Estimation of Submarine Cable Location Using Optical-Fiber Distributed Acoustic Sensing Combined With Ship-Borne Sound Sources

Abstract

Ascertaining the precise locations of submarine cables is crucial to their maintenance and to monitoring marine environments using equipment reliant on such cables. Traditional detection methods such as underwater robots equipped with optical, acoustic, and electromagnetic sensors have several limitations, including a short detection range, limited applicability, and low operational efficiency. Distributed acoustic sensing (DAS) is an emerging technology that uses optical-fiber (OF) cables as dense acoustic sensor arrays to detect submarine cable routes. Here, we describe a method to locate submarine cables that combines DAS with ship-borne sound sources. The spatial location of the cable is determined by connecting the coordinates of each DAS channel, which are jointly estimated by the Chan and snow ablation optimizer algorithms. Furthermore, a blind signal evaluation and selection method is used to improve the correlation between DAS demodulated signals in complex marine environments, thereby substantially reducing the estimation errors of the DAS channels. Localization results for a ∼5 km length of submarine cable closely matched the actual route, with an average error of ∼9.53 m. The results of this study demonstrate the potential of DAS-instrumented OF for detecting long-distance submarine cable routes.