Subject: [IGSMAIL-46] Preliminary look at GPS Earth orientation
From: Dennis McCarthy
Date: 20 JUL 1992 14:06:38

***********************************************************************
IGS Electronic Mail       20-JUL-1992 14:06:38       Message Number 46
***********************************************************************
 
==============================================================================
                   THIS FILE CONTAINS 6 MESSAGES
==============================================================================

From:     Dennis McCarthy
Subject:  Preliminary look at GPS Earth orientation
          -----------------------------------------

Date:     16 July 1992

An updated look at Earth orientation data submitted to the IERS
follows.  Units are milliseconds of arc for x and y, and
milliseconds of time for UT1-UTC.

Contributor Data Span Points       Mean          Standard Deviation
                                (NEOS-GPS)  
                              x     y   UT1-UTC   x     y   UT1-UTC
U. of Texas  48794.0    11  -0.46 -0.71          0.62  2.33  
             -48800.5

Scripps      48779.5    29  -0.89 -0.75          0.85  0.95
             -48808.0     

U. of Berne  48792.5     8  -0.42  0.34  -1.50   1.85  1.87  0.14 
 (ITRF90)    -48799.5

U. of Berne  48800.5     8  -0.72 -0.62  -0.44   0.89  0.87  0.10 
 (ITRF91)    -48807.5

JPL          48794.5    18  -0.95 -1.60          0.99  1.80 
             -48811.5

Plots are available by FAX to anyone interested.

Regards,

Dennis McCarthy
  [email-masked]

==============================================================================

From:     Carey Noll
Subject:  CDDIS GPS Data Holdings for IGS Week 3/GPS Week 652
          ------------------------------------------------------------------

          Current IGS GPS Data Holdings (as of 16-Jul-92 11:07)             
 IGS Week 3/GPS Week 652 (July 05 thru July 11, 1992; Days 187 thru 193)    
                                                                                
                                         1   1   1   1   1   1   1              
                     Mon.                8   8   8   9   9   9   9    No.       
    Site Name        Name    Receiver    7   8   9   0   1   2   3   Sites      
------------------   ----   ----------   -   -   -   -   -   -   -   -----      
Albert Head          ALBH   ROGUE        X   X   X   X   X   X   X       7      
Algonquin            ALGO   ROGUE        X   X   X   X   X   X   X       7      
Fairbanks            FAIR   ROGUE        X   X   X   X   X   X   X       7      
Goldstone            DS10   ROGUE        X   X   X   X   X   X   X       7      
Graz                 GRAZ   ROGUE        X   X   X   X   X   X   X       7      
Hartebeesthoek       HART   ROGUE        X   X   X   X   X   X   X       7      
Herstmonceux         HERS   ROGUE        X                   X   X       3 *
Hobart               HOBA   MINIMAC      X   X   X   X   X   X   X       7 *    
Kokee Park           KOKB   ROGUE        X   X   X   X   X   X   X       7      
Kootwijk             KOSG   ROGUE        X   X   X   X   X   X   X       7      
Madrid               DS60   ROGUE        X   X   X   X   X   X   X       7      
Mas Palomas          MASP   ROGUE        X   X   X   X   X   X   X       7      
Matera               MATE   ROGUE        X   X   X   X   X   X   X       7 *    
McMurdo              MCMU   ROGUE        X   X   X   X   X       X       6      
Metsahovi            METS   ROGUE        X   X   X   X   X   X   X       7 *    
Mojave               MOJ1   MINIMAC      X   X   X   X   X   X   X       7 *    
Ny Alesund        NYAL/NALL ROGUE        X   X   X   X   X   X   X       7 *    
Onsala               ONSA   ROGUE        X   X   X   X   X   X   X       7 *    
Pamate               PAMA   ROGUE        X   X   X   X   X   X   X       7      
Pasadena             MESA   ROGUE        X   X   X   X       X   X       6      
Penticton            DRAO   ROGUE        X   X   X   X   X   X   X       7      
Pinyon Flat          PINY   ROGUE        X   X   X   X   X   X   X       7      
Richmond             RCMA   MINIMAC      X   X   X   X   X   X   X       7 *    
Saint John's         STJO   ROGUE        X   X   X   X   X   X   X       7      
Santiago             SANT   ROGUE        X   X   X   X   X   X   X       7      
Taiwan               TAIW   ROGUE        X   X   X   X   X               5 *    
Tidbinbilla          DS40   ROGUE        X   X   X   X   X   X   X       7      
Townsville           TOWN   TRIMBLE      X   X   X   X       X   X       6 *    
Tromso               TROM   ROGUE        X   X   X   X   X   X   X       7 *    
Tsukuba              TSUK   MINIMAC      X   X   X   X   X   X   X       7 *    
Usuda                USUD   ROGUE        X   X   X   X   X   X   X       7      
Victoria             PGC1   ROGUE        X                   X   X       3      
Wellington           WELL   TRIMBLE      X   X   X   X   X   X   X       7 *    
Westford             WES1   MINIMAC      X   X   X   X   X   X   X       7 *    
Wettzell             WETT   ROGUE        X   X   X   X   X   X   X       7 *    
Yaragadee            YAR1   ROGUE        X   X   X   X   X   X   X       7      
Yellowknife          YELL   ROGUE        X   X   X   X   X   X   X       7      
Zimmerwald           ZIMM   TRIMBLE      X   X   X   X   X   X   X       7      
------------------   ----   ----------  --  --  --  --  --  --  --   -----      
Totals:                38 stations      38  36  36  36  34  36  37     253

Notes:  * indicates some data replaced by CIGNET on July 15 because of error 
          in the RINEX version number (days 188 through 194)

        Data from DARWin station has arrived at CDDIS for days 169 to 177
          from AUSLIG via Peter Morgan.  Additional Darwin plus Orroral data
          expected in near future.

==============================================================================

From:    Ch. Reigber
Subject: Report for GPS Week 650 (Days 173-179) from GFZ
         ------------------------------------------------

This report is generated by the GeoForschungsZentrum Potsdam (GFZ) 
on a weekly basis for the International GPS Geodynamics Service (IGS). 

