MASSLOC: A Massive Sound Source Localization System based on Direction-of-Arrival Estimation

TL;DR

MASSLOC is a scalable indoor sound source localization system that accurately identifies multiple sources using sparse array geometries and Zadoff-Chu sequences, achieving high precision in reverberant environments.

Contribution

The paper introduces MASSLOC, a novel system combining sparse array geometries and Zadoff-Chu sequences for multi-source localization and identification in challenging acoustic conditions.

Findings

Successfully localizes up to 14 sources simultaneously.

Achieves median 3D localization error of 55.7 mm.

Maintains high accuracy in reverberant environments.

Abstract

Acoustic indoor localization offers the potential for highly accurate position estimation while generally exhibiting low hardware requirements compared to Radio Frequency (RF)-based solutions. Furthermore, angular-based localization significantly reduces installation effort by minimizing the number of required fixed anchor nodes. In this contribution, we propose the so-called MASSLOC system, which leverages sparse two-dimensional array geometries to localize and identify a large number of concurrently active sources. Additionally, the use of complementary Zadoff-Chu sequences is introduced to enable efficient, beamforming-based source identification. These sequences provide a trade-off between favorable correlation properties and accurate, unsynchronized direction-of-arrival estimation by exhibiting a spectrally balanced waveform. The system is evaluated in both a controlled anechoic chamber and a highly reverberant lobby environment with a reverberation time of 1.6 s. In a laboratory setting, successful direction-of-arrival estimation and identification of up to 14 simultaneously emitting sources are demonstrated. Adopting a Perspective-n-Point (PnP) calibration approach, the system achieves a median three-dimensional localization error of 55.7 mm and a median angular error of 0.84 deg with dynamic source movement of up to 1.9 mps in the challenging reverberant environment. The multi-source capability is also demonstrated and evaluated in that environment with a total of three tags. These results indicate the scalability and robustness of the MASSLOC system, even under challenging acoustic conditions.