GPS satellite mounted atop booster for Feb. 20 launch

Beginning a slate of three launches in five months to fortify the Global Positioning System, the first craft was mounted atop its Delta 4 booster rocket Wednesday for liftoff Feb. 20. The launch is precisely timed at 8:40 p.m. EST to replace a 16-year-old member of the navigation network -- the GPS 2A-28 satellite. The evening launch opportunity extends 19 minutes. Built by Boeing, the new GPS 2F-5 satellite brings with it modernized features including greater accuracy, better anti-jamming and a civil signal for commercial aviation as the fifth Block 2F bird. More

(Source: SpaceFlight Now - Feb 6)