The US Air Force (USAF) has successfully launched the ninth global positioning system (GPS) IIF (GPS IIF-9) satellite from Space Launch Complex 37B of Cape Canaveral Air Force Station, Florida, US.

The satellite launched aboard a United Launch Alliance (ULA) Delta IV launch vehicle. It reached orbit approximately three hours and 20 minutes after launch, and sent signals confirming its health.

Orbit testing and a checkout will be carried on the aircraft, designatated as SVN-71, before it begins full operations later in the year. It is the first of three GPS IIF space vehicles scheduled to be launched in 2015.

USAF Space and Missile Systems Center Global Positioning Systems Directorate director brigadier-general Cooley said: "I’m elated with today’s successful launch. The GPS constellation remains healthy, strong and robust and in more than 20 years since initial operational capability, GPS has never failed to deliver on its global positioning, navigation, and timing commitments.

"Each new generation of GPS satellites provides enhanced capability over the prior generations, and has delivered reliable performance demonstrating our commitment that GPS remains the gold standard space-based positioning, navigation, and timing service for the future."

"Orbit testing and a checkout will be carried on the aircraft before it begins full operations later in the year."

Boeing Government Space Systems vice-president Dan Hart said: "As they enter service, the IIFs are advancing and modernising the GPS constellation by improving accuracy, signal strength and, anti-jamming capability.

"We are also introducing the L-5 civilian ‘safety-of-life’ signal intended mainly for aviation and transportation."

The GPS IIF satellites are capable of providing jam-resistant military signals in hostile environments. They are an interim class of next-generation satellites designed to replace the GPS Block IIA satellites, which were launched between 1990 and 1997.

Apart from offering greater navigational accuracy through improvements in atomic clock technology, the satellites also deliver a second civil signal (L2C) for dual-frequency equipment, and a new third civil signal (L5) to support commercial aviation and safety-of-life applications.

Boeing is under contract for production of 12 GPS IIF satellites. It has so far manufactured nine satellites, while the remaining three are stored and maintained at the Boeing Satellite Development Center in El Segundo, California, US.

Image: A ULA Delta IV rocket launches the GPSIIF-9 satellite from Cape Canaveral Air Force, Florida, US. Photo: courtesy of ULA.