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New GPS signal for civil users being put to the test

Posted: June 10, 2010

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The next-generation Global Positioning System satellite launched two weeks ago has begun testing the new civilian navigation signal debuting operationally on this spacecraft.

An artist's concept shows a GPS 2F satellite in Earth orbit. Credit: Boeing
The GPS 2F-1 craft was successfully delivered into an orbit 11,000 nautical miles above the planet May 27 by a United Launch Alliance Delta 4 rocket. (See launch coverage)

Since then, Air Force controllers and engineers from satellite-builder Boeing have commenced a lengthy checkout process for the advanced GPS bird before it's accepted into the constellation in late summer or early autumn.

The Space and Missile Systems Center's Global Positioning Systems Wing says test transmissions of the L5 signal started June 5.

This signal will be broadcast from all future GPS satellites as part of the Air Force's efforts to upgrade and expand the capabilities from the navigation system.

Transportation experts say the L5 signal will spur new benefits for civilian and commercial air, water, land and rail travel across the globe.

"The L5 signal is a key element of efforts to modernize the GPS constellation for civil users. It was designed in close coordination with civil aviation and other organizations worldwide and is transmitted in a frequency band protected for Safety-of-Life applications," the Air Force says.

All 12 satellites in the new Block 2F series of GPS satellites to be deployed in the coming years will support the L5 signal. But it will take time to populate the constellation with enough of the new satellites to truly harness the additional signal.

"We're continuously replacing satellites in the constellation to ensure GPS remains the world's gold standard for position, timing and navigation," Lt. Col. Mike Manor, 2nd Space Operations Squadron's director of operations, said recently. "The GPS constellation is made up of 24 slots in space surrounding the Earth where we place our satellites. This slot scheme and satellite placement ensures GPS users receive the most accurate navigation data at any time, at any place around the entire globe."

The squadron, which is located at Schriever Air Force Base in Colorado, controls the orbiting GPS fleet.

The Delta 4 rocket launches GPS 2F-1. Credit: Stephen Clark/Spaceflight Now
Launch gallery | More pad cameras

GPS 2F-1 will join 30 other satellites currently supporting an estimated billion users around the world.

"The new GPS 2F satellites bring key improvements, including a more jam-resistant military signal, a new civil signal to enhance commercial aviation and search-and-rescue operations, and significantly improved signal accuracy as more of these new satellites go into operation," said Craig Cooning, vice president and general manager, Boeing Space and Intelligence Systems.

The Air Force hopes to launch the GPS 2F-2 satellite by year's end.