An Underwater Source Localization Method Using Bearing Measurements.

Area of Science:

• Acoustics
• Signal Processing
• Underwater Navigation

Background:

• Angle-of-arrival (AOA) measurements are crucial for underwater acoustic localization.
• Traditional methods often require both azimuth/elevation and range data, limiting applications where range is unavailable.
• Ultra-Short Baseline (USBL) systems commonly use bearing measurements, but lack closed-form solutions without range.

Purpose of the Study:

• To develop a closed-form solution for underwater acoustic localization using solely bearing measurements.
• To address the limitations of traditional methods that require range information.
• To enhance positioning accuracy in scenarios with limited or no range data.

Main Methods:

• Derived a pseudo-linear measurement model linking source position and bearing measurements.
• Established a weighted least-squares optimization equation incorporating multiple constraints.
• Employed semidefinite programming (SDP) for an initial solution, followed by a bias compensation method.

Main Results:

• Numerical simulations demonstrated performance approaching the Cramer-Rao lower bound (CRLB).
• Field tests confirmed the method's ability to locate sources without range information.
• The proposed method achieved superior positioning accuracy compared to existing techniques.

Conclusions:

• The developed method provides an effective solution for underwater acoustic localization using only bearing measurements.
• It overcomes the range dependency of traditional methods, offering broader applicability.
• The technique achieves high accuracy, validated by simulations and field tests.