A business case approach for maritime mine countermeasures capability replacement

Sea mines are cost-effective weapons to disturb sea traffic and deny access to sea. Many nations across the world have sea mines and are capable to deploy them. Mine stocks globally contain a wide variety of mine types and the technology of sea mines is still developing further. In addition, the environments in which sea mines may be encountered...

Time-Evolving Acoustic Propagation Modeling in a Complex Ocean Environment

During naval operations, sonar performance estimates often need to be computed in-situ with limited environmental information. This calls for the use of fast acoustic propagation models. Many naval operations are carried out in challenging and dynamic environments. This makes acoustic propagation and sonar performance behavior particularly...

Time-Evolving Acoustic Propagation Modeling in a Complex Ocean Environment

During naval operations, sonar performance estimates often need to be computed in-situ with limited environmental information. This calls for the use of fast acoustic propagation models. Many naval operations are carried out in challenging and dynamic environments. This makes acoustic propagation and sonar performance behavior particularly...

SAKAMATA: Managing the risk of sonar sound on marine mammals

SAKAMATA is a risk assessment and mitigation tool developed by TNO and used by the Royal Netherlands Navy. It supports the user in planning and carrying out active sonar operations in an environmentally responsible way. Recently, a new version has been developed, which makes it possible to quantify the number of marine mammals affected, taking...

Experimental evaluation of a dedicated underwater loudhailer for diver warning

To improve port security capability there is a need for systems for detection, warning and deterrence of unwanted divers in harbour environments. In a complex environment such as a harbour, these topics present challenging problems and as such are subject to research and development. Already a few dedicated systems are commercially available,...

Thin line array for littoral ASW

Experimental evaluation of a dedicated underwater air gun for diver deterrence

To improve port security capability there is a need for systems for detection, warning and deterrence of unwanted divers in harbour environments. In a complex environment such as a harbour, these topics present challenging problems and as such are subject to research and development. Already a few dedicated systems are commercially available on...

Range-dependent sonar performance modelling during Battlespace Preparation 2007

Spatial and temporal variations in sound speed can have substantial effects on sound propagation and hence sonar performance. Operational oceanographic models can provide forecasts of oceanographic variables as temperature, salinity and sound speed up to several days ahead. These four-dimensional forecasts can be used as input for a sonar...

At-sea Real-time Coupled Four-dimensional Oceanographic and Acoustic Forecasts during Battlespace Preparation 2007

Systems capable of forecasting ocean properties and acoustic performance in the littoral ocean are becoming a useful capability for scientific and operational exercises. The coupling of a data-assimilative nested ocean modeling system with an acoustic propagation modeling syste was carried out at sea for the first time, within the scope of...

Acquisition concepts for MIMO sonar

The objective of sonar processing is to enhance the signal received from the target with respect to noise or clutter in order to enhance detection, classification and localisation. Range-bearing information is commonly obtained through beamforming and matched-filtering of data acquired with a densely sampled detector array. The source sampling,...

Frequency-dependent effects of the Atlantic meridional overturning on the tropical Pacific Ocean

Using the ECHAM5/MPI-OM model, we study the relation between the variations in the Atlantic meridional overturning circulation (AMOC) and both the Pacific sea surface temperature (SST) and the El Niño-Southern Oscillation (ENSO) amplitude. In a 17-member 20C3M/SRES-A1b ensemble for 1950–2100 the Pacific response to AMOC variations on different...