Underwater Sound Source Localization Based on Passive Time-Reversal Mirror and Ray Theory

Area of Science:

• Acoustics
• Oceanography
• Signal Processing

Background:

• Underwater acoustic source localization is crucial for various applications.
• Passive time-reversal mirrors (TRMs) offer a promising approach for acoustic detection.
• High-frequency (3-7 kHz) sound propagation in water presents unique challenges.

Purpose of the Study:

• To evaluate the performance of a passive time-reversal mirror (TRM) combined with acoustic ray theory for localizing underwater sound sources.
• To assess the accuracy of the proposed localization method in controlled (towing tank) and real-world (ocean) environments.
• To identify sources of error and suggest improvements for underwater acoustic localization.

Main Methods:

• Utilized a passive time-reversal mirror (TRM) with four hydrophones on a floating buoy.
• Employed the BELLHOP ray-tracing code to compute acoustic transfer functions.
• Convolved time-domain transfer functions with time-reversed received signals to reconstruct the pressure field.

Main Results:

• The TRM successfully localized underwater sound sources with high accuracy.
• Distance deviations between estimated and actual source locations were predominantly less than 2 meters, even at ranges up to 1600 meters.
• Depth estimation errors were identified as the primary source of inaccuracy.

Conclusions:

• The passive TRM combined with acoustic ray theory provides an effective method for high-frequency underwater sound source localization.
• The system demonstrates robust performance in both tank and ocean tests.
• Future improvements can be achieved by increasing the number of TRM elements and their apertures to enhance depth estimation accuracy.