[IGSREPORT-7837] Wk 1091 MIT T2 Analysis Report

Tom Herring tah at mtglas.mit.edu
Wed Dec 20 23:42:21 PST 2000


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IGS Electronic Report   20 Dec 23:42:23 PST 2000      Message Number 7837
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Author: Thomas Herring

********************************************************************************
MIT ANALYSIS REPORT GPS-WEEK 1091    Dates: 00dec03  to  00dec09 
********************************************************************************

MIT (Massachusetts Institute of Technology) 
Room 54-618
77 Massachusetts Avenue, 
Cambridge,  MA  02139
e-mail: tah at mtglas.mit.edu 
tel:    (617)253-5941 (Tom Herring)
fax:    (617)253-1699

PRODUCTS GENERATED:
The following products are generated and uploaded into CDDIS @ NASA/GSFC
   MIT1091g.SNX   Combined sinex file from all available analysis centers
   MIT1091g.SUM   Name of this summary file
   MIT1091g.RES   File of the individual AC position estimates residuals 
                  to the combined solution for the week. 

0.0 Starting Week 1066, we adopted the IGS realization of the ITRF97
    (referred to as IGS97).  We also replaced our constrained solution
    a loose solution with translation (+-1 mm) and orientation (+-0.1 mas)
    constraints applied.
0.1 Starting Week 1020, we adopted the ITRF97 reference frame
0.2 Starting Week 1002, we re-ordered the summary to give the residual
    summary and the SINEX file errors first.  


CENTER SUMMARY STATISTICS
 CENTER   #       North           East           Up
               RMS    Chi     RMS    Chi    RMS     Chi
              (mm)           (mm)          (mm)
 COD      0     .0     .0      .0     .0      .0     .0  
 JPL      0     .0     .0      .0     .0      .0     .0  
 SIO      0     .0     .0      .0     .0      .0     .0  
 EMR     52     .0     .0      .0     .0      .1     .0  
 ESA      0     .0     .0      .0     .0      .0     .0  
 GFZ      0     .0     .0      .0     .0      .0     .0  
 NGS      0     .0     .0      .0     .0      .0     .0  
 
CENTER SINEX ERRORS: (corrected during processing).
 CNT  Site Type of Error           Used values                       IGS.SNX values

HISTORY and PROCEDURES
----------------------

0.0 Starting Week 998 we adopted full checking of the center sinex
    headers and we correct the solutions for differences between the
    headers and a modified version of IGS.SNX.  (The modifications are
    to put full precision antenna L1/L2 offsets and to correct the WUHN
    entry.  The station log for this site shows height to BCR not ARP).
    A new error reporting block has been added below.  We also have 
    removed some of the routine documention in this summary.

0.1 Starting week 993 we started to add corrections for the pole-tide to
    the SIO, NGS, and ESA sinex.  According to the analysis descriptions
    none of these centers apply the pole tide correction.  Starting with
    the re-submission of week 992, we corrected the LOD values in JPL sinex
    files from regularized LOD (should be called LODR in the SINEX file)
    to standard LOD.  (Since starting multiday polar motion combinations
    we have been correcting the sign error in the JPL LOD values.

0.2 Starting week 989 we include as Section 5.0 of this summary, the
    Earth rotation parameter estimates from the constrained combination
    solution in the IERS format.

0.3 Starting Week 980 we include multiday polar motion/UT1 estimates into
    our analysis.   We also no longer need to deconstrain the AC sinex 
    files although to add back into the covariance matrices at rotational
    uncertainity which is coupled between station positions and EOPs.


0.4 Starting Week 0943 we base the analysis on the ITRF96 system and the
    reference site list for the ITRF96 system. The increase in the number
    of sites used to obtain analysis variances increases the variance 
    factors for all centers by factors between 2 and 4.  The Chi**2 for
    the center residuals is now much closer to 1.0

0.5 Starting Week 0931 we added a new residual file to our submissions.  
    A description of the contents of the file is given in the file itself.
    We also changed the treatment of the translation of the individual 
    AC solutions.  The generation of the weighting factors and the constrained
    combined solution remains unchanged.  However, in the unconstrained 
    analyses (used for AC comparisons) we now allow explicit translation
    and scale parameters in the solution.  The net effect is to generate
    more realisitic sigmas for the center of mass position estimates and to
    make the coordinate estimates immune to real center of mass translations
    and scale changes. 

