An experimental setup for the calibration of acoustic antenna

One of the most common applications of the acoustic antennas is the detection and the localization of sources. The geometric distribution of the sensors is not the only parameter that influences the measure; also the electromechanical features of the microphones play an important role, strongly affecting the delay of the signals. For this reason, a dedicated calibration process, considering both the geometric location of the sensors and their intrinsic features, can increase the accuracy level of the measure. In this paper at hand, a dedicated calibration method is proposed, providing a global measure of the locations, comprehensive of all the above mentioned causes of delay. The acoustic signals detected by the sensors are used to determine their distances from a reference microphone; on this basis, through a triangulation method, their locations are computed. First, the calibration method was tuned in a simulation environment: the effect of the location of sound sources and reference microphone was investigated using a dedicated numerical model to theoretically predict signal produced by each microphone. A dedicated optimization process was adopted to identify layout configuration guaranteeing the right calibration also for large size antenna compatibly with anechoic room available space constraint. The proposed solution was experimentally tested on a linear shape acoustic antenna.