[IGSMAIL-6007]: proposed change to IGL sp3 file contents POSTPONED

Jim.Ray jim.ray at noaa.gov
Tue Sep 29 07:11:55 PDT 2009

IGS Electronic Mail      29 Sep 07:12:08 PDT 2009      Message Number 6007

Author: Jim Ray & Jake Griffiths

Our earlier proposal to merge IGS Final SP3 files for
GPS and GLONASS orbits (see message below) is postponed!

Among other suggestions, it was recommended that rather
than change the contents of the present IGL files, a
better approach would be to create a completely new SP3
file to contain all future GNSS satellites.  In trying
to implement this suggestion, we realized that the
satellite clock information in any merged file would be
inconsistent between systems (as well as some more minor
consistency problems).  To comply with the SP3 standards,
non-GPS clocks would have to be deleted until future
improvements allow consistent estimates of all clocks
relative to a common timescale.

We will continue to study options for a multi-GNSS Final
SP3 product that is consistent with the format specs.
Meanwhile no changes will be made.

-------- Original Message --------

IGS Electronic Mail      28 May 11:23:53 PDT 2009      Message Number 5950

Author: Jim Ray & Jake Griffiths

It has been suggested that probably very few users of
IGS GLONASS orbit products (file types iglWWWWD.sp3)
fail to also use at the same time the associated GPS
orbits for the same week WWWW and day D (files
igsWWWWD.sp3).  So as a convenience to users it is
proposed to change the contents of the igl files to
include *both* GLONASS *and* GPS orbits together.  The
associated igs sp3 files would not be changed in any

We therefore plan to implement such a change starting
with the release of Final products on 01 October 2009.

If any igl users object to such a change or the proposed
implementation date, please contact us to explain how
this would present a problem for you, at:

igs.acc @ noaa.gov


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