At sea: safe and precise unmanned take-offs and landings on ships
Global maritime routes are the backbone of worldwide trade, yet at the same time constitute highly sensitive infrastructure. Ships are exposed to a multitude of risks, be it extreme weather, accidents or criminal activities. Being able to quickly get an overview of any potentially dangerous situation is vital. The necessary response speed could be achieved by deploying unmanned aircraft for maritime use. These would take off directly from a ship and take situation images from the air automatically. As part of the Maritime RPAS Operation project (MaRPAS) , the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) has been working with the German Federal Sea Police since 2016 on unmanned remotely piloted aircraft systems (RPAS), their application possibilities and conditions for their use at sea. The project was successfully completed with a series of test flights in mid-October 2018.
Test flights demonstrate how systems interact
The test flights took place in Hohe Düne harbour in Rostock-Warnemünde, and demonstrated take-off and landing technology for unmanned helicopters, to support them in maritime scenarios. The unmanned DLR superARTIS helicopter took off from, and then landed on the deck of the Sea Police ship BP 21 Bredstedt. The newly developed landing gear, comprising a rope winch and electromagnet, was attached to its underside, initially 'tying' it to the helideck of the police boat. Then superARTIS took off, released its magnetic connection with the ship and pulled in the rope. When it came in to land, the flying helicopter let the rope down onto the deck of the ship using the winch, and magnetically secured it. The helicopter was then pulled down to the point of attachment on the deck automatically. "This is a real challenge, as air turbulence caused by the structure of the boat, not to mention sudden gusts of wind and the movements of the ship itself, can affect precision on the approach flight," says Stefan Krause of the DLR Institute of Flight Systems, which developed the landing gear.
Real-time parameters for wind and weather conditions were factored into the flight planning. The relative position of the superARTIS to the boat served as the basis for precision navigation during the landing. The DLR Institute of Flight Guidance in Braunschweig was responsible for the necessary precision navigation and also led the project as a whole. The interplay between all of the components involved – the ship platform, the aircraft with the rope winch and the ground station – were successfully tested in the process. Back in June 2017, DLR scientists installed a wind and weather measuring device and an antenna system on board the BP 21 Bredstedt and, over the course of a five-day patrol, gathered real-time data about the kind of conditions at sea that should typically be reckoned with when performing a landing on the deck of a boat. These data formed the basis for planning the subsequent test flights.
Challenging requirements for precision navigation and flight system
Getting a remotely piloted aircraft system (RPAS) to fly and then land again safely is a challenging endeavour even on land. Using unmanned flight systems in the maritime sector is made even more complex by the sea swell and the highly dynamic nature of wind and weather conditions. In the MaRPAS project, the DLR Institutes of Flight Guidance and Flight Systems in Braunschweig have joined forces to devise the concept for and implement an accurate navigation system and precise flight control technology for ship-based RPAS.
The flight tests conducted at the culmination of the MaRPAS project took place from the deck of the BP 21 Bredstedt, which was berthed in Hohe Düne harbour. In the follow-up MaRPAS 2 project, which is scheduled for 2019–2021, the scientists aim to test enhanced versions of the systems at sea.
Security research at DLR
In DLR’s security-related work, defence and security research and development activities are planned and monitored in conjunction with partners in government, science, industry and international organisations. The cross-sectoral field of security research combines the core strengths of established DLR programmes in the fields of aeronautics, space, energy and transport. In total, over 20 DLR institutes and facilities contribute towards the development, testing and evaluation of technologies, systems and concepts as part of their security-related work, as well as conducting analysis and assessments of security-related applications. The MaRPAS project falls within the field of maritime security.