Date: Tue, 14 Jul 2009 09:30:37 -0400
From: "Jim.Ray" <jim.ray@noaa.gov>
Subject: [IGSMAIL-5969]: IGU clock prediction exclusion policy modified
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IGS Electronic Mail      14 Jul 06:30:59 PDT 2009      Message Number 5969
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Author: Jim Ray & Jake Griffiths (ACC)

At the request of some users, the exclusion policy for
the IGS Ultra-rapid (IGU) clock predictions announced in
IGS Mail 5965 has now been modified.  Starting with IGU
combination 1540_2_12, clock predictions for the IIA Cs
satellites will be restored.  This affects the clocks in
the second half of each SP3 file for PRNs 3, 8, 9, 10, 24,
27, and 30, which are usually all highly unstable.  Despite
this change, users should be aware that clock predictions
for these satellites will remain particularly unreliable
and should only be used with great care.

The clock prediction exclusion policy will continue to
apply for satellites with NANU announcements for UNUSUFN
(presently PRN 1) and MX (presently none) events.