Lockheed Martin deployed its first GPS II satellite recently, and now confirms the unit is communicating effectively with ground-control operators. "This is the Air Force's first GPS III, so we are excited to begin on-orbit test and demonstrate its capabilities," according to Lockheed’s Johnathon Caldwell, v.p. for Navigation Systems. "By this time next year, we expect to also have a second GPS III on orbit and users should be receiving signals from this first satellite."
GPS — Global Positioning System — satellites are used by the NAVSTAR radionavigation system owned by the U.S. government and operated by the U.S. Air Force. Currently, a total of 31 satellites complete two orbits each day at an altitude of about 12,550 miles (20,200 km.)
The first satellite, Navstar 1, was launched in 1978, and the GPS system achieved full operational capability in 1995. Advances in technology and new demands on the existing system prompted the decision to modernize the system in 2000, and the contract to develop the Next Generation GPS Operational Control System (OCX) platform was placed with Raytheon in 2010.
The GPS III program involves new ground stations and new, higher-power satellites, with additional navigation signals for both civilian and military users, and aims to improve the accuracy and availability for all users. GPS III offers three times better accuracy and up to eight times improved anti-jamming capabilities, according to Lockheed. The first series of GPS III satellites consists of 10 satellites, and USAF chose Lockheed to build three of these in 2016.
GPS Block IIIA is the first series of third-generation GPS satellites, incorporating new signals and broadcasting at higher power levels. In September 2016, the Air Force awarded Lockheed Martin a contract option for two more Block IIIA satellites, setting the total number of GPS IIIA satellites to ten. It was the first of these satellites, SV01, that was launched aboard a SpaceX Falcon 9 rocket on December 18, 2018.
Once GPS III SV01 is declared operational it will assume a place in the current GPS constellation. The satellite’s service life is expected to be 15 years, 25% longer than any currently deployed GPS satellites on-orbit today.
Block IIIA satellites use Lockheed’s A2100 satellite bus structure. The propellant and pressurant tanks are manufactured in high-strength composite material by Orbital ATK. Each satellite will carry eight deployable JIB antennas, designed and manufactured by Northrop Grumman Astro Aerospace.
GPS III's L1C civil signal will make it the first GPS satellite broadcasting a signal that is compatible with other international global navigation satellite systems, improving connectivity for civilian users.
"In the coming days, GPS III SV01 will use its liquid apogee engines to climb into its operational orbit about 12,550 miles above the earth. We will then send it commands to deploy its solar arrays and antennas, and begin on-orbit checkout and tests, including extensive signals testing with our advanced navigation payload provided by Harris Corporation," said Caldwell.
USAF and Lockheed engineers are controlling GPS III SV01's launch and checkout test using elements of the GPS Next Generation Operational Control System (OCX) Block 0. Satellite control and operations are expected to shift to the Air Force's current Operational Control
A second series of up to 22 satellites are expected to be produced, for deployment through 2035.