Subject: [IGSREPORT-3600] Wk 0894 G-SNX Comparisons
From: AC Coordinator / NRCan GSDivision
Date: Wed, 2 Apr 1997 13:13:08 PST

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IGS Electronic Report    Wed Apr  2 13:13:08 PST 1997      Message Number 3600
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Author: AC Coordinator / NRCan GSDivision
Subject: Wk 0894 G-SNX Comparisons

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As requested by the IGS GB, and recently recommended by most ACs present at
the March 97 IGS AC workshop in Pasadena, here is the first of our weekly
reports comparing the three GNAAC SINEX station combinations performed
weekly by JPL, MIT and NCL, as a part of the IGS ITRF Densification Pilot
Project. For completeness, the comparisons were done for all GPS Wks since
the Wk 0878. For your convenience and information the corresponding files
gcomp.0WWW were put on our anonymous ftp:

   macs.geod.emr.ca  
   cd pub/requests/g-snx
   files: gcomp.0878  to  gcomp.0894 

please refer any suggestions/questions/comments to the contact persons below.
    *********************************************************

Comparison of GNAAC Combined SINEX Solutions - Week 0894   
(FEB 23, 1997 - MAR 1, 1997)

Contacts: J. Kouba ([email-masked])
          D. Hutchison([email-masked])

COMPARISON ALGORITHM:

   1. MIT and NCL GNAAC  combined  SINEX  solutions  for the week in question
      were deconstrained. The JPL SINEX file is already unconstrained.

   2. Any stations  not  present  in  all GNAAC combined SINEX files were de-
      leted  from all three combined solutions.  Every solution was then sub-
      jected to a 7-parameter transformation  into  a common reference system
      (the 13 ITRF94 station positions). 

   3. Outliers are determined at the 99.0% confidence level for each coordin-
      ate.  If a station  has  an outlier in either latitude,  longitude,  or
      height, it is ignored in all subsequent computations.

FILES COMPARED:
   mit0894g.snx at cddis.gsfc.nasa.gov
   jpl0894g.snx at cddis.gsfc.nasa.gov
   ncl0894g.snx at cddis.gsfc.nasa.gov

GNAACs: MIT JPL NCL

STATIONS WITH INCONSISTENT ANTENNA ECCENTRICITY INFORMATION:
(FILE: / STATION / L1 (UNE) / L2 (UNE) / ECCENTRICITY (UNE))
(UNE = Up North East (metres))

jpl0894g.snx: ANKR    .110   .000   .000   .128   .000   .000   .000   .000   .000
mit0894g.snx: ANKR    .110   .000   .000   .128   .000   .000   .060   .000   .000
ncl0894g.snx: ANKR    .110   .000   .000   .128   .000   .000   .060   .000   .000
jpl0894g.snx: BAHR    .000   .000   .000   .000   .000   .000  3.122   .000   .000
mit0894g.snx: BAHR    .110   .000   .000   .128   .000   .000  3.122   .000   .000
jpl0894g.snx: BISH    .070   .000   .000   .068   .000   .000   .046   .000   .000
mit0894g.snx: BISH    .078   .000  -.003   .074  -.003  -.001   .046   .000   .000
jpl0894g.snx: DRAO    .110   .000   .000   .128   .000   .000   .000   .000   .000
mit0894g.snx: DRAO    .110   .000   .000   .128   .000   .000   .100   .000   .000
ncl0894g.snx: DRAO    .110   .000   .000   .128   .000   .000   .100   .000   .000
jpl0894g.snx: GOPE    .070   .000   .000   .068   .000   .000   .046   .000   .000
mit0894g.snx: GOPE    .078   .000  -.003   .074  -.003  -.001   .046   .000   .000
jpl0894g.snx: GRAZ    .110   .000   .000   .128   .000   .000  1.964   .000   .000
mit0894g.snx: GRAZ    .078   .000   .000   .096   .000   .000  1.964   .000   .000
jpl0894g.snx: IISC    .110   .000   .000   .128   .000   .000   .078   .000   .000
mit0894g.snx: IISC    .110   .000   .000   .128   .000   .000   .000   .000   .000
jpl0894g.snx: JOZE    .070   .000   .000   .068   .000   .000   .198   .000   .000
mit0894g.snx: JOZE    .069   .000  -.003   .068  -.003  -.001   .198   .000   .000
jpl0894g.snx: MATE    .110   .000   .000   .128   .000   .000   .101   .000   .000
mit0894g.snx: MATE    .078   .000   .000   .096   .000   .000   .101   .000   .000
jpl0894g.snx: MOIN    .110   .000   .000   .128   .000   .000  -.103   .000   .000
mit0894g.snx: MOIN    .110   .000   .000   .128   .000   .000   .994   .000   .000
jpl0894g.snx: MONP    .000   .000   .000   .000   .000   .000   .119   .000   .000
mit0894g.snx: MONP    .110   .000   .000   .128   .000   .000   .119   .000   .000
jpl0894g.snx: TAEJ    .000   .000   .000   .000   .000   .000   .660   .000   .000
mit0894g.snx: TAEJ    .069   .002  -.001   .068  -.001   .002   .660   .000   .000
jpl0894g.snx: UPAD    .070   .000   .000   .068   .000   .000  1.962   .000   .000
mit0894g.snx: UPAD    .078   .000  -.003   .074  -.003  -.001  1.962   .000   .000
jpl0894g.snx: USUD    .078   .000   .000   .096   .000   .000  -.035   .000   .000
mit0894g.snx: USUD    .078   .000   .000   .096   .000   .000  -.035   .000   .000
ncl0894g.snx: USUD    .110   .000   .000   .128   .000   .000  -.035   .000   .000
jpl0894g.snx: ZIMM    .070   .000   .000   .068   .000   .000   .000   .000   .000
mit0894g.snx: ZIMM    .069   .000  -.003   .068  -.003  -.001   .000   .000   .000

