Fraunhofer IOSB and Düsseldorf district assess Ruhr using autonomous drone

30 Jul 2025

With optical and sonar sensor combination, drone automatically maps riverbed and banks.

The Düsseldorf district government, together with the Fraunhofer Institute for Optronics, System Technologies and Image Exploitation (IOSB) in Karlsruhe, has carried out a pioneering pilot project to survey the Ruhr – one of Germany’s more important rivers. For the first time, an autonomous water drone developed by IOSB was used to collect high-resolution data from both deep and shallow areas of the river over a six-kilometer stretch of the Ruhr near Essen.

The water drone measures the elevation relief both below and above the water surface with unprecedented precision and almost entirely automatically. Equipped with a combination of optical and sonar sensors, it can not only map the riverbed and bank areas in a single pass, but also independently avoid obstacles. Larger objects and the beginnings of scouring on structures, i.e., depressions caused by water turbulence, are clearly visible.

“This technology has given us insights into the underwater world of the Ruhr that were never possible before,” said District President Thomas Schürmann. “For the first time, the entire survey section could be mapped in almost its entirety, including the shallow water areas and shallow tributaries. This level of detail significantly improves the basis for decision-making — for example, in waterway maintenance or when calculating flood events.”

The drone is only two meters long, weighs around 80 kilograms, and has a low draft, making it particularly suitable for use in shallow, natural waters. Another advantage is that, unlike conventional surveying with large, manned vessels or manual measuring rods, sensitive shallow water areas no longer need to be entered. This keeps the ecological impact to a minimum.

Towards market maturity; seeking partners

The trials in the Ruhr region not only served to collect current data, but also to compare it with previous measurement methods. For the engineers at IOSB, this was the first practical application under real conditions after the system had been developed as an internal research project.

“With the idea of measuring water bodies as fully automatically as possible using a lightweight, unmanned platform, we deliberately broke new ground. We are pleased that this approach has also paid off here from the user’s point of view,” said project manager Dr. Janko Petereit. “In addition, every application helps us to further optimize our technology.”

The researchers are hoping for further practical pilot projects with challenging application scenarios for their drone. However, corporate partners will ultimately be needed to enable the new technology to deliver its expected benefits on a larger scale.

Petereit added, “As a research institute, we are dependent on partners to achieve our ultimate goal: to establish the new technology on the market and make it widely available for water maintenance and safe navigation.”