Unmanned Systems Technology 038 l Skyeton Raybird-3 l Data storage l Sea-Kit X-Class USV l USVs insight l Spectronik PEM fuel cells l Blue White Robotics UVIO l Antennas l AUVSI Xponential Virtual 2021 report

51 “The Surveyor is based on the same technology, which has been developed through seven or eight generations of Explorer, and is a fully mature bathymetry platform in terms of range, reliability and endurance.” The Surveyors will be capable of covering an average of 10,000 nautical miles in mapping missions before docking for routine maintenance. As with the Explorer, these operations can also involve surveys for climate research, weather monitoring and related applications. More power also means more high-end sensors can be used in surveys. Examples include deep-ocean bathymetry using Kongsberg’s EM 304 multi-beam echo sounder, inspecting fisheries using the Simrad EK90 echo sounder, and maritime domain awareness for organisations focused on ocean security or other strategic concerns. “Less than 7% of the deep ocean has been mapped, and it would take centuries to map the rest with manned ships, so the Surveyor has been sized around the EM 304 as its primary sensor,” Jenkins says. “It’s a 1 º x 1 º multi- beam unit that draws 3 kW continuously, and can map at 7 km below the ocean surface – so long as you have a quiet enough vehicle, which we do.” To provide sufficient energy, the Surveyor integrates a small diesel engine. It will not run all the time; Jenkins suggests that just a few hours per day might be needed. It drives a generator at its most efficient rpm to charge the battery, and potentially a propeller, to enable survey speeds of 6 knots and top speeds of 10 knots when required. The Surveyors will still rely primarily on wind, solar and hydroelectricity for their day-to-day operation though, although the fuel tank and propeller can provide for up to 2500 nautical miles if one of the renewable power systems suffers a fault or damage. “Also, while the diesel engine is off, the sonar swathe width grows by 20%, and we can capture even the most quiet returns, meaning improved accuracy and coverage over fuel-powered USVs,” Jenkins adds. “Even electrically propelled craft still need to stop their e-motors to cut out excess noise, but we can keep moving and surveying with that 1 º x 1 º resolution until the batteries need a top-up. For a mapping mission lasting potentially decades, 20% more sonar coverage while moving makes a gigantic difference. “We’re now working on a mid-sized vehicle, the Saildrone Voyager, to USVs | Insight Unmanned Systems Technology | June/July 2021