An AR system is provided, the AR system including one or more sensors, storage, one or more communications modules, and one or more processors. The one or more sensors generate sensed data representing at least part of an environment in which the AR system is located. The one or more communications modules transmit localization data to be used in determining the location and orientation of the AR system. The one or more processors are arranged to obtain sensed data representing an environment in which the AR system is located, process the sensed data to identify a first portion of the sensed data which represents redundant information, derive localization data, wherein the localization data is derived from the sensed data and the first portion is obscured during the derivation of the localization data, and transmit at least a portion of the localization data using the one or more communication modules.