PRODUCT SUMMARY 

   GFZ06507.EPH:  GPS ephemerides for GPS Week 650 (SP3 format, pos. and vel.)
   GFZ06507.ERP:  Earth rotation parameter (UT1 corrections are not included)
   GFZ06507.SUM:  Summary file for reporting week 

The above specified products are available at CDDIS. The ERP results are 
additionally submitted to IERS Central Bureau and IERS Sub Bureau for Rapid
Service and Predictions.

CORE STATION SUMMARY

The Core Station data used in the solutions is given below.  

                                      Day of Week 650
                                    S  M  T  W  T  F  S
                                    U  O  U  E  H  R  A
        Site                        N  N  E  D  U  I  T
Name            Code      
---------------------------------------------------------
Algonquin       ALGO                X  X  X  X  X  X  X
Fairbanks       FAIR                X  X  X  X  X  X  X
Goldstone       GOLD                X  X  X  -  X  X  X
Hartebeesthoek  HART                X  X  -  -  X  -  X
Kokee Park      KOKB                X  X  X  X  -  -  -
Mc Murdo        MCMU                X  X  X  X  X  X  X
Ny-Alesund      NYAL                X  X  X  X  X  X  X
Pamatai         PAMA                -  X  X  X  X  X  X
Santiago        SANT                X  X  X  X  X  X  X
Taipei          TAIW                -  -  X  X  X  X  X
Tromsoe         TROM                X  X  X  X  X  X  X 
Usuda           USUD                X  X  X  X  X  X  X
Wettzell        WETT                X  X  X  X  X  X  X
Yellowknife     YELL                X  X  X  X  X  X  X
Yarragadee      YAR1                X  X  X  X  X  X  X
---------------------------------------------------------

SOLUTION CHARACTERISTICS

1. Analysis Center: GFZ/DLR
2. Analysing Team: D. Angermann, R. Galas, Th. Nischan,
                   Ch. Reigber, S.Y. Zhu 
3. Solution Identifier: EPH(GFZ)92G01-DDD
                        ERP(GFZ)92G01-DDD
                        CLK(GFZ)92G01-DDD (only relative)
4. Software used: GEPARD4.0
5. Defintion of Terrestrial Reference Frame
   Origin: Nominally ITRF-90
   Orientation: Nominally ITRF-90
   Reference Epoch: 1992.352 (MJD 48750)
   Fixed set of stations: Y. Bock Solution (IGS Message No.35)
   ALGO, YELL, FAIR, KOKR, TROM, WEZ1, YAR1, USUD, NALL
6. Data used:
   - undifferenced pseudo ranges and carrier phases
   - 2-day arc solutions with one day overlap
7. Adjusted parameters:
   - State vector of all GPS satellites
   - Daily polar motion
   - Coordinate corrections for non-fixed stations
   - Troposheric zenith path delay 
   - Solar radiation scale and y-bias 
   - Ambiguities
   - ST and SV clock parameters of each observation epoch (the 
     maser-based clock at Fairbanks is taken as reference clock)

SOLUTION STATISTICS

                         Arc No.      0     1     2     3     4     5     6    
   ------------------------------------------------------------------------
   Number of observations         32817 28814 25957 25946 28223 30366 32672
   RMS of carrier phases [cm]       4.1   4.0   4.6   4.4   3.5   2.8   3.1
   RMS of code measurements [cm]   70.1  67.5  46.9  45.1  44.7  44.3  44.6
   ------------------------------------------------------------------------

INFORMATIONS TO PRODUCT GENERATION

  The calculation of the 7-day ephemerides file is described below.

            Day of GPS Week 650        [Day 0=Sunday; Day 6=Saturday]
  Arc No.   0   1   2   3   4   5   6    
       0     XXXX----
       1         XXXX----
       2             XXXX----
       3                 XXXX----
       4                     XXXX----
       5                         XXXX----
       6                             XXXX----

   XXXX : The first day of the 2-day arc is used for ephemeris
          dissemination
   ---- : The second day is used for quality control by overlap

   The pole coordinates are estimated for three epochs (beginning
   of each day) with the 2-day arc's. Using the above described 
   method (one day overlaps) there are three solutions for each
   pole parameter. The submitted ERP-results are the mean values
   of these different solutions.  

-  GFZ06507.EPH (Seven 1-day segments)

   In the table below the overlap rms differences [m] in radial,
   cross- and along-track component are presented.

