Navigation Center
United States Coast Guard
U.S. Department of Homeland Security

GPS Constellation

The Global Positioning System Directorate has approved a change to the Navstar GPS Control Segment to User Support Community Interfaces (ICD-GPS-240 and ICD-GPS-870) which will remove GPS satellite plane/slot and clock information from the Operational Advisory message. This change proposal was approved by the GPS Interface Control Working Group in December of 2018. SVN/PRN, Block Type, and NANU details will continue to be included.

A depiction of the GPS constellation of satellites with slot and plane designations is provided here as an easy-to-read graphic which will be updated as satellites enter or leave the constellation. During the GPS modernization process, the orbital configuration, as indicated by the constellation slant chart, and control station configuration may not match over the long term. For modelling purposes, the slant chart indicates actual orbital slot and plane assignments. It should be noted that the graphic merely identifies orbital slot and plane assignments and does not reflect the operational status of GPS satellites. The operational status of the GPS constellation is detailed below.

GPS CONSTELLATION STATUS FOR
Plane Slot SVN PRN Block-Type Clock Outage Start NANU Type NANU Subject Sort descending
D 2 63 1 IIF RB
F 6 43 13 IIR RB
A 4 48 7 IIR-M RB
E 3 50 5 IIR-M RB
A 2 52 31 IIR-M RB
B 1 56 16 IIR RB
C 5 59 19 IIR RB
B 2 62 25 IIF RB
A 1 65 24 IIF CS
C 2 66 27 IIF RB
D 4 67 6 IIF RB
E 1 69 3 IIF RB
B 5 71 26 IIF RB
E 2 73 10 IIF RB
F 4 74 4 III RB
E 5 76 23 III RB
F 5 41 22 IIR RB 26 JAN 2022 USABINIT SVN41 (PRN22) USABLE JDAY 026/2140 1
D 3 45 21 IIR RB 08 APR 2022 FCSTSUMM SVN45 (PRN21) FORECAST OUTAGE SUMMARY JDAY 098/0315 - JDAY 098/1342 0
E 4 51 20 IIR RB 24 MAR 2022 FCSTSUMM SVN51 (PRN20) FORECAST OUTAGE SUMMARY JDAY 083/1530 - JDAY 083/2324 0
C 4 53 17 IIR-M RB 21 APR 2022 FCSTSUMM SVN53 (PRN17) FORECAST OUTAGE SUMMARY JDAY 111/1613 - JDAY 111/2114 0
F 2 55 15 IIR-M RB 07 JUN 2022 FCSTSUMM SVN55 (PRN15) FORECAST OUTAGE SUMMARY JDAY 158/1317 - JDAY 158/2044 0
C 1 57 29 IIR-M RB 03 DEC 2021 FCSTSUMM SVN57 (PRN29) FORECAST OUTAGE SUMMARY JDAY 337/0358 - JDAY 337/0931 0
B 4 58 12 IIR-M RB 26 MAY 2022 FCSTSUMM SVN58 (PRN12) FORECAST OUTAGE SUMMARY JDAY 146/1726 - JDAY 147/0007 0
D 1 61 2 IIR RB 10 MAR 2022 FCSTSUMM SVN61 (PRN02) FORECAST OUTAGE SUMMARY JDAY 069/2356 - JDAY 070/0418 0
A 3 64 30 IIF RB 17 MAR 2022 FCSTSUMM SVN64 (PRN30) FORECAST OUTAGE SUMMARY JDAY 076/1434 - JDAY 076/1920 0
F 3 68 9 IIF RB 24 JUN 2022 FCSTDV SVN68 (PRN09) FORECAST OUTAGE JDAY 175/0745 - JDAY 175/1945 1
F 1 70 32 IIF RB 24 FEB 2022 FCSTSUMM SVN70 (PRN32) FORECAST OUTAGE SUMMARY JDAY 055/0946 - JDAY 055/1448 0
C 3 72 8 IIF CS 30 JUN 2022 FCSTSUMM SVN72 (PRN08) FORECAST OUTAGE SUMMARY JDAY 181/0736 - JDAY 181/1431 1
D 6 75 18 III RB 19 MAY 2022 FCSTSUMM SVN75 (PRN18) FORECAST OUTAGE SUMMARY JDAY 139/2019 - JDAY 140/0203 0
B 6 77 14 III RB 28 MAR 2022 UNUSABLE SVN77 (PRN14) UNUSABLE JDAY 087/0740 - JDAY 087/2035 0
D 5 78 11 III RB 25 MAY 2022 USABINIT SVN78 (PRN11) USABLE JDAY 145/1712 1

General Information NANUs
2020089 NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2020089 NANU TYPE: GENERAL
*** GENERAL MESSAGE TO ALL GPS USERS ***
Please disregard NANU 2020088 due to an error in the naming convention. Outage start and stop times remain accurate. The correct NANU will be labeled UNUSABLE.
*** GENERAL MESSAGE TO ALL GPS USERS ***

POC: CIVILIAN - NAVCEN AT 703-313-5900, HTTPS://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 276-3526. COMM 805-606-3526.
JSPOCCOMBATOPS@US.AF.MIL
2022002 NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2022002 NANU TYPE: GENERAL
*** GENERAL MESSAGE TO ALL GPS USERS ***
On approximately 20 JAN 2022, SVN41 will resume transmitting L-band utilizing PRN22.

On 20 JAN 2022, after 2200Z, GPS will transition SVN41 (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 SVN41 (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 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 276-3526. COMM 805-606-3526.
JSPOCCOMBATOPS@US.AF.MIL
2022016 NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2022016 NANU TYPE: GENERAL
*** GENERAL MESSAGE TO ALL GPS USERS ***
PLEASE DISREGARD NANU 2022015 DUE TO AN ERROR IN THE NAMING CONVENTION. OUTAGE START AND STOP TIMES REMAIN ACCURATE. THE CORRECT NANU WILL BE LABELED UNUSABLE.
*** GENERAL MESSAGE TO ALL GPS USERS ***

POC: CIVILIAN - NAVCEN AT 703-313-5900, HTTPS://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 276-3526. COMM 805-606-3526.
JSPOCCOMBATOPS@US.AF.MIL