Abstract: A data processing device for use in a communications network capable of supporting users of mobile stations, as well as a method of processing data elements exchanged between a pair of entities in such a network. The invention relies on techniques for receiving and processing the content of data elements that are exchanged or generated in the course of ordinary network operation in order to derive information that can be used to ascertain the location of mobile stations in the network. The location information is provided to a location-based services (LBS) application. Thus, mobile station location information is obtained without the LBS application specifically requesting that such information be generated or exchanged, which potentially relieves the network of a considerable amount of congestion and resource scarcity.