SUBJ: GPS STATUS 29 MAR 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, TBD CLOCK : CS, CS, RB, CS, CS, CS, TBD 2. CURRENT ADVISORIES (ADV) AND FORECASTS (FCST): INFORMATION IS REPEATED FOR SEVEN DAYS AFTER EVENT CONCLUDES NANU MSG DATE/TIME PRN TYPE SUMMARY 038-90052 221705Z FEB 90 PRN8 ADV L-BANDS ENABLED 51/1615 050-90079 191629Z MAR 90 ALLSV FCST REPHASING PLAN 053-90080 211940Z MAR 90 PRN13 FCST CHANGE REPHASING TO 28 MAR 054-90081 231605Z MAR 90 PRN13 FCST CHANGE REPHASING TO 29 MAR 055-90087 291643Z MAR 90 PRN9 ADV UNUSABLE 87/1055 UFN 056-90088 291650Z MAR 90 PRN13 ADV UNUSABLE 88/0142-88/1105 3. REMARKS: A. THE DEPARTMENT OF DEFENSE (DOD) IS WORKING TO ESTABLISH A FULLY OPERATIONAL GPS SATELLITE CONSTELLATION. SELECTIVE AVAILABILITY AND ANTI-SPOOFING ARE SYSTEM CAPABILITIES AND MAY BE IMPLEMENTED AT ANY TIME. IN KEEPING WITH NATIONAL POLICY, SELECTIVE AVAILABILITY WAS IMPLEMENTED ON 25 MARCH 1990. B. THE SATELLITE REPHASING SCHEDULE FOR 1990 IS TENTATIVE AND WILL BE UPDATED AS ADDITIONAL INFORMATION IS AVAILABLE. IN GENERAL, SATELLITES WILL BE UNUSABLE ON INITIATE AND TERMINATE DATES ONLY AS A RESULT OF REPOSITIONING. 4. SATELLITE REPOSITIONING: PRN INITIATE TERMINATE#1 TERMINATE#2 UNUSABLE (DAY/UTC) 11 15 MAR 90 31 OCT 90 74/0335-75/0225 3 20 MAR 90 17 OCT 90 79/0700-79/1220 13 29 MAR 90 3 OCT 90 88/0142-88/1105 18 7 APR 90 24 NOV 90 8 DEC 90 97/1207- 19 12 APR 90 31 DEC 90 102/0938- 9 19 APR 90 19 APR 90 109/0928- 16 26 APR 90 20 SEP 90 116/1317- 2 3 MAY 90 1 DEC 90 14 13 MAY 90 10 NOV 90 12 20 MAY 90 20 MAY 90 ADDITIONAL ALMANACS WILL BE PROVIDED AS REQUIRED UPON A SATELLITE'S RETURN TO SERVICE. 5. OPERATIONAL ALMANAC: 6. POINT OF CONTACT: MAJ FAUVER AT (719)550-6379