On the Accuracy of Passive Source Localization Using Acoustic Sensor Array Networks

Angles of arrival (AOAs), gain ratios of arrival (GROAs), and time differences of arrival (TDOAs) are the three most commonly used signal metrics for source localization in acoustic sensor array networks. It is intuitive to expect a performance increase by combining those metrics. In this paper, we develop a feasible new source positioning framework using joint AOA-GROA-TDOA measurements, and establish the Cramér-Rao lower bound (CRLB) of the new method to quantify the performance increase compared with existing methods. Our analysis starts from the received waveforms rather than directly from the signal metrics, and hence these bounds characterize the fundamental limits of localization accuracy. The CRLB derived in this paper reveals that the GROAs can be utilized in conjunction with AOAs and TDOAs to improve the source localization accuracy. The improvement could be great for some special localization geometries. Moreover, the improvement from GROAs increases when the value of spatial coherence across the arrays is low and the signal propagation speed is high.