From kouba@geod.nrcan.gc.ca Thu Oct 29 06:54:34 EST 1998
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From: Jan Kouba
Subject: Satellite Antenna Offsets, etc.
To: bock@pgga.ucsd.edu (Dr. Y. Bock), gend@gfz-potsdam.de (Dr. G. Gendt),
gerry@mozart.grdl.noaa.gov (Dr. Gerry Mader),
jdow@esoc.esa.de (Dr. J. Dow),
rothacher@aiub.unibe.ch (Dr. M. Rothacher),
mbh@cobra.jpl.nasa.gov (M.B. Heflin),
pierre@geod.emr.ca (Pierre Tetreault),
pfang@pgga.ucsd.edu (Dr. Peng Fang),
mark@tony.grdl.noaa.gov (Dr. M.S. Schenewerk),
tmur@esoc.esa.de (J.T. Martin Mur),
springer@aiub.unibe.ch (Dr. T. Springer),
jimr@Maia.usno.navy.mil (Dr. Jim Ray),
mmw@cobra.jpl.nasa.gov (Dr. M.M. Watkins),
jrr@clem.usno.navy.mil (Jim Rhode), matthijs@lox.ucsd.edu (matthijs)
Date: Thu, 29 Oct 1998 11:52:41 +0000 (UTC)
Cc: beutler@aiub.unibe.ch (Prof. G. Beutler)
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Dear AC colleagues,
However, the main reason, why we're writing to you today is to seek and
suggest a consensus on the SATELLITE ANTENNA OFFSETS, (recall this is
one of the agenda
item ("Action 1.B" to be specific) of the "IGS Clock Analysis Plan"
distributed recently by Jim Ray of USNO). If our recollection is correct
we, after extensive discussions over the summer months, agreed to a
principle that ACs in their analyses should be free to use
any satellite offsets they prefer, but their clock solutions submitted
to IGS must be consistent with the "conventional" (agreed upon) IGS
satellite antenna offsets. We've also agreed that for the time being,
since there are conflicting offset information / solutions for PRN13,
the best value for PRN13 (Block IIR) offset would be 0 for all
coordinates. So the remaining issue is to choose the conventional
antenna offsets for the remaining Block II satellites (The Block II and IIa
are asumed to be the same). For your
information and convenience, below we've compiled the list of antenna
offsets used by each of the 7 ACs. The list was compiled from the ACN AC
summary files currently available at the IGS CB (BTW, some of the ACN
files are rather old, one of them dates from Feb. 1995! Perhaps a new
year resolution to update the ACN file might be a good idea for some of
ACs!):
COD Block II .2794 0. 1.0259 m
Block IIR .0 0. 1.2053 m
EMR Block II .279 0. 1.0229 m
ESA Block II .279 0. 1.026 m
GFZ Block II .2794 0. 1.0229 m
JPL Block II .2794 0. 0.9529 m
NGS Block II .2790 0. 1.0230 m (Note: BRD clocks)
SIO Block II .2794 0. 0.9519 m (Note: no clock sol.)
Block IIR -.0031 -.0012 0.0000 m ( " " )
As you can see for Block II's most ACs use the the value of about 1.02 m,
differing only by
a few mm with the exception of JPL and SIO who use about .95m. Though
the difference
of about 7 cm (about 0.23 ns) on all satellites is hardly of any
significance as it can be fully absorbed into the corresponding station
reference clock error. However, for the sake of consistency and perhaps
in view of the future local clock calibrations, we feel we should agree
upon and use (for AC clock solution submissions), a common Block II
antenna offset. Based on the above table, and the fact that the old IERS
Standards (1992) gave the z value of 1.0229 (p. 9) and no GPS offset
values are given in the 1996 IERS conventions, we would like to suggest
that 1.023m is adopted as the conventional value for the Block II's. So,
in summary we would like to suggest the following set of Block II and
Block IIR values be adopted as the conventional values for all AC clock
solution reporting and submissions:
Block II & IIa dx=0.279m dy=0.000m and dz=1.023m
Block IIR dx=0.000m dy=0.000m and dz=0.000m
If you agree, we should adopt it as soon as possible. However, for the
sake of consistency, it should be adopted at the same time and for
both Final and Rapid clock solutions! Otherwise
we could develop problems for PRN13 clock combinations. We suggest, if
you agree, to start it again for the week starting on Nov. 29, (GPS Wk 986),
the date already suggested for the new (16:00h) rapid submissions. Also ACs
could, for the sake of completenes and to publicize the newly adopted
satellie offset values, include them in the clock file headers
(e.g. in the comment lines). If you have better suggestions how to and where
to include the above adopted offset values and how to make them public,
(in addition to IGS Mail) please let us know.
