Subject: [IGSREPORT-1497] Wk 0782 COD Analysis Report
From: M. Rothacher
Date: Mon, 16 Jan 1995 10:08:17 PST

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IGS Electronic Report    Mon Jan 16 10:08:17 PST 1995      Message Number 1497
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Author: M. Rothacher
Subject: Wk 0782 COD Analysis Report

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CODE ANALYSIS REPORT GPS WEEK 0782 (DAYS 001-007, DATES 01-01-95 - 07-01-95)
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Submitted by: Astronomical Institute, University of Berne, Switzerland
 
FILES SENT TO CDDIS:
-----------------------------------------------------------------------------
COD07827.SUM           THIS TEXT FILE
COD07827.ERP           EARTH ROTATION PARAMETERS FOR GPS WEEK 0782
COD0782N.EPH           GPS EPHEMERIDES FOR GPS WEEK 0782, SP3 FORMAT (N=0..6)
-----------------------------------------------------------------------------
 
THREE DAY SOLUTION STATISTICS:
------------------------------------------------------
MIDDLE DAY  FILES  OBSERVATIONS   PARAMETERS  RMS (MM)
------------------------------------------------------
  1         146    187884          7805        3.3
  2         145    186693          8188        3.2
  3         150    192775          8673        3.4
  4         154    195849          9009        3.4
  5         157    207733          8803        3.4
  6         158    211884          8739        3.4
  7         158    212212          8255        3.4
------------------------------------------------------
 
ORBIT REPEATABILITY (CM) FOR PRN: (>X = VALUE > X METERS, >> = NOT INCLUDED)
-------------------------------------------------------------------------------
     01 02 04 05 06 07 09 12 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 31
-------------------------------------------------------------------------------
  1  11 41 32 40 26 24 24 20 21 39 20 44 12 31 56 23 53 18 35 20 15 26 28 12 30
  2  10 44 34 45 27 30 24 21 22 39 22 38 11 20 61 24 51 22 36 21 14 23 28 11 29
  3   8 48 36 48 29 30 25 21 21 41 25 39 10 23 65 26 49 27 39 22 12 23 30 10 30
  4   9 47 38 48 28 27 23 19 21 43 25 38 12 24 65 24 52 16 40 24 12 24 28 11 28
  5   9 47 36 49 28 27 21 17 21 44 26 41  9 21 67 26 56 20 41 23 11 21 26 11 27
  6  10 48 34 50 28 27 21 17 20 42 21 44  9 20 70 27 59 26 36 19 12 19 27 10 28
  7   9 49 34 53 30 29 21 19 20 39 25 43 11 21 73 23 58 27 40 20 11 22 28 11 28
-------------------------------------------------------------------------------
 
STATION SUMMARY:
--------------------------------------------------------------------------------
   GRAZ  MADR* METS  TROM* DRAO  KOKB* RCM5  YELL* TIDB* PAMA  USUD  JOZE  TOTAL
    HERS  MAS1  NYAL  WETT* FAIR* PIET  STJO  KOUR  HOB2  YAR1* ZIMM  FORT
     KOSG* MATE  ONSA  ALGO* GOLD* QUIN  WES2  SANT* MCMU  TAIW  HART* BRMU
      BRUS  MDO1  TSKB  AREQ  BORO  DAV1  SEIS  KIT3  CAS1  POTS  BOGT  KERG    
       LAMA                                                                  
--------------------------------------------------------------------------------
  1  XXXXX X-XX  XXXX  XXXX  XXX-  XXXX  XXX-  XXX-  X-XX  XXX-  XX-X  XXX-42/49
  2  X-XXX X-XX  XXXX  XXXX  XXXX  XXXX  XXX-  XXX-  X-XX  XXX-  XX-X  XXXX42/49
  3  X-XX- X-XX  XXXX  XXXX  XXXX  XXXX  XXX-  XXX-  X-XX  XXX-  XX-X  XXXX41/49
  4  X-XXX XXXX  XXXX  XXXX  XXX-  XXXX  XXX-  XXX-  X-XX  XXX-  XX-X  XXXX42/49
  5  X-XXX XXXX  XXXX  XXXX  XXX-  XXXX  XXX-  XXXX  X-XX  XXXX  XX-X  -XXX43/49
  6  XXXXX XXXX  XXXX  XXXX  XX-X  XXXX  XXX-  XXXX  X-XX  -XXX  XX--  XXXX43/49
  7  XXXXX XXXX  -XXX  XXXX  XXXX  XXXX  XXX-  XXXX  X-XX  XXXX  -X--  XXXX43/49
--------------------------------------------------------------------------------
 
REMARKS concerning transition from ITRF92 to ITRF93: 
 
Starting with day 001 of 1995 we implemented the ITRF93 coordinates and the
ITRF93 velocity field for the routine global analysis. We fix (more correctly:
heavily constrain) the same 13 sites as in 1994.

We recomputed our erp series using the new ITRF93 coordinates and velocities
for all days from day 200/1993 to day 365/1994. We saw the following 
differences between the two erp series (ITRF93 and ITRF92) when looking at 
this time interval of 1.5 years:

         Differences "ITRF93(CODE) - ITRF92(CODE)"

                       x-pole                               y-pole

Epoch       Offset [mas]    Drift [mas/yr]       Offset [mas]    Drift [mas/yr] 
                                                                                
1993.0     0.09   +- 0.06    -0.35 +- 0.05     -0.88   +- 0.08   -0.42 +- 0.06  
1994.0     -.10   +- 0.04                      -1.11   +- 0.06    
1995.0     -.45   +- 0.05                      -1.67   +- 0.07                  
                                           
This means that the change in the velocity model resulted in a change
in the drift rate in x and y pole of -0.35 resp. -0.42 mas/yr.

A comparison between the actual C04 pole series corrected by the offset and 
drift values given in Table II-3 of the IERS 1993 Annual Report on page 
II-19 and our series based on ITRF93 coordinates and velocities shows a 
good consistency:

                        Differences between ITRF93(CODE) and C04

                       x-pole                               y-pole

Epoch       Offset [mas]    Drift [mas/yr]       Offset [mas]    Drift [mas/yr] 
                                                                                
1993.0    -0.06   +- 0.06    0.03  +- 0.04      0.21   +- 0.07   -0.40 +- 0.05  

There is no discontinuity between the ITRF92 and the ITRF93 erp series
at the end of the year, if the corrections given in Table II-3 of the IERS 
1993 Annual Report and those of the corresponding Table in the IERS 1992 
Annual Report are taken into account for the erp values of 1995 resp. 1994.

Starting with day 001/1995 the new ITRF93 coordinates (and velocities) should 
be used to be consistent with the reference frame of the orbits. 

[Mailed From: MARKUS ROTHACHER <[email-masked]>]