Global Positioning System (GPS) which is a space-based global navigation satellite system (GNSS) that provides location and time information in all weather.
Assisted GPS (A-GPS) is an enhanced version of GPS. A-GPS retrieves assistance data over a data connection (like GPRS or 3G), which helps your device calculate the coordinates of your current location when receiving signals from satellites.
What are the benefits of A-GPS?
A-GPS is designed to get a fix on satellites faster and more reliably, meaning you get a smoother GPS experience. It reduces the time a GPS enabled device requires to find its current position, known as Time To First Fix (TTFF), for most geographical locations worldwide.
A-GPS is most useful in urban areas, where you could be navigating through "urban canyons", or in a moving car.
A-GPS improves user experience for all applications on your device which use integrated GPS.
Are there any extra costs for using A-GPS?
You pay your service provider for data transferred over the cellular network. Please keep in mind that the charges might be higher while roaming.