Finsphere's Mobile Location Agent (MLA) Proof of Concept App for iOS demonstrates how mobile apps can detect and report significant location changes with no measurable impact to the battery life of the device. The mobile phone's geographic coordinates are captured either at the point a subscriber's phone transitions between cell sites or when a subscriber connects to a Wi-Fi network.
MLA does not need high accuracy location information such as GPS coordinates. Rather, it can operate effectively using iOS Location Services which approximates a location based on GPS, crowd-sourced Wi-Fi access points and cell tower locations.
Standard Apple Disclaimer: Continued use of GPS running in the background can dramatically decrease battery life.