High Quality Content by WIKIPEDIA articles! Assisted GPS, generally abbreviated as A-GPS or aGPS, is a system which can, under certain conditions, improve the startup performance, or time-to-first-fix (TTFF) of a GPS satellite-based positioning system. It is used extensively with GPS-capable cellular phones as its development was accelerated by the U.S. FCC`s 911 mandate making the location of a cell phone available to emergency call dispatchers.