By Unmanned Systems Technology

The use of renewable energy technologies to power USVs for longer missions and more efficient operations has already been established by platforms such as the Autonaut or Liquid Robotics’ Wave Glider. Both systems combine solar cells with wave propulsion to provide persistent electrically powered operation for surveying and mapping large swathes of the ocean. The XO-450 from Ireland-based XOCEAN is the latest such unmanned vessel to be designed with an atypical powertrain to enable persistent ocean surveys. “Ocean data is the foundation for all marine-based activity; the challenge is that it can be expensive and difficult to collect that data,” says James Ives, CEO of XOCEAN. “According to the OECD, in 2010 the ocean economy was valued at $1.5 trillion [£1.1 trillion/€1.26 trillion], with the potential for that to double by 2030.

“A key enabler of that growth is ocean data. USVs allow that data to be collected more efficiently and at a lower cost.” To that end, the XO-450 is designed with a hybrid power system, comprising a top deck of solar cells, Lithium-ion batteries and a micro diesel generator, to provide 1050W of continuous power over 18 days and a range of 1512 nautical miles with carrying up to 100kg of sensors. The system also features a wave-piercing catamaran hull, cited by XOCEAN as important for providing a stable platform for mounting sensors. Ives says, “The XO-450 is designed to be large enough to carry and power the necessary sensors for commercial ocean data capture, yet small enough to minimise propulsion power consumption for extended-duration operations”.

The 4.5 x 2.2 x 2.2 m hull encompasses a sonar post, CTD sensor winch, weather station and mounting areas for a motion reference unit and acoustic Doppler current profiler. The XO-450’s satellite data link uses the Iridium and Inmarsat constellations to provide redundancy for BVLOS comms and telemetry, and to enable each one to compensate for any issues with the other’s latency, stability and speed. “Technological factors that drove the development of the XO-450 included improvements in the performance – and a reduction in the cost – of satellite comms, as well as imaging systems and processing power,” Ives says.

Specific improvements in these systems include a reduction in packaging size, weight and power requirements. Ongoing advances in power systems including large lithium-ion batteries, solar arrays and controllers were also critical.