Editing Wide Area Augmentation System (section)

===Improvement to aviation operations===
In 2007, WAAS vertical guidance was projected to be available nearly all the time (greater than 99%), and its coverage encompasses the full continental U.S., most of Alaska, northern Mexico, and southern Canada.<ref>Federal Aviation Administration. [http://gps.faa.gov/programs/waas/questionsanswers.htm WAAS 200ft Minimum Related Questions and Answers] {{webarchive|url=https://web.archive.org/web/20060925215639/http://gps.faa.gov/programs/waas/questionsanswers.htm |date=2006-09-25 }}. Accessed June 12, 2006.</ref> At that time, the accuracy of WAAS would meet or exceed the requirements for Category 1 [[Instrument Landing System|ILS]] approaches, namely, three-dimensional position information down to 200 feet (60 m) above touchdown zone elevation.<ref name="faa.gov" />