Impulse source localization in an urban environment: Time reversal versus time matching

This study investigates two approaches for localizing an impulse sound source with distributed sensors in an urban environment under controlled processing time. In both approaches, the numerical model used for calculating the sound propagation is a finite-difference time-domain (FDTD) model. The simulations are drastically accelerated by restricting to the lower frequencies of the impulse signals and are evaluated against in situ measurements. The first tested localization technique relies on the time reversal of the measurements with the model. In the second technique, the source is localized by matching the observed differences in the first times of arrival of the signals to those obtained from a pre-defined database of simulations with known source positions. The localization performance is physically investigated on the basis of the measurements, considering two source positions and all possible combinations from 5 to 15 microphones. The time matching localization attains an accuracy of 10 m, which is targeted in this study, in the vast majority of the configurations. In comparison, the time reversal localization is affected by the weakness of contributions from sensors masked and distant from the source. Practical requirements are also discussed, such as real-time constraints, hardware and description of the urban environment. (C) 2016 Acoustical Society of America.