Research on Time Delay Estimation Algorithm Based on Generalized Cross Correlation in Acoustic Emission Source Location

Because of containing several model waveforms, the source rub-impact acoustic emission signal transmitting in complicated body would cause waveform distortion for varying transmission speed of each model and dispersion effect. It is difficult to achieve exact source location by traditional correlation algorithm. To avoid the deviation caused by these factors, the generalized cross correlated time delay estimation was introduced to the calculation of time difference. A transmission model of acoustic emission (AE) was established based on modal AE and stochastic process theory. An optimal linear filter algorithm based on fractional Fourier transform was proposed to de-noise; the distorted waveform due to different speed in transmission would induce difficulty in extraction maximum correlated point, therefore, the correlated production and log transform based on section were proposed to solve this problem. The experiment results show that the method is prior to common time-delay estimation in location accuracy.