Kategorie: News
TU Graz develops GPS-supported underwater system
For many people, diving is one of the most fascinating experiences nature has to offer. Whether for leisure, research, or protective measures, safe orientation underwater is essential. Until now, divers have relied primarily on traditional methods such as reading a compass or orienting themselves using distinctive underwater landmarks.
Technologies such as sonar have also been developed for years to determine position in the water. However, these devices have significant disadvantages: they require high sound pressure levels, affect the sensitive ecosystem, and cause stress to fish and other marine life.
Now, however, Graz University of Technology is introducing an innovation that promises a sustainable, precise, and animal-friendly solution. As part of the “ScubaPOIs” project, scientists have developed an underwater navigation system based on GNSS-supported buoys that emit electromagnetic signals. This technology combines the precision of satellite-based GPS systems with underwater signal transmission, enabling divers to find their way to specific destinations in the water even more safely and, above all, in a more environmentally friendly way.
What makes this system special is that it provides precise positioning without harming wildlife. Divers wear a small display – a head-up display in their mask – that shows them the route. This allows them to navigate safely to dive sites, research areas, boats, or around restricted areas without relying on acoustic signal sources.
How it works and challenges
The system is based on a clever interaction between several components. Buoys placed in the water determine their position via the European satellite service GALILEO High Accuracy Service (HAS). A signal generator in the buoys sends electromagnetic signals to receivers in the divers' masks.
Based on several signals received simultaneously and the resulting distances, a mathematical process known as trilateration is used to calculate the exact position and depth of the divers. “The biggest challenge was the propagation of electromagnetic signals underwater,” explains project manager Philipp Berglez from the Institute of Geodesy at Graz University of Technology. “Water, especially salt water, is a complex medium for electromagnetic signals. Factors such as salinity, temperature, depth, and the conductivity of the water significantly influence the signal strength and range.”
Despite the difficulties, the researchers have found a solution that can transmit signals horizontally over 150 meters. For greater depths – up to 100 meters – the developers see further potential for optimization to increase the range even more.
Practical applications and environmental compatibility
The new navigation system has great potential for various areas of application. In the leisure sector, diving schools and recreational divers at tourist attractions could be equipped with the position buoys to easily find underwater sights. The head-up display ensures intuitive navigation, so divers do not have to rely on complicated maps or mazes. The Austrian company Oxygen Scientific has already developed a special display for this purpose that can be mounted directly on the mask.
The system also offers advantages for scientists working in the fields of aquaristics, underwater archaeology, and environmental monitoring. It allows precise, reliable orientation without disturbing the sensitive ecosystem. And this is precisely one of the most important differences from conventional sonar systems: the electromagnetic signals are animal-friendly.
To test this, measurements were taken as part of the project using golden rainbow trout, a species known for its sensitivity to external influences. The result: the fish did not react to the electromagnetic signals nor did they show any behavioral changes after the tests. Even after several months, their freedom of response to the signals remained intact. This proves that the system is unlikely to have any long-term negative effects on wildlife.