A system comprising: an indoor localisation system to localise a tracked entity in an indoor environment and to output an indoor location data stream comprising indoor location data representing locations assumed by the tracked entity in the indoor environment; an analytics computing system designed to receive and process the indoor location data stream from the indoor localisation system to compute entity-related analytics; wherein the analytics computing system is designed to: identify in the indoor location data stream one or more sessions, each representing a corresponding period during which a tracked entity carries out an associated activity in the indoor environment, based on an indoor environment model specifying one or more session open/close rules, and compute, for one or more identified sessions, associated track data representing a track travelled by the tracked entity in the indoor environment during an identified session, based on the indoor location data stream (208).