[IGSREPORT-25339] Wk 1946 MIT T2 RNAAC Analyis Report

[Tom Herring]

Author: Thomas Herring

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MIT R/GNAAC  ANALYSIS REPORT GPS-WEEK 1946    Dates: 17apr23  to  17apr29 
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MIT (Massachusetts Institute of Technology) 
Room 54-332
77 Massachusetts Avenue, 
Cambridge,  MA  02139
e-mail: tah at mit.edu 
tel:    (617)253-5941 (Tom Herring)
fax:    (617)253-6385

PRODUCTS GENERATED:
The following products are generated and uploaded into CDDIS @ NASA/GSFC
   MIT1946p.SNX   RNAAC combination sinex file from all available analysis centers
                  with the GNAAC sinex files.
   MIT1946p.SUM   Name of this summary file

0.0 Starting Week 1934, Switched to IGS14 realization of the reference frame.

0.1 Starting Week 1632, Switched to IGb08 realization of the reference frame.

0.2 Starting Week 1395, adopted IGS05 for reference frame.  The combination
    is now minimum constraint.

0.3 Starting Week 1239 we adopted IGb00 reference system (given in
    IGS03P33_RS99.snx)

0.4 Starting Week 1016 we starting using ITRF97

0.5 Starting Week 0939 we starting using ITRF96 and its reference site list.  

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.  This change will 
    effect the corrdinate corrections given in this summary. 
 
1.0 Analysis Procedures:

(1) Each centers sinex solutions are de-constrained before
 combination.  When center constraints are available, the
 constraints are loosened to +-1 meters.
 
(2) Covariance matrices from each center are re-scaled based
 on the change in chi**2 when the RNAAC's sinex file is
 combined with the loose combination of the GNAAC's 
 sinex files.  To generate reasonable sigmas, the scale factor
 is set at 0.3 times the chi**2/degree of freedom increment.
 
(3) Reference frame is defined translation, rotation to the IGS05
 reference frame defined with the following sites:
 vesl vill madr sfer rabt asc1 hofn mas1 reyk pdel chpi qaq1 braz
 kely stjo ohi2 ohi3 lpgs alrt hlfx cord cro1 unsa sch2 riog thu3
 sant wes2 conz nrc1 scub gode usno algo mana glps nlib chur dubo
 flin mdo1 amc2 pie1 ispa yell gold holm drao quin will whit thti
 mkea hnlc kokb aspa chat mcm4 bili noum mac1 petp tidb hob2 tow2
 lae1 guam yssk tskb alic cedu jab1 darw tixi daej pimo karr bjfs
 pert yar1 wuhn cas1 ulab irkt kunm coco lhaz nril guao novj hyde
 dav1 iisc pol2 dgar kerg kit3 maw1 artu reun sey1 bahr mali trab
 syog mdvj ramo polv nico mbar glsv harb hrao mets joze suth tro1
 trom bor1 mate not1 pots wtzr onsa nya1 nyal nklg cagl zimm gras
 wsrt brus  

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) The summary below gives 
    (a) The RMS difference between the GNAAC loose analysis and
the GNAAC+RNAAC loose analysis.  If this RMS is small then the 
RNAAC combination is not effecting the global coordinates solution
significiantly.
    (b) For each RNAAC Center we give:
        (b.1)  the VARIANCE rescaling factors used (determined as 
discussed above) and
        (b.2)  the adjustment to the apriori coordinates
of the sites for each RNAAC which are not included in the GNAAC
analyses.  The apriori coordinates are based on the analysis
of the first five weeks of RNAAC sinex files.  When an RNAAC
has no unique sites, the adjustments are given for all sites
in the center based on the analysis from that center alone.
 
 SUMMARY OF POSITIONS FOR WEEK 1946
 
 IMPACT OF RNAACs on GNAAC Loose solution
 
 CENTER RESULTS
 
 For Center EUR VARIANCE FACTOR 9.27
 Site       dN     +-         dE     +-         dU    +-   Center
           (mm)   (mm)       (mm)   (mm)      (mm)   (mm) 
No uniques sites for center  EUR
Giving coordinate adjustments for all sites
 
 For Center GSI VARIANCE FACTOR 1.57
 Site       dN     +-         dE     +-         dU    +-   Center
           (mm)   (mm)       (mm)   (mm)      (mm)   (mm) 
No uniques sites for center  GSI
Giving coordinate adjustments for all sites
 MKEA      15.8    4.5       69.7    5.6      -13.1   11.2 Center GSI
 MCIL      30.6    0.8       27.0    1.1       22.8    3.2 Center GSI
 GUAM     -17.1    1.1       61.8    1.6       12.9    4.6 Center GSI
 YSSK       9.2    0.6       15.4    0.6      -40.1    2.1 Center GSI
 CCJ2      -3.2    0.4       17.0    0.5       10.4    1.1 Center GSI
 STK2     191.5    0.6     -254.5    0.6       26.1    2.0 Center GSI
 MIZU      18.5    0.4      -18.0    0.4        0.6    1.2 Center GSI
 TSKB       9.6    0.4       -7.9    0.4       -7.8    1.3 Center GSI
 TSK2     -56.8    0.4     1067.9    0.4       73.5    1.6 Center GSI
 USUD       5.1    0.4      -10.8    0.5      -19.0    1.8 Center GSI
 P118      86.3    0.4       97.3    0.5      -19.5    1.5 Center GSI
 KNYA      21.1    0.5      -11.2    0.6       98.4    1.9 Center GSI
 AIRA     -24.5    0.6      -12.5    0.8       18.3    3.1 Center GSI
 P124     -21.1    0.3      -37.1    0.5       -2.8    1.2 Center GSI
 DAEJ      -4.9    0.4       37.5    0.4      -39.7    1.2 Center GSI
 SUWN      -0.9    0.4       38.6    0.4      -38.4    1.2 Center GSI
 TWTF     -42.1    0.6       -5.5    0.9       -2.5    2.4 Center GSI
 PIMO     -58.8    1.1       27.2    1.8       12.1    4.9 Center GSI
 BJFS     -36.5    0.7      -37.1    1.1      -44.0    2.6 Center GSI
 
 For Center NCL VARIANCE FACTOR 1
 Site       dN     +-         dE     +-         dU    +-   Center
           (mm)   (mm)       (mm)   (mm)      (mm)   (mm) 
No uniques sites for center  NCL
Giving coordinate adjustments for all sites
 
 For Center SIR VARIANCE FACTOR 10.08
 Site       dN     +-         dE     +-         dU    +-   Center
           (mm)   (mm)       (mm)   (mm)      (mm)   (mm) 
No uniques sites for center  SIR
Giving coordinate adjustments for all sites