   prn            174    175    176    177    178    179
  ======================================================
     2 radial   0.654  0.288  0.200  0.310  0.235  0.329
     2 cross    0.802  0.917  0.645  0.733  0.511  0.667
     2 along    1.403  0.877  1.194  0.889  0.576  0.636
  ------------------------------------------------------
     3 radial   0.337  0.197  0.466  0.365  0.196  0.274
     3 cross    1.082  0.698  0.937  0.874  0.766  0.460
     3 along    0.684  0.725  1.056  0.899  0.492  0.598
  ------------------------------------------------------
    11 radial   0.561  0.857  1.261  0.598  0.326  0.285
    11 cross    0.693  1.087  2.158  1.471  0.546  0.417
    11 along    1.143  1.647  2.728  1.032  1.006  0.473
  ------------------------------------------------------
    12 radial   0.651  0.997  1.475  0.322  0.158  0.197
    12 cross    1.056  1.057  1.731  0.697  0.523  0.924
    12 along    2.132  1.815  3.376  0.668  0.597  0.539
  ------------------------------------------------------
    13 radial   0.337  0.400  0.216  0.142  0.240  0.251
    13 cross    0.701  0.461  0.480  0.765  0.507  0.159
    13 along    1.081  0.908  0.980  0.688  0.691  0.478
  ------------------------------------------------------
    14 radial   0.928  0.759  1.089  1.178  0.854  0.627
    14 cross    0.823  0.906  1.077  1.329  0.707  0.869
    14 along    1.892  1.654  2.062  2.170  1.690  1.196
  ------------------------------------------------------
    15 radial   0.243  0.300  0.470  0.236  0.376  0.212
    15 cross    0.332  0.482  0.738  1.230  0.394  0.948
    15 along    0.795  0.739  1.064  0.798  0.917  0.522
  ------------------------------------------------------
    16 radial   0.375  0.895  1.230  1.243  0.751  0.584
    16 cross    0.937  1.309  1.426  0.991  0.954  0.994
    16 along    1.285  1.765  2.218  2.238  1.680  1.003
  ------------------------------------------------------
    17 radial   0.253  0.312  0.714  0.384  0.415  0.227
    17 cross    0.778  1.316  0.609  0.435  0.339  0.724
    17 along    0.790  0.832  1.559  0.897  0.786  0.587
  ------------------------------------------------------
    18 radial   0.544  0.129  0.564  0.398  0.176  0.221
    18 cross    1.059  0.558  1.376  0.667  0.356  0.630
    18 along    1.681  0.539  1.341  0.922  0.468  0.463
  ------------------------------------------------------
    19 radial   0.429  0.621  0.551  0.341  0.270  0.374
    19 cross    0.877  0.882  0.659  0.606  0.259  0.500
    19 along    1.594  1.048  1.331  0.905  0.582  0.749
  ------------------------------------------------------
    20 radial   0.146  0.127  0.574  0.160  0.352  0.374
    20 cross    0.523  0.912  0.958  0.835  1.228  0.701
    20 along    0.353  0.741  1.321  0.556  1.001  0.655
  ------------------------------------------------------
    21 radial   0.223  0.286  0.181  0.418  0.374  0.117
    21 cross    0.306  0.731  0.792  0.835  0.414  0.434
    21 along    0.464  0.505  0.502  0.980  0.655  0.337
  ------------------------------------------------------
    23 radial   0.180  0.165  0.200  0.227  0.096  0.085
    23 cross    0.688  0.659  0.289  0.675  1.027  0.734
    23 along    0.606  0.530  0.491  0.592  0.550  0.419
  ------------------------------------------------------
    24 radial   0.400  0.382  0.298  0.455  0.319  0.309
    24 cross    0.667  0.895  0.488  1.005  1.019  0.658
    24 along    1.029  0.709  0.893  1.118  0.783  0.615
  ------------------------------------------------------
    25 radial   0.461  0.263  0.314  0.319  0.420  0.461
    25 cross    0.989  1.276  2.113  1.424  0.864  0.371
    25 along    1.027  0.694  0.808  1.051  1.422  0.995
  ------------------------------------------------------
    28 radial   0.346  0.529  0.274  0.851  0.316  0.285
    28 cross    0.395  0.612  0.986  1.815  0.626  0.490
    28 along    0.724  1.648  1.578  3.078  1.020  0.534
  ======================================================

-  GFZ06507.ERP

   MJD    x    sigmax    y    sigmay

 48795 -.1555  .001   0.3531  .001   
 48796 -.1520  .001   0.3554  .001   
 48797 -.1511  .001   0.3592  .001   
 48798 -.1474  .001   0.3592  .001   
 48799 -.1524  .001   0.3673  .001   
 48800 -.1489  .001   0.3695  .001   

-  GFZ06507.CLK

   The dissemination of clock corrections is under preparation.

==============================================================================

From:     IERS CENTRAL BUREAU
Subject:  Bulletin number 2

                  *******************************************
                  *                                         *
                    IGS'92 EARTH ORIENTATION BULLETIN   2
                  *                                         *
                  *******************************************
                                                               17 JULY 1992

  VERSION 1
============

This bulletin gives the description of the the Earth orientation analyses
performed by the IGS Processing Centres. Updated versions of it will be
distributed as new information becomes available. Each new version is as
complete as possible and supersedes the previous one.

-----------------------
PROCESSING CENTRE: CODE                                      EOP(CODE) 92 P 01
-----------------------

DESCRIPTION OF ESTIMATION OF EARTH ROTATION PARAMETERS AT THE CODE
PROCESSING CENTER FOR IGS

M. Rothacher, G. Beutler, S. Fankhauser, W. Gurtner, L. Mervart,
E. Brockmann, S. Botton , T. Springer  , T. Friedli, U.Wild

Outline of the Analysis
-----------------------

The orbits and the earth rotation parameters are estimated in the
same parameter estimation process at AIUB. Earth rotation parameters
and orbital elements are not the only parameters in this process. The
following parameter types are usually solved for:

(a) orbital parameters (in general 8 per satellite=6 elements,
    2 radiation pressure parameters)

(b) tropospheric zenith corrections (in general 4 per day
    and station)

(c) station coordinates for those stations with insufficient
    coordinate/local tie information

(d) ambiguity parameters (at least one per day and satellite, in
    general it is necessary to introduce more (after breaks, losses of
    lock).

(e) earth rotation parameters.

At CODE, we process data in overlapping time intervals.  We do this to keep
the reference system changes minimal.  Each time interval consists of a
central day, and two adjacent time intervals (see Figure 1).

   Figure 1: Processing in Overlapping Intervals at AIUB
   -----------------------------------------------------
Interval      Observations used

   1      I-----I----------I-----I
   2                 I-----I----------I-----I
   3                            I-----I----------I-----I
   .                                      .....
   .
         -------I----------I----------I----------I------->
time
                   day 1       day 2       day 3    ...

We set up one set of pole parameters (dx,dy,dut) for the central day
and for each of the adjacent time intervals. The pole parameters
in our result file are those estimated for the central days.

At present the time intervals to the left and right of the central day
have a length of one day too, which means that we are actually analyzing
three day arcs in each case.

