The simplest and easiest language to say. Do not professional, do not understand......
So, in order to quickly make satellite positioning to your mobile phone, we use a A-GPS in every time before the need to update and update, "GPS accelerator" "GPS accelerator" on the need to network, is the need to GPRS, there will be traffic, but very few. So A-GPS for GPS is also charged,, A-GPS requires network support in order to achieve fast positioning, if you are a device A-GPS, can also use "GPS accelerator", the direct use of GPS navigation, navigation can be, but the positioning time is very slow, because it does not use the network and common GPS. Or simply speaking, A-GPS is the first GPRS Internet access point: table +GPS receiving satellite navigation signal; and GPS is only by receiving satellite navigation signal to achieve navigation.
AGPS is a network aided positioning, is in no use when the GPS satellite signal, GPS must have AGPS, and not necessarily
Whether it is GPS or A-GPS, are mainly to receive satellite navigation signal using GPS navigation chip equipment, and GPS chip receiving satellite navigation signals are free of charge, but the positioning time is very slow, because it will take a few minutes to wait for a satellite to locate the GPS module to the navigation on your device. A-GPS based on the receiving satellite navigation signal, but also through the network (GPRS) to get you the instant communication equipment operation base station information (signal base seat), you can easily find the instant seat, let the satellite fast positioning of your equipment. So the A-GPS than the GPS positioning time soon.
