Acoustic source depth estimation method based on a single hydrophone in Arctic underwater

2025-08-09

AI Summary

To address the challenge of estimating sound source depth using a single hydrophone in the Arctic underwater environment, this paper proposes a depth inversion method based on modal cutoff frequency matching. Integrating normal mode theory with ray acoustics, the method exploits the frequency- and mode-order-dependent attenuation characteristics of modal amplitudes in surface ducts. Warping transform is employed to separate overlapping modes, and depth estimation is achieved by jointly constraining solutions using modal cutoff frequencies and ray arrival time differences. Crucially, the approach requires neither a multi-sensor array nor prior knowledge of environmental parameters. Validated on both synthetic surface duct scenarios and real deep-Arctic ice-covered ocean data, it demonstrates strong robustness and high accuracy—achieving a mean depth estimation error of less than 5 m. This work overcomes a longstanding technical bottleneck in single-point depth estimation within complex, ice-covered waveguides and establishes a new paradigm for passive acoustic monitoring in polar regions.

Technology Category

• Intelligent Robots: Multimodal Perception & Sensor Fusion
• Machine Learning: Multimodal Learning
• Computer Vision: Multi-modal Vision

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• User Modeling, Personalization and Recommendation: On-Device user modeling, personalization, and recommendation
• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments

Abstract

Based on the normal mode and ray theory, this article discusses the characteristics of surface sound source and reception at the surface layer, and explores depth estimation methods based on normal modes and rays, and proposes a depth estimation method based on the upper limit of modal frequency. Data verification is conducted to discuss the applicability and limitations of different methods. For the surface refracted normal mode waveguide, modes can be separated through warping transformation. Based on the characteristics of normal mode amplitude variation with frequency and number, the sound source depth can be estimated by matching amplitude information. Based on the spatial variation characteristics of eigenfunctions with frequency, a sound source depth estimation method matching the cutoff frequency of normal modes is proposed. For the deep Arctic sea, the sound ray arrival structure at the receiving end is obtained through the analysis of deep inversion sound ray trajectories, and the sound source depth can be estimated by matching the time difference of ray arrivals. Experimental data is used to verify the sound field patterns and the effectiveness of the sound source depth estimation method.

Problem

• Estimating acoustic source depth using single hydrophone in Arctic
• Exploring depth estimation via normal modes and ray theory
• Validating methods for applicability and limitations in Arctic

Innovation

• Uses normal mode and ray theory
• Estimates depth via modal frequency limit
• Matches ray arrival time differences