On 10 July 2023, GPS satellite SVN-63, at D2A in the D plane, experienced a clock anomaly that caused the Space Force’s 2d Space Operations Squadron to set the satellite as “off” (Unhealthy) to all users until further notice. SVN-63 is a GPS-IIF satellite launched in July of 2011. GPS IIF satellites have a design life of 12 years. SVN-63 is operating on its last clock, a Rubidium Frequency Standard, which demonstrated instances of unpredictable performance starting in January 2023. The GPS community concurred on transferring SVN 63 out of the active constellation and into a test status. SVN-44 will now be reactivated out of a residual status and harvest PRN-22 from SVN-41. Next GPS-III launch (SVN-80/GPSIII-07) is scheduled for no-earlier than Summer next year.
To learn more about the Coast Guard Navigation Center, visit www.navcen.uscg.gov
NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2023042 NANU TYPE: GENERAL *** GENERAL MESSAGE TO ALL GPS USERS *** On approximately 14 AUG 2023, SVN44 will resume transmitting L-band utilizing PRN22.
On 10 AUG 2023, GPS will transition SVN44 (PRN22) into the broadcast almanac for all satellites. The almanac transition, accomplished one satellite at a time, will require approximately 24 hours to complete. Before, during, and after transition SVN44 (PRN22) will remain unusable until further notice. Future NANUs will notify users of any changes to the above stated status. *** GENERAL MESSAGE TO ALL GPS USERS ***
POC: CIVILIAN – NAVCEN AT 703-313-5900, HTTPS://WWW.NAVCEN.USCG.GOV MILITARY – GPS WARFIGHTER COLLABORATION CELL at HTTPS://GPS.AFSPC.AF.MIL/GPSOC, DSN 560-2541, COMM 719-567-2541, email@example.com, HTTPS://GPS.AFSPC.AF.MIL MILITARY ALTERNATE – JOINT SPACE OPERATIONS CENTER, DSN 276-3526. COMM 805-606-3526. JSPOCCOMBATOPS@US.AF.MIL