NOTICE ADVISORY TO NAVSTAR USERS (NANU) #054-90082
SUBJ: SECOND UPDATE TO TENTATIVE GPS REPHASING SCHEDULE FOR PRN13
1. CONDITION: PLANNED SATELLITE REPOSITIONING FOR 1990 IN INDICATED
IN PARA 2 BELOW. CHANGES TO THESE PLANS MAY OCCUR WITHOUT NOTICE,
HOWEVER, USERS WILL CONTINUE TO BE NOTIFIED VIA THE NORMAL ADVISORY
MESSAGE (NANU) IMMEDIATELY PRIOR TO EACH EVENT. ACTUAL TIMES OF
OUTAGES WILL BE PROVIDED/UPDATED AS SPECIFIC INFORMATION BECOMES
AVAILABLE. NOTE CHANGE OF SCHEDULE FOR PRN13.
2. SATELLITE MAY BE UNUSABLE FOR UP TO 24 HOURS FOLLOWING INITIATE
AND TERMINATE TIMES:
A. PRN13 INIT 15 MAR 90 0355Z TERM 31 OCT 90
B. PRN18 INIT  7 APR 90 1607Z TERM 24 NOV 90 AND 8 DEC 90
C. PRN19 INIT 12 APR 90 0938Z TERM 31 DEC 90
D. PRN 9 INIT 19 APR 90 0928Z TERM 19 APR 90
E. PRN16 INIT 26 APR 90 1317Z TERM 20 SEP 90
F. PRN 2 INIT  3 MAY 90       TERM  1 DEC 90
G. PRN14 INIT 13 MAY 90       TERM 10 NOV 90
H. PRN12 INIT 20 MAY 90       TERM 20 MAY 90
3. RECOMMENDATION: CONFRIRM AVAILABILITY OF GPS SATELLLITES PRIOR TO
USE.
4. POINT OF CONTACT: MAJ WILLIAM FAUVER AT COMMERCIAL (719)550-6379
OR AUTOVON 560-6379.