This Friday (05 March, 2010), the GPS program will be revising the Ground Control Segment (OCS) software to the 5.5.0 D version. This software upgrade does not modify the content of the broadcast navigation message and should therefore be transparent to all users. All testing has been completed for this version of the software and confidence is very high that it will perform without any change noticeable to users. We would like your confirmation on this. If you observe anything unusual in the GPS constellation or in user GPS equipment operation on the 5th, or during the following week, please notify GPSOC or NAVCEN (per the NANU below) as soon as possible. Thank you for helping us support everyone’s GPS operations.
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NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2010041 NANU TYPE: GENERAL

*** GENERAL MESSAGE TO ALL GPS USERS *** The purpose of this notification is to inform users of an upcoming event related to the GPS satellite constellation. The 2nd Space Operations Squadron will be installing a ground software upgrade on 5 March 2010 (J064). There are no planned GPS satellite outages for this activity, and the broadcast navigation signal will remain IS-GPS-200 compliant. If military or civil users encounter any user equipment problems they feel are related to this minor software change, please call the GPSOC (military) or NAVCEN (civil) immediately.

POC:
CIVILIAN - NAVCEN AT 703-313-5900, HTTPS://WWW.NAVCEN.USCG.GOV MILITARY - GPS OPERATIONS CENTER AT HTTP://GPS.AFSPC.AF.MIL/GPSOC, DSN 560-2541, COMM 719-567-2541, GPS_SUPPORT@SCHRIEVER.AF.MIL, HTTPS://GPS.AFSPC.AF.MIL
MILITARY ALTERNATE - JOINT SPACE OPERATIONS CENTER, DSN 276-3514,
COMM 805-606-3514, JSPOCCOMBATOPS@VANDENBERG.AF.MIL