Passive source depth estimation using beam intensity striations of a horizontal linear array in deep water

Area of Science:

• Acoustics
• Signal Processing
• Oceanography

Background:

• Source depth estimation is crucial for passive sonar systems, particularly with horizontal linear arrays (HLAs).
• Accurate depth estimation is challenging due to complex acoustic propagation in deep water.

Purpose of the Study:

• To propose an efficient two-step scheme for source depth estimation using HLAs in deep water.
• To utilize constructive and deconstructive striation patterns from direct (D) and sea surface reflected (SR) arrivals.

Main Methods:

• Horizontal source-array ranges derived from solid angle estimates via subarray beamforming.
• Cost functions developed to match measured and modeled beam intensity striations.
• Ray theory used for modeling D-SR time delay templates to mitigate spatial smoothing effects.

Main Results:

• Investigated applicability in deep water via Monte Carlo simulations with varying subarray partitioning.
• Analyzed performance degradation from limited source range, striation distortion, and range errors.
• Validated the method's effectiveness using two experimental datasets.

Conclusions:

• The proposed two-step scheme effectively estimates source depth using interference striations from HLAs.
• The method demonstrates robustness and accuracy in deep water conditions.
• The approach offers a computationally efficient solution for passive sonar applications.