Editing Assisted GNSS (section)

{{short description|System to improve the time-to-first-fix of a GNSS receiver}}
[[File:A-GPS.svg|thumb|320px|Assisted GPS]]
'''Assisted GNSS''' ('''A-GNSS''') is a [[GNSS augmentation]] system that often significantly improves the startup performance—i.e., [[time to first fix|time-to-first-fix]] (TTFF)—of a [[global navigation satellite system]] (GNSS). A-GNSS works by providing the necessary data to the device via a radio network instead of the slow satellite link, essentially "warming up" the receiver for a fix. When applied to [[GPS]], it is known as '''assisted GPS''' or '''augmented GPS''' (abbreviated generally as '''A-GPS''' and less commonly as '''aGPS'''). Other local names include '''A-GANSS''' for Galileo and '''A-Beidou''' for BeiDou. 

A-GPS is extensively used with GPS-capable [[cellular phones]], as its development was accelerated by the U.S. [[Federal Communications Commission|FCC]]'s [[Enhanced 911|911 requirement]] to make cell phone location data available to emergency call dispatchers.<ref>{{cite web |url=http://www.gpsworld.com/innovation-assisted-gps-a-low-infrastructure-approach/ |title=Assisted GPS: A Low-Infrastructure Approach |publisher=GPS World |date=March 1, 2002 |access-date=11 June 2008}}</ref>