NOTICE ADVISORY TO NAVSTAR USERS (NANU) #053-90080
SUBJ: UPDATE TO TENTATIVE GPS REPHASING SCHEDULE FOR PRN13
1. CONDITION: PLANNED SATELLITE REPOSITIONING FOR 1990 IS
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 TO SCHEDULE
FOR PRN13.
2. SATELLITE MAY BE UNUSABLE FOR UP TO 24 HOURS FOLLOWING
INITIATE AND TERMINATE TIMES:
A. PRN11 INIT 15 MAR 90 0355/ TERM 31 OCT 90
B. PRN 3 INIT 20 MAR 90 0604/ TERM 17 OCT 90
C. PRN13 INIT 28 MAR 90 0644/ TERM  3 OCT 90
D. PRN18 INIT  7 APR 90 1607/ TERM 24 NOV 90 AND 8 DEC 90
E. PRN19 INIT 12 APR 90 0938/ TERM 31 DEC 90
F. PRN 9 INIT 19 APR 90 0928/ TERM 19 APR 90
G. PRN16 INIT 26 APR 90 1317/ TERM 20 SEP 90
H. PRN 2 INIT  3 MAY 90       TERM  1 DEC 90
I. PRN14 INIT 13 MAY 90       TERM 10 NOV 90
J. PRN12 INIT 20 MAY 90       TERM 20 MAY 90
3. RECOMMENDATION: CONFIRM AVAILABILITY OF GPS SATELLITES PRIOR
TO USE.
4. POINT OF CONTACT: MAJ WILLIAM FAUVER AT COMMERCIAL
(719)550-6379 OR AUTOVON 560-6379.