%A Renzo Azaro %A Massimo Donelli %A Manuel Benedetti %A Paolo Rocca %A Andrea Massa %X A mobile positioning system based on GSM signals analysis and on a cooperative stochastic optimization algorithm is presented. The proposed technique is intended as a backup solution in those applicative scenarios where the GPS system fails to work (e.g., urban canyons). The hardware architecture of the system and the positioning algorithm are described and validated by means of a numerical assessment. %L elediasc12331 %D 2007 %I University of Trento %T A GSM signals based positioning technique for mobile applications