Editing Wide Area Augmentation System (section)

===Accuracy===
{{missing information|section|flight phases (En-route, Terminal, LNAV, LNAV/VNAV, LPV, and LPV-200) and associated precision requirements; LPV-200 is especially under-explained in the article|date=August 2023}}
A primary goal of WAAS was to allow aircraft to make a Category I approach without any equipment being installed at the airport. This would allow new GPS-based [[instrument approach|instrument landing approach]]es to be developed for any airport, even ones without any ground equipment. A Category I approach requires an accuracy of {{convert|16|m}} laterally and {{convert|4.0|m}} vertically.<ref name="faa.gov">Federal Aviation Administration (FAA), Press Release  [http://www.faa.gov/news/press_releases/news_story.cfm?contentKey=4006 FAA Announces Major Milestone for Wide Area Augmentation System (WAAS)]. March 24, 2006.</ref>

To meet this goal, the WAAS specification requires it to provide a position accuracy of {{convert|7.6|m}} or less (for both lateral and vertical measurements), at least 95% of the time.<ref name=WASSspec>FAA. [http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/library/documents/media/waas/2892bC2a.pdf Specification for the Wide Area Augmentation System(WAAS)] {{webarchive|url=https://web.archive.org/web/20081004122449/http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/library/documents/media/waas/2892bC2a.pdf |date=2008-10-04 }}. FAA-E- 2892b. August 13, 2001.</ref> Actual performance measurements of the system at specific locations have shown it typically provides better than {{convert|1.0|m}} laterally and {{convert|1.5|m}} vertically throughout most of the [[contiguous United States]] and large parts of [[Canada]] and [[Alaska]].<ref name="WAAS_NSTB_PAN_Report_Jul06">National Satellite Test Bed (NSTB), [http://www.nstb.tc.faa.gov/REPORTS/waaspan17.pdf WAAS PAN Report (July 2006)]. Retrieved November 22nd, 2006.</ref>