FEM-Based Study of Acoustic Shadowing Effects on Underwater Acoustic Vector Sensor Due to Nearby Supports

For passive measurements of acoustic signals for oceanographic and military applications, an Acoustic Vector Sensor (AVS) may be used. A PU AVS is a compact sensor that measures a four-dimensional vector quantity of acoustic particle velocity in the water medium along three orthogonal axes and scalar pressure. Its primary purpose is to sense these four components from which the acoustic intensity vector is derived to estimate the Direction of Arrival (DOA) of one or more radiating acoustic sources in the medium. This sensor is deployed in water with the help of a supporting structure of a mother platform. Also, the AVS assembly may be placed inside a protective cage. However, these structures might act as potential obstacles to the propagation of sound waves, thereby corrupting the signals being captured by the AVS and thus reducing the accuracy of the DOA estimation. Understanding these effects is crucial for optimizing the deployment and operation of AVS systems in real-world scenarios. To estimate the impact of acoustic shadowing, we conduct Finite Element Method (FEM) simulations in COMSOL Multiphysics software and validate the findings experimentally. These analyses aid in strategically placing structures alongside the AVS during deployment, ultimately enhancing the accuracy of DOA estimates obtained from the recorded signals.