Forward scatter target strength extraction in a marine environment (L)

Area of Science:

• Ocean acoustics
• Underwater acoustics
• Scattering theory

Background:

• Measuring forward scattering in underwater environments is challenging due to strong source signal interference.
• Spherical shells are common underwater targets, and understanding their acoustic scattering properties is important for various applications.

Purpose of the Study:

• To accurately measure the forward scattered target strength of a spherical shell on the seafloor.
• To develop and validate a signal processing technique for isolating forward scattered acoustic waves.

Main Methods:

• Utilized a 48-meter rail system with a moving receiver in the Gulf of Mexico.
• Employed a wavenumber filter to effectively remove the dominant incident acoustic wave from received signals.
• Positioned the spherical shell target midway between the acoustic source and the receiver array.

Main Results:

• Successfully obtained the forward scattered target strength of the spherical shell.
• The measured results showed favorable agreement with predictions from numerical models.
• Demonstrated the efficacy of the wavenumber filtering technique in overcoming source signal interference.

Conclusions:

• The developed wavenumber filtering method is effective for measuring forward scattering in the presence of strong incident waves.
• Accurate forward scattered target strength measurements of underwater objects are achievable with advanced signal processing.
• This technique has implications for underwater acoustic target identification and characterization.