Deep water acoustic range estimation based on an ocean general circulation model: Application to PhilSea10 data.

Area of Science:

• Oceanography
• Acoustics
• Signal Processing

Background:

• Accurate acoustic transmitter-receiver range estimation is critical for deep ocean operations.
• Existing methods face challenges due to complex oceanographic conditions and signal propagation effects.

Purpose of the Study:

• To identify general characteristics of reliable methods for estimating absolute acoustic range in the deep ocean.
• To evaluate the performance of novel ranging techniques using experimental data and ocean model simulations.

Main Methods:

• Utilized data from the PhilSea10 experiment with a fixed acoustic transmitter and multiple receiver depths.
• Compared observed acoustic records with synthetic records generated by the Hybrid Coordinate Ocean Model (HYCOM).
• Developed and tested ranging methods involving amplitude normalization, travel time measurement, and waveform rejection.

Main Results:

• Over 8900 transmissions analyzed over three days revealed statistical variations in range errors.
• Reliable methods de-emphasize signal components less likely to be reproduced by synthetic models, such as arrival amplitudes and the 'finale' of acoustic records.
• All proposed methods, based on the time and path-averaged HYCOM model, provided reliable range estimates, with one specific method performing best.

Conclusions:

• The developed acoustic ranging methods offer reliable deep ocean range estimations.
• The principles are transportable to diverse deep water environments, enhancing underwater acoustic applications.
• Focusing on reproducible signal characteristics is key to improving ranging accuracy.