Whereas it is possible to solve for dx and dy of the pole with GPS
provided the pole in the inertial space (System J2000.0) is known
(what we assume in our ananlysis), the UT1-UTC term may only be
estimated relative to an arbitrary starting epoch.  In our result file
the first value of UT1-UTC is taken from the a priori pole, the other
values are estimates relative to this first value. The a priori pole,
which defines the starting value for our UT1-UTC results, is of no
particular importance elsewhere. It is taken from the files distributed
by D. McCarthy through e-mail.

Models used
___________

We followed Prof. Clyde Goad's instructions as closely as possible
(a set of these instructions were sent to the IERS Directing
Board).

In summary we used

 - the GEM-T3 (8,8) model (including the non-zero terms C21, S21 (!))
 - the value GM=398.6004415d+12
 - ae = 6378137.d0 m
 - Gravitation by sun/moon
 - the Rock 4, Rock42 models according to Fliegel, 1992  *)
 - the y-bias                                            *)
 - solid tides
 - correct handling of light <--> shadow changes (!)

*) only used as a priori, additional parameters estimated (one for
   each effect).

The system J2000.0 was used as intertial system (for orbit integration).
The IAU 1980 models for precession and nutation are used without estimating
something in this context.

Crucial in the analysis are the station coordinates kept fixed (and
the excentricities at these points).  Basically the ITRF90 system
(epoch 1988.0) is used as earth fixed system, our realization is (hopefully)
identical with the information distributed by the IGN (Paris) lately through
IGS e-mail.

It is worth being noted that at present six satellites are having earth shadow
transits.  It is also clear that the orbits are not of the same quality for
these satellites as for the other ones.  This circumstance also seems to affect
the determination of the earth rotation parameters.  It may well be that in
future we will decide to reduce the arc length for eclipsing satellites.

================================================================================

-----------------------
PROCESSING CENTRE: CSR                                       EOP(CRS) 92 P 01
-----------------------

EARTH  ORIENTATION RESULTS SUBMITTED TO IERS

   Prof. B. E. Schutz
   [email-masked]

   Dr. P. A. M Abusali
   [email-masked]

Solution description
--------------------

1. Analysis Center: University of Texas/Center for Space Research
2. Solution Identifier: EOP(CSR) 92 P 01
3. Software used: MSODP1/TEXGAP
4. Definition of Terrestrial Reference Frame:
     Origin: ITRF91
     Orientation: ITRF91
     Reference epoch: 1992.5
     Relativity Scale: Geocentric (LE)
     Speed of light: 299792458.0 m/sec
     Geogravitational constant (GM) = 398600.4415 km^3/s^2
     Permanent tidal correction: Applied for dynamic tides
                                 Not applied to station coordinates
5. Station Coordinates:  ITRF91 (IGS Message Number 33/Boucher and Altamimi)
6. UT1:  not estimated, reference from UTX/CSR Lageos
7. Force Model:  IERS Standards
8. Data:  L1/L2 GPS phase, processed as double differences
9. Adjusted parameters:
   One-day arcs with no apriori covariance on any parameters
   Orbit parameters: 6 epoch elements, 2 nongravitational
                     force parameters for each satellite
   Zenith delay parameter each 2.5 hr for each station
   Double difference bias parameters
   Pole position
   Estimated Stations:  MADR(DS60), SANT, KOSG, YELL, CANB(DS40),
                        MCMU, USUDA, NYAL, TAIW, MASP, PAMA

Solution characteristics (Report period:1992 June 21 - 27)
------------------------

Reference Frame:  Defined by fixed stations in SLR (CSR91L03) and VLBI (GLB718)
Software:  MSODP1/TEXGAP
Data:  L1/L2 GPS phase sampled at 2 min., processed as double differences
Minimum Elevation:  15 degrees
Arc Length:
   UTX06507.EPH:   7-day continuous arc
   UTX06507.ERP:   1-day arcs
Adjusted Parameters:
   6 epoch elements, nongravitational force parameters for each satellite
   Zenith delay parameter each 2.5 hr for each station
   Double difference bias parameters
   Pole position (in one-day arcs)

================================================================================

----------------------
PROCESSING CENTRE: GFZ                                       EOP(GFZ) 92 P 01
----------------------

ANALYSIS RESULTS FROM GFZ

Chris Reigber

Solution description
--------------------

1. Analysis Center: GFZ/DLR
2. Solution Identifier: EPH(GFZ)92G01-DDD
                        ERP(GFZ)92G01-DDD
                        CLK(GFZ)92G01-DDD (only relative)
3. Software used: GEPARD4.0
4. Defintion of Terrestrial Reference Frame
   Origin: Nominally ITRF-90
   Orientation: Nominally ITRF-90
   Reference Epoch: 1992.352 (MJD 48750)
   Fixed set of stations: Y. Bock Solution (IGS Message No.35)
   ALGO, YELL, FAIR, KOKR, TROM, WEZ1, YAR1, USUD, NALL
5. Data used:
   - undifferenced pseudo ranges and carrier phases
   - 2-day arc solutions with one day overlap
6. Adjusted parameters:
   - State vector of all GPS satellites
   - Daily polar motion
   - Coordinate corrections for non-fixed stations
   - Troposheric zenith path delay
   - Solar radiation scale and y-bias
   - Ambiguities
   - ST and SV clock parameters of each observation epoch (the
     maser-based clock at Fairbanks is taken as reference clock)

================================================================================

----------------------
PROCESSING CENTRE: JPL                                        EOP(JPL) 92 P 01
----------------------

JPL ANALYSIS RESULTS

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

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

Tracking data from the global network of Rogue GPS receivers were analyzed
using the GIPSY/OASIS-II software, described in JPL internal documents.
(These documents are available on request.)

Data were analyzed in daily batches with 24-hour satellite arcs.

The measurements consist of undifferenced dual-frequency carrier phase
decimated to 6 minutes, and carrier-smoothed dual-frequency P-code
pseudorange. For both carrier phase and P-code, linear combinations of the
individual frequencies provide the ionosphere-free phase and pseudorange.
Data below 15 degrees elevation were not used.

