Filesystem:/Applications/Compass.app

From The Apple Wiki

iOS refers to the compass internally as the magnetometer. It exists in all iPhones since the iPhone 3GS and all iPad models except the iPad. The compass found in the iPhone 3GS is the AKM Semiconductor AKM8973, whereas the iPhone 4 and iPad 2 use the AKM Semiconductor AKM8975, the others' are not confirmed. [1] [Archived 2013-11-08 at the Wayback Machine]