Passive matched sound intensity localization using a deep ocean-bottom seismograph in the direct-arrival zone

Area of Science:

• Ocean acoustics
• Signal processing
• Underwater acoustics

Background:

• Accurate depth and range estimation are vital for underwater target localization.
• Traditional methods using ocean bottom seismographs struggle with elevation angle accuracy, impacting sonar performance.
• Existing matched sound intensity processing (MSIP) is sensitive to elevation angle errors.

Purpose of the Study:

• To introduce a novel multidimensional matched sound intensity processing (MD-MSIP) method for improved underwater target localization.
• To overcome the limitations of elevation angle estimation in direct-arrival zone acoustic processing.
• To enhance the accuracy and robustness of range and depth estimation for underwater targets.

Main Methods:

• Proposed the multidimensional matched sound intensity processing (MD-MSIP) method.
• MD-MSIP jointly estimates initial range, target speed, closest approach range, and source depth.
• This approach bypasses the need for explicit elevation angle calculation in replica field generation.

Main Results:

• MD-MSIP achieves relative errors within 10% for depth and 20% for range estimation.
• The method enables target trajectory estimation using azimuth information.
• MD-MSIP demonstrates enhanced robustness against sound speed profile mismatches by utilizing low-frequency signal characteristics.

Conclusions:

• MD-MSIP offers a significant advancement in underwater acoustic target localization.
• The method effectively mitigates errors associated with elevation angle estimation.
• MD-MSIP provides a more reliable and robust solution for sonar applications in complex underwater environments.