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The presence of snipers in modern conflicts leads to high insecurity for the soldiers. In order to improve the soldier's
protection against this threat, the French German Research Institute of Saint-Louis (ISL) has been conducting studies in
the domain of acoustic localization of shots. Mobile antennas mounted on the soldier's helmet were initially used for
real-time detection, classification and localization of sniper shots. It showed good performances in land scenarios, but
also in urban scenarios if the array was in the shot corridor, meaning that the microphones first detect the direct wave and
then the reflections of the Mach and muzzle waves (15% distance estimation error compared to the actual shooter array
distance). Fusing data sent by multiple sensor nodes distributed on the field showed some of the limitations of the
technologies that have been implemented in ISL's demonstrators. Among others, the determination of the arrays'
orientation was not accurate enough, thereby degrading the performance of data fusion.
Some new solutions have been developed in the past year in order to obtain better performance for data fusion.
Asynchronous localization algorithms have been developed and post-processed on data measured in both free-field and
urban environments with acoustic modules on the line of sight of the shooter. These results are presented in the first part
of the paper. The impact of GPS position estimation error is also discussed in the article in order to evaluate the possible
use of those algorithms for real-time processing using mobile acoustic nodes. In the frame of ISL's transverse project
IMOTEP (IMprovement Of optical and acoustical TEchnologies for the Protection), some demonstrators are developed
that will allow real-time asynchronous localization of sniper shots. An embedded detection and classification algorithm
is implemented on wireless acoustic modules that send the relevant information to a central PC. Data fusion is then
processed and the estimated position of the shooter is sent back to the users. A SWIR active imaging system is used for
localization refinement. A built-in DSP is related to the detection/classification tasks for each acoustic module. A GPS
module is used for time difference of arrival and module's position estimation. Wireless communication is supported
using ZigBee technology. These acoustic modules are described in the article and first results of real-time asynchronous
sniper localization using those modules are discussed.
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