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US Space Force’s fourth GPS III satellite now operational

Falcon 9 with GPS III SV04
A Falcon 9 carrying GPS III SV04 lifts off from Cape Canaveral Air Force Station, Florida, Nov 5. Photo: SpaceX

The US Space Force’s fourth GPS III satellite, the Space Vehicle (SV) 04, obtained operational acceptance approval less than a month after it launched from Cape Canaveral Air Force Station, Florida.

It is the fourth GPS III satellite delivered into the operational constellation in the past 12 months and the second in the past three months. Additionally, this is the first GPS III vehicle delivered to the warfighter through an expedited satellite control authority transfer process, which cuts ten days off the previous operational acceptance timeline.

“With the onset of SV04, the GPS constellation continues moving forward in next generation modernization. The 2nd Space Operations Squadron is one step closer to providing Military Code (M-Code) capability for the entire 24 satellite baseline. The highly encrypted M-Code to protect GPS signals from jamming and spoofing is currently enabled on 22 GPS satellites of various generations; 24 are needed to bring the M-Code to the next level of operational capability,” said Capt. Collin Dart, the 2 SOPS DOA Flight commander.

“SV04 brings the constellation to 23 M-Code capable vehicles. SV05 will launch no earlier than July 2021. This will add the 24th M-Code capable vehicle. SV04 also sets a new standard for handover from the contractor launch team to operational acceptance, setting the satellite healthy to the global user community approximately 30 days post launch. Moving forward with future GPS III launches, the timeline between launch and the satellite being set healthy will be at a minimum.”

SV04 was launched on a SpaceX Falcon 9 Block 5 vehicle on November 5. The Air Force has been flying 31 operational satellites for years in order to ensure the United States’ commitment to have 24 operational GPS satellites available 95% of the time. GPS III SV04 joins this operational constellation of 31 GPS satellites orbiting in medium-Earth orbit. This system delivers improved accuracy, advanced anti-jam capabilities and increased resiliency for the GPS III constellation.

“The operational acceptance of GPS III SV04 is another significant milestone for GPS Modernization, delivering critical new capabilities to our Military and Civil Users. We now have a total of 23 M-Code spacecraft for our Warfighters. For our billions of civil users, it brings the count up to 23 L2C spacecraft and 16 L5 spacecraft,” said Col. Ryan Colburn, director of the SMC Portfolio Architect Office’s Spectrum Warfare Division.

“For professional users with existing dual-frequency operations, L2C enables faster signal acquisition, enhanced reliability, and greater operating range. L5 is broadcast in a radio band reserved exclusively for aviation safety services. It features higher power, greater bandwidth, and an advanced signal design. Future aircraft will use L5 in combination with L1 C/A to improve accuracy (via ionospheric correction) and robustness (via signal redundancy). The operational acceptance of this spacecraft is another display of the fantastic teamwork across SMC’s Corps, Space Delta 8, National Geospatial-Intelligence Agency, Department of Transportation, Federal Aviation Administration, our industry partners and many others who work together to make these missions possible.”

GPS satellites provide position, navigation, and timing to more than four billion military and civilian users worldwide.