Estimates of a 9-component state vector for each GPS satellite (3 parameters
each for position, velocity, and solar radiation pressure) were made, with
nominal values of position and velocity from the broadcast ephemeris. Weak a
priori constraints of 1 km and 10 mm/s for position and velocity, respectively,
were imposed.

Also estimated were 3-component position vectors for each terrestrial site.
Those for Fairbanks (Alaska,US), Algonquin Park (Ontario, Canada), and Madrid
(Spain) had a priori constraints of 0.1 mm, effectively making them fiducial
stations (see tables below, where they are identified by FAIR, ALGO, and MADR).

The ITRF'90 coordinates for these fiducial sites were realized by applying a
7- parameter similarity transformation of our GPS solution for the GIG'91
experiment into the ITRF'90 reference frame (see Blewitt et al., GRL vol. 19,
no. 9, May 4, 1992]. This transformation was estimated using 12 globally-
distributed stations, and resulted in a WRMS of 15 mm. These coordinates were
then mapped to epoch 1992.5 using VLBI-derived velocities of solution GLB718
[Ma, Ryan and Caprette, private comm., 1991] with the additional constraint
that the vertical velocities are zero (see 'Model B' in Blewitt et al. [1992]).
Since the fiducial coordinates define the reference frame of the orbits, they
are listed here.

Station     Monument         X [m]             Y [m]            Z [m]

 ALGO      ARO 883160     918129.5841     -4346071.2094     4561977.7947
 FAIR      Gilmore      -2281621.3243     -1453595.7491     5756961.9449
         Creek NCMN
 MADR      Top of        4849202.5864      -360329.2017     4114913.0940
         choke ring

Coordinates for all other sites were loosely (1 km) constrained. The other
sites are Alberthead (Canada), Canberra (Australia), Goldstone (US),
Hartebeesthoek (S. Africa), Herstmonceaux (UK), JPL (US), Kootwijk
(Netherlands), Madrid (Spain), Matera (Italy), McMurdo (Antarctica), Metshovi
(Finland), Ny Allesund (Norway), Onsala (Sweden), Tahiti, Penticton (Canada),
Pacific Geoscience Centre (Canada), Pinyon Flat (US), Santiago (Chile),
Scripps (US), St. Johns (Canada), Taiwan, Tromso (Norway), Usuda (Japan),
Wettzell (Germany), Yaragadee (Australia), and Yellowknife (Canada).

The wet troposphere zenith delays at each site were modeled as a random walk
in time with a 1 cm^2/hour variance derivative, and were mapped to satellite
elevations using the Lanyi mapping function. Their nominal values were 0.1 m
at every site and were estimated with 500-m a priori constraints.

The zenith dry delays were assumed fixed at 2 m for every site, and were also
mapped to satellite elevations using the Lanyi mapping function. (Because the
wet and dry delays are nearly degenerate parameters, the estimated wet delay
in fact represents the combined delay which deviates from the nominal 2.1 m.)

Clocks for each station and satellite (except for the reference clock, taken
as the maser-based clock at Fairbanks, and believed accurate to ~1 microsecond
or better) were estimated as a white-noise process with updates every 6 minutes.

The carrier phase ambiguities were estimated as real-valued parameters.

Nominal values for X and Y polar motion and UT1R-UTC were obtained from
interpolation in the IERS Bulletin B predicted values. Estimates of polar
motion had weak (5-m) constraints, while UT1R-UTC was constrained (0.01 mm)
to be the nominal.

The Williams solid Earth tide model was used. Pole tide and ocean loading were
not modeled.

The Earth's gravity field was described by the GEM-T3 multipole expansion using
terms up through degree and order 8. (IERS-recommended values for C21 and S21
of -0.17E-09 and 1.19E-09 were also used.) The value of GM was taken as
398600.4415km^3/s^2.

Description of the Terrestrial System for Solution EOP(JPL) 92 P 01
-------------------------------------------------------------------

(1)  Technique:                       GPS
(2)  Analysis Center:                 JPL
(3)  Solution identifier:             EOP(JPL) 92 P 01
(4)  Software used:                   GIPSY/OASIS-II
(5)  Relativity scale:                Local Earth
(6)  Permanent tide correction:       No
(7)  Tectonic plate model:            None (single epoch solution)
(8)  Velocity of light                299792458 m/sec
(9)  GM                               3.986004415E+14 m^3/s^2
(10) Reference epoch                  1992.5
(11) Adjusted parameters:             Station X, Y, Z at 1992.5
                                      PMX, PMY every 24 hours;
                                      GPS epoch state and 3 solar
                                      radiation biases every 24 hours;
                                      Random walk zenith tropospheres;
                                      White noise clocks (Fairbanks
                                      H-maser is the reference clock);
                                      Carrier phase ambiguities as
                                      real valued (not bias-fixed)
(12) Definition of origin             Defined though a realization of ITRF90
                                      and by fixing gravity field to GEM-T3.
(13) Definition of orientation        Defined through a realization of ITRF90
(14) Constraint for time-evolution    No time evolution.

================================================================================

----------------------
PROCESSING CENTRE: SIO                                        EOP(SIO) 92 P 01
----------------------

SIO ANALYSIS RESULTS

Yehuda Bock

The revised analysis described below is based on the analysis of the first 29
days of the IGS campaign.

1. Analysis Center: Scripps Institute of Oceanography
2. Solution Identifier: Preliminary Submission 920624
3. Software used: GAMIT/GLOBK
4. Definition of Terrestrial Reference Frame:
     Origin: Nominally ITRF-90
     Orientation: Nominally ITRF-90
     Reference epoch: 1992.51  (MJD 48808.5)
     Relativity Scale: Terrestrial
     Velocity of light: 299792458.0 m/sec
     Permanent tidal correction: None

5. Adjusted parameters:
   (a) Double-difference data
   (b) Single day orbit arcs, 6 ICs and 3 radiation parameters per
       satellite-per-day
   (c) One-per-day-per-station zenith tropospheric parameter,
   (d) Bias parameters, one for each independent double difference
       combination.
   (e) Station positions with +- 10 m constraints at stations other
       than: ALGO, YELL, PIN1, PINB, JPL1, JPLB, SIO1, SIO2, FAIR, KOKR,
       USUD, DS10, DS1B, DS40, DS41, DS60, YAR1, MCMU, TAIW, ONSA, WTZ1,
       METS, MATE, TROM, NALL, KOSG.  For these stations constraints of
       +0.001 m for horiziontal and +-0.005 m for the height were used.
   (f) X and Y pole position once per day. No estimate is made of UT1-AT
       since these deviations are absorbed into the orbital parameters.

