 With the purchase of Ryan by Northrop Grumman in July 1999, the aircraft became the Northrop Grumman Global Hawk.The Global Hawk is not particularly stealthy, but it has sophisticated long-range sensors to allow it to operate outside of hostile air defenses, and can survey as much as of terrain a day.In comparison to the Predator, if a Global Hawk were flown out of San Francisco, it would be able to operate in Maine for 24 hours, observe a 370 x 370 kilometer (230 x 230 mile) grid, and then fly back home.