0.6 Starting Week 0901 we started using a new apriori file not Non-ITRF94 coordinates
    based on the analysis of week 0822-0900 sinex files.

1.0 Analysis Procedures:

(1) Each centers sinex solutions are de-constrained by adding back
 in a rotational uncertainty.
 
(2) Covariance matrices from each center are re-scaled to generate
 unit increment in chi square per degree in the tight constraints solution.
 The values are are based in the chi**2 per degree of freedom increment
 when the loosely constrained solution is constrained to the ITRF1996
 coordinates of the 55 Reference sites.  Orientation changes are estimated
 in this step, but translations and scale are NOT estimated.
 
(3) The tight solution is generated with the following constraints on
 the core sites.  Starting Week 0858, ITRF94 is used for the coordinate
 system.  Starting Week 0878, we changed the site selection here to use
 WTZR and GOL2.  Starting Week 0897 we stopped using MADR as a core site.
 We continue not use MADR in the reference site list.

 Earth rotation parameters are estimated for each center (even when not given
 in the original SINEX files.  In this case the partial derivatives are
 computed from the station coordinates).

(4) When the combined and center solutions are compared to ITRF97, the
heights are given a variance 10 times larger than the horizontal coordinates.
The same variance ratio is used when the RMS to ITRF97 core sites is
computed.

(5) Starting Week 0826, we show the differences in the coordinates for
five non-core sites, in remote areas.  Four of these sites are processed 
by all centers.  These sites are not used in the RMS calculations or 
the transformation estimation to the 13 core sites.  The change in procedure
was because FORT is no longer being processed by all centers.  AREQ has
been added to the list for this reason.  After Week 0943, when the reference
site list increased we no long summarize additional sites.

(6) Starting Week 0826, we start to show a comparison of each centers
results with the combined solution for the week.  When the constraints
are applied to loose combined solution to translate, rotate and scale it
to the ITRF97, the constraints are actually applied using the full 
covariance matrix of the combined solution (rather than simply directly
applying the transformations to the coordinates).  The approach we use
constrains the center of mass to have zero variance relative to ITRF97.
The result of this is that the combined solution has the same center
of mass position and scale as ITRF97, and therefore when each of the
centers are compared to the combined solution, they generate very similar
translations and scales as they do the ITRF97.  Had we simply applied
the transformations to the coordinates, the translations and scale would
have been the difference between the combined translations and scale and
the individual center's translations and scale.
This new section is numbered 4.0.

(7) Starting Week 868, we updated the coordinates of sites not included
in the ITRF94 coordinate files.  This introduces a discontinuity in the
the adjustments to some of the "isolated" sites shown below.

 
 2.0 COMBINED FIT TO IGS97 
 Transformation of loose solution COMBINED to IGS97
 -----------------------------------------------
 For   34 Sites, RMS after 7 parameter transformation   4.0 mm  COMBINED wrt IGS97 
   X-tran  +-      Y-tran  +-      Z-tran   +-   Scale   +-
   (mm)   (mm)     (mm)   (mm)      (mm)   (mm)  (ppb)  (ppb)
    4.2   10.5     -1.6   11.2     14.8   28.8  -2.461  0.295  COMBINED  CoM
 
