SUBJ: GPS STATUS 21 Mar 97 1. SATELLITES, PLANES, AND CLOCKS (CS=CESIUM RB=RUBIDIUM): A. BLOCK I : NONE B. BLOCK II: PRNS 1, 2, 3, 4, 5, 6, 7, 9, 10, 14, 15, 16, 17, 18, 19 PLANE : SLOT F1, B3, C2, D4, B4, C1, C4, A1, E3, E1, D2, E5, D3, F3, A4 CLOCK : RB, CS, CS, CS, CS, CS, CS, CS, CS, CS, CS, CS, CS, CS, RB BLOCK II: PRNS 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 PLANE : SLOT E2, B1, E4, D1, A2, F2, A3, C5, F4, B2, C3 CLOCK : CS, CS, CS, RB, CS, CS, CS, CS, CS, CS, RB 2. CURRENT ADVISORIES AND FORECASTS : A. FORECASTS: FOR SEVEN DAYS AFTER EVENT CONCLUDES. NANU MSG DATE/TIME PRN TYPE SUMMARY (JDAY/ZULU TIME START - STOP) 026-97076 101717Z Mar 97 02 FCST MX 076/0800- UP TO 12 HOURS 029-97073 111750Z Mar 97 17 FCST MX 073/1640 UP TO 20 HOURS 032-97085 171928Z Mar 97 30 FCST DV 085/2140- UP TO 12 HOURS 033-97074 150701Z MAR 97 17 FCSTSUMM 073/2116Z- 074/0636Z 034-97090 172139Z Mar 97 3 FCST MX 090/1830 UP TO 12 HOURS B. ADVISORIES: NANU MSG DATE/TIME PRN TYPE SUMMARY (JDAY/ZULU TIME START - STOP) 179-96309 041717Z NOV 96 28 UNUSABLE 309/1634- UNTIL FURTHUR NOTICE C. GENERAL: NANU MSG DATE/TIME PRN TYPE SUMMARY (JDAY/ZULU TIME START - STOP) 3. REMARKS: A. ANTI-SPOOF WAS DEACTIVATED ON JDAY 033 (02 FEB 97) AT OOOOZ. ANTI-SPOOF WAS REACTIVATED ON JDAY 055 (24 FEB 97) AT 0000Z. B. SELECTIVE AVAILABILITY WAS REACTIVATED AT STANDARD POSITIONING SERVICE ACCURACY LEVELS ON DAY 182 (01 JUL 91) AT 0400 UTC. VARIATIONS MAY BE SEEN IN THE EFFECT OF SA DURING TESTING, BUT THE EFFECT SHOULD NOT EXCEED STANDARD POSITIONING LEVELS. THE POINT OF CONTACT IS LTCOL DAVIS (719)554-2634 OR DSN 692-2634. C. CIVILIAN: FOR INFORMATION, CONTACT US COAST GUARD NAVCEN AT COMMERCIAL (703)313-5900 24 HOURS DAILY, COMPUTER BBS (703)313-5910, AND INTERNET HTTP://WWW.NAVCEN.USCG.MIL OR FTP://FTP.NAVCEN.USCG.MIL. D. MILITARY: FOR INFORMATION, CONTACT 2LT BRIAN BARKER, 2SOPS/DOUAN NAVIGATION ANALYST AT (719)567-6378, DSN 560-6378, OR COMPUTER BBS (719)567-6379.