Research On Multi-resource Separation Of Ship Noise Based On High-order Spectrum And Cyclic Spectrum

The technique of feature extraction of ship-radiated noise is of importance to underwater equipment, and it is a hotspot and difficult area in the national and international research. In this dissertation, in the light of actuality, primary problems and engineering application of extracting features of ship-radited noise,a comprehensive survey on several features extraction method of underwater target is conducted and it is tested by experimental ship noise in ocean to show the validation. The digital acoustic fuze platform for feature extraction of ship-radited noise is designed and realized. The main work and originality in this thesis can be summarized as follows:1. Based on high-order statistics,the feature of bispectrum and the phase coupling featuresof 11/2-dimensional spectrum and 21/2-dimensional spectrum of ship-radiated noise have been studied. The method of subband energy feature extraction of 11/2 -dimensional and21/2 -dimensional spectrum is presented. The phase coupling features of three types ofship-radiated noise are analyzed , and the distribution features of subband energy are extracted.2. Based on the basic theory of ceptrum and biceptrum, the feature extraction method of descending dimension spectrum of bicepstrum is presented. The characters differences between power ceptrum and desceding dimension spectrum of biceptrum about typical signals and ship-radiated noise are analyzed, and the superiority of the latter is analyzed. Finaly,the features of desceding dimension spectrums of three types of ship-radiated noise are extracted.3. Based on the basic theory of analyzing cyclostationary signals, the expressions of cyclic auto-correlation and cyclic spectrum density for several typical signals are deduced. The cyclic stationary characteristics of single-frequency signals and amplitude-modulated signals are studied, and the method of cyclic spectrum feature extraction of operating frequencies of ship auxiliaries and propulsion system is presented. Lastly, the characteristics of operating frequencies of three types of ship auxiliaries and propulsion system are extracted.4. Based on simplified algorithm for high-order statistics, hardware system which adopts [DSP is designed and realized. Subsequently, functions , work principle and implement method ofthe main modules in this platform is discussed, and the source assembling programs of simplication algorithm for high-order statistics by TMS320C5000 series are debugged in CCS. In the end. the testing correct results by experiment is presented.