Resolution dependence of rough surface scattering using a power law roughness spectrum

Area of Science:

• Ocean acoustics
• Seafloor characterization
• Sonar signal processing

Background:

• Modern sonar systems utilize broadband pulses and long arrays for enhanced resolution.
• Understanding the impact of high-resolution sonar on seafloor scattering measurements is crucial.

Purpose of the Study:

• To define and investigate the broadband scattering cross section (σbb) for high-resolution sonar.
• To analyze the dependence of σbb and scintillation index (SI) on resolution for rough seafloor models.

Main Methods:

• Integral equations and Fourier synthesis were employed to model scattering from 1D rough surfaces.
• The study analyzed surfaces with power-law spectra in a backscattering geometry.

Main Results:

• No resolution dependence was found for the broadband scattering cross section (σbb).
• The scintillation index (SI) increases with higher resolution, lower grazing angles, and increased spectral strength.
• Incoherently averaged frequency-domain scattering cross section showed negligible bandwidth dependence.

Conclusions:

• While seafloor slopes contribute to intensity fluctuations, multiple scattering and shadowing effects also play a significant role.
• The findings provide insights into quantitative seafloor acoustic scattering under high-resolution sonar conditions.