 Adjustments to core site positions for COMBINED
 SITE    dNorth  +-     dEast   +-    dUp    +- 
          (mm)  (mm)    (mm)   (mm)   (mm)  (mm)
 VILL    -3.0    2.0   -0.2    3.2   -9.5    5.7  COMBINED wrt IGS97
 FORT    -3.1    4.2   12.8   10.8   -7.6   16.4  COMBINED wrt IGS97
 KOUR    -3.8    3.3   -4.1    5.6    7.1   12.3  COMBINED wrt IGS97
 BRMU    -1.6    2.0   -2.5    3.2  -14.3    6.5  COMBINED wrt IGS97
 THU1    -3.1    2.6   -1.6    2.7    3.8    7.9  COMBINED wrt IGS97
 SANT     4.4    3.8   10.1    4.7    6.0    8.3  COMBINED wrt IGS97
 AREQ     0.4    3.3    6.9    5.1   30.7    9.2  COMBINED wrt IGS97
 ALGO    -0.7    1.8   -3.5    2.6  -10.4    5.3  COMBINED wrt IGS97
 NLIB     0.8    2.4   -1.7    3.9  -11.1    8.4  COMBINED wrt IGS97
 PIE1     1.7    2.3   -9.1    3.9   -5.4    7.2  COMBINED wrt IGS97
 YELL    -8.3    2.4    1.5    3.1    9.7    6.2  COMBINED wrt IGS97
 DRAO     1.6    2.1    1.1    2.9    6.5    5.6  COMBINED wrt IGS97
 FAIR    -2.0    3.4   -8.1    4.3   14.8    8.7  COMBINED wrt IGS97
 CHAT     3.0    2.4    4.8    3.9   -9.4    8.0  COMBINED wrt IGS97
 AUCK     6.9    2.2    2.4    3.4  -14.0    7.2  COMBINED wrt IGS97
 KWJ1     2.8    4.1  -10.2    8.6    8.4   14.0  COMBINED wrt IGS97
 MCM4    -4.4    5.3    7.8    6.2    7.7   18.1  COMBINED wrt IGS97
 MAC1     2.8    2.5    1.3    3.6  -12.1    7.8  COMBINED wrt IGS97
 TIDB     5.0    2.2   -7.2    3.5    9.4    7.5  COMBINED wrt IGS97
 HOB2     2.4    3.7    2.0    5.7   -0.9   13.0  COMBINED wrt IGS97
 GUAM     4.1    3.8   -4.8    7.4  -12.4   13.8  COMBINED wrt IGS97
 TSKB     4.0    2.9   14.6    4.3    2.5    8.7  COMBINED wrt IGS97
 PERT    -0.9    4.1   -1.4    7.3    1.9   13.5  COMBINED wrt IGS97
 YAR1     3.2    3.3   -8.5    6.0   15.5   11.2  COMBINED wrt IGS97
 CAS1    -3.8    3.8   -2.1    4.4   -3.6    9.4  COMBINED wrt IGS97
 IRKT     0.6    2.6    8.2    3.6    9.4    7.1  COMBINED wrt IGS97
 LHAS    -3.1    2.5    2.1    4.2  -13.7    7.7  COMBINED wrt IGS97
 KIT3    -4.9    2.6   -1.3    4.1    8.4    8.9  COMBINED wrt IGS97
 BAHR    -1.5    2.3    4.2    3.2    4.9    6.9  COMBINED wrt IGS97
 MALI    -3.4    5.0  -18.9   12.7   -7.6   19.3  COMBINED wrt IGS97
 ZWEN    -4.1    3.1   -3.8    3.7   -7.0    9.3  COMBINED wrt IGS97
 MATE    -2.1    2.1    5.0    3.0   -4.1    6.0  COMBINED wrt IGS97
 ONSA    -2.3    2.0   -0.8    2.6    7.2    5.5  COMBINED wrt IGS97
 NYAL    -0.5    2.8    3.0    3.1   -8.2    8.8  COMBINED wrt IGS97
 Reference sites NOT used 
 
 
 3.0 CENTER FITS TO IGS1997
 CENTER EMR
 -------------------
 VARIANCE RESCALING FACTOR FOR EMR 5.04
 
 Transformation of loose solution EMR to IGS97
 -----------------------------------------------
 For   34 Sites, RMS after 7 parameter transformation   4.0 mm  EMR wrt IGS97 
   X-tran  +-      Y-tran  +-      Z-tran   +-   Scale   +-
   (mm)   (mm)     (mm)   (mm)      (mm)   (mm)  (ppb)  (ppb)
    4.2   10.5     -1.6   11.2     14.8   28.8  -2.461  0.295  EMR  CoM
 
