WASHINGTON – As the U.S. Air Force works to develop its next generation of Global Positioning System satellites, the service and Boeing signed an agreement to continue support of the existing constellation.

Boeing will continue to support the Boeing-built GPS 2A and 2F satellites currently in orbit for the next five years under the agreement announced Thursday.

“This agreement continues Boeing’s strong legacy of GPS innovation and mission support,” said Dan Hart, vice president of Government Satellite Systems, in the release. “We are focused on delivering reliable, affordable and resilient GPS capability now and for generations to come.”

The Block 2A satellites are not currently in service, but some are kept as back-ups should there be a problem with more modern additions to the constellation.

Block2F, on the other hand, is the newest part of the constellation, with the last satellite launched in 2016. It currently transmits the bulk of GPS signals used by the military and civilians worldwide.

The value of the extension was not disclosed in the press release. SpaceNews has reached out to Boeing for more information.

Boeing is responsible for building the majority of the GPS satellites used by the military, equaling “550 years of on-orbit operation,” according to the company.

Competitor Lockheed Martin, however, is heading up the initial deployment of the next generation of satellites, known as GPS 3.

The launch of the initial unit had been scheduled for late 2017, but could wind up being delayed until 2018. Lockheed Martin has a roughly $4 billion contract to build 10 GPS 3 satellites for the Air Force, all of which could be in orbit by as early as 2022.

After that, however, the Air Force is holding a competition to see which aerospace company will build the next batch of GPS 3 satellites. The service awarded $5 million each to Boeing, Lockheed Martin, and Northrop Grumman in 2016 to demonstrate their concepts for the next block.

“Industry told us they were ready to compete for the GPS III space vehicles,” said Lt. Gen. Samuel Greaves, the commander of the Air Force Space and Missile Systems Center, in a May 2016 press release following the award. “We look forward to working with Boeing, Lockheed Martin, and Northrop Grumman to assess the feasibility of a follow-on, competitive production contract.”

Phillip Swarts is the military space reporter for SpaceNews. He previously covered space and advanced technology for Air Force Times, the Justice Department for The Washington Times, and investigative journalism for the Washington Guardian;...