River bed classification using multi-beam echo-sounder backscatter data

The Netherlands form the delta for some of the major river systems of Europe, comprising the Rhine, the Meuse, the Scheldt and the Eems. These rivers are valuable parts of national and international ecological networks and are of high economic importance. A minimum depth should be guaranteed to keep the rivers navigable. This depth depends not...

Monitoring of rapid sand filters using an acoustic imaging technique

A novel instrument is developed to acoustically image sand filters used for water treatment and monitor their performance. The instrument consists of an omnidirectional transmitter that generates a chirp with a frequency range between 10 and 110 kHz, and an array of hydrophones. The instrument was extensively tested in a lab before being...

Aircraft Noise Simulation for a Virtual Reality Environment

Aircraft noise annoyance predictions based on traditional tools lack fidelity when modelling a single aircraft flyover. For evaluating annoyance of new procedures, different aircraft types or changing atmospheric conditions, a new modelling approach is necessary. A research effort has been initiated to develop a toolchain that links each of the...

Using MBES backscatter strength measurements for assessing a shallow water soft sediment environment

Shallow water naval operations require detailed knowledge of the environmental characteristics. In this context, the BP’07 experiment was carried out in the Mediterranean Sea, south-east of Elba Island, in 2007. Measurements that were taken during this experiment employ a large set of sensors, thereby providing all information required to fully...

A model-based method for reducing the sound speed induced errors in multi-beam echo-sounder bathymetric measurements

We present a method for accurately estimating the bathymetry from multi-beam echo-sounder (MBES) travel-time measurements in environments with large variations in the water column sound speeds (both temporally and spatially). In this type of environments the water column sound speeds at the time of the MBES transmission are often not known,...

A highly versatile autonomous underwater vehicle with biomechanical propulsion

An autonomous underwater vehicle with a biomechanical propulsion system is a possible answer to the demand for small, silent sensor platforms in many fields. The design of Galatea, a bio-mimetic AUV, involves four aspects: hydrodynamic shape, the propulsion, the motion control systems and payload. The shape of the hull is based on a modified...

Inverting for bottom parameters in shallow-water soft sediment environments using MBES backscatter strength

Shallow water naval operations require detailed knowledge of the environmental properties. In addition to parameters such as water depth, knowledge about the sediment properties is of high importance for a wide range of operations. In this context, the MREA BP'07 experiment was carried out in the Mediterranean Sea in 2007. Measurements employed...

An efficient method for reducing the sound speed induced errors in multibeam echosounder bathymetric measurements

Nowadays extensive use is made of multibeam echosounders (MBES) for mapping the bathymetry of sea- and river-floors. The MBES is capable of covering large areas in limited time by emitting an acoustic pulse along a wide swathe perpendicular to the sailing direction. The angle and the corresponding two-way travel-time of the received signals are...

Using multi-beam echo sounder backscatter data for sediment classification in very shallow water environments

In a recent work described in Ref. [1], an angle-independent methodology was developed to use the multi-beam echo sounder backscatter (MBES) data for the seabed sediment classification. The method employs the backscatter data at a certain angle to obtain the number of sediment classes and to discriminate between them by applying the Bayes...

The potential of inverting geo-technical and geo-acoustic sediment parameters from single-beam echo sounder returns

Seafloor characterization is important in many fields including hydrography, marine geology, coastal engineering and habitat mapping. The advantage of non-invasive acoustic methods for sediment characterization over conventional bottom grabbing is the nearly continuous versus sparse sensing and the enormous reduction in survey time and costs....

Using the Mbes for classification of riverbed sediments

A comparison between modeled and measured high frequency bottom backscattering

High frequency scattering measurements for mussel bed characterisation

Correcting bathymetry measurements for water sound speed effects using inversion theory

High-frequency multibeam echosounder classification for rapid environmental assessment

Estimating the frequency dependent behavior of marine sediment sound speeds using low frequency aircraft sound

Studying converted waves in shallow marine environment