*       92         89         88         90         94         94
KOSG        90         88         83         88         91         90
MADR*       58         90         90         91         84         86
MASP        96         99         96         99         99         94
MATE        91         91         90         90         91         87
MCMU        77         99        102        108        108        107
METS        95         98         96         98        100         95
NALL        72          0         70         74          0         84
ONSA        95         84         89         90         91         92
PAMA        83         84         79         80         82         81
PENT        97         97         94         95         96         97
PINY        95         95         94         96         98         99
RCM2        94         96         90         91         94         65
SANT*       91         92         92          0         91         90
STJO        94         93         91         94         96         90
TAIS        84         85         81         82         72         77
TROM*      107        109        106        106        107        107
USUD         0         10          0          0          0         54
WETB        91         91         27          0          0         82
YAR1*       91         90         86         89         91         90
YELL       101         98        101        101        102         98

      92  8  3   92  8  4   92  8  5   92  8  6   92  8  7
ALBH        70         97         97         97         96
ALGO*       58         88         85         90         89
CANB        62         86         93         92         92
FAIR*       72         98         99        100         94
GOLD        63         77         46         47         45
HART*       52         88         87         88         86
HERS         0         83         83         83         78
JPLM        68         93         95         96         92
KOKB*       69         94         93         94         90
KOSG        64         91         91         91         90
MADR*       49         87         87         82         64
MASP        61         89         10          0          0
MATE        59         83         85         91         87
MCMU        80        109        109        109        108
METS        70        101        101        101         96
NALL         0         49          0        103        110
ONSA        57         94         90         82         97
PAMA        63         91         92         43          0
PENT        68         98        100         99         99
PINY        68         99         98         96         90
RCM2        54         91         92         92         88
SANT*        0         92         92         92         88
STJO        63         94         96         96         90
TAIS        56         85          0         87         87
TROM*       76        107        106        107        103
USUD        47         86         85         89         65
WETB        63         91         92         92         87
YAR1*       69         80         92         93         94
YELL        71         98        101        104         97
_______________________
*Indicates fiducial site.
END GROUND STATION INCLUSION TABLEs