[IGSREPORT-219] EMR Analysis Report (week 691)

[J.]

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IGS Electronic Report     15-APR-1993 16:59:54       Message Number 219
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From:  J. Kouba
Subj: EMR Analysis Report (week 691)
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    Submitted by:
       J. Kouba **, P. Tetreault, R. Ferland, F. Lahaye, P. Heroux, L. Mancuso

    Geodetic Survey Division (GSD), Surveys Mapping & Remote Sensing Sector
    (SMRS), Energy Mines and Resources (EMR), 615 Booth Str., Ottawa, K1A 0E9
     **  on secondment to the Geodetic Survey from the Geophysics Div.
         Geological Survey of Canada (GSC), EMR, 1 Observatory Crescent,
	 Ottawa, K1A 0Y3

      Our analysis utilizes the JPL GIPSY/OASIS II (UNIX) software system
and data from all (up to 7) Canadian stations augmented by up to 12, globally
distributed, core stations (see Table 1 for the list of stations).

      This effort is a part of a joint pilot project to test the so called
"Active Control System" in Canada and involves the Geodetic Survey Division
(GSD), SMRSS, the Geophysics Division and Pacific Geoscience Centre of the
Geological Survey of Canada, all three institutions are part of the
Department of Energy, Mines & Resources (EMR).

      Table 1 : Station Summary (also indicated are day no. for which a
particular station is not included in the daily solution, either due to
being down or data being late).

   STATION            IGS code       MISSING DAY NO. 1993
Albert Head, CAN       ALBH
Algonquin, CAN         ALGO*
Fairbanks              FAIR*
Goldstone              GOLD*
Hartebeesthoek         HART*
Holberg,CAN            HOLB
Kokee Park             KOKB
Madrid                 MADR*           096
McMurdo                MCMU*
Pamatai                PAMA            094 to 100
Penticton, CAN         DRAO
Santiago               SANT*
St. Johns, CAN         STJO
Canbera                TIDB*
Tromsoe                TROM*
Wettzell               WETT*           094
Yarragadee             YAR1*
Yellowknife, CAN       YELL*
* indicates constrained stations, remaining are solved for (50m apriori sig.)

SOLUTION CHARACTERISTICS

Reference frame and orientation:
      Nominally ITRF91, at epoch 1992.5 is realized by constraining up to 11
of the above stations at the IGS coordinates (see IGS message #90).
Orientation is realized through the above coordinates and, once a week,
the fixed DUT1 values from the current NEOS/IERS (Bull. A).

Constants and models:
- no change, see the IGS mess. #101 for details.

Estimation strategies:
- no change, see the IGS mess. #101 for details - , except for the estimation
  of DUT1, stochastic orbit modeling, new weighting of L3,P3,
  see IGS mess. #130.

      ALGO was used as time reference.
      Aposteriori variance factors typically are between 0.5 and 1.0 (noise
about 3mm and 200mm for phase and smoothed pseudorange observations, resp.).


PRODUCTS GENERATED:
The following products are generated and uploaded into CDDIS @ NASA/GSFC
(Starting this week we are uploading daily ehem files)
   EMR0691*.EPH        *=1-7 GPS ephem. for days 1-7, week # 691 in sp3 format
   EMR06917.ERP        	pole x,y and DUT1 solutions for week # 691
   EMR06917.SUM		name of this text summary file


REMARKS on EMR's products:
1. ALGO hydrogen maser used as a time reference. In the sp3 EPH file sat.
   epochs with no reference (e.g. ALGO not observing a satellite) have a value
   of 99999. microseconds.
   ALGO clock error & drift were about -1980ns (49081) & -60 ns/day w.r.t.
   GPS time.
2. PRN31 was tracked on Apr09-10, but deleted from processing.
3. Modelling problems with PRN01 from April 07 on.  Errors up to 5.0 m.