UAV updates: Overcoming a navigation challenge, autonomous UAS rolls out The Boeing B-777 or “Triple-7” is a big airplane — at over 200 feet long, with a wingspan of more than 200 feet, it carries more than 300 people. But getting it from one airport to its destination, which could be up to 8,500 nautical miles away, presents a significant navigation challenge. Combined Air Data and Inertial Reference Unit(s) (ADIRU) and three GPS L1 receivers form the certified primary navigation sensor cluster for the B-777-200. Boeing has been undertaking its ecoDemonstraor program using various models of its aircraft, and in 2019 a B-777-200 was available for a number of technology demonstrations.