AGPS is also regular GPS it stands for Assisted GPS as it gets some sat info over the data connection via the use of a server I know Sprint has one bc it locks in under 10 seconds. but the GPS works fine by turning all the radios off and only having GPS i can get a cold lock in about 2 min or less. There is also another GPS chip that is not as popular its something like EGPS for enhanced GPS. Pleas correct me on the EGPS...
http://en.wikipedia.org/wiki/Global_Positioning_System
http://en.wikipedia.org/wiki/Assisted_GPS