As indicated before, we'd also like to encourage you to start, ASAP,
submitting your Final station and satellite clock solutions, at 15 min
intervals, in the new format and both included in single file (this is
another action item (1.C) of the above mentioned clock plan!). Note that
the satellite clock solutions should be included in both the sp3 as well
as in the new clock file (in the new clock format).
As a minimum, as suggested in the above mentioned plan, ACs should
include station clock solutions for as many stations as possible of
the 22 Primary Fiducial Clock Stations listed below (all equipped with H
masers):
ALGO, DRAO, FAIR, FORT, GODE, GOL2, HOB2, IRKT, KOKB, MAD2,
MATE, NLIB, NYAL, ONSA, PIE1, TID2, WES2, WTZR, YELL,
BRUS, NRC1, USNO.
ACs are also encouraged to include (or consider including) the following
"secondary fiducial clock" stations;
HRAO, MDVO, MEDI, METS, MKEA, NOTO (H masers)
GRAZ, MAS1, MDO1, TSKB, VILL, YAR1 (Cs')
As mentioned in the plan, we hope to develop the station clock
combination early the next year (by Feb. 99), and also after that we
should address the Rapid clock solution submissions/combinations. In any
case , in order to get ready, as well as to provide individual AC
station clock solutions to the timing pilot project, it is important
that we start submitting the new station clock solutions (in the new
clock format) ASAP.
At the end, we again, would like to thank you for your super effort and
support,
with many greetings
Jan & Tim
cc. Prof. G. Beutler
--
Jan Kouba
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: kouba@geod.emr.ca
From kouba@geod.nrcan.gc.ca Tue Nov 10 03:31:24 EST 1998
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(1.38.193.4/16.2) id AA28388; Tue, 10 Nov 1998 08:30:16 GMT
From: Jan Kouba
Subject: Re: Satellite Antenna Offsets, etc. (fwd)
To: bock@pgga.ucsd.edu (Dr. Y. Bock), gend@gfz-potsdam.de (Dr. G. Gendt),
gerry@mozart.grdl.noaa.gov (Dr. Gerry Mader),
jdow@esoc.esa.de (Dr. J. Dow),
rothacher@aiub.unibe.ch (Dr. M. Rothacher),
mbh@cobra.jpl.nasa.gov (M.B. Heflin),
pierre@geod.emr.ca (Pierre Tetreault),
pfang@pgga.ucsd.edu (Dr. Peng Fang),
mark@tony.grdl.noaa.gov (Dr. M.S. Schenewerk),
tmur@esoc.esa.de (J.T. Martin Mur),
springer@aiub.unibe.ch (Dr. T. Springer),
jimr@Maia.usno.navy.mil (Dr. Jim Ray),
mmw@cobra.jpl.nasa.gov (Dr. M.M. Watkins),
jrr@clem.usno.navy.mil (Jim Rhode), matthijs@lox.ucsd.edu (matthijs)
Date: Tue, 10 Nov 1998 08:30:16 +0000 (UTC)
Cc: noll@cddis.gsfc.nasa.gov (Carey Noll)
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Forwarded message:
>From kouba Mon Nov 9 12:14:25 1998
Subject: Re: Satellite Antenna Offsets, etc.
