Depth estimation of objects with vector vertical array

The existing vibration and noise reduction technology still can not eliminate the radiated noise in Very Low Frequency band, so underwater targets will usually have explicit line spectrum. In order to distinguish surface and underwater targets effectively, an approach was derived, which utilized reactive component signum of the pressure and horizontal velocity cross spectra of vertical vector receiver array. This depth estimation technology can be used in the shallow ocean Very Low Frequency (VLF) acoustic environment with shifty sound velocity. Under the condition of two normal modes, the relationship of water depth and detected frequency range was presented in this paper. Simulation under different sound velocity environment was analyzed also. The signal data collected in the Qiandao Lake water acoustic experiment were analyzed. The estimation results are in good agreement with the measured, and the accuracy rate is more than 80%.