Outboard abnormal noise source localization method with curved surface projection based on time delay matching and weighting criterion

An improved localization method consisting of ‘filtering-time delay estimation-hyperbolic localization’ is proposed. Combining the Empirical Mode Decomposition(EMD) and weighted average magnitude difference function time delay estimation method, the original signals are decomposed into Intrinsic Mode Function(IMF) components,and energy distribution criterion and spectrum consistency criterion are used to select IMFs which can represent the physical characteristics of source signal. Then applying several sets of signals to estimate the time delay, and a vector matching criterion is proposed to select the correct time delay estimation. Considering the hydrophones location, a shell model is established and projected to plane according to quadrant before hyperbolic localization. Results of mooring and sailing tests show that the proposed method improves the localization accuracy, and reduces the influence caused by time delay estimation errors.