To: gend@gfz-potsdam.de (Gerd Gendt)
Date: Mon, 9 Nov 1998 12:14:25 +0000 (UTC)
In-Reply-To: <199811021212.NAA10502@mehl.gfz-potsdam.de> from "Gerd Gendt" at Nov 2, 98 01:12:17 pm
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Dear Gerd,
The 5 min sampling is fine, we'll skip the unwanted epochs in the combinations
as long as we can get the 15 min intervals. Please start submitting as soon
as possible, as you recall, according the new clock format convention,
this new sat/station clock file should be named CCCWWWWD.CLK, I'll
write to Carey Noll to warn her about these new clock files form ACs.
Regarding some standardization in the sp3 header comments for the inclusion
of the sat offset used for clocks (BTW the same comment line should be
pu into the CCCWWWD.CLK file as well) I would suggest to use one
line (#22) and for that to use the last comment line (starting with /*), i.e.
the comment line which is followed by the epoch and the format proper
with no comment lines). For the line we could use e.g.
/* SV ANT OFFSETS USED FOR CLOCKS: BLK II/IIA .279 .0 1.023m; BLK IIR .0 .0 .0m
Hope this is OK with all ACs, we've checked (with Tim) all AC sp3 and for
most this line is not used.
Please let me know if this is acceptable to you, and if so if I can
forward this (including your original message) to all ACs for information
and comments/actions.
With many thanks for all the cooperation,
many greetings
Jan
>
> Dear Jan,
>
> I don't know whether we have already confirmed that we will meet the Rapid
> submission deadline of 16:00 by Now 28/98. We will of course do. In
> fact normally we submit our results between 6:00 and 8:00 UT already
> now.
>
> We would also agree in using
> Block II & IIa 0.279 0.0 1.023
> Block IIR 0.0 0.0 0.0
> as soon as you give the date for the start.
> I agree with you that it would be good if the used values could be put
> into comment lines of the clock file headers and also into the
> SP3-files (here clocks are also given). It would be helpful if these
> comment lines would have a standardized form so that users can grep the
> information easily. Could you propose a format for it?
>
> Since week 976 we already compute clock files containing station and
> sat clock solution in the new format. We use a 5 min interval (its our
> sampling rate; so we will not have different internal and external
> files) We would like to stay on this 5 min interval, does this make any
> problem? These files we could submit as soon as you like. e.g. next
> week.
>
>
> Best regards
>
> Gerd
>
> PS. Sorry that we have not yet consistence results. We will start in
> the next weeks with consistent EOP, i.e. our erp-file will be taken
> from our SINEX solution.
> For the orbits we now have a clear plan how to proceed. However, at the
> moment we are very busy with other projects, so I am afraid that the
> new consistent solution will not be ready before the end of this year.
