NOTICE ADVISORY TO NAVSTAR USERS (NANU) #073-91094
SUBJ: FORECAST OUTAGES DAY 101 PRN3 1015-1300 & PRN23 1230-1500 UTC
1. CONDITION: ON DAY 101 (11 APR 91) PRN3 (MCS: SVN11) AND PRN23
(MCS: SVN23) ARE EXPECTED TO BE UNUSABLE AT TIMES DURING THE
FOLLOWING WINDOWS:
A. PRN3 FORECAST UNUSABLE BEGINNING 1015 UNTIL 1300 UTC
B. PRN23 FORECAST UNUSABLE BEGINNING 1230 UNTIL 1500 UTC
2. RECOMMENDATION: TIMES GIVEN ARE FORECASTS AND ARE SUBJECT TO
CHANGE. CONFIRM AVAILABILITY OF SATELLITES PRIOR TO USE.
3. POINT OF CONTACT: MAJOR FAUVER AT COMMERCIAL (719)550-6379
OR DSN: 560-6379.
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PRN3 and PRN23 will be set unusable on day 101 (11 Apr 91) during routine
tests of new Master Control Station software. These outages are NOT the
result of SA/A-S. Efforts are being made to minimize the effects on users
of the system; however, reduced accuracy may be experienced in the western
hemisphere particularly between 1015 and 1115 UTC as a result of this
testing. Users of the Global Positioning System are cautioned to confirm
availability of satellites prior to use. GPS users experiencing any
problems with PRN3 or PRN23 during this period are requested to contact
the GPS Information Center.
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