Unmanned Systems Technology 026 I Tecdron TC800-FF I Propellers I USVs I AUVSI 2019 part 1 I Robby Moto UAVE I Singular Aircraft FlyOx I Teledyne SeaRaptor I Simulation & Testing I Ocean Business 2019 report

45 keeping for gathering sonar imagery amid waves and wind. Also, for vehicles of its size class, surveys tend to be conducted at speeds of between 3 and 5 knots, and at such speeds a catamaran design tends to provide the right hydrodynamic efficiency and stability, as well as the necessary balance for controlled pitch and roll. “When you’re engineering a system to run on batteries, you really have to prioritise efficiency, and optimise everything around that,” Douglass says. “And, somewhat uniquely for a catamaran USV, we don’t hang anything between the two pontoons. “We have an acoustic doppler current profiler (ADCP), an EdgeTech 6205 side- scan sonar and other sensors, all fared into the hull. That allows us to have a 1.8 m hull that can move at up to 7 knots and survey for up to 6-8 hours.” Under the rear of each pontoon is a 1 kW BLDC thruster to provide the craft’s speed and endurance. The payload bays are essentially ‘buried’ into the pontoons. For example, a well for integrating ADCPs or DVLs is on the forward part of the left pontoon. This design approach was originally used for another Sea Robotics USV, the Hycat. That vessel was developed in partnership with YSI, Hypack and Sontek for water quality inspections, and was fitted with a Sontek M9 ADCP for current profiling, discharge measurement and bottom tracking installed in the well. On the forward well of the M1.8’s right pontoon, an AML micro SV sensor is typically installed to provide sound velocity measurements for the EdgeTech sonar. Other motion compensation for the sensors (and for navigation referencing) is provided by an SBG Systems Ekinox INS. At the top of the forward main hull, a Velodyne Puck Lidar can be installed for terrestrial mapping. “We designed USVs | Insight We’ve identified an increasing demand for man-portable bathymetry units that can operate in shallow waters or remote areas Unmanned Systems Technology | June/July 2019 The SR-Surveyor M1.8 is powered by a customised lithium-ion battery, with specifications suited to support the USV’s required performance and sensor architecture The new Sounder USV from Kongsberg Maritime has been designed with a Simrad SX90 for detecting and tracking schools of fish