Navigating the Depths: Pioneering water depth measurements through distributed acoustic sensing

Abstract

Maritime transport facilitates close to 80 % of global trade, standing as an unparalleled cornerstone in international commerce. Projections herald a further increase in maritime activity, due to the low carbon footprint and cost-effectiveness, elevating the need for ensuring navigational safety within ports and waterways. At the heart of safe maritime navigation lies the pivotal concept of maintaining adequate nautical-depth, a threshold where a ship’s keel encounters navigational constraints. However, this necessity inherently demands incessant monitoring and recurring dredging operations, resulting in high costs amounting to millions of euros and, contributing significantly to carbon emissions. These factors underscore an urgent call for optimization of monitoring the nautical-depth to reduce monitoring and dredging costs, and increase marine navigational safety.
Presently, common methods for nautical-depth monitoring rely heavily on acoustic echo sounders, rooted in dated methodologies with limited innovation over nearly a century. Acoustic echo sounders measure the two-way travel time of sound pulses, assuming a known propagation velocity of the acoustic energy. However, accurately approximating the pressure-wave velocity in shallow marine environments poses challenges due to variations in temperature and salinity among different water layers, leading to depth measurement inaccuracies. Furthermore, this method is limited by vessel availability and requires access to quay walls, often occupied by loading or unloading ships....