>
> --
>
> ******************************************************************************
> * _/_/_/ _/_/_/_/_/_/ Gerd Gendt Phone : ++49 331 288 1114 *
> * _/ _/ _/ GeoForschungsZentrum Fax : ++49 331 288 1111 *
> * _/ _/_/ _/_/ _/ Aufgabenbereich 1 E-Mail: gendt@gfz-potsdam.de *
> * _/ _/ _/ _/ Telegrafenberg A17 *
> * _/_/_/ _/ _/_/_/ D-14473 Potsdam AFTP : \\ftp.gfz-potsdam.de *
> * GERMANY /pub/igsprod *
> * WWW: http://www.gfz-potsdam.de/pb1/IGS/IGS.html *
> ******************************************************************************
>
--
Jan Kouba
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: kouba@geod.emr.ca
From kouba@geod.nrcan.gc.ca Tue Nov 10 12:03:43 EST 1998
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(1.38.193.4/16.2) id AA07164; Tue, 10 Nov 1998 16:36:32 GMT
From: Jan Kouba
Subject: Re: Satellite Antenna Offsets, etc. (fwd)
To: mireault@macs.geod.nrcan.gc.ca (Yves Mireault)
Date: Tue, 10 Nov 1998 16:36:31 +0000 (UTC)
Cc: bock@pgga.ucsd.edu (Dr. Y. Bock), gend@gfz-potsdam.de (Dr. G. Gendt),
gerry@mozart.grdl.noaa.gov (Dr. Gerry Mader),
jdow@esoc.esa.de (Dr. J. Dow),
rothacher@aiub.unibe.ch (Dr. M. Rothacher),
mbh@cobra.jpl.nasa.gov (M.B. Heflin),
pierre@geod.emr.ca (Pierre Tetreault),
pfang@pgga.ucsd.edu (Dr. Peng Fang),
mark@tony.grdl.noaa.gov (Dr. M.S. Schenewerk),
tmur@esoc.esa.de (J.T. Martin Mur),
springer@aiub.unibe.ch (Dr. T. Springer),
jimr@Maia.usno.navy.mil (Dr. Jim Ray),
mmw@cobra.jpl.nasa.gov (Dr. M.M. Watkins),
jrr@clem.usno.navy.mil (Jim Rhode), matthijs@lox.ucsd.edu (matthijs)
In-Reply-To: from "Yves Mireault" at Nov 10, 98 01:39:07 pm
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Status: RO
Yves, you're absolutely right, it's only 60 chars!
Here is our (Tim's & mine) 'counter' proposal, as we thought
eating up 2 out of 4 comment lines is too much to ask:
/* CLK ANT Z-OFFSET(M): II/IIA 1.023; IIR 0.000
This is 47 chars in total and has the potential to 'grow', hope
you like it. Sorry for not including you amongst ACs, it is a big
mistake on my part!
Thanks for the help
Greetings
Jan
PS Tim told me, again, but that he dislike AWK, I wonder why?
Would you happen to know why?
>
> > ...
> > Regarding some standardization in the sp3 header comments for the inclusion
> > of the sat offset used for clocks (BTW the same comment line should be
> > pu into the CCCWWWD.CLK file as well) I would suggest to use one
> > line (#22) and for that to use the last comment line (starting with /*), i.e.
> > the comment line which is followed by the epoch and the format proper
> > with no comment lines). For the line we could use e.g.
> >
> > /* SV ANT OFFSETS USED FOR CLOCKS: BLK II/IIA .279 .0 1.023m; BLK IIR .0 .0 .0m
> >
> > Hope this is OK with all ACs, we've checked (with Tim) all AC sp3 and for
> > most this line is not used.
> >
> > Please let me know if this is acceptable to you, and if so if I can
> > forward this (including your original message) to all ACs for information
> > and comments/actions.
> >
>
> Tim,
>
> If you see this before Jan does, please tell him I just send him a copy as well
> Thanks.
>
> Jan,
>
> I got your message via P. Tetreault. I have two comments:
>
> 1- Be aware that according to the SP3 format, lines 19-22 should be
> columns 1-2 Symbols /*
> column 3 Unused
> column 4-60 Comments
>
> So the comment you proposed is too long !
>
> /* SV ANT OFFSETS USED FOR CLOCKS: BLK II/IIA .279 .0 1.023m; BLK IIR .0 .0 .0m
>
>
> 2- Thinking about Unix (grep, cut, awk, etc.) it would be preferable to have
> a LABEL followed by a SPACE between the LABEL and each offset.
> For Example you could use the following (on 2 lines!) or something
> similar.
