Double frequency narrow directivity technology with single acoustic vector sensor

The single acoustic vector sensor performs better than traditional scalar hydrophone in small sonar system.However,its natural directivity is not sharp enough,and the -3dB beamwidth is about 90 degrees,so it cannot be used to distinguish multi_targets commonly.This study was conducted to decrease the directivity beamwidth of a single vector sensor.The instantaneous acoustic energy flow,which is the product of acoustic pressure and particle,consists of the base_frequency part and double_frequency part.The double_frequency part also has the information of base band with narrow beamwidth.With the double_frequency narrow directivity method described in this paper,emulation calculations indicate that the new directivity -3dB beamwidth is about 26 degrees.This method gives the single vector sensor the basic resolving ability of double_targets.