Maximum likelihood estimators and Cramér-Rao bound for estimating azimuth and elevation angles using compact arrays (PDF)

Urazghildiiev, I.R. and D. Hannay

Journal of the Acoustical Society of America 141: 2548-2555 (2017)

DOI: 10.1121/1.4979792

The problem of estimating the azimuth and elevation angle of a sound source using a compact array of hydrophones is addressed. The closed-form representations for several time-difference of arrival (TDOA) based estimators are given, and their accuracies are evaluated using both statistical simulations and in situ tests. Simulations demonstrated that the accuracy provided by the estimators is close to the Cramér–Rao bounds. In real conditions, the main cause of azimuth and elevation errors can be refraction, surface and bottom reflections and other unpredictable sound propagation effects resulting in large and slowly changing errors.