Abstract:

In practical applications, the current ocean internal wave detection technology has large errors, and is significantly affected by the marine environment, and cannot be identified independently. In view of these problems, this study proposes a monitoring method for ocean internal wave early warning based on vector field processing. This method is based on the combined information processing of sound pressure and vibration velocity, and uses the three-dimensional information of the sound field picked up by the ultra-low frequency vector hydrophone. The time-space-frequency three-dimensional tracking and locking of non-cooperative targets can be carried out in the complex ocean background noise field according to the azimuth estimation algorithm. The arrival of internal wave causes the change of the three-dimensional sound velocity profile. The fluctuation of the sound field will lead to the change of the acoustic energy flow intensity of the target signal source. This method realizes the monitoring and prediction of ocean internal waves based on the abnormal jump of the vertical grazing angle caused by the channel distortion of the target signal in the internal wave space. The simulation results show that the vertical grazing angle fluctuates slightly in a normal environment, and the range of change is small. When the internal wave strikes, the grazing angle changes strongly, and the maximum deflection can be abruptly changed to a negative angle, which proves the effectiveness of the method.

Key words: vector hydrophone, azimuth estimation, acoustic energy flow, glancing angle, complex sound intensity device, sound velocity profile, three-dimensional tracking, internal wave