Up-to-date maps are an indispensable tool for maintaining port facilities and shipping lanes. And when it comes to flood protection, it is also important to regularly take a look beneath the surface of the water. Unmanned water drones can be used to improve the quality and quantity of data collection in this area, as confirmed by a pilot project carried out by the Düsseldorf district government and the Fraunhofer Institute for Optronics, System Technologies and Image Exploitation (IOSB).
To ensure that ships of any size can enter a port, not only must the quays and loading cranes be suitable, but the navigation channels must also be deep enough. Regular measurements must be taken to ensure that no dangerous shoals form in river beds or that shipping is endangered in any other way. The condition of the embankments and port facilities must also be constantly monitored. However, the precise surveying of waterways is a demanding and cost-intensive task that requires a large number of mapping vessels and trained personnel. Unmanned, automated or even (partially) autonomous USVs (Uncrewed Surface Vessels) can be an environmentally friendly and resource-saving alternative to traditional methods, as a joint project between the Düsseldorf district government and the Fraunhofer Institute for Optronics, System Technologies and Image Exploitation (IOSB) has shown. The project involved the fully automated creation of precise map material for a 6-kilometre section of the Ruhr.
Visually, the 2-metre-long, 80-kilogram boat resembles a ‘standard’ catamaran without a mast. This is no coincidence. This design results in a particularly shallow draught, allowing the USV, which is packed with high-tech sensors, to be used even in extremely shallow waters. The sensitive shallow water zones that cannot be reached by traditional survey vessels no longer need to be entered by humans to be explored with manual measuring rods. This keeps the ecological impact to a minimum.
During operation, the drone developed at Fraunhofer IOSB simultaneously maps the elevation profile above and below the water surface. This is made possible by a combination of sonar and optical sensors mounted on the support deck and on the hulls. In a single pass, both the riverbed and the shore zones are recorded, providing important information not only about the condition of the riverbed, but also about structures such as bridges or jetties. For example, early signs of scouring on structures can be detected at an early stage. These are water-filled depressions caused by eddies that can damage the structure. In addition to the sensors for data collection, the water drones are also equipped with sophisticated technology for automated navigation and autonomous obstacle avoidance.
The aim of the joint pilot project between the Düsseldorf district government and Fraunhofer IOSB was to compare the results obtained by drone with data collected using established methods. It was also the baptism of fire for the UAS under real conditions. Previously, the system had only been designed and tested as part of the internal research project TAPS (semi-automatic positioning system for rivers and lakes). ‘With the idea of surveying water bodies as fully automatically as possible using a lightweight, unmanned platform, we deliberately broke new ground. We are very pleased that this approach has also paid off here from the user's point of view,’ explains project manager Dr Janko Petereit.
The researchers at the Fraunhofer Institute are now hoping for further projects with challenging application scenarios for their drone. However, corporate partners are ultimately needed to ensure that the new technology can deliver its benefits on a larger scale in the long term. ‘As a research institute, we are dependent on partners to achieve our ultimate goal,’ says Dr. Janko Petereit. Only then will it ultimately be possible to establish the new technology on the market and use it for waterway maintenance and safe shipping.
> This article was written in cooperation with Drones, the magazine for the drone economy. www.drones-magazin.de