==============================================================================

From:    Yehuda Bock
Subject: SIO analysis results

A) An error in our calender date to MJD routine caused our
   earlier submissions to have MJD's 0.5 days greater than
   they should have been.  This error has now been corrected.

B) The revised analysis described below is based on the analysis
   of the first 29 days of the IGS campaign.

1. Analysis Center: Scripps Institute of Oceanography
2. Solution Identifier: Preliminary Submission 920624
3. Software used: GAMIT/GLOBK
4. Definition of Terrestrial Reference Frame:
     Origin: Nominally ITRF-90
     Orientation: Nominally ITRF-90
     Reference epoch: 1992.51  (MJD 48808.5)
     Relativity Scale: Terrestrial
     Velocity of light: 299792458.0 m/sec
     Permanent tidal correction: None

5. Adjusted parameters:
   (a) Double-difference data
   (b) Single day orbit arcs, 6 ICs and 3 radiation parameters per 
satellite-per-day
   (c) One-per-day-per-station zenith tropospheric parameter,
   (d) Bias parameters, one for each independent double difference 
combination.
   (e) Station positions with +- 10 m constraints at stations other 
than: ALGO, YELL, PIN1, PINB, JPL1, JPLB, SIO1, SIO2, FAIR, KOKR, 
USUD, DS10, DS1B, DS40, DS41, DS60, YAR1, MCMU, TAIW, ONSA, WTZ1, 
METS, MATE, TROM, NALL, KOSG.  For these stations constraints of
+0.001 m for horiziontal and +-0.005 m for the height were used.
   (f) X and Y pole position once per day.  (No estimate is made of UT1-
AT since these deviations are absorbed into the orbital parameters).

6. Station coordinates used.

  DOMES #  Name          X            Y             Z        Epoch    Dur        +- X   +- Y   +- Z    Vx       Vy      Vz
                        (m)          (m)           (m)        MJD      days       (m)    (m)   (m)    (m/yr)  (m/yr)  (m/yr)
X13407S011 DS60 (?)   4849202.502  -360329.180  4114912.961 48808.5    25.0      0.004  0.002  0.004 -0.0101  0.0185  0.0135 
X?????     MASPollom  5439189.142 -1522054.840  2953464.085 48808.5     5.0      0.008  0.004  0.006 -0.0040  0.0185  0.0169 
X40701     SANTogue   1769692.989 -5044573.785 -3468321.402 48808.5    26.0      0.010  0.011  0.007  0.0013 -0.0044  0.0071 
X40104M002 ALGO        918129.628 -4346071.218  4561977.781 48808.5    28.0      0.002  0.003  0.003 -0.0193 -0.0029  0.0012 
X40127M003 YELL      -1224452.371 -2689216.059  5633638.271 48808.5    29.0      0.002  0.002  0.003 -0.0231 -0.0029 -0.0064 
X40407M00? PIN1 PEQ  -2369510.372 -4761207.146  3511396.058 48808.5     7.0      0.003  0.005  0.004 -0.0224  0.0218 -0.0004 
X40407M002 PIN1      -2369510.392 -4761207.164  3511396.033 48808.5    22.0      0.003  0.003  0.004 -0.0224  0.0218 -0.0004 
X40405S0?? DS10 PEQ  -2353614.083 -4641385.355  3676976.402 48808.5     4.0      0.004  0.006  0.005 -0.0159  0.0069 -0.0081 
X40405S026 DS10 (?)  -2353614.078 -4641385.364  3676976.426 48808.5    21.0      0.003  0.004  0.004 -0.0159  0.0069 -0.0081 
X40460M001 SIO1      -2455521.684 -4767213.382  3441654.860 48808.5    12.0      0.003  0.005  0.004 -0.0335  0.0302  0.0180 
X40460     SIO2      -2455539.233 -4767224.071  3441628.818 48808.5    23.0      0.003  0.004  0.004 -0.0335  0.0302  0.0180 
X40400M005 JPL1      -2493304.063 -4655215.510  3565497.280 48808.5    22.0      0.003  0.004  0.004 -0.0372  0.0153  0.0120 
X40400M00? JPL1 PEQ  -2493304.072 -4655215.488  3565497.266 48808.5     7.0      0.003  0.005  0.004 -0.0372  0.0153  0.0120 
X40105S004 DRAO (?)  -2059164.593 -3621108.342  4814432.375 48808.5    29.0      0.002  0.002  0.003 -0.0201 -0.0023 -0.0103 
X40408M001 FAIR      -2281621.313 -1453595.746  5756961.963 48808.5    29.0      0.002  0.002  0.004 -0.0233 -0.0027 -0.0099 
X92201M002 PAMA (?)  -5245195.144 -3080472.123 -1912825.685 48808.5     5.0      0.013  0.012  0.007 -0.0416  0.0527  0.0293 
X40424M004 KOKR      -5543838.047 -2054587.474  2387809.481 48808.5    22.0      0.005  0.003  0.006 -0.0100  0.0613  0.0294 
X?????S??? MCMU (?)  -1310696.417   310469.332 -6213368.516 48808.5    26.0      0.013  0.012  0.007  0.0091 -0.0107 -0.0024 
X50103S    DS42 (?)  -4460996.153  2682557.281 -3674444.134 48808.5    24.0      0.011  0.010  0.008 -0.0363  0.0023  0.0458 
X21729S001 USUD      -3855262.621  3427432.238  3741020.938 48808.5    20.0      0.006  0.004  0.008 -0.0212 -0.0097 -0.0130 
X23902S001 TAIW      -3024781.850  4928936.970  2681234.492 48808.5    27.0      0.007  0.008  0.009 -0.0232 -0.0078 -0.0118 
X50107M004 YAR1      -2389025.457  5043316.885 -3078531.092 48808.5    24.0      0.011  0.010  0.008 -0.0485  0.0107  0.0552 
X30302M001 HART (?)   5084625.136  2670366.576 -2768494.246 48808.5    12.0      0.014  0.012  0.008 -0.0013  0.0241  0.0209 
X10503     METS (?)   2892571.006  1311843.296  5512634.000 48808.5    14.0      0.003  0.002  0.004 -0.0192  0.0132  0.0070 
X10302M003 TROM       2102940.434   721569.354  5958192.082 48808.5    29.0      0.002  0.002  0.004 -0.0186  0.0110  0.0052 
X12734     MATE new   4641949.794  1393045.251  4133287.214 48808.5    26.0      0.004  0.002  0.005 -0.0157  0.0179  0.0117 
X14201     WTZ1 1200  4075578.649   931852.641  4801569.953 48808.5    26.0      0.004  0.002  0.004 -0.0161  0.0165  0.0105 
X10402M004 ONSA       3370658.736   711876.990  5349786.800 48808.5    29.0      0.003  0.001  0.004 -0.0168  0.0147  0.0086 
X10317M001 NALL       1202431.359   252626.760  6237770.778 48808.5    29.0      0.002  0.002  0.004 -0.0178  0.0083  0.0031 
X13504M003 KOSG (?)   3899225.316   396731.763  5015078.257 48808.5    21.0      0.003  0.002  0.004 -0.0150  0.0161  0.0104 

