Waveform Prediction For Deep-ocean Reverberation And Data Analysis

As an important tool for human being to cognize and exploit the ocean, active sonar systems always be interfered by ocean reverberation which terribly affects the performance of sonars. The time domain waveform of ocean reverberation can be the foundation for the investigation of the anti-reverberation technology of active sonars, as is evidenced by the fact that prediction of the time domain waveform for signals of ocean reverberation can provide data support for the workers devoting themselves to anti-reverberation technology research for active sonars. As the exploitation for human beings toward the ocean expands from the shallow sea to the deep-ocean, it has become a major concern for sonar workers to do research into anti-reverberation technology in the deep-ocean. However, few people at home have done researches into reverberation in the deep ocean, so this thesis investigates the prediction of the time domain waveform of the reverberation in the deep-ocean. On the premise of rich knowledge about the formation of ocean reverberation. Firstly, the ray theory for underwater acoustic propagation as well as the sound scattering in the ocean are discussed. Secondly,combined with time-series modeling method for the underwater acousticians, the waveform prediction method for the deep-ocean reverberation is researched.Considering the difference of geometric configuration between monostatic and bistatic sonar systems, the waveform of monostatic and bistatic reverberation are separated simulated.Two kinds of transmitting pulses of CW and LFM are considered. In order to acquire the complete time domain waveform of deep-ocean reverberation, three different kinds of reverberation waveform are modeled and simulated separately,and then the deep-ocean reverberation waveform is acquired by adding them up linearly.Then the statistic characteristics of reverberation are analyzed and compared with the theoretical values for the waveforms of the three different kind of reverberation as well as the complete deep-ocean reverberation waveform obtained from the prediction. Meanwhile, the statistic characteristics of the reverberation and time-spatial-frequency correlation characteristics of the data acquired from the reverberation experiment are also analyzed, then the results of the processing are discussed brieflyFinally,based on the platform of Lab VIEW virtual instrument,a software is developed to prediction the time domain waveform of reverberation combined with Fortran and Matlab languages. The software could predict the time domain waveform for the surface, seafloor and volume reverberation and complete deep-ocean reverberation in the case of monostatic and bistatic sonar systems, and it is also capable of analyzing the statistic characteristics of predicted waveforms. Through making the input parameter interface independent of the reverberation prediction interface, the complexity was simplified for the prediction interface of the time domain waveform of reverberation, making the interface easy-to-use and artistic.