Transmission possible

Swarms of autonomous vehicles may soon be combing the ocean floors swapping vital information on deep-sea wreckage investigations or possible naval defence missions, thanks to technology that makes underwater wireless communication faster and more reliable.

The breakthrough — that could make the transmission of clearer images, sound and videos possible — gives a glimpse into the future of a digital ocean in which integrated networks of instruments, sensors, robots and vehicles will operate in a variety of environments.

The applications not only include collaborative search missions but also ad hoc deployable sensor networks for monitoring environmental conditions such as climate change and oil spills.

The system from the

FOI is claimed to be the first to reduce the effects of echoes, which limit data rate in underwater transmission.

When wireless communication is transmitted through the air by systems like Bluetooth, there are significantly fewer technical obstacles to overcome. But in seawater there is limited bandwidth available and signals are subject to signal interference. In shallow water, signals bounce from the surface and sea bed, while in deep water, acoustic waves tend to travel in the depth of water where sound moves the slowest. The scattered movement of these waves creates signal echoes, which create interference in a digital communication system.