Localization error analysis for near-field hydro-acoustic detection with distributed fiber acoustic sensing

Hydro-acoustic localization based on distributed fiber acoustic sensing (DAS) technology has made great progress recently, becoming a hot spot for its unique advantages. Different from nodal transducers, the unique DAS response is the spatial integral of the acoustic wave over a gauge length, in the near-field condition. The distinctive response mechanism introduces specific localization errors with conventional array signal processing (ASP) methods for hydro-acoustic detection. A detailed error analysis focusing on the integral response of DAS is performed to explore its effect on localization accuracy. Theoretical modeling and simulations are conducted to verify the errors caused by the unique DAS detection aperture and cable shape distortion. Experimental verifications further demonstrate the impact of these factors on hydro-acoustic localization. This work is expected to lay a theoretical foundation and promote further development for underwater high-precision target localization technology with DAS.