iPhone GPS and Maps
iPhone 3G came with a very new and important feature, the GPS capability, which is integrated along with Google Maps. The GPS technology along with iPhone software, together would present a totally different mobile mapping interface.GPS means Global Positioning System. It uses information from earth-orbiting satellites to find your present location. A receiver estimates the distance to GPS satellites based on the time it takes for signals to reach it, then uses that information to identify its location. But there is more. iPhone 3G uses not only the GPS technology, but A-GPS , i.e, it tracks your location through the Wi-Fi signals and the information from cellular towers to determine a more accurate location. Thus, in a sense , the GPS technology helps us get a better location.
In iPhone 3G, if GPS is available, the iPhone displays a blue GPS indicator. But if you’re inside — without a clear line of sight to a GPS satellite — iPhone finds you via Wi-Fi. If you’re not in range of a Wi-Fi hot spot, iPhone finds you using cellular towers. And the size of a location circle tells you how accurately iPhone is able to calculate that location: The smaller the circle, the more accurate the location.
