PROCEEDINGS ARTICLE | May 31, 2013
Proc. SPIE. 8713, Airborne Intelligence, Surveillance, Reconnaissance (ISR) Systems and Applications X
KEYWORDS: 3D acquisition, Sensors, Interference (communication), Data acquisition, Surveillance systems, Signal processing, Acoustics, Source localization, Ranging
This paper aims at developing a new technology that will enable one to conduct an autonomous and silent surveillance to
monitor sound sources stationary or moving in 3D space and a blind separation of target acoustic signals. The underlying
principle of this technology is a hybrid approach that uses: 1) passive sonic detection and ranging method that consists of
iterative triangulation and redundant checking to locate the Cartesian coordinates of arbitrary sound sources in 3D space,
2) advanced signal processing to sanitizing the measured data and enhance signal to noise ratio, and 3) short-time source
localization and separation to extract the target acoustic signals from the directly measured mixed ones. A prototype based
on this technology has been developed and its hardware includes six B and K 1/4-in condenser microphones, Type 4935, two
4-channel data acquisition units, Type NI-9234, with a maximum sampling rate of 51.2kS/s per channel, one NI-cDAQ
9174 chassis, a thermometer to measure the air temperature, a camera to view the relative positions of located sources,
and a laptop to control data acquisition and post processing. Test results for locating arbitrary sound sources emitting
continuous, random, impulsive, and transient signals, and blind separation of signals in various non-ideal environments
is presented. This system is invisible to any anti-surveillance device since it uses the acoustic signal emitted by a target
source. It can be mounted on a robot or an unmanned vehicle to perform various covert operations, including intelligence
gathering in an open or a confined field, or to carry out the rescue mission to search people trapped inside ruins or buried
under wreckages.
