Acoustic Vector Sensor Based Source Localization Using MEMS Structures

The conventional techniques to estimate the Direction-of-Arrival (DOA) of acoustic sources includes employing multiple Acoustic Pressure Sensors (APSs) in an array configuration. Recently with the advent of MEMS technology, the sensors are capable of capturing the acoustic particle velocity along with the acoustic pressure and thesesensors are referred to as Acoustic Vector Sensors (AVSs). In order to capture the velocity field information, AVSs contain two (three) vector sensors which are aligned along the corresponding coordinate axes in the two (three) dimensional acoustic space. Based on the narrow-band processing techniques and for a single far-field source scenario, we discuss the advantages obtained by an AVS array in comparison to a conventional APS array based on their respective beam patterns. Later the discussion is extended to a configuration where each AVS in the array contains only one vector sensor (which measures one component of the vector field), such that it can have a variable orientation, and a pressure sensor, which is referred to as a 1D AVS. We discuss the similarities and differences between a 2D AVS array and 1D AVS array through beam patterns.Also we discuss the bias in the source location estimate obtained by using a 1D AVS array. Further we derive the Cram´er- Rao bounds for a 2D AVS, 1D AVS and APS array configurations. Finally we compare the performance of a 1D AVS array and 2D AVS array in the covariance domain in terms of the localization of quasi-stationary sources.

Keywords:

acoustic localization , sound detection , sound source localization , AVS , DOA , Vector Sensors , APS