A team from Chalmers University of Technology, in Sweden, is developing a fully autonomous UAV system for rescue operations at sea (writes Nick Flaherty).

The system uses a mixture of fixed-wing and rotary UAVs with a USV to provide comms links to search an area independently, alert authorities to people in distress and provide basic assistance before crewed rescue vehicles have arrived.

The USV is a marine catamaran called the SeaCat, which serves as a base for a fleet of fixed-wing UAVs that monitor the surrounding area. A rotary quadcopter can then approach people in distress and deliver items such as supplies, healthcare aids or flotation devices.

The quadcopter can carry loads of up to 2 kg, while the fixedwing UAVs have a longer range to search a larger area.

“The project is based on the simple principle that different drones have different advantages, and by allowing several types of autonomous drones to work together, search efficiency and rescue response speed can be significantly improved, with the potential to save more lives,” said Xin Zhao at the Fluid Mechanics Division of Chalmers.

The SeaCat provides an internet uplink as well as a local comms link that is used to coordinate the UAVs in flight, and includes a launch pad for the fixed-wing versions. All the UAVs have cameras and a positioning system for autonomous operation.

The catamaran follows a predefined route with a closed loop, and the fixed-wing UAVs are automatically assigned to search areas according to an algorithm that partitions an area depending on the number of them that are available and their battery power. When a fixed-wing UAV detects objects in the water, the quadcopter is sent to the scene to take pictures. The photographs can then be sent to a rescue centre on land via the USV.

The rescue centre can also send out the quadcopter with supplies. When one of the fixed-wing UAVs runs out of power it lands in the water near the SeaCat, where it can be picked up and recharged automatically, then sent out again.