Spread spectrum orthogonal time-frequency space underwater acoustic communication based on second-order differential encoding dataset

The sound field in the ocean is a vector field, and its vector characteristics can be obtained by a single vector hydrophone. This paper focuses on the vector characteristics of the sound field, analyzing the coherence function, energy component ratio, and phase spectrum of the signal received by a single vector hydrophone. The research aim is to lay a research foundation for applying the vector characteristics of the sound field to target detection and recognition. Simulation results show that when the signal-to-noise ratio is -10 dB, the total coherence function of the sound field is approximately 0.5. At this time, the coherence spectrum of the sound field is approximately equal to the diffusion spectrum, and the target quadrant can be identified based on the phase difference of the sound field. The results of the anechoic tank and sea trials show that under background noise conditions, the coherence function value is usually less than 0.2, except for certain specific frequency points. Detection using the coherence spectrum can improve the signal-to-noise ratio by approximately 8 dB. The overall coherence function of the sound field, the total sound field spectrum, and the coherence spectrum all show obvious interference from moving targets. This file is the database of the article.