 Adjustments to core site positions for EMR
 SITE    dNorth  +-     dEast   +-    dUp    +- 
          (mm)  (mm)    (mm)   (mm)   (mm)  (mm)
 VILL    -3.0    2.0   -0.2    3.2   -9.5    5.7  EMR wrt IGS97
 FORT    -3.1    4.2   12.8   10.8   -7.6   16.4  EMR wrt IGS97
 KOUR    -3.8    3.3   -4.1    5.6    7.1   12.3  EMR wrt IGS97
 BRMU    -1.6    2.0   -2.5    3.2  -14.3    6.5  EMR wrt IGS97
 THU1    -3.1    2.6   -1.6    2.7    3.8    7.9  EMR wrt IGS97
 SANT     4.4    3.8   10.1    4.7    6.0    8.3  EMR wrt IGS97
 AREQ     0.4    3.3    6.9    5.1   30.7    9.2  EMR wrt IGS97
 ALGO    -0.7    1.8   -3.5    2.6  -10.4    5.3  EMR wrt IGS97
 NLIB     0.8    2.4   -1.7    3.9  -11.1    8.4  EMR wrt IGS97
 PIE1     1.7    2.3   -9.1    3.9   -5.4    7.2  EMR wrt IGS97
 YELL    -8.3    2.4    1.5    3.1    9.7    6.2  EMR wrt IGS97
 DRAO     1.6    2.1    1.1    2.9    6.5    5.6  EMR wrt IGS97
 FAIR    -2.0    3.4   -8.1    4.3   14.8    8.7  EMR wrt IGS97
 CHAT     3.0    2.4    4.8    3.9   -9.4    8.0  EMR wrt IGS97
 AUCK     6.9    2.2    2.4    3.4  -14.0    7.2  EMR wrt IGS97
 KWJ1     2.8    4.1  -10.2    8.6    8.4   14.0  EMR wrt IGS97
 MCM4    -4.4    5.3    7.8    6.2    7.7   18.1  EMR wrt IGS97
 MAC1     2.8    2.5    1.3    3.6  -12.1    7.8  EMR wrt IGS97
 TIDB     5.0    2.2   -7.2    3.5    9.4    7.5  EMR wrt IGS97
 HOB2     2.4    3.7    2.0    5.7   -0.9   13.0  EMR wrt IGS97
 GUAM     4.1    3.8   -4.8    7.4  -12.4   13.8  EMR wrt IGS97
 TSKB     4.0    2.9   14.6    4.3    2.5    8.7  EMR wrt IGS97
 PERT    -0.9    4.1   -1.4    7.3    1.9   13.5  EMR wrt IGS97
 YAR1     3.2    3.3   -8.5    6.0   15.5   11.2  EMR wrt IGS97
 CAS1    -3.8    3.8   -2.1    4.4   -3.6    9.4  EMR wrt IGS97
 IRKT     0.6    2.6    8.2    3.6    9.4    7.1  EMR wrt IGS97
 LHAS    -3.1    2.5    2.1    4.2  -13.7    7.7  EMR wrt IGS97
 KIT3    -4.9    2.6   -1.3    4.1    8.4    8.9  EMR wrt IGS97
 BAHR    -1.5    2.3    4.2    3.2    4.9    6.9  EMR wrt IGS97
 MALI    -3.4    5.0  -18.9   12.7   -7.6   19.3  EMR wrt IGS97
 ZWEN    -4.1    3.1   -3.8    3.7   -7.0    9.3  EMR wrt IGS97
 MATE    -2.1    2.1    5.0    3.0   -4.1    6.0  EMR wrt IGS97
 ONSA    -2.3    2.0   -0.8    2.6    7.2    5.5  EMR wrt IGS97
 NYAL    -0.5    2.8    3.0    3.1   -8.2    8.8  EMR wrt IGS97
 Reference sites NOT used 
 
 
 4.0 CENTER FITS TO COMBINED SOLUTION 
 CENTER EMR
 -------------------
 VARIANCE RESCALING FACTOR FOR EMR 5.04
 
 Transformation of loose solution EMR to COMB
 -----------------------------------------------
 For   34 Sites, RMS after 7 parameter transformation   0.0 mm  EMR wrt COMB 
   X-tran  +-      Y-tran  +-      Z-tran   +-   Scale   +-
   (mm)   (mm)     (mm)   (mm)      (mm)   (mm)  (ppb)  (ppb)
    4.3   10.5     -1.6   11.2     14.8   28.8  -2.459  0.296  EMR  CoM
 
