Satellite navigation system now also for divers

Computing

Technological Innovation Website Editorial Team - September 22, 2025

Test site, with markings showing buoy locations. [Image: Susanne Scherbaum et al. - 10.3390/w17091345]

Underwater positioning system

While global navigation satellite systems now allow us to navigate accurately through the air or on land, underwater navigation for divers remains limited primarily to waypoint orientation or traditional compass navigation.

Underwater navigation concepts already exist using technology similar to sonar, which allows position determination using acoustic signal sources. However, these systems are impractical and, worst of all, require high sound pressure levels, which affect the ecosystem and are not well-received by the communities most involved in diving, such as scientists and nature lovers.

To overcome both challenges, Susanne Scherbaum and colleagues at Graz University of Technology in Austria developed a new underwater positioning system using buoys. The buoys detect their own location via satellite positioning systems and then emit electromagnetic signals into the depths, enabling precise underwater positioning without harming animals.

Using a small screen that fits inside the mask, divers track the signals, allowing them to find their way to their desired destinations and return to the dive boat or bypass restricted areas. They can also be reached in case of an emergency.

"The biggest challenge for us was calculating the propagation of electromagnetic signals underwater to obtain the appropriate distance values," said team member Philipp Berglez. "Water properties, such as salinity, temperature, depth, or conductivity, have a significant impact here. Because of these diverse and variable influencing factors, modeling the propagation properties underwater was particularly challenging."

Concept of a satellite-based navigation system for divers. [Image: Susanne Scherbaum et al. - 10.3390/w17091345]

No impact on marine animals

The team managed to transmit signals horizontally over a distance of over 150 meters, but the researchers say there's still a lot of room for improvement in the technology. They plan to initially focus on depth, aiming to make their system operational at at least 100 meters.

To confirm that the new positioning system does not affect wildlife, the team monitored golden rainbow trout, which typically react very sensitively to external influences. The fish displayed no abnormal behavior during measurements at different transmission powers, and they also behaved normally after the measurements were completed.

Golden rainbow trout were also unaffected one week, one month and four months after the measurements, meaning that delayed negative effects can also be ruled out with a very high degree of probability, the team assures.

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