Using Generalized Cross-Correlation estimators for leak signal velocity estimation and spectral region of operation selection

In this paper, the performance of a set of Frequency Domain, Cross-Correlation (CC) estimators is studied, withing the framework of a Time-Difference-Of-Arrival (TDOA) approach for the estimation of the velocity of propagation of acoustic leak signals in metallic pipelines. The CC estimates are used for the necessary time delay derivation, upon the accuracy of which, much of the overall performance of the TDOA technique rests. Eight estimators adhering to the so-called Generalized Cross-Correlation (GCC) paradigm are considered, going through performance testing, utilizing leak (vibro-acoustic) signals captured from a real workplace pipe installation. The resulting test data are initially used in order to verify and highlight the theorized suitability of the low spectral region for efficient deployment of CC-TDOA approaches. Finally, the performance characteristics of the estimators are illustrated with the help of certain assessment metrics, like the accuracy of the estimated speed of propagation and the rate of successful estimates from the processing of multiple experiment data.