Acoustic Radar Employing Particle Velocity Sensors

Abstract

A concept, practical realization and applications of a passive acoustic radar for automatic localization and tracking of sound sources were presented in the paper. The device consists of the new kind of multichannel miniature sound intensity sensors and a group of digital signal processing algorithms. Contrary to active radars, it does not emit a scanning beam but after receiving surroundings sounds it provides information about the directions of incoming acoustical signals. Practical examinations of the sensitivity and accuracy of the developed radar were also presented and discussed. The sensitivity of the realized acoustic radar was examined in a free sound field. Several kinds of sound signals were used, such as: pure tone from 125 to 16000 Hz, one third octave band noise in the same frequency range and impulsive sounds. The obtained results for every kind of signal groups were presented and discussed. Results from experiments show that in some cases even a small value of the signal to noise ratio was sufficient to localize the sound source correctly. A video camera can be pointed automatically to the place where the detected acoustical source is localized. Hence, information about the sound event direction can be used for the automatic and remote control of the PTZ (Pan Tilt Zoom) cameras. The automatic and continuous tracking in real time of the selected sound source movement is also possible. The proposed solution can significantly improve the functionality of traditional surveillance monitoring systems.