Free-Field TDOA-AOA Sound Source Localization Using Three Soundfield Microphones

Luka Kraljevic,Mladen Russo,Marjan Sikora,Maja Stella

doi:10.1109/access.2020.2993076

Luka Kraljevic, Mladen Russo + Show 2 more

Open Access

https://doi.org/10.1109/access.2020.2993076

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Abstract

Accurate source localization is an important problem in many research areas as well as practical applications in wireless communications and acoustic signal processing. This paper presents a passive three-dimensional sound source localization (SSL) method that employs a geometric configuration of three soundfield microphones. Two methods for estimating the angle of arrival (AOA) and time difference of arrival (TDOA) are proposed based on Ambisonics A and B format signals. The closed-form solution for sound source location estimation based on two TDOAs and three AOAs is derived. The proposed method is evaluated by simulations and physical experiments in our anechoic chamber. Simulations demonstrate that the estimation method can theoretically obtain Cramer-Rao lower bound for a small Gaussian noise present in AOA and TDOA observations. Investigation on the uncertainty of TDOA and AOA measurements depending on the length of measurement interval is also conducted. Experimental results in terms of RMSE indicate that the proposed solution can be used to accurately find a 3D position of the sound source in free-field environment. Performance evaluation regarding the number of estimation steps shows that higher accuracy can be achieved by longer observations of stationary sound source.

Highlights

The sound source localization (SSL) is an essential step in a wide range of audio/acoustic-based applications
A simulation is made to demonstrate a margin of localization error regarding uncertainty in time difference of arrival (TDOA)-angle of arrival (AOA) observations
To alleviate the dependency on the particular geometry, TDOA-AOA values are calculated by sampling the angles between three microphone stations from a uniform distribution

Summary

INTRODUCTION

The sound source localization (SSL) is an essential step in a wide range of audio/acoustic-based applications. In the work [54], the authors proposed a modified cross-correlation algorithm to obtain a more reliable measurement of time difference of arrival in the reverberation environment They performed a triangulation procedure using calculated TDOA values to obtain a sound source position in 3D space. Given that the solution (17) performs minimization of the sum of squared residuals with respect to measurement error, it was essential to determine observation uncertainties σRD and σAOA of the proposed TDOA-AOA estimation method in free field conditions. To validate estimation algorithm (17) using real measurements, this paper proposes two methods for calculating TDOA and AOA values from observed sound signal emitted from unknown source location s.

AOA ESTIMATION

LOCALIZATION RESULTS AND PERFORMANCE EVALUATION

CONCLUSION