GPS Control Software Glitch: NANU Issued

January 21, 2010

The GPS AEP Command and Control operational software update previously reported enables new capabilities for the warfighter. The new capabilities are not something we can discuss in this venue. They are considerable, but require absolute compliance with the published GPS Interface Control Document (ICD). Some of the new features that are incorporated only work with authorized military receivers that have successfully passed security tests. However the live introduction of the new functions is causing problems wherein some of these receivers are intermittently not tracking Y-code, and non-compliant civilian receivers are also reporting continuing problems.

Corrective action could encompass either the Air Force rolling back the update or revising its software, or the manufacturers modifying GPS software within the receivers to be totally compliant with the ICD.

In November and December 2009, the new software uploaded operational GPS IIA and IIR space vehicles with navigation data and completed normal operational functions. The software is part of the GPS modernization effort, with its principal features being telemetry, tracking, and commanding for the new GPS IIF space vehicle — as yet unlaunched -- and more robust security for the military M-code signal.

On January 24, the GPS Wing issued the following notice:

NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2010011 NANU TYPE: GENERAL
*** GENERAL MESSAGE TO ALL GPS USERS ***
On 11 January 2010, the GPS Master Control Station loaded new
operational control system software to support future GPS modernization
capabilities and signals. The software has been in operational soak and
the GPS Master Control Station has received a few user concerns related
to the software update. Military users can find additional information
at the GPSOC SIPRNet website at http://gpsoc.afspc.af.smil.mil. The GPS
Master Control Station is preparing to complete soak of the new software
in preparation for final install. In support of the final install
decision, the GPS Master Control Station requests that operational
military and civil users provide any impacts encountered that are
believed to be related to the new software or started after the 11
January 2010 install.   Military or civil users please contact the GPSOC
(military) or NAVCEN (civil) at the numbers listed below no later than
29 January 2010. Any user impacts will be presented at the decision
brief for final install of the new GPS Master Control Station software.
*** GENERAL MESSAGE TO ALL GPS USERS ***

   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