Subject: [IGSMAIL-0576] Final IGS Orbits (w 734-737)
From: Analysis Centre Coordinator
Date: Thu, 21 Apr 1994 8:13:18 PDT

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IGS Electronic Mail      Thu Apr 21  8:13:18 PDT 1994      Message Number 0576
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Author: Analysis Centre Coordinator
Subject: Final IGS Orbits (w 734-737)

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IGS Final orbits/clocks completed and put onto CDDIS (Weeks 734, 735, 736, 737)
                                                        ( Jan.30- Feb26, 1994)
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According to the recommendations of the Analysis Centre Workshop the IGS
Rapid Orbits were recomputed using up to date orbits and the final EOP values
of Bulletin B, published by IERS. ( Daily values, page 2 of Bull. B were
used). The EOP were corrected for the difference between the IERS pole series 
and ITRF as published in the IERS 1992 Annual Report (p. II-17, Table II-3),
so both the IGS orbits and associated ERP files are consistent with ITRF92
(current epoch).

We have downloaded all submitted ephemeris and ERP files from CDDIS before the
final orbit/clock combination to ensure that the sets are complete and up to
date. In the final combination we have largely followed the actions taken
during the Rapid orbit generation and since there were very few orbit
resubmissions, both the IGS Rapid  and Final orbits are virtually same except
for the orientation difference (the current Bull.A and final Bull.B). Orbit
evaluation are also nearly the same, since we used centre specific ERP in
these long arc evaluations. For more information see the corresponding summary
files on CDDIS.

PRODUCTS GENERATED:

The resulting Final average ephemeris and clocks are in daily files in the SP3
format. The satellite accuracy codes displayed in the headers are based on
weighted RMS for each satellite. Note that each file contains all the submitted
satellites. If satellite or centre had to be excluded from the combination it
is noted in the summary file along with the reason for doing so.

The IGS FINAL ORBIT files generated and uploaded into CDDIS @ NASA/GSFC are:

IGS07340-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0734
IGS07350-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0735
IGS07360-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0736
IGS07370-6.SP3   IGS GPS orbit/clock files for days 0-6, week 0737

IGS07347.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS07357.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS07367.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)
IGS07377.ERP    EOP associated with the above orbits (Bull. B aligned to ITRF)

IGS07347.SUM    Complete summary/statistics report
IGS07357.SUM    Complete summary/statistics report
IGS07367.SUM    Complete summary/statistics report
IGS07377.SUM    Complete summary/statistics report

The old Rapid Orbit files have been renamed (on CDDIS) to:
(Note this is temprorary, based on discussions with AC and GB and may be
changed )

IGR073040-6.SP3   Rapid service orbits/clocks for days 0-6, week 734
IGR073050-6.SP3   Rapid service orbits/clocks for days 0-6, week 735
IGR073060-6.SP3   Rapid service orbits/clocks for days 0-6, week 736
IGR073070-6.SP3   Rapid service orbits/clocks for days 0-6, week 737

IGR07347.ERP     Rapid service EOP associated with the above orbits (Bull A)
IGR07357.ERP     Rapid service EOP associated with the above orbits (Bull A)
IGR07367.ERP     Rapid service EOP associated with the above orbits (Bull A)
IGR07377.ERP     Rapid service EOP associated with the above orbits (Bull A)

IGR07347.SUM     Rapid service complete summary/statistic report 
IGR07357.SUM     Rapid service complete summary/statistic report 
IGR07367.SUM     Rapid service complete summary/statistic report 
IGR07377.SUM     Rapid service complete summary/statistic report 

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REMARKS/CORRECTIONS:

By mistake, the IGSREPORT#909  and IGS07347.SUM refered to "USNO Bulletin B"
in the remark #2, instead of the correct IERS Bulletin B. We have corrected
the IGS07347.SUM file and put it into CDDIS. The other Final Orbit combination
sum files (weeks 735-7) and the corresponding IGSREPORTS do not contain this
remark and thus are not affected.  

We apologize for our mistake and inconvenience it might have caused.

-- 
Jan Kouba
Geodetic Survey of Canada
Ottawa, Ontario, Canada
Internet: [email-masked]