The United States Air Force has extended a deal for Boeing to improve the GPS satellite system for up to five more years.

The Air Force, which operates the GPS network, awarded Boeing a $51 million, one-year contract with four one-year options. The contract covers GPS IIF satellite shipment to the launch site in Florida, pre-launch preparation, post-launch checkout, handover and on-orbit support.

"The contract provides mission continuity for the Boeing GPS IIF fleet as we continue to deliver on our commitments," said Craig Cooning, vice president and general manager of Boeing Space & Intelligence Systems, a division of Boeing. "With nine GPS IIFs still awaiting deployment, the contract scope includes supplying all support needed until the Air Force calls for the vehicles."

Boeing, which has been part of GPS since the network’s inception in the 1970s, has produced nearly 70 percent of the satellites launched in support of the GPS constellation.

The company is on contract for 12 GPS IIF satellites, three of which are in service. The IIFs provide greater navigational accuracy through advances that include atomic clock technology, a civilian L5 signal and an improved military signal.

The next IIF is to launch during the second quarter. Boeing will complete production of the remaining ones by the end of the year.

"We have the capability to maintain the remaining IIF spacecraft to be delivered and the flexibility to launch up to three within a single year if required to sustain the network," said Jan Heide, Boeing GPS IIF program director.