Team of researchers Aki Hakkarainen, Janis Werner, Nikhil_Gulati, Damiano Patron, Doug Pfeil, Henna_Paaso, Aarne Mämmelä, Kapil Dandekar, Mikko Valkama from Tampere University of Technology, Finland, VTT Technical Research Centre of Finland and Drexel University, Philadelphia, USA, is working on a localization system which would help to localize a transmitter which is non – cooperativing with the signal receiving unit. This system can be used f.e. in penitentiary system and in other cases when there is a need to track or catch a subject without its cooperation. They presented their research on CROWNCOM conference in Oulu, Finland, in June 2014
For these situations, the basic research was focused on ensuring signal transmitting from primary user, who is just the transmitter and cannot receive the signal, to secondary users, who are localizators and receivers of the signal.
There are cases in which there is impossible to use large antenna arrays. So the challenge is in proposing the model with reconfigurable antennas and creating the algorithm with help of which receivers of the signal will be able to discover the direction of movement of the localized subject.
Researchers have tested the system in the challenging environment of busy lobby with many people crossing and several active wifi hotspots around. They settled three signal transmitters (tracked subjects) and six signal receivers. Despite these conditons, the localization system, using collaborative localization and Stansfield fusion algoritm was able to tocalize the primary user with fairly good accurancy.
The full paper can be accessed here.