A Co-Localization Algorithm for Underwater Moving Targets with an Unknown Constant Signal Propagation Speed and...

Area of Science:

• Acoustics
• Signal Processing
• Underwater Navigation

Background:

• Underwater acoustic source localization is critical but challenged by unknown signal propagation speed and platform uncertainties.
• Existing methods often struggle with unknown sound speed and systematic platform errors, increasing complexity and cost.

Purpose of the Study:

• To develop a novel, closed-form localization algorithm for underwater mobile acoustic sources.
• To jointly estimate angle of arrival (AOA), time difference of arrival (TDOA), and frequency difference of arrival (FDOA) under challenging conditions.

Main Methods:

• A two-step closed-form algorithm utilizing auxiliary variables to construct pseudo-linear equations for initial estimation.
• Derivation of an exact solution by exploiting the relationship between unknown and auxiliary variables, avoiding iterative processes.

Main Results:

• Accurate estimation of source position, velocity, and sound speed despite unknown parameters and platform systematic errors.
• The algorithm approaches the Cramér-Rao lower bound (CRLB), demonstrating asymptotic optimality.
• Validated effectiveness across various scenarios, outperforming comparative algorithms in simulations.

Conclusions:

• The proposed algorithm effectively addresses key challenges in underwater acoustic localization.
• It offers a computationally efficient, cost-effective solution with reduced platform requirements.
• The method provides a robust and accurate approach for mobile acoustic source tracking.