There’s a new article about Assisted GPS over on Embedded Star. Assisted GPS, or A-GPS, is a service that enables immediate positioning on demand, 24 hours a day, 7 days a week. It uses mobile phone networks to access assistance data, which consists of satellite constellation, precise satellite position and time data. The instant availability of this data enables the receiver to compute a position fix within seconds.
Assisted GPS services enable applications that provide on the go, accurate and reliable location information with minimal maintenance. The range of applications that require, or greatly benefit from, instant positioning is very broad. From enhanced personal navigation services that can be consulted on the fly from a PDA or a mobile phone for instance, to complex, multi-user/terminal management systems, the ability to provide instant location information has significantly widened the spectrum of GPS-enabled applications.