Vector sensor cross-spectral density for surface noise in a stratified ocean-Formulas for arbitrary sensor geometries

Area of Science:

• Acoustics
• Signal Processing
• Oceanography

Background:

• Cross-spectral density calculations are crucial for analyzing noise fields using vector sensors.
• Existing methods are limited to orthogonal sensor orientations, hindering analysis for arbitrary configurations.
• Vector sensors measure both acoustic pressure and particle velocity, providing richer directional information.

Purpose of the Study:

• To develop general equations for cross-spectral density between two vector sensors with arbitrary orientation and separation.
• To address the limitations of existing methods for non-orthogonal sensor configurations.
• To enable improved analysis of directional noise fields in various aquatic environments.

Main Methods:

• Development of analytic solutions for cross-spectral density for vector sensors with arbitrary orientations.
• Derivation of special case solutions for azimuthally symmetric environments and orthogonal velocity sensors.
• Utilizing Green's functions for pressure and orthogonal particle velocity components within a general propagation model.

Main Results:

• General equations for vector sensor cross-spectral density applicable to arbitrary orientations and separations were derived.
• Analytic solutions for special cases were developed and validated against previous findings.
• Simulations demonstrated the impact of sensor geometry and propagation conditions on array performance in directional noise.

Conclusions:

• The developed equations are suitable for diverse propagation models and sensor configurations.
• Vector sensor beamforming provides significant performance gains in directional noise fields compared to isotropic noise.
• This work enhances the capability to analyze and mitigate acoustic noise in underwater environments.