Improved TOA Estimation Method for Acoustic Ranging in a Reverberant Environment

Indoor localization based on the time-of-arrival (TOA) measurements of acoustic signals has advantages of low cost, high accuracy and no electromagnetic interference compared with other location technologies such as Bluetooth and Wi-Fi. However, conventional TOA estimation approaches based on peak extraction or fixed thresholds have difficultly maintaining high ranging accuracy and robustness in reverberant indoor enclosed environments. To address this situation, this paper presents an improved TOA estimation method for acoustic ranging in a reverberant environment that is composed of two processes. One is an acoustic reverberant cancellation technique based on the signal power spectra, and the other is a first-extremum-based match filter. To verify the performance of the improved TOA estimation method, indoor experiments were conducted in an enclosed noisy and reverberant underground parking garage. The experimental results demonstrate that the proposed algorithm is superior to a traditional quadratic cross-correlation and match filter in terms of estimation accuracy and robustness.