Subject: [IGSMAIL-1538] Precise estimates of GPS clocks every 30 sec
From: J F Zumberge
Date: Wed, 12 Feb 1997 10:09:06 PST

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IGS Electronic Mail      Wed Feb 12 10:09:06 PST 1997      Message Number 1538
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Author: J F Zumberge
Subject: Precise estimates of GPS clocks every 30 sec

The JPL GPS analysis team now offers a daily sp3 file with precise
estimates of GPS satellite clock parameters every 30 s.  These clocks
are consistent with our JPL precise GPS ephemerides, which are also
contained at 30-s intervals in the new sp3 file.  The new files may be
found at URL

   ftp://sideshow.jpl.nasa.gov/pub/jpligsac/hirate/JPL<wwww><d>.sp3.Z

where <wwww> indicates the 4-digit GPS week and <d> indicates the day of
week (0 for Sun, ..., 6 for Sat).

(Note the uppercase "JPL" to distinguish these files from our normal
submissions to the IGS at URL
ftp://sideshow.jpl.nasa.gov/pub/jpligsac/<wwww>/jpl<wwww><d>.sp3.Z.  A
1-day, 30-s sp3.Z file is about 1.6 Mb; once a file is placed on the
aftp area, it will stay there for about 6 months before it's removed.)

At typical levels of selective availability, these 30-s GPS clocks can
be interpolated to intermediate times with about 7-cm rms interpolation
error.  Together with precise orbits, they allow kinematic
post-processing of single-receiver high-rate GPS data with
decimeter-level or better accuracy.

The delivery of these files will follow the regular weekly contribution
from JPL's IGS AC within a few days.  We currently have such files going
back to Aug 11, 1996.

(Note to Gipsy users:  tdp files can be retrieved from
sideshow.jpl.nasa.gov using anonymous ftp; they are in directory
/pub/gipsy_products/hrclocks/ with the usual naming convention.)

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