>
> /* SV ANT OFFSETS (CLOCKS): BLK_II/IIA: .279 .0 1.023 m;
> /* BLK_IIR: .0 .0 .0 m;
>
>
>
>
> --
> ==============================================================================
> # Yves Mireault /\ Geodetic Survey of Canada #
> # Internet: mireault@geod.emr.ca \/ Ottawa, Ontario, Canada #
> ==============================================================================
>
--
Jan Kouba
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: kouba@geod.emr.ca
From tim.springer@aiub.unibe.ch Thu Nov 26 07:04:39 EST 1998
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Date: Thu, 26 Nov 1998 13:02:17 +0100 (MET)
From: Tim Springer
Subject: Antenna Offset Change
Sender: tim.springer@aiub.unibe.ch
To: tim.springer@aiub.unibe.ch (Tim Springer),
rothacher@aiub.unibe.ch (Markus Rothacher),
schaer@aiub.unibe.ch (Stefan Schaer),
daniel.ineichen@aiub.unibe.ch (Daniel Ineichen),
cagarcia@esoc.esa.de (C. Garcia-Martinez),
pbernedo@esoc.esa.de (Pelayo Bernedo), jdow@esoc.esa.de (J. Dow),
gend@gfz-potsdam.de (G. Gend),
gerry@mozart.grdl.noaa.gov (Gerry Mader),
billk@ngs.noaa.gov (Bill Kass), pfang@pgga.ucsd.edu (P. Fang),
bock@pgga.ucsd.edu (Y. Bock),
matthijs@lox.ucsd.edu (Matthijs v Domselaar),
pault@rses.anu.edu.au (Paul Tregoning),
mmw@cobra.jpl.nasa.gov (Mike Watkins),
yeb@cobra.jpl.nasa.gov (Yoaz E. Bar-Sever),
robliu@igscb.jpl.nasa.gov (Robert Liu),
rjm@cobra.jpl.nasa.gov (R. J. Muellerschoen),
djeff@cobra.jpl.nasa.gov (David C. Jefferson),
yvonne.vigue-rodi@jpl.nasa.gov (Yvonne Vigue-Rodi),
jimr@maia.usno.navy.mil (J. Ray), jrr@clem.usno.navy.mil (Jim Rohde),
kammeyer@tos.usno.navy.mil (Peter Kammeyer),
msc@maia.usno.navy.mil (Merri Sue Carter),
huot@geod.nrcan.gc.ca (Caroline Huot),
kouba@geod.nrcan.gc.ca (Jan Kouba),
heroux@geod.nrcan.gc.ca (Pierre Heroux),
beck@geod.nrcan.gc.ca (Norman Beck),
mireault@geod.nrcan.gc.ca (Yves Mireault)
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Status: RO
Dear AC colleagues,
Here one more reminder about the upcoming change in the satellite antenna
offsets. It almost escaped our attention.
Starting with the orbit products for this Sunday November 29, 1998,
GPSWEEK 986, the following antenna offsets should be used:
Block II/IIA: 0.279 0.000 1.023 X, Y, Z in meters
Block IIR : 0.000 0.000 0.000 X, Y, Z in meters
Remember that all ACs are free to use what ever offset they like but
that the clock values which are reported should be corrected to reflect
the above offsets. This means that those ACs not estimating satellite clocks
do not really have to change anything. Nevertheless we hope that all ACs
will use this "standard" values.
Notice furthermore that we all agreed to add the following line in the
SP3 orbit files, as last line of the 4 possible comment lines in the SP3
format:
/* CLK ANT Z-OFFSET(M): II/IIA 1.023; IIR 0.000
This will ensure that if there are any changes in these offsets the
users of the IGS product will still know which offsets were actually
used.
Kind Regards,
You coordination team,
Tim and Jan
ps. Please remember to update your AC questionaire (some are really old)!
-----------------------------------------------------------------------------
Tim Springer Astronomical Institute, University of Berne
Tel: +41 31 6318592 Sidlerstrasse 5, CH-3012 Bern, Switzerland
Fax: +41 31 6313869 ftp: ubeclu.unibe.ch -or- 130.92.6.17
e-mail: springer@aiub.unibe.ch after login: cd "aiub$ftp"
www: http://www.cx.unibe.ch/aiub/
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