NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2014038 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. AIR FORCE SPACE COMMAND WILL BE IMPLEMENTING CNAV MESSAGES ON THE GPS L2C AND L5 SIGNALS BEGINNING J118/1430Z WITH UPDATES FROM THE CONTROL SEGMENT APPROXIMATELY TWICE PER WEEK. THE MESSAGE POPULATED SIGNAL CONTENT WILL INCLUDE BROADCAST MESSAGE TYPES (MT) 10, 11, 12, 30, AND 33. THERE ARE NO PLANNED GPS SATELLITE OUTAGES OR DEGRADATIONS FOR THIS ACTIVITY. L2C AND L5 CNAV MESSAGES SHOULD BE TRANSPARENT TO GPS RECEIVERS THAT DO NOT PROCESS L2C OR L5 CNAV MESSAGES. THESE POPULATED SIGNALS ARE INTENDED TO FACILITATE USER FAMILIARIZATION AND DEVELOPMENT OF COMPATIBLE USER EQUIPMENT.

NOTE: UNTIL FURTHER NOTICE, THE L2C AND L5 SIGNALS ARE CONSIDERED PRE-OPERATIONAL. A PRE-OPERATIONAL SIGNAL MEANS THE AVAILABILITY AND OTHER CHARACTERISTICS OF THE BROADCAST SIGNAL MAY NOT COMPLY WITH ALL REQUIREMENTS OF THE RELEVANT INTERFACE SPECIFICATIONS AND SHOULD BE EMPLOYED AT THE USERS? OWN RISK. THEREFORE THESE SIGNALS SHOULD NOT BE USED FOR SAFETY-OF-LIFE OR OTHER CRITICAL PURPOSES. ANY MILITARY OR CIVIL USERS WHO ENCOUNTER USER EQUIPMENT PROBLEMS FOLLOWING MESSAGE POPULATION OF THE L2C AND L5 SIGNALS SHOULD CONTACT THE APPLICABLE POCS IDENTIFIED BELOW AS SOON AS POSSIBLE. AVIATION USERS SHOULD FILE REPORTS CONSISTENT WITH FAA-APPROVED PROCEDURES.
*** GENERAL MESSAGE TO ALL GPS USERS ***

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

NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2014039 NANU TYPE: GENERAL
*** GENERAL MESSAGE TO ALL GPS USERS ***
REFERENCE NANU 2014038. UPDATE:


THE PURPOSE OF THIS NOTIFICATION IS TO INFORM USERS THAT THE CNAV MESSAGES ON THE GPS L2C AND L5 SIGNALS BEGINNING ON APPROXIMATELY J118/1430Z, WILL INCLUDE BROADCAST MESSAGE TYPES (MT) 10, 11, 30, AND 33, BUT WILL EXCLUDE BROADCAST MT 12.


ADDITIONALLY, THE CNAV MESSAGE HEALTH BITS WILL INDICATE THAT THE L1 AND L2 SIGNALS ARE HEALTHY, BUT THAT THE L5 SIGNAL IS UNHEALTHY. THE CNAV MESSAGE HEALTH BITS MAY FUNCTION INDEPENDENTLY FROM THE LEGACY MESSAGE HEALTH BITS AND SHOULD NOT BE CONSIDERED RELIABLE INDICATORS OF SIGNAL QUALITY OR PERFORMANCE DURING PRE-OPERATIONAL USE.


REMINDER: UNTIL FURTHER NOTICE, THE L2C AND L5 SIGNALS ARE CONSIDERED PRE-OPERATIONAL. A PRE-OPERATIONAL SIGNAL MEANS THE AVAILABILITY AND OTHER CHARACTERISTICS OF THE BROADCAST SIGNAL MAY NOT COMPLY WITH ALL REQUIREMENTS OF THE RELEVANT INTERFACE SPECIFICATIONS AND SHOULD BE EMPLOYED AT THE USERS? OWN RISK. THEREFORE THESE SIGNALS SHOULD NOT BE USED FOR SAFETY-OF-LIFE OR OTHER CRITICAL PURPOSES. ANY MILITARY OR CIVIL USERS WHO ENCOUNTER USER EQUIPMENT PROBLEMS FOLLOWING MESSAGE POPULATION OF THE L2C AND L5 SIGNALS SHOULD CONTACT THE APPLICABLE POCS IDENTIFIED BELOW AS SOON AS POSSIBLE. AVIATION USERS SHOULD FILE REPORTS CONSISTENT WITH FAA-APPROVED PROCEDURES.
*** GENERAL MESSAGE TO ALL GPS USERS ***

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

NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2016069
SUBJ: LEAP SECOND
1. CONDITION: THE INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS
SERVICE (IERS) HAS ANNOUNCED THE INTRODUCTION OF A LEAP SECOND TO
OCCUR AT THE END OF DEC 2016.

2. COORDINATED UNIVERSAL TIME (UTC) WILL SEQUENCE AS FOLLOWS:
31 DEC 2016 23 HOURS 59 MINUTES 59 SECONDS
31 DEC 2016 23 HOURS 59 MINUTES 60 SECONDS
01 JAN 2017 00 HOURS 00 MINUTES 00 SECONDS

3. FOR GPS, AS WITH PREVIOUS LEAP SECOND UPDATES, THE UTC DATA IN
THE NAVIGATION MESSAGE WILL CHANGE IN ACCORDANCE WITH IS-GPS-200.

BEFORE THE LEAP SECOND
GPS-UTC IS 17 (GPS IS AHEAD OF UTC BY 17 SECONDS)

AFTER THE LEAP SECOND
GPS-UTC WILL BE 18 (GPS WILL BE AHEAD OF UTC BY 18 SECONDS)

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

NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2017001 NANU TYPE: GENERAL
*** GENERAL MESSAGE TO ALL GPS USERS ***
ON APPROXIMATELY 05 JAN 2017, SVN49 WILL RESUME TRANSMITTING L-BAND UTILIZING PRN04. AT L-BAND ACTIVATION, SVN49/PRN04 WILL BE UNUSABLE UNTIL FURTHER NOTICE. ADDITIONALLY, NO BROADCAST ALMANACS WILL INCLUDE SVN49/PRN04 UNTIL FURTHER NOTICE.
*** GENERAL MESSAGE TO ALL GPS USERS ***

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