The Study Of Tri-axis Capactive Vector Hydrophone

With so many excellences such as low profile,light weight,high sensitivity, wide bandwidth,good directionality,the vector hydrophone has many advantages in sonar system,sonobuoy,tow array,and solving cyclically ambiguous.And there is a lot of potential still need to be developed,so new kinds of sensor will be widely used in the development of vector hydrophone.Base on the acoustics theory,the measuring method of a kind of sphere, resonant-column vector hydrophone has been researched,and the velocity pickup condition for particle velocity hydrophone also been analyzed.The theory for the designing of vector hydrophone and the constrain condition are obtained.The paper adopts the capacitive accelerometer as the vector channel,and the measuring method of capacitive accelerometer is analyzed.With the character of low amplitude of underwater particle,the finite-element software-ANSYS is applied to design the sensitive element of the accelerometer.The result of the designed three-dimensional sensitivity are respective as 0.12pF/g,0.12pF/g and 0.116pF/g.And the sample is presented by MEMS technology.A tri-axis vector hydrophone with a diameter of 64ram was constructed and measured in the standing wave filed,having an essentially flat response between 0～500Hz with three-dimensional sensitivity respectively as-201 dB,-201 dB,-200dB (0dB=1V/μPa,500Hz ).The average resolving power of the directivity is bigger than 20dB,and sensitivity of the pressure channel is-202dB.