Study On Passive Ranging Methods Using Dual Vertical Hydrophones In The Deep Sea

The problem of underwater passive ranging of surface ship targets is a hot topic in ocean monitoring.The distance information of ship targets can be extracted from either the channel structure or the receiving array.For the latter,since the ship target radiation noise is characterized by random signal,unknown spectral structure,and the energy is mainly concentrated in low frequencies,only a large-aperture receiving hydrophone array can solve the distance information.Extracting the distance information of the ship target from the channel structure is a cost-effective way.Theoretically,a single hydrophone can extract the channel structure and thus estimate the target distance,but a dual vertical hydrophone can improve the ranging performance of ship targets with little increase in complexity.In this thesis,the deepsea vertical dual hydrophone passive ranging method is investigated based on the single hydrophone ranging.First,a single-hydrophone based channel structure extraction method is given.Theoretical derivation and accuracy analysis of multi-channel delay estimation based on conventional autocorrelation method and cepstrum method are presented.A composite multipath delay structure estimation algorithm is proposed for the problem of blurred para flaps by the selfcorrelation and high signal-to-noise ratio requirement for cepstrum.The thesis also combines some a priori information of the receiver hydrophone,channel and sound source,and gives the delay structure course extraction method,the discrimination strategy of multipath and the discrimination basis.Secondly,the single hydrophone ranging method and performance are analyzed under the assumption of uniform sound velocity profile,and a single hydrophone passive ranging method based on sound line bending correction is given on this basis.When the target is a uniform linear motion,the single hydrophone passive ranging algorithm is constructed based on the continuous time-delay structure extraction combined with the extended Kalman filter theory.Then,the time delay structure of the vertical double hydrophone received signal is analyzed,and the double hydrophone time delay estimation method and performance analysis are given.Based on the experimental data,the discrimination strategy and discrimination basis of the multipath structure of the double hydrophone received signal are given by combining some a priori information of hydrophone configuration,channel and sound source.Finally,the passive ranging method of dual vertical hydrophones under deep-sea conditions is given,the ranging performance is analyzed,and the deployment strategy of hydrophones is analyzed and suggested.A template matching-based acoustic line bending correction method is given for the deep-sea channel to realize passive ranging of surface targets,and the experimental data are used to verify it.