A High-Precision Underwater Acoustic Source Localization System Based on ϕ-OTDR Technique

This paper proposes and demonstrates a high-precision underwater acoustic source localization system based on the phase-sensitive optical time-domain reflectometry (ϕ-OTDR) technique. The system utilizes a highly sensitive mandrel hydrophone structure, which is fabricated by using the 3D printing technology. The design offers low manufacturing costs and short production cycles. This study systematically investigated and compared the impact of the sensing element number on the localization accuracy. Ultimately, nine hydrophone elements were employed to achieve high-precision underwater localization. In terms of localization algorithm, the system used the time-of-arrival method combined with the Chan algorithm to locate discrete underwater acoustic sources. Meanwhile, the cross-correlation algorithm was employed for continuous source localization. The final localization results show an average overall (the root mean square of all the three axes) localization error of 1.3 cm for discrete underwater signals and 4.9 cm for continuous signals. These findings highlight the significant potentials of the proposed system in fields such as ocean exploration, autonomous underwater vehicle navigation, and underwater oil pipeline safety monitoring.