Editing Instrument landing system (section)

==Future==
The advent of the [[Global Positioning System]] (GPS) provides an alternative source of approach guidance for aircraft. In the US, the Wide Area Augmentation System (WAAS) has been available in many regions to provide precision guidance to Category I standards since 2007. The equivalent [[European Geostationary Navigation Overlay Service]] (EGNOS) was certified for use in safety of life applications in March 2011.<ref name="ESA20110302">{{cite web|url=http://www.esa.int/esaNA/SEM98MUTLKG_egnos_0.html |title=EGNOS navigation system begins serving Europe's aircraft |archive-url=https://web.archive.org/web/20110306195653/http://www.esa.int/esaNA/SEM98MUTLKG_egnos_0.html |archive-date=2011-03-06 |access-date=2011-03-03 |url-status=dead }}</ref> As such, the number of Cat I ILS installations may be reduced, however there are no plans in the United States to phase out any Cat II or Cat III systems.<ref name="2017 Federal Radionavigation Plan">{{Cite web|url=https://rosap.ntl.bts.gov/view/dot/32801|title = 2017 Federal Radionavigation Plan|year = 2017|last1 = Mattis|first1 = James N.}}</ref>

Local Area Augmentation System (LAAS) is under development to provide for Category III minimums or lower. The FAA Ground-Based Augmentation System (GBAS) office is currently working with the industry in anticipation of the certification of the first GBAS ground stations in Memphis, TN; Sydney, Australia; Bremen, Germany; Spain; and Newark, NJ. All four countries have installed GBAS ground stations and are involved in technical and operational evaluation activities.

The Honeywell and FAA team obtained System Design Approval of the world's first non-federal U.S. approval for LAAS Category I at Newark Liberty International Airport, operations in September 2009 and Operational Approval on September 28, 2012.<ref>{{cite web |url=http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/mobileAll/GBAS_Newark.pdf |title=Archived copy |access-date=2013-05-20 |url-status=dead |archive-url=https://web.archive.org/web/20140222223921/http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/techops/navservices/gnss/mobileAll/GBAS_Newark.pdf |archive-date=2014-02-22 }}</ref>

In Norway, a [[Differential GPS|D-GPS]] based landing system, called [[SCAT-I]], is in operation on some [[STOLport|short runway airports]].