Diffrence between A-GPS & GPS

A-GPS & GPS

A-GPS & GPS

A-GPS and GPS are different navigational aids that both use information from satellites to determine their exact location on Earth. GPS stands for Global Positioning System. A GPS device communicates with four or more satellites to determine its exact location coordinates anywhere on Earth. It works in cloudy weather as long as the device has a clear line of sight to the satellites.

A-GPS stands for Assisted Global Positioning System. While it works on the same principles as a GPS the difference here is that it gets the information from the satellites by using network resources e.g. mobile network, also called assistant servers.

Comparison chart

	A-GPS	GPS
Stands for:	Assisted Global Positioning System	Global Positioning System
Source of triangulation information:	Radio signals from satellites and assistance servers e.g. mobile network cell sites	Radio signals from GPS satellites
Speed:	A-GPS devices determine location coordinates faster because they have better connectivity with cell sites than directly with satellites.	GPS devices may take several minutes to determine their location because it takes longer to establish connectivity with 4 satellites.
Reliability:	Location determined via A-GPS are slightly less accurate than GPS	GPS devices can determine location coordinates to within 1 meter accuracy
Cost:	It costs money to use A-GPS devices on an ongoing basis because they use mobile network resources.	GPS devices communicate directly with satellites for free. There is no cost of operation once the device is paid for.
Usage:	Mobile phones	Cars, planes, ships/boats