Performance analysis of accelerometer-based array sensors for underwater passive sound navigation and ranging systems

The array sensors commonly used in hull-mounted passive sonar have a structure in which acoustic pressure sensors are mounted on a soft baffle combined with a heavy signal conditioning plate to enhance received signal quality. As an alternative, accelerometers can achieve comparable receiving sensitivity in lightweight configurations. The array gain is improved and platform-induced noise is effectively attenuated due to the inherent high directivity of the sensor. However, to mount these sensors on the platform, it is essential to design an appropriate mounting structure that allows a floating condition to preserve the intrinsic characteristics of the sensors. A quantitative analysis of the vibration sensitivity with respect to the mounting configuration is also necessary. In this study, an accelerometer-based array structure applicable to hull-mounted passive sonar is proposed. Its vibration sensitivity to platform-induced noise and acoustic performance are analyzed. To validate the proposed design, a prototype was fabricated and the acoustic properties were measured in a water tank under varying frequencies. The results verified that the array sensors achieved high array gain and low vibration sensitivity, confirming the suitability of the mounting structure. These observations substantiate the effectiveness of accelerometer-based array sensors for application in hull-mounted passive sonar systems.