Simultaneous Estimation of Direction of Arrival and Sound Speed Using a Non-Uniform Sensor Array

Direction of arrival (DOA) estimation is a crucially important task of signal processing for audio applications. Infrasound might form Lamb or acoustic gravity waves and accordingly propagate at a speed that is different from the general speed. Therefore, conventional DOA methods that require a presumed sound speed are not applicable. As described herein, a newly proposed algorithm can estimate DOA and sound speed simultaneously. The algorithm, which is based on arrival time differences measured using a non-uniform sensor array, obtains estimates by nonlinear optimization with a constraint. Comparisons with conventional methods through computer simulations showed superior performance of the proposed algorithm in some conditions, such as a case where sound speeds differ from the assumed ones.