 Adjustments to core site positions for EMR
 SITE    dNorth  +-     dEast   +-    dUp    +- 
          (mm)  (mm)    (mm)   (mm)   (mm)  (mm)
 VILL     0.0    2.0    0.0    3.2    0.0    5.7  EMR wrt COMB
 FORT     0.0    4.2    0.0   10.7   -0.1   16.4  EMR wrt COMB
 KOUR     0.0    3.3    0.0    5.6   -0.1   12.3  EMR wrt COMB
 BRMU     0.0    2.0    0.0    3.2   -0.1    6.5  EMR wrt COMB
 THU1     0.0    2.6    0.0    2.7    0.0    7.9  EMR wrt COMB
 SANT     0.0    3.8   -0.1    4.7   -0.1    8.3  EMR wrt COMB
 AREQ     0.0    3.3   -0.1    5.1   -0.1    9.2  EMR wrt COMB
 ALGO     0.0    1.9    0.0    2.6    0.0    5.3  EMR wrt COMB
 NLIB     0.0    2.4    0.0    3.9    0.0    8.4  EMR wrt COMB
 PIE1     0.1    2.3    0.0    3.9    0.0    7.2  EMR wrt COMB
 YELL     0.1    2.4    0.0    3.1    0.0    6.2  EMR wrt COMB
 DRAO     0.0    2.1    0.0    2.9    0.0    5.6  EMR wrt COMB
 FAIR     0.0    3.4    0.0    4.3    0.1    8.7  EMR wrt COMB
 CHAT    -0.1    2.4    0.0    3.9    0.0    8.0  EMR wrt COMB
 AUCK     0.0    2.2    0.0    3.4    0.0    7.2  EMR wrt COMB
 KWJ1    -0.1    4.1    0.1    8.6    0.0   14.0  EMR wrt COMB
 MCM4     0.1    5.3    0.0    6.2    0.0   18.1  EMR wrt COMB
 MAC1     0.0    2.5    0.0    3.6    0.0    7.8  EMR wrt COMB
 TIDB    -0.1    2.2    0.0    3.5    0.1    7.5  EMR wrt COMB
 HOB2     0.0    3.7    0.0    5.7    0.0   13.0  EMR wrt COMB
 GUAM     0.0    3.8    0.1    7.4    0.0   13.8  EMR wrt COMB
 TSKB     0.0    2.9    0.1    4.3    0.0    8.7  EMR wrt COMB
 PERT     0.0    4.1   -0.1    7.3    0.0   13.5  EMR wrt COMB
 YAR1     0.0    3.4   -0.1    6.0    0.0   11.2  EMR wrt COMB
 CAS1     0.1    3.8    0.0    4.4    0.0    9.4  EMR wrt COMB
 IRKT     0.1    2.6    0.0    3.6    0.1    7.1  EMR wrt COMB
 LHAS     0.0    2.5    0.0    4.2    0.0    7.7  EMR wrt COMB
 KIT3     0.0    2.6    0.0    4.1    0.1    8.9  EMR wrt COMB
 BAHR     0.0    2.3    0.0    3.2    0.0    6.9  EMR wrt COMB
 MALI    -0.1    5.0    0.1   12.7    0.0   19.3  EMR wrt COMB
 ZWEN     0.0    3.1    0.0    3.7    0.0    9.3  EMR wrt COMB
 MATE     0.0    2.1    0.0    3.0    0.0    6.0  EMR wrt COMB
 ONSA     0.0    2.0    0.0    2.6    0.0    5.5  EMR wrt COMB
 NYAL     0.0    2.8    0.0    3.1    0.0    8.8  EMR wrt COMB
 Reference sites NOT used 
 
 
 5.0 EOP ESIMATES FROM THE CONSTRAINED COMBINED SOLUTION
  MJD      Xpole   Ypole  UT1-UTC    LOD  Xsig  Ysig   UTsig  LODsig  Nr Nf Nt    Xrt    Yrt  Xrtsig  Yrtsig XYcorr XUTcor YUTcor
             (10**-6")       (0.1 usec)    (10**-6")     (0.1 usec)              (10**-6"/d)    (10**-6"/d)
51874.50  -77711  328795  1193416   5838 21484 21435   66670     169  52  0  0  -1068   2098    294    294    -.002   .000   .000
51875.50  -78545  330880  1188204   4682 21484 21435   66674     153  52  0  0   -891   1942    256    255    -.002   .000   .000
51876.50  -78861  332577  1183727   4390 21484 21435   66677     149  52  0  0   -581   1913    248    247    -.002   .000   .000
51877.50  -79153  334288  1179163   4823 21484 21435   66681     147  52  0  0   -522   1877    244    244    -.002   .000   .000
51878.50  -79480  336245  1174020   5511 21484 21435   66685     135  52  0  0   -787   1829    234    235    -.002   .000   .000
51879.50  -80160  337897  1168169   6254 21484 21435   66688     135  52  0  0   -797   1865    232    234    -.002   .000   .000
51880.50  -80707  339710  1161236   7660 21484 21435   66692     159  52  0  0   -461   1852    266    274    -.002   .000   .000



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