NOTES:
 (a) Those sites without a DOMES point number are at unknown locations,
and those sites with a (?) in the Alternate descriptions possibly have
an incorrect DOMES number.
 (b) The epoch refers to the epoch at which the site position applies
and not the mid-point of the data span.  We have also added the
velocities adopted for these sites at the end of each line.  For most sites
these are the NUVEL-1 velocities with the North American AM0-2 velocity
added.  For PIN1 and DS10, Observed velocities (based on a combined VLBI/
GPS solution using ~10 years of data have been used).
 (c) The PE notation in the site name (PINB, DS1B and JPLB) denotes 
post-Landers earthquake position (applicable after 11:58 UTC June 28, 1992.
 (d) These coordinates were estimated from the first 29 days of IGS data.
They have been rotated and translated into the ITRF 1990 frame by use
of the horizontal coordinates at YELL_GPS, PIN1_GPS, SIO1_GPS, FAIR_GPS, 
USUD_GPS, DS10_GPS, DS60_GPS, YAR1_GPS, ONSA_GPS, WTZ1_GPS, TROM_GPS, 
KOSG_GPS.  The rms difference between the horizontal coordinates of 
these sites and our previous realization (first IERS submission) was
15 mm).

6. Solution 920714

* MIT_TO_IERS: Run on 1992/ 7/17 17:15
* Input file : pmu920717.mit
 48779.5  -0.15531  0.31885 -0.517136  0.00019 0.00020 0.000000 1.93  0.001  0.000  0.000   21  17 0
 48780.5  -0.15624  0.32115 -0.519883  0.00021 0.00021 0.000000 1.84  0.109  0.000  0.000   21  16 0
 48781.5  -0.15368  0.32302 -0.522617  0.00027 0.00025 0.000000 1.32  0.046  0.000  0.000   21  17 0
 48782.5  -0.15451  0.32460 -0.525143  0.00026 0.00023 0.000000 1.32  0.117  0.000  0.000   21  17 0
 48783.5  -0.15472  0.32779 -0.527309  0.00020 0.00020 0.000000 1.80 -0.010  0.000  0.000   21  17 0
 48784.5  -0.15513  0.33001 -0.529055  0.00027 0.00024 0.000000 1.50  0.080  0.000  0.000   22  17 0
 48785.5  -0.15373  0.33206 -0.530225  0.00023 0.00022 0.000000 1.42  0.000  0.000  0.000   22  17 0
 48786.5  -0.15389  0.33508 -0.531264  0.00023 0.00022 0.000000 1.64 -0.023  0.000  0.000   21  17 0
 48787.5  -0.15227  0.33830 -0.532088  0.00037 0.00033 0.000000 1.63 -0.062  0.000  0.000   17  17 0
 48788.5  -0.15213  0.34141 -0.532830  0.00020 0.00022 0.000000 1.59 -0.011  0.000  0.000   21  17 0
 48789.5  -0.15235  0.34447 -0.533614  0.00024 0.00025 0.000000 1.36 -0.040  0.000  0.000   20  17 0
 48790.5  -0.15193  0.34715 -0.534539  0.00025 0.00025 0.000000 1.64 -0.044  0.000  0.000   21  17 0
 48791.5  -0.15280  0.35032 -0.535654  0.00023 0.00024 0.000000 1.79  0.109  0.000  0.000   20  17 0
 48792.5  -0.15191  0.35305 -0.536981  0.00020 0.00019 0.000000 2.22  0.060  0.000  0.000   20  17 0
 48793.5  -0.15268  0.35566 -0.539967  0.00018 0.00019 0.000000 1.54  0.011  0.000  0.000   20  17 0
 48794.5  -0.15108  0.35789 -0.541918  0.00021 0.00021 0.000000 1.35  0.000  0.000  0.000   23  17 0
 48795.5  -0.15072  0.35924 -0.543939  0.00019 0.00020 0.000000 1.81  0.023  0.000  0.000   24  17 0
 48796.5  -0.15012  0.36213 -0.545936  0.00017 0.00018 0.000000 1.50  0.098  0.000  0.000   24  17 0
 48797.5  -0.14935  0.36385 -0.547805  0.00020 0.00023 0.000000 1.87  0.062  0.000  0.000   23  17 0
 48798.5  -0.14714  0.36625 -0.549454  0.00026 0.00025 0.000000 1.36  0.121  0.000  0.000   21  17 0
 48799.5  -0.14706  0.36930 -0.551219  0.00027 0.00028 0.000000 1.25  0.146  0.000  0.000   21  17 0
 48800.5  -0.14466  0.37204 -0.552509  0.00024 0.00024 0.000000 1.30  0.085  0.000  0.000   22  17 0
 48802.5  -0.14321  0.37720 -0.554140  0.00024 0.00027 0.000000 1.25  0.158  0.000  0.000   22  17 0
 48803.5  -0.14155  0.38038 -0.555153  0.00020 0.00025 0.000000 1.89  0.119  0.000  0.000   21  17 0
 48804.5  -0.14115  0.38151  0.443530  0.00016 0.00017 0.000000 2.21  0.129  0.000  0.000   23  17 0
 48805.5  -0.13910  0.38475  0.441782  0.00018 0.00021 0.000000 1.98  0.083  0.000  0.000   22  17 0
 48806.5  -0.13795  0.38644  0.439604  0.00020 0.00023 0.000000 1.58  0.133  0.000  0.000   22  17 0
 48807.5  -0.13692  0.38956  0.437134  0.00021 0.00024 0.000000 1.72  0.096  0.000  0.000   23  16 0
 48808.5  -0.13486  0.39141  0.434606  0.00018 0.00020 0.000000 1.62  0.038  0.000  0.000   24  16 0
 48809.5  -0.13434  0.39332  0.432253  0.00015 0.00017 0.000000 2.95  0.134  0.000  0.000   26  16 0
 48810.5  -0.13191  0.39555  0.430247  0.00017 0.00018 0.000000 3.01  0.057  0.000  0.000   27  16 0
 48811.5  -0.13042  0.39820  0.428660  0.00014 0.00016 0.000000 2.63  0.095  0.000  0.000   27  17 0
 48812.5  -0.12983  0.39940  0.427483  0.00015 0.00018 0.000000 2.82  0.142  0.000  0.000   26  17 0
 48813.5  -0.12726  0.39815  0.427699  0.00019 0.00024 0.000000 6.56  0.290  0.000  0.000   27  16 0
 48814.5  -0.12639  0.40500  0.427271  0.00014 0.00016 0.000000 3.01  0.192  0.000  0.000   28  17 0

