By Robin Mitchell | 05-08-2020

The Challenges of Underwater Communication

However, the researchers continued to work on the system to try to integrate a positioning scheme. One year one, and researchers from MIT have done just this, and their system utilises a new technique called Underwater Backscatter Localisation (UBL). Simply listening to a signal underwater cannot tell you much with regard to positioning as echoes hitting underwater obstacles, as well as the water surface, can cause large amounts of interference. To get around this issue, the researchers deployed frequency hopping whereby a transmitter emits sounds on different frequencies and then compares the incoming phases of received signals to position a distant device accurately. The use of different frequencies works well thanks to how different frequencies reflect off objects and surface differently. But the system was still able to use the same battery-less technology used in the underwater communication system developed in 2019. However, researchers have had to drop the data rates to hundreds of bits per second when used in shallow water, a problem still being worked on.

Our apps