SUBJ: GPS STATUS 30 APR 90
1. SATELLITES, PLANES AND CLOCKS (CS=CESIUM RB=RUBIDIUM):
SLOTS MAY NOT BE FINAL UNTIL AFTER 21-SATELLITE REPHASING
A. BLOCK I : PRNS  3,  6,  9, 11, 12, 13
   PLANE   : SLOT D1, A3, A2, C2, A1, C1
   CLOCK   :      RB, RB, RB, CS, CS, CS
B. BLOCK II: PRNS  2, 14, 16, 17, 18, 19, 20
   PLANE   : SLOT B2, E1, D2, F2, F3, A4, B3
   CLOCK   :      CS, CS, RB, CS, CS, CS, CS
2. CURRENT ADVISORIES (ADV) AND FORECASTS (FCST):
INFORMATION IS REPEATED FOR SEVEN DAYS AFTER EVENT CONCLUDES
NANU      MSG DATE/TIME   PRN    TYPE  SUMMARY
074-90103 140045Z APR 90  PRN6   ADV   UNUSABLE 104/2226-103/2300
075-90107 170400Z APR 90  PRN11  ADV   UNUSABLE 106/2346-107/0010
076-90107 171600Z APR 90  PRN9   FCST  CHANGE REPHASING TO 2126UTC
077-90107 180400Z APR 90  PRN11  ADV   UNUSABLE 107/2221-107/2258
078-90108 181839Z APR 90  PRN19  FCST  UNUSABLE 113/1200-114/0001
079-90108 190830Z APR 90  PRN12  ADV   UNUSABLE 108/2144-108/2200
080-90109 192300Z APR 90  PRN6   ADV   UNUSABLE 109/2119-109/2144
081-90110 200100Z APR 90  PRN9   ADV   UNUSABLE 110/2310-111/0030
082-90110 201621Z APR 90  PRN20  ADV   NEW SV USABLE 108/2313
083-90110 201628Z APR 90  ALLSV  FCST  URA=15 118/1630-119/0630
084-90111 211620Z APR 90  PRN9   ADV   UNAVAILABLE 111/1035-111/1440
085-90115 250100Z APR 90  PRN6   ADV   UNUSABLE 114/220-114/2212
086-90115 251630Z APR 90  PRN3   ADV   UNUSABLE 115/1408-115/1419
087-90119 292350Z APR 90  PRN11  ADV   UNUSABLE 119/2207-119/2220
088-90120 300550Z APR 90  PRN11  ADV   UNUSABLE 120/0424-120/0515
3. REMARKS:
A. THE CURRENT GPS CONSTELLATION BEGAN BROADCASTING NAVIGATION
MESSAGES AT ACCURACY LEVELS CONSISTENT WITH STANDARD POSITIONING
SERVICE ON 25 MAR 90. GPS IS NOT EXPECTED TO BE DECLARED FULLY
OPERATIONAL UNTIL 1993. ANY GPS USERS ARE OPERATING AT THEIR OWN
RISK.
4. SATELLITE REPOSITIONING:
PRN  INITIATE  TERMINATE#1 TERMINATE#2 UNUSABLE (DAY/UTC)
11   15 MAR 90 31 OCT 90                74/0335-75/0225   ACTUAL
 3   20 MAR 90 17 OCT 90                79/0700-79/1220   ACTUAL
13   29 MAR 90  3 OCT 90                88/0142-88/1105   ACTUAL
18    7 APR 90 24 NOV 90   8 DEC 90     97/0318-97/1902   ACTUAL
19   11 APR 90                         101/0421-101/0634  RESCHD
19   12 APR 90 31 DEC 90               102/0440-102/1411  ACTUAL
 9   19 APR 90 19 APR 90               109/2126-110/2126  RESCHD
 9   21 APR 90 21 APR 90               111/1035-111/1440  ACTUAL
16   26 APR 90 20 SEP 90               116/0736-116/1509  ACTUAL
 2    3 MAY 90  1 DEC 90               123/2033-124/2033  FORECAST
14   14 MAY 90 10 NOV 90               134/0236-135/0236  FORECAST
12   21 MAY 90 21 MAY 90               141/2156-142/2156  FORECAST
5. POINT OF CONTACT: MAJ FAUVER AT (719)550-6379.