Near real-time nautical depth mapping via horizontal optical fibers and distributed acoustic sensing

Safe navigation in ports and waterways subjected to siltation requires nautical depth monitoring. For this purpose, surveying vessels equipped with a zero-offset echo sounder and intrusive point measurements are frequently used. Because these measurements depend on the availability of a surveying vessel and require access to quay walls, such as...

Monitoring tidal water-column changes in ports using distributed acoustic sensing

We show results of of using distributed acoustic sensing (DAS) for continuous relative water-column changes monitoring by relating the oscillating frequencies to measurements of a nearby tidal-station. The oscillations have a great qualitative agreement with the tidal-station, having a period of 12 hours and 25 minutes. No calibration is...

Monitoring shear-stress changes using seismic measurements from controlled sources and ambient noise and optical fibres

Monitoring the nautical depth is vital for the safe passage of water transport. Port authorities worldwide have different navigable depth criteria and use various methods to ensure the safe navigability and manoeuvrability of ships in ports and waterways. These measurements often require a surveying vessel and are limited in repeatability and...

Water-depth estimation using propeller noise by distributed acoustic sensing

This work shows the potential of using DAS for continuous water-depth monitoring by using the difference in acoustic energy in water and mud. The advantage over conventional methods is that our method can be used continuously and remotely, given that there is traffic nearby. Due to the low cost of fibres and the far-reaching dynamic range of...

Continuous monitoring of the depth of the water‑mud interface using distributed acoustic sensing

Purpose<br/><br/>Current surveying techniques used by port authorities to estimate the nautical depth are limited in depth resolution and temporal resolution. Because of this, certain heavily occupied quay walls cannot be optimised in terms of utilisation. Therefore, a permanent continuous measuring system with a higher depth resolution is...

Fluid mud monitoring using optical fibers combined with DAS and DTS

Non-Intrusive Characterization and Monitoring of Fluid Mud: Laboratory Experiments with Seismic Techniques, Distributed Acoustic Sensing (DAS), and Distributed Temperature Sensing (DTS)

In ports and waterways, the bathymetry is regularly surveyed for updating navigation charts ensuring safe transport. In port areas with fluid-mud layers, most traditional surveying techniques are accurate but are intrusive and provide one-dimensional measurements limiting their application. Current non-intrusive surveying techniques are less...