[IGSREPORT-34] EMR analysis report
Jan
Jan
Fri Dec 4 15:36:06 PST 1992
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IGS Electronic Report 4-DEC-1992 15:36:06 Message Number 34
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From: Jan Kouba
Subject: EMR analysis report
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Jan Kouba
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: kouba at geod.emr.ca
from: J. Kouba
Subject: Geodetic Survey Division (GSD), SMRSS, EMR analysis results
for the GPS weeks # 671 (Nov 22-28, 1992)
submitted by:
J. Kouba * , P. Tetreault, R. Ferland, F. Lahaye, M. Caissy, P. Heroux
Geodetic Survey Division (GSD), Surveys Mapping & Remote Sensing Sector
(SMRS), Energy Mines and Resources (EMR), 615 Booth Str., Ottawa, K1A 0E3
* on secondment to the Geodetic Survey from the Geophysics Div., Geological
Survey of Canada (GSC), EMR, 1 Observatory cresc., 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).
Submitted results start with GPS Week # 672 and include only days when
AS was not invoked.
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 (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. of 1992
Albert Head, CAN ALBH
Algonquin, CAN ALGO*
Fairbanks FAIR*
Goldstone GOLD*
Hartebeesthoek HART*
Holberg,CAN HOLB
Kokee Park KOKB 327-333 (see remarks on EMR prod. #5)
Madrid MADR*
McMurdo MCMU
Pamatai PAMA
Penticton, CAN DRAO
Santiago SANT*
St. Johns, CAN STJO
Canbera TIDB*
Tromsoe TROM*
Wettzell WETT*
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, realized by constraining up to 11
above stations at the IGS coordinates (see IGS message #90):
Orientation is realized through the above coordinates and the fixed, once a
week, 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.
Aposterioi variance factors typically are between 0.5 and 1.0 (noise
about 3mm and 200mm for phase and smoothed pseudorange observations, resp.).
Due to data quality for the AS days the results for the corresponding
days (with AS turned on) are not included here.
SUMMARY OF CANADIAN EMR SOLUTION
1. Analysis centre : Geodetic Survey Division (GSD), SMRSS , EMR
2. Solution identifier: Submission 921202
3. Software used : GIPSY/OASIS II (UNIX )
4. Definition of Terrestrial frame:
origin : Nominally ITRF91
orientation : " "
reference epoch : 1992.5
velocity of light : 299792458 m/s
GM : 389600.4414 km^3/s^5
gravity model : GEMT3( 8,8) +C21+S21
permanent tide corr: None
ocean loading : Pagiatakis, global model
5. Adjusted parameters:
undifferenced phase and smoothed pseudorange data > 15 degrees @ 5 min.
single day (24h) arc with 6 IC and 3 rad. parameters per satellite (19
satellites)
tropospheric zenith delay corr. parameter augmented with random walk stoch.
process
initial phase ambiguity parameters (one for each satellite station pass or
initial phase)
station positions X,Y,Z, up to 19 stations, ALGO, FAIR, GOLD, HART, SANT,
TROM, WETT, YELL, MADR, TIDB and YAR1 constrained.
x, y pole position once a day (DUT1 fixed/solved; DUT1,x,y apriori sigma=3m)
station clock biases once per each epoch/station (except for ALGO h. maser
which provides the time reference) with sigma 1 s
satellite clock biases once per each epoch/satellite with 1ms or .1ms sigma
Pole solution for non AS days
MJD date x(") y(") DUT1(s) xsig ysig utsig xyc
48948.5 11/22/92 AS on
48949.5 11/23/92 AS on
48950.5 11/24/92 .17199 .44515 .15473 .00021 .00017 0 0
48951.5 11/25/92 .17197 .44347 .15256 .00021 .00017 .00015 0
48952.5 11/26/92 .17246 .44129 .15023 .00022 .00018 .00021 0
48953.5 11/27/92 .17349 .43881 .14845 .00022 .00018 .00025 0
48954.5 11/28/92 AS on
Products generated:
The following products are generated and uploaded into CDDIS @ NASA/GSFC
EMR06724.EPH GPS ephemeris for week # 672 in sp3 format(day 3,4)
EMR06725.EPH GPS ephemeris for week # 672 in sp3 format(day 5,exl. PRN13)
EMR06727.EPH GPS ephemeris for week # 672 in sp3 format(day 6)
EMR06727.ERP pole x,y and DUT1 solutions for weeks# 672
EMR06727.SUM name of this text file
remarks on EMR's products:
1. only days with no AS included
2. 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 -6400ns(48948) &-35ns/day w.r.t. GPS time
during this period.
3. DUT1 var-covariance matrix is fully populated, consequence of a random walk
orbit model. i.e. cov(i,j)= var(i,i). Differences or LODs are uncorrelated
with var= var(j,j)-var(i,i); j=i+1. DUT1 solutions may or may not be real,
they may reflect orbit (longitude) mismodeling common to all satellites.
4. PRN13 deleted on Nov26 due to modelling problems (possible orbit change);
also PRN11 is poorly modelled (errors up to 12m) on Nov26-27,92.
5. KOKB not used due to a poor (pseudorange) data quality.
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