Abstract
Accurate acoustic source localization at a low sampling rate (less than 10 kHz) is still a challenging problem for small portable systems, especially for a multitasking micro-embedded system. A modification of the generalized cross-correlation (GCC) method with the up-sampling (US) theory is proposed and defined as the US-GCC method, which can improve the accuracy of the time delay of arrival (TDOA) and source location at a low sampling rate. In this work, through the US operation, an input signal with a certain sampling rate can be converted into another signal with a higher frequency. Furthermore, the optimal interpolation factor for the US operation is derived according to localization computation time and the standard deviation (SD) of target location estimations. On the one hand, simulation results show that absolute errors of the source locations based on the US-GCC method with an interpolation factor of 15 are approximately from 1/15- to 1/12-times those based on the GCC method, when the initial same sampling rates of both methods are 8 kHz. On the other hand, a simple and small portable passive acoustic source localization platform composed of a five-element cross microphone array has been designed and set up in this paper. The experiments on the established platform, which accurately locates a three-dimensional (3D) near-field target at a low sampling rate demonstrate that the proposed method is workable.
Highlights
Passive acoustic source localization has been extensively investigated in the last two decades
An accurate time delay estimation (TDE) is essential for the good performance of the acoustic source location based on the Time delay of arrival (TDOA) method, since any error in the TDE leads to a high error of the target location estimation [2]
For a small portable system, especially for a multitasking micro-embedded system, a modification of the generalized cross-correlation (GCC) method based on the US theory is proposed to improve the TDOA accuracy and, the localization accuracy at a low sampling rate
Summary
Passive acoustic source localization has been extensively investigated in the last two decades. The performance of time delay estimation based on the GCC method is dependent on the sampling rate [3], namely a high sampling rate [4,5,6] can contribute to a high localization accuracy. There is the up-sampling (US) method in the SRC field that can increase the original sampling rate of the input signal In this sense, to achieve accurate localization at a low sampling rate, a modification of the GCC method is proposed based on the US theory and defined as the US-GCC. Increasing the interpolation factor can result in the increase of the sampling rate, as well as the improvement of the TDOA estimation and localization accuracy. For the near-field acoustic source in this paper, the optimal interpolation factor is selected according to localization computation time and the standard deviation (SD) of target location estimation.
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