Study On The Schemes And Signal Processing Of The Intelligent Underwater Acoustic Decoy With The Transmitting-while-receiving Function Of Class One

The intelligent torpedo with advanced signal processing performances has become a major threat to naval vessels, but most of existing underwater acoustic decoy systems can not confront the intelligent torpedo effectively because of technique decline, so the intelligent underwater acoustic decoy systems with the transmitting-while-receiving function should be designed, developed and constructed. The transmitting-while-receiving function of class one means the underwater acoustic decoy can realize the torpedo detection and early warning when it's transmitting the simulated ship radiated noise, and the key technique is the detection and estimation of the active homing signal of the torpedo in the simulated ship radiated noise and its reverberation.In order to realize the torpedo detection and early warning and, then, the transmitting-while-receiving function of class one, the simulated ship radiated noise and its reverberation should be restrained effectively. This restraint could be realized making use of the combined direction of the single vector sensor, so two schemes of the intelligent torpedo system with the transmitting-while-receiving function of class one based on the vector sensor are proposed in this paper, and the signal-to-noise ratio of the receive signal in the towed decoy scheme is estimated.Because of the lack of the torpedo active homing signal's prior knowledge, the adaptive signal processing methods are used for the detection and estimation in the schemes proposed in this dissertation. First, the properties of the zero crossing frequency estimator, the adaptive line enhancer (ALE) and the adaptive notch filter based on the least mean-square error (LMS) rule are introduced and analyzed briefly in theory. Then, there is a study on numerical simulations about their algorithms. Through the numerical simulations, the frequency estimation property of the zero crossing frequency estimator, and the filtering property and the signal parameters estimation property of the adaptive line enhancer (ALE) and the adaptive notch filter are studied and validated relatively comprehensively and thoroughly, and their parameters are optimized.The results of theory and simulation prove that the torpedo active homing signal detection and estimation can be realized by the signal processing methods used in this dissertation in the SNR rang estimated, so the scheme of the towed underwater acoustic decoy system with the transmitting-while-receiving function of class one based on the vector sensor proposed in this dissertation could be hopefully realized.