GPS III SVN-74, First of Its Kind, Goes Active - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

GPS III SVN-74, First of Its Kind, Goes Active

The U.S. Air Force Second Space Operations Squadron (2 SOPS) has turned the first GPS III satellite, SVN-74, healthy and active. 2 SOPS issued a statement on January 13 that the satellite is “available for backup.” While occupying the same plane as SVN-68, the new satellite broadcasts healthy, usable signals and assumes an active role in the constellation in the vicinity of slot F3, near SVN-68.

SVN-74/PRN-04 launched on Dec. 23, 2018. Having successfully completed rigorous operational testing on orbit, the satellite now enters broadcast service. It is the first satellite of the third generation to undertake active duty.

To operate the new generation in space, 2 SOPS first installed an interim ground control system, the Architecture Evolution Plan 8.0. Also known as the GPS III Contingency Operations (COps) upgrade, it enables 2 SOPS to handle the legacy satellite constellation and the new, more powerful GPS III satellites simultaneously. Lockheed Martin delivered COps to the Air Force in May 2019, and it was first used to contact and control the satellite in October. The full next-generation operational control system, OCX, has yet to be completed.

A second GPS III satellite now orbits but has yet to be turned “on,” available to users. A third satellite will launch later in 2020.

The Initial Use (USABINIT) Notice Advisory to Navstar Users (NANU) runs thusly:

SVN74 (PRN04) USABLE JDAY 013/1734
NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2020004
SUBJ: SVN74 (PRN04) USABLE JDAY 013/1734 
1.     NANU TYPE: USABINIT
       NANU NUMBER: 2020004
       NANU DTG: 131735Z JAN 2020
       REFERENCE NANU: N/A
       REF NANU DTG: N/A
       SVN: 74
       PRN: 04
       START JDAY: 013
       START TIME ZULU: 1734
       START CALENDAR DATE: 13 JAN 2020
       STOP JDAY: N/A
       STOP TIME ZULU: N/A
       STOP CALENDAR DATE: N/A

2.  CONDITION: GPS SATELLITE SVN74 (PRN04) WAS USABLE AS OF JDAY 013
    (13 JAN 2020) BEGINNING 1734 ZULU.

3.  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 276-3514, 
    COMM 805-606-3514, JSPOCCOMBATOPS@VANDENBERG.AF.MIL

SVN-74/PRN-04 was launched on Dec. 23, 2018. Now, having successfully undergone rigorous operational testing on orbit, the satellite has taken its place, backing up SVN-68/PRN-9 at F3 in the active GPS constellation.