Where Am I? Finding Your Way with Core Location

Abstract

Your iPhone has the ability to determine where in the world it is using a framework called Core Location. There are actually three technologies that Core Location can leverage to do this: GPS, cell tower triangulation, and Wi-Fi Positioning Service (WPS). GPS is the most accurate of the three but is not available on first-generation iPhones. GPS reads microwave signals from multiple satellites to determine the current location. Cell tower triangulation determines the current location by doing a calculation based on the locations of the cell towers in the phone’s range. Cell tower triangulation can be fairly accurate in cities and other areas with a high cell tower density but becomes less accurate in areas where there is a greater distance between towers. The last option, WPS, uses the IP address from iPhone’s Wi-Fi connection to make a guess at your location by referencing a large database of known service providers and the areas they service. WPS is imprecise and can be off by many miles.