Covert Underwater Acoustic Communication Based On Ship Radiation Noise

In recent years,with the development of marine resources and the need for national defense security,underwater acoustics communication technology has become one of the hotspots in the field of underwater acoustic engineering.It has developed rapidly.In addition to communication rate,reliability,etc.The hidden requirements for underwater communication systems are increasing.Traditional concealed underwater acoustic communication technology reduces the signal-to-noise ratio by extending the power spectrum of the communication signal.Concealing the communication signal under the noise of the marine environment to achieve the purpose of concealment.Different,camouflage covert communication is by simulating the sound of marine life or artificially synthesizing marine environmental noise.When the communication signal is detected,let the inspectors treat it as a real ocean noise and exclude it.Implement covert communication different from the camouflage concealed underwater acoustic communication technology that mimics the sound of marine life,this paper selects the ship's radiation noise in the noise caused by ocean people as the research object.To develop research on camouflage underwater acoustic communication technology for shipborne radiated noise camouflage expand the field of camouflage communication research.The specific work of this paper is as follows:1.Analyze the characteristics of ship radiation noise.By observing and analyzing the power spectrum and time-frequency diagram of the ship's radiated noise,the noise signal suitable for camouflage covert communication is selected.Pseudo-random sequence analysis.In order to improve the anti-interference ability of the system,it is proposed to use a pseudo-random sequence to modulate source information before camouflage modulation.2.A kind of imitation ship noise camouflage concealed underwater acoustic communication technology based on audio steganography is proposed.The technology is intended to use two audio steganography methods:DFT audio steganography and DWT-DCT audio steganography,Modulating source information to ship radiated noise,to achieve covert communication.Simulation experiments verify the feasibility of the proposed method,and analyze the performance of the two methods from three aspects:concealment,robustness and communication rate.3.A ship's radiated noise is used to cover the spread spectrum signal camouflage concealed underwater acoustic communication technology.According to the masking characteristics of the human auditory system,the spread spectrum communication signal generated by information modulation is hidden in the ship radiated noise signal with its frequency range,and the receiving end uses an adaptive filter to extract the spread spectrum signal and demodulate it.Implement covert communication.Simulation and pool experiments verify the feasibility of the method.In summary,after fully analyzing the ship's radiation noise,two methods of imitation ship noise camouflage concealed underwater acoustic communication and ship noise concealing spread spectrum signal camouflage concealed underwater acoustic communication based on audio steganography are proposed and verified by simulation or pool test.Its feasibility and performance are analysed.