LANG@UNB.CA (Richard Langley) (03/09/91)
The navigation signals from Navstar GPS satellite PRN 9, the one that was being spin stabilized to provide service for the Gulf region (and coincidently western North America) during the war, have been permanently turned off. The following is the official announcement from Falcon AFB via the U.S. Coast Guard and the Naval Observatory: USCG GPS INFORMATION CENTER (GPSIC) RECORDING AS OF 1400 UTC, MARCH 7, 1991. 1. THE GPS CONSTELLATION CONSISTS OF 15 SATELLITES. 2. PRN09's NAVIGATION SIGNAL WAS TERMINATED AT 0342 UTC ON 6 MAR; PRN09 WILL NOT RESUME SERVICE. 3. PRN12 IS UNUSABLE BEGINNING AT 1535 UTC ON 6 MAR AND WILL REMAIN UNUSABLE UNTIL FURTHER NOTICE. ADDRESS QUESTIONS ABOUT THIS REPORT TO THE GPSIC AT 703-866-3806; HOURS OF OPERATION ARE 8:00 AM TO 4:00 PM EASTERN TIME, MONDAY THRU FRIDAY, EXCEPT FEDERAL HOLIDAYS; SEE FILE GPSIC FOR MORE INFORMATION. P R 061613Z MAR 91 FM 2SCS FALCON AFB CO//DOS// UNCLAS //NANU// NOTICE ADVISORY TO NAVSTAR USERS (NANU) 063-91065 SUBJ: TERMINATE OPERATIONS FOR PRN9 DAY 65 AT 0342 UTC 1. FORECASTS/ADVISORIES AS OF DAY 65 (06 MAR 91): A. PRN9 (MCS: SVN6) TERMINATED NAVIGATION/POSITIONING OPERATIONS ON DAY 65 (06 MAR 91) AT 0342 UTC. PRN9 IS NOT USABLE AND WILL NOT RESUME SERVICE. B. PRN17 (MCS: SVN17) WILL BE REPOSITIONED ON DAY 72 (13 MAR 91): PRN17 IS EXPECTED TO BE UNUSABLE BEGINNING 0900 UTC FOR UP TO 24 HOURS. PAGE 17 OF SUBFRAME 4 OF ALL SATELLITES WILL CONTAIN A SPECIAL MESSAGE DESCRIBING THIS EVENT. THIS MESSAGE WILL READ: 310HDD9010000000000000 AND SHOULD BE INTERPRETED AS MONTH 3 (MAR) MESSAGE 1 (FIRST MSG) PREVIOUS MESSAGE 0 (NONE) SVID H (PRN17) STATUS D (UNUSABLE) DAY D (13) HOUR 9 (0900 UTC) MINUTE 0 (00) DURATION DAY 1 (1 DAY) HOUR 0 (0) MINUTES (0). THE REMAINDER OF THE MESSAGE IS BLANK OR ZEROS. C. PRN12 (MCS: SVN10) WAS UNUSABLE ON DAY 65 BEGINNING 1535 UTC. AT THIS TIME, THE SATELLITE HAS NOT RETURNED TO SERVICE. USE PRN12 BROADCASTS FOR REAL-TIME STATUS. NANU 064-91066 WILL CONFIRM START/END TIMES OF THIS OUTAGE. 2. RECOMMENDATION: CONFIRM AVAILABILITY OF SATELLITES PRIOR TO USE. 3. POINT OF CONTACT: MAJ WILLIAM FAUVER AT COMMERCIAL (719)550-6379 OR AUTOVON 560-6379. RECEIVED AT USNO VIA COURIER 7 MAR. ============================================================================== Richard B. Langley BITnet: LANG@UNB.CA or SE@UNB.CA Geodetic Research Laboratory Phone: (506) 453-5142 Dept. of Surveying Engineering Telex: 014-46202 University of New Brunswick FAX: (506) 453-4943 Fredericton, N.B., Canada E3B 5A3 ==============================================================================