ANTENNA PHASE CENTRE CONFLICTS IN FILE mit0894g.snx                             
   AREQ Multiple Sites      
   UPO1 Multiple Sites      
   MDVO Multiple Sites      
Multiple sites are subsequently excluded, since there is confusion as to
how to match them with corresponding sites in other GNAAC SINEX files.
 
SITES AFFECTED BY ABOVE CONFLICTS, NON-FIDUCIAL SITES SUBSEQUENTLY EXCLUDED:
   Stations: AREQ UPO1 MDVO 
 
ANTENNA PHASE CENTRE CONFLICTS IN FILE ncl0894g.snx                             
   ASC1 Missing Antenna      
   CHAT Missing Antenna      
   KIRU Missing Antenna      
   KWJ1 Missing Antenna      
   MKEA Missing Antenna      
 
SITES AFFECTED BY ABOVE CONFLICTS, NON-FIDUCIAL SITES SUBSEQUENTLY EXCLUDED:
   Stations: ASC1 CHAT KIRU KWJ1 MKEA 

CONFIDENCE  LEVEL  FOR OUTLIER DETECTION: 99%
OUTLIERS REJECTED (COORD/STATION/GNAACs):
   Lat IRKT MIT-JPL   Lat KIT3 MIT-JPL   Lat SANT MIT-NCL
   Lon TSKB JPL-NCL   Lon GUAM JPL-NCL   Lon TAIW MIT-JPL
   Hgt KOUR MIT-JPL   Hgt LPGS MIT-NCL   Hgt KOUR MIT-NCL

36 GLOBAL STATIONS:
   ALBH ALGO BOGT BRAZ BRMU CAS1 COCO DAV1 FAIR FORT
   GOLD HART HOB2 KELY KERG KOKB KOSG LHAS MAC1 MADR
   MALI MCM4 NYAL OHIG ONSA PAMA PERT RCM6 REYK STJO
   TIDB WES2 WTZR YAR1 YELL ZWEN    

11 FIDUCIAL STATIONS:
   ALGO FAIR GOLD HART KOKB KOSG MADR TIDB WTZR YAR1
   YELL         

AVERAGE COORDINATE RMS:

             36    GLOBAL  STATIONS         11   FIDUCIAL   STATIONS
        MIT-JPL   MIT-NCL   JPL-NCL MIT-ITRF94 JPL-ITRF94 NCL-ITRF94
           (mm)      (mm)      (mm)       (mm)       (mm)       (mm)
        -------   -------   ------- ---------- ---------- ----------
Lat        1.7       2.0       1.5        7.4        8.0        8.1 
Lon        2.2       3.2       2.4        7.3        7.4        8.5 
Hgt        4.7       6.0       3.9       13.7       13.1       13.7 
3D         5.5       7.1       4.8       17.2       17.0       18.0

VARIANCE FACTORS (CHI-SQUARE / (DEGREES OF FREEDOM)):

        36    GLOBAL  STATIONS         11   FIDUCIAL   STATIONS
   JPL-NCL   MIT-JPL   MIT-NCL MIT-ITRF94 JPL-ITRF94 NCL-ITRF94
   -------   -------   ------- ---------- ---------- ----------
     0.346     0.657     0.829      1.068      0.739      1.020

OFFSETS AND SCALE FACTOR WRT ITRF94 (FIDUCIAL STATIONS):

      Tx (mm) STD(mm) Ty (mm) STD(mm) Tz (mm) STD(mm) Scale (ppb) STD(ppb)
      ------- ------- ------- ------- ------- ------- ----------- --------
JPL     -14.8     5.8    11.7     6.0   -33.1     8.2        -2.7      0.6
MIT     -13.8     4.4    14.7     4.6   -21.2     5.6        -2.1      0.5
NCL     -10.0     5.6    -2.6     5.7   -22.9     7.3        -2.7      0.6

REMARKS:

THE FOLLOWING FIDUCIAL STATIONS ARE MISSING FROM mit0894g.snx :
   Stations: TROM

THE FOLLOWING FIDUCIAL STATIONS ARE MISSING FROM jpl0894g.snx :
   Stations: TROM

THE FOLLOWING FIDUCIAL STATIONS ARE MISSING FROM ncl0894g.snx :
   Stations: TROM

[Mailed From: Jan Kouba <[email-masked]>]