Robust Detection of Underwater Target Against Non-Uniform Noise With Optical Fiber DAS Array
Abstract
The detection of underwater targets is severely affected by the non-uniform spatial characteristics of marine environmental noise. Additionally, the presence of both natural and anthropogenic acoustic sources, including shipping traffic, marine life, and geological activity, further complicates the underwater acoustic landscape. Addressing these challenges requires advanced underwater sensors and robust signal processing techniques. In this paper, we present a novel approach that leverages an optical fiber distributed acoustic sensing (DAS) system combined with a broadband generalized sparse covariance-fitting framework for underwater target direction sensing, particularly focusing on robustness against non-uniform noise. The DAS system incorporates a newly developed spiral-sensitized optical cable, which significantly improves sensitivity compared to conventional submarine cables. This innovative design enables the system to capture acoustic signals with greater precision. Notably, the sensitivity of the spiral-wound sensitized cable is around -145.69 dB re: 1 rad / (uPa*m), as measured inside the standing-wave tube. Employing simulations, we assess the performance of the algorithm across diverse noise levels and target configurations, consistently revealing higher accuracy and reduced background noise compared to conventional beamforming techniques and other sparse techniques. In a controlled pool experiment, the correlation coefficient between waveforms acquired by the DAS system and a standard hydrophone reached 0.973, indicating high fidelity in signal capture.
The following analysis is generated by AI and may contain errors. It is separate from the authors’ abstract and is not peer review.
Research summary
The paper presents a novel approach to underwater target detection using a robust optical fiber DAS system, significantly improving sensitivity and accuracy in complex noise environments. The integration of advanced signal processing techniques enhances the potential for practical applications in marine monitoring and exploration.
Methodology
The paper introduces a novel optical fiber distributed acoustic sensing (DAS) system that utilizes a spiral-sensitized optical cable, significantly enhancing sensitivity for underwater target detection in non-uniform noise environments. The methodology combines this innovative sensor design with a broadband generalized sparse covariance-fitting framework, specifically the $q$-SPICE algorithm, which adapts to the challenges posed by non-uniform noise. The integration of a grid refinement strategy to tackle off-grid direction of arrival (DOA) estimation is a noteworthy contribution, allowing for improved resolution in DOA estimates. The approach is well-structured, with clear delineation of the proposed methods and their theoretical underpinnings.
Results & evaluation
The experimental validation is robust, featuring both controlled tank experiments and real-world lake deployments. The correlation coefficient of 0.973 between the DAS system and a standard hydrophone indicates high fidelity in signal capture. The experiments comprehensively assess the performance of the proposed method across various noise levels and target configurations, demonstrating superior accuracy and reduced background noise compared to conventional techniques. The results are well-presented, with detailed figures and data supporting the claims made in the paper.
Reproducibility
While the paper provides a thorough description of the methodology and experimental setup, it lacks specific implementation details necessary for full reproducibility, such as code availability or data sharing. The absence of a project URL further limits the ability of other researchers to replicate the findings or build upon this work.
Limitations
The paper acknowledges the challenges posed by environmental noise and cable coupling variability, which may affect system reliability. Additionally, the reliance on simulations and controlled experiments may not fully capture the complexities of real-world underwater environments. The performance under extreme noise conditions or highly dynamic scenarios remains to be thoroughly evaluated.
Broader impact
This research has significant implications for underwater monitoring applications, including marine resource exploration, environmental monitoring, and security. The advancements in DAS technology and signal processing techniques could lead to more effective and cost-efficient underwater acoustic sensing solutions, potentially transforming practices in marine science and engineering. The paper presents a novel approach to underwater target detection using a robust optical fiber DAS system, significantly improving sensitivity and accuracy in complex noise environments. The integration of advanced signal processing techniques enhances the potential for practical applications in marine monitoring and exploration.
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