The 50th Space Wing at Schriever AFB, Colo., has completed the first of a two-phase Global Positioning System (GPS) constellation expansion known as “Expandable-24,” the wing said yesterday.
When fully complete, this expansion will increase global GPS coverage and provide civil, military and commercial users with more robust satellite availability and a higher probability of signal acquisition in terrain-challenged environments, according to the Air Force.
The GPS constellation consists of 24 operational slots positioned within six equally-spaced orbital planes surrounding the earth. This plane/slot scheme and enhanced satellite placement ensure GPS users receive the most accurate navigation data at any time, at any place around the world.
Expandable-24 was directed by U.S. Strategic Command. Under the order, the 50th Space Wing’s 2nd Space Operations Squadron (2 SOPS) repositioned six satellites in the current GPS constellation. As a result, the Air Force increased the robustness of satellite availability by expanding three of the baseline 24 constellation slots.
Given the strength and number of satellites in the constellation, Air Force Space Command was in a unique position to enact this revolutionary strategy to benefit global users, according to the service.
Phase one of Expandable-24 began one year ago when three GPS satellites began repositioning. The last of the satellites completed repositioning this week, the Air Force said.
Phase two of Expandable-24 began in August 2010 and is expected to be complete in June 2011. During Phase two, three other GPS satellites will be repositioned. When complete, the constellation will attain the most optimal geometry in its 42-year history, according to the officials, maximizing GPS coverage for all users.
“Our primary focus is to execute flawless operations to maintain GPS as the world’s gold standard for positioning, navigation, and timing,” said Lt. Col. Mike Manor, director of operations for 2 SOPS. “By repositioning a handful of our satellites to optimize their locations in space, we’ve not only improved the accuracy for military users in disadvantaged terrain like Afghanistan, but also improved the accuracy for all GPS users worldwide.”