Abstract: A method aggregates a number of visitor mobile devices visiting one or more locations within a facility. The method includes providing a location aggregation network to the facility, transmitting a burst of calibrating probe requests from one or more mobile calibration devices at the one or more locations to one or more of a plurality of receivers in order to calibrate the location aggregation network and form a radio map of the facility. The method further includes intercepting probe requests from a plurality of visitor mobile devices at one or more of the receivers, and comparing at least one physical characteristic of the intercepted probe requests to physical characteristic values of the radio map to yield, associated with the each location for the each receiver, a vector representing a probability that each of the plurality of visitor mobile devices is located at that location.