SUBJ: GPS STATUS 31 JUL 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
126-90172 211629Z JUN 90  ALLSV  FCST  TESTING  175/0000-240/0000
145-90205 241000Z JUL 90  PRN13  ADV   UNUSABLE 205/0748-205/0805
146-90205 241700Z JUL 90  PRN12  ADV   UNUSABLE 205/1350-205/1415
147-90207 262200Z JUL 90  PRN11  ADV   UNUSABLE 207/2100-207/2114
148-90208 270100Z JUL 90  PRN16  FCST  UNUSABLE 212/2200-213/1600
149-90209 291000Z JUL 90  PRN11  ADV   UNUSABLE 209/1500-209/1515
3. REMARKS:
A. IMPLEMENTATION OF STANDARD POSITIONING SERVICE:
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.
B. NOTICE ADVISORY INFORMATION WILL NOT BE AVAILABLE DIRECTLY FROM
THE MASTER CONTROL STATION FOR CIVIL USERS BEGINNING 1 AUG 90. THIS
INFORMATION MAY BE OBTAINED FROM THE US COAST GUARD, THE GENERAL
DYNAMICS GPS BULLETIN BOARD, AND THE US NAVAL OBSERVATORY.
C. SATELLITE REPOSITIONING:
THE SATELLITES WHICH BEGAN REPOSITIONING EARLIER THIS YEAR WILL
CONTINUE GRADUAL CHANGES TO THEIR ORBITAL POSITIONS UNTIL
REPOSITIONING TERMINATE DATES AS SHOWN BELOW:
PRN  TERMINATE#1 TERMINATE#2  REMARKS
11   31 OCT 90                FINAL MANEUVER
 3   17 OCT 90                FINAL MANEUVER
13    3 OCT 90                FINAL MANEUVER
18   24 NOV 90   8 DEC 90     24 NOV 90 WILL SLOW THE RATE OF CHANGE
19   31 DEC 90                FINAL MANEUVER
16   20 SEP 90                FINAL MANEUVER
 2    1 DEC 90                FINAL MANEUVER
14   10 NOV 90                FINAL MANEUVER
D. LIMITED SELECTIVE AVAILABILITY TESTING CONDUCTED DURING THE
PERIOD BEGINNING DAY 174 (24 JUN 90) UNTIL DAY 240 (28 AUG 90)
SHOULD NOT DEGRADE NAVIGATION ACCURACY BEYOND LEVELS IN EFFECT
SINCE THE IMPLEMENTATION OF THE STANDARD POSITIONING SERVICE.
HOWEVER, USERS MAY OBSERVE SOME CHANGES IN DAY-TO-DAY POSITIONING
AND NAVIGATION ACCURACY AS A RESULT OF THIS TEST. POINT OF CONTACT
IS MAJOR WYSOCKI AT USSPACECOM/SPJ3OS, (719)554-2634 OR AUTOVON
692-2634.
4. POINT OF CONTACT: MAJ FAUVER AT (719)550-6379.