An Inertial-Type Acoustic Vector Sensor Used in Airborne Sonobuoy

Abstract

An inertial-type acoustic vector sensor (AVS) prototype used as an acoustic directional receiver in the airborne sonobuoy was designed, fabricated and tested. The AVS prototype consists of a hydrophone, a biaxial piezoelectric accelerometer, a magnetic compass, and the related signal-conditioning circuits. Calibration experiments were performed in an acoustic standing wave calibrator. Test results show that the acoustic pressure sensitivity of the hydrophone is –157 dB (0 dB re 1 V/μPa), and the biaxial accelerometer provides equivalent acoustic pressure sensitivities of –166 and –167 dB (0 dB re 1 V/μPa) at 100 Hz, respectively. The operating frequencies of the AVS prototype extend from 5 Hz to around 2.5 kHz, and the equivalent self-noise pressure levels are less than 45 dB/√Hz at 1 kHz.