During recent military conflicts, as well as for security interventions, the urban zone has taken a preponderant place.
Studies have been initiated in national and in international programs to stimulate the technical innovations for these
specific scenarios. For example joint field experiments have been organized by the NATO group SET-142 to evaluate
the capability for the detection and localization of snipers, mortars or artillery guns using acoustic devices. Another
important operational need corresponds to the protection of military sites or buildings. In this context, unattended
acoustic and seismic sensors are envisaged to contribute to the survey of specific points by the detection of approaching
This paper describes some measurements done in an anechoic chamber and in free field to characterize typical sounds
generated by the soldier activities (walking, crawling, weapon handling, radio communication, clothing noises...).
Footstep, speech and some specific impulsive sounds are detectable at various distances from the source. Such detection
algorithms may be easily merged with the existing weapon firing detection algorithms to provide a more generic
"battlefield acoustic" early warning system.
Results obtained in various conditions (grassy terrain, gravel path, road, forest) will be presented. A method to
extrapolate the distances of detection has been developed, based on an acoustic propagation model and applied to the