Waveform design of camouflage underwater acoustic communication and its application

A camouflage underwater acoustic communication waveform is designed. The spread spectrum digital watermarking is added in the complex logarithmic spectrum of dolphin whistles to carry information. The PEAQ algorithm is used to compute the similarity in auditory aspects and the correlation coefficient is used to compute the similarity in waveform, which are as two metrics to evaluate the camouflage effect. In addition, a self-synchronization method that combines the correlation and OMP algorithm is proposed and hence the frame structure of transmitted signal could be designed as same as the origin whistles, which would improve the camouflage performance. The validity of the proposed method is verified by the computer simulation and sea experiment. The grade of PEAQ is higher than -0.5 and the correlation coefficient is higher than 0.98, which ensure good camouflage performance in waveform and auditory aspects.The communication distance in experiment is 5 km. The bit error rate with a single array element is less than 10-3 and the bit error rate with the 32 array elements is 0. Furthermore, the robustness of the communication system is improved by using the vertical time reversal equalization technique.