The Underwater Technology research area supports the Swedish Armed Forces’ capability development in both the short and long term, including materiel supply in the underwater domain.

The work covers maritime surveillance and warning systems for submarines, surface vessels, and unmanned platforms, as well as deployable and fixed underwater systems. Research is also conducted on underwater communications, the environmental impact of underwater noise, the management of underwater signatures, underwater weapons, and underwater countermeasures.

The primary focus is Sweden’s immediate neighbourhood, above all the Baltic Sea region, but the North Sea area is also taken into account. The principal clients are the Swedish Armed Forces and the Swedish Defence Materiel Administration (FMV).

Underwater Acoustics

Within underwater acoustics, we study sound propagation under water, with particular focus on the Baltic Sea’s complex conditions. This work is carried out using both experimental methods and through modelling.
Experimental research is conducted in laboratory environments, where FOI’s tank laboratory in Kista is a central resource, and through extensive sea trials in the Baltic Sea. The experimental work is supported by a modelling group in which a broad range of computational methods is developed and applied to many different types of problems.
Around 30 engineers and researchers work in underwater acoustics, roughly half of whom hold PhDs.

Electromagnetics

The marine electromagnetics research area examines the magnetic and electric signatures emitted by different platforms and by the surrounding environment. These signatures can be exploited by underwater systems for surveillance, detection, classification, and target tracking, which is why we develop numerical and physical models of electromagnetic wave propagation.

To validate and complement the modelling work, we develop our own sensor systems. These are used in experiments conducted both in controlled environments, such as water tanks, and in full-scale field trials together with the Swedish Navy. To help the Navy protect its platforms, we also study methods to reduce signatures and thereby lower the risk of detection.

Questions arising within marine electromagnetics span areas of expertise in physics, chemistry, applied mathematics, software development, and measurement technology.

Signal Processing

Signal processing is fundamentally about methods for extracting useful, information-bearing features from noisy and disturbed measurement data. The research area is mainly focused on the detection, classification, and localisation of targets in passive and active underwater sensor systems, as well as on the development of methods for underwater communications.

The research area includes expertise in adaptive and statistical signal processing, array signal processing, artificial intelligence, and machine learning (AI/ML), signal-processing techniques to support sonar operators, sensor and communications networks, fusion of sensor information, sonar techniques for submarines and surface vessels, and the impact on signals of the underwater environment in shallow waters.