[IGS-DCWG-64] Re: Change in compression scheme
Angelyn W. Moore
Angelyn.W.Moore at jpl.nasa.gov
Wed Mar 31 18:13:16 PDT 2010
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IGS-DCWG Mail 31 Mar 18:13:29 PDT 2010 Message Number 64
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Author: Angelyn Moore
Regarding vendor software, it is not unheard of to make format changes that
introduce dependencies on the vendor's side. See below. We sent this directly
to each vendor and reaction was very positive. We did have to chase down some
responses, but several of them made a point to thank us for making a clear
request well in advance, and I don't recall any complaints. Note the language
"whether modifications can be made available to affected users," not just
whether modifications can be made. If someone had said "no, we need another 6
months," that would have been a fair answer.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Angelyn W. Moore, Ph.D. Geodynamics and Space Geodesy Group, 335N
JPL/Caltech Angelyn.W.Moore at jpl.nasa.gov
4800 Oak Grove Dr. MS 238-540 voice: +1 818 354 5434
Pasadena CA 91109 USA fax: +1 818 393 6686
-------- Original Message --------
Subject: Revision of IGS orbit format requires software changes
Date: Wed, 09 Feb 2005 17:03:43 -0800
From: Angelyn W. Moore <Angelyn.W.Moore at jpl.nasa.gov>
Reply-To: igscb at igscb.jpl.nasa.gov
CC: Angelyn W Moore <Angelyn.W.Moore at jpl.nasa.gov>
From: IGS Analysis Coordinator Gerd Gendt, GFZ Potsdam
IGS Network Coordinator Angelyn Moore, JPL
Re: sp3 format revised to version sp3c;
software that reads sp3 orbits must be modified prior to
discontinuation of IGS orbits in sp3 format.
Action requested: Reply to IGS Central Bureau (igscb at igscb.jpl.nasa.gov)
advising what software is affected and whether modifications can
be made available to affected users by 18 Sep 2005.
Dear colleagues,
With this e-mail we would like to draw your attention to
some improvements introduced into the SP3 format.
As announced previously in two IGSMAIL messages:
http://igscb/mail/igsmail/2004/msg00224.html (which
includes a Perl script to convert sp3c to sp3) and
http://igscb/mail/igsmail/2004/msg00232.html (which
discusses the error codes),
the IGS has started to use a revised SP3 format called SP3-c,
which offers many new interesting features, such as provision of
epoch-specific accuracy codes for orbits and clocks, event flags
and more. For details see
http://igscb.jpl.nasa.gov/igscb/data/format/sp3.txt
http://igscb.jpl.nasa.gov/igscb/data/format/sp3c.txt
At present we provide all products in both formats, the usual
sp3 files (in sp3-a format) and the new SP3-c files named with the
file extension ".sp3c". This allows all users to prepare their
software for the final transitions, which is foreseen for
GPS week 1341 beginning 18 Sep 2005.
As of this date, sp3 version 'a' files will no longer be offered
and all IGS orbit files will be in sp3c format, in files named
with the .sp3 extension.
As you can see from the examples, it is very easy to adopt the new
SP3-c format. Software must accept
- the letter 'c' in addition to the letter 'a' as
second character in the first line,
- and the character G for naming the GPS satellites.
All the new information introduced into the SP3-c format was put
into the '%c' and '%f' lines, as well as into the characters beyond
position 60 in the 'P' and 'V' lines. These places were unused in the
SP3 version 'a' format.
We kindly ask you to adapt your software to support, at minimum,
reading the information which was in sp3 files from the new sp3c
files. Further software changes to benefit from the new SP3-c features
are recommended, but will be at your decision.
We would also like to ask you to pass this information to relevant
customers, so that they can adapt own written software too.
Please reply to the IGS Central Bureau to indicate
- that this message has reached appropriate personnel who can
arrange for sp3c support in relevant software
- which software products are affected by the discontinuation of
IGS sp3 version 'a' orbits
- whether modifications can be made available to users on the
suggested schedule.
