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[IGSMAIL-1202] IGS Preliminary (IGP) Orb/clock combination
- Subject: [IGSMAIL-1202] IGS Preliminary (IGP) Orb/clock combination
- From: Analysis Coordinator/IGS Analysis Centers
- Date: Sat, 3 Feb 1996 19:59:07 PST
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IGS Electronic Mail Sat Feb 3 19:59:07 PST 1996 Message Number 1202
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Author: Analysis Coordinator/IGS Analysis Centers
Subject: IGS Preliminary (IGP) Orb/clock combination
Dear IGS Colleagues,
In response to an increasing demand for rapid orbit/clock solutions,
starting on January 1, 1996, the IGS Analysis Centers (ACs) initiated IGS
"super" rapid orbit/clock combinations . The AC participation in this pilot
project is voluntary with submissions within 36h delays (from the last
observation). The IGS combinations, designated as "IGS Preliminary" (IGP)
of orbit/clocks and erp, are then produced within 2 hours after the
submission deadline, i.e. at about 14:00h UT every day, i.e. within a delay
of about 38h. For the erp, only pole positions are currently combined,
UT1-UTC from the Bull A prediction is used. Five ACs (CODE, ESA,
GFZ, JPL, SIO, EMR) elected to participate and are submitting their
solutions daily, well within the 36h delay deadlines. The IGP orbit/clock
and erp combinations are available daily (at about 14:00h UT) from the IGS
CB and, as a back up, also at the following anonymous ftp site:
ftp macs.geod.emr.ca
cd pub/gps/prelim_igs
files (compressed): igp0WWWD.sp3.Z; igp0WWWD.erp.Z; igp0WWWD.sum.Z,
where WWW and D denote the GPS week and day (0-6), respectively. Only
rather limited quality testing and evaluation are performed daily as part
of the IGP combination. To provide the final quality evaluation, starting
with GPS week 0837 (Jan 21, 1996), the IGP orbits/clocks are themselves
included as another AC (for statistical purposes only) in the IGS Rapid
combinations which are produced weekly within 11 days from the last
observation. Based on the first month experience, the AC submissions and
IGP orbits were well within the above deadlines and the current IGP
orbits/clocks are approaching the 10 cm/1 ns precision level.
It is our hope that this additional effort of the participating ACs is
found useful and worthwhile.
Jan Kouba
[Mailed From: Jan Kouba <kouba @ geod.emr.ca>]