Apple with iOS 8 is advancing the CoreLocation API with new features designed to provide users with even more reliable, faster and precise indoor positioning in supported venues. Currently, iOS determines your location using a combination of GPS, a crowd-sourced location database of nearby Wi-Fi hotspots and the cellular triangulation technique that determines your rough location based on cell tower signal strength.
As GPS/cellular are often unavailable or perform poorly inside buildings and in underground places like parking lots, iOS 8 can resort to using a combination of iBeacon transmitters, if any, and motion data provided by your device's accelerometer, compass and gyroscope sensors...