Best regards
ACC Coordinator Network Coordinator
Gerd Gendt Angelyn Moore
Example 1: present SP3 Version
#aP2004 11 29 0 0 0.00000000 96 ORBIT IGb00 HLM IGS
## 1299 86400.00000000 900.00000000 53338 0.0000000000000
+ 30 1 2 3 4 5 6 7 8 9 10 11 13 14 15 16 17 18
+ 19 20 21 22 23 24 25 26 27 28 29 30 31 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
++ 4 4 3 3 3 3 3 3 3 3 3 4 3 3 4 3 4
++ 4 4 3 4 4 3 3 3 3 4 3 3 3 0 0 0 0
++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
%c cc cc ccc ccc cccc cccc cccc cccc ccccc ccccc ccccc ccccc
%c cc cc ccc ccc cccc cccc cccc cccc ccccc ccccc ccccc ccccc
%f 0.0000000 0.000000000 0.00000000000 0.000000000000000
%f 0.0000000 0.000000000 0.00000000000 0.000000000000000
%i 0 0 0 0 0 0 0 0 0
%i 0 0 0 0 0 0 0 0 0
/* RAPID ORBIT COMBINATION FROM WEIGHTED AVERAGE OF:
/* cod emr esa gfz jpl ngs sio usn
/* REFERENCED TO IGS TIME AND TO WEIGHTED MEAN POLE:
/* CLK ANT Z-OFFSET (M): II/IIA 1.023; IIR 0.000
* 2004 11 29 0 0 0.00000000
P 1 -4700.318435 16538.932514 20422.975048 375.760870
P 2 -12812.964800 -19886.417395 11734.891828 -80.015497
P 3 2003.787244 16536.935378 -20761.761566 64.704179
P 4 5690.419609 -14650.171714 21377.825999 530.470791
P 5 -13748.267382 -11823.930349 19305.073761 62.576502
P 6 -25023.070258 5509.386033 7410.710235 465.771466
...
Example 2: New SP3c-Version
#cP2004 11 29 0 0 0.00000000 96 ORBIT IGb00 HLM IGS
## 1299 86400.00000000 900.00000000 53338 0.0000000000000
+ 30 G01G02G03G04G05G06G07G08G09G10G11G13G14G15G16G17G18
+ G19G20G21G22G23G24G25G26G27G28G29G30G31 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
+ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
++ 4 4 3 3 3 3 3 3 3 3 3 4 3 3 4 3 4
++ 4 4 3 4 4 3 3 3 3 4 3 3 3 0 0 0 0
++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
++ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
%c G cc GPS ccc cccc cccc cccc cccc ccccc ccccc ccccc ccccc
%c cc cc ccc ccc cccc cccc cccc cccc ccccc ccccc ccccc ccccc
%f 1.2500000 1.025000000 0.00000000000 0.000000000000000
%f 0.0000000 0.000000000 0.00000000000 0.000000000000000
%i 0 0 0 0 0 0 0 0 0
%i 0 0 0 0 0 0 0 0 0
/* RAPID ORBIT COMBINATION FROM WEIGHTED AVERAGE OF:
/* cod emr esa gfz jpl ngs sio usn
/* REFERENCED TO IGS TIME AND TO WEIGHTED MEAN POLE:
/* CLK ANT Z-OFFSET (M): II/IIA 1.023; IIR 0.000
* 2004 11 29 0 0 0.00000000
PG01 -4700.318435 16538.932514 20422.975048 375.760870 13 13 10 193
PG02 -12812.964800 -19886.417395 11734.891828 -80.015497 10 14 14 132
PG03 2003.787244 16536.935378 -20761.761566 64.704179 12 11 11 170
PG04 5690.419609 -14650.171714 21377.825999 530.470791 11 10 9 166
PG05 -13748.267382 -11823.930349 19305.073761 62.576502 12 12 7 128
PG06 -25023.070258 5509.386033 7410.710235 465.771466 10 12 12 178
...
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