Boeing on July 9 shipped the third of 12 Global Positioning System (GPS) IIF satellites for the U.S. Air Force from the company's Satellite Development Center in El Segundo to Cape Canaveral Air Force Station, Fla., aboard a Boeing-built C-17 Globemaster III airlifter.

SVN-65 is scheduled to be launched in the fourth quarter of this year aboard a United Launch Alliance Delta IV rocket. It will join the first and second Boeing-built GPS IIF satellites, launched May 27, 2010, and July 16, 2011, to continue the sustainment and modernization of the GPS network.

"As each IIF satellite becomes operational, we continue the seamless transformation of the GPS constellation into an even more accurate, reliable and durable navigation resource for the U.S. military and the global civilian user community," said Craig Cooning, vice president and general manager of Boeing Space and Intelligence Systems.

"Our efficient pulse-line manufacturing process, adapted from Boeing's commercial airplane production lines, also ensures that we deliver each spacecraft on time and on cost."

SVN-65 will now undergo preflight checkout, fueling and integration to prepare for the early October launch.

When on orbit, it will be controlled by the Operational Control Segment, the GPS network's ground control system. Developed by a Boeing-led team, the OCS entered service in 2007 and was turned over to the Air Force 50th Space Wing in April 2011.

GPS IIF features greater navigational accuracy through improvements in atomic clock technology, a more secure and jam-resistant signal for the military, and a protected, more precise, and interference-free civilian L5 signal for commercial aviation and search-and-rescue operations.

Other enhancements to the IIF include an extended 12-year design life and a re-programmable on-orbit processor that can receive software uploads for improved system operation.

Of the remaining nine IIFs that Boeing is building for the Air Force, three are complete and in storage, and six are being assembled and tested.