NOTES: UT1 not estimated.  Value given is apriori used in analysis.  The rms is the square of chi**2
per degree of freedom in our solution.  It nominally should be 1.0.  st and sv are numbers of stations
and satellites in solution.

==============================================================================

From:     Bob E. Schutz
Subject:  UTX SOLUTIONS
          -------------

      Earth  Orientation Results Submitted to IERS

EARTH ROTATION PARAMETERS
ANALYSIS CENTER:  UNIVERSITY OF TEXAS CENTER FOR SPACE RESEARCH
DATA:  GPS
SOLUTION IDENTIFIER:  EOP(CSR) 92 P 01
SUBMISSION DATE:  16 JULY 1992

   MJD         x        y    UT1        sx       sy     sUT1     RMS   cxy   cxUT1 cyUT1     Sta  Sat Passes

 48794.5 -0.15206  0.35361  0.0       0.00034  0.00038  0.0      2.1   0.0    0.0    0.0      16  17   275
 48795.5 -0.15130  0.35812  0.0       0.00032  0.00035  0.0      2.1   0.0    0.0    0.0      16  17   275
 48796.5 -0.14994  0.36261  0.0       0.00020  0.00024  0.0      1.7   0.0    0.0    0.0      17  17   308
 48797.5 -0.14854  0.36192  0.0       0.00028  0.00041  0.0      1.9   0.0    0.0    0.0      17  17   249
 48798.5 -0.14854  0.36618  0.0       0.00038  0.00046  0.0      1.4   0.0    0.0    0.0      15  17   247
 48799.5 -0.14708  0.36858  0.0       0.00034  0.00034  0.0      1.7   0.0    0.0    0.0      17  17   282
 48800.5 -0.14507  0.37326  0.0       0.00031  0.00033  0.0      1.4   0.0    0.0    0.0      14  17   286
 48801.5 -0.14509  0.37373  0.0       0.00031  0.00030  0.0      1.4   0.0    0.0    0.0      19  17   350
 48802.5 -0.14465  0.37779  0.0       0.00024  0.00026  0.0      1.5   0.0    0.0    0.0      19  17   371
 48803.5 -0.14158  0.38167  0.0       0.00017  0.00017  0.0      1.9   0.0    0.0    0.0      19  17   398
 48804.5 -0.14168  0.38466  0.0       0.00016  0.00017  0.0      1.9   0.0    0.0    0.0      19  17   382
 48805.5 -0.14409  0.38765  0.0       0.00016  0.00017  0.0      2.1   0.0    0.0    0.0      20  17   392  
 48806.5 -0.13850  0.38859  0.0       0.00018  0.00020  0.0      2.2   0.0    0.0    0.0      19  17   392
 48807.5 -0.13451  0.38798  0.0       0.00018  0.00024  0.0      2.3   0.0    0.0    0.0      18  17   350
 48808.5 -0.13579  0.39443  0.000000  0.00019  0.00027  0.000000 1.53 -0.090  0.000  0.000    20  16   331
 48809.5 -0.13384  0.39514  0.000000  0.00017  0.00017  0.000000 1.73  0.016  0.000  0.000    20  16   383
 48810.5 -0.13257  0.39760  0.000000  0.00021  0.00022  0.000000 1.75  0.069  0.000  0.000    20  16   339
 48811.5 -0.13019  0.39898  0.000000  0.00015  0.00014  0.000000 1.92  0.102  0.000  0.000    20  17   412

Notes:
 1.  RMS is in cm
 2.  MJD 48809.5 through 48810.5 excluded PRN12 based on the RMS which exceeded 2.3 cm.