SUBJ: GPS STATUS 01 May 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) 045-97114 091429Z Apr 97 6 FCST MX 114/1820 UP TO 12 HOURS 050-97114 241830Z APR 97 6 FCSTCANC 051-97125 301937Z Apr 97 18 FCST MX 125/2350 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.