112 Also installed above deck are meteorology stations for tracking weather, an AIS receiver, and a high accuracy, survey-grade GNSS-INS from Veripos. Together, the sensors provide data for a comprehensive picture of everything the USV requires to navigate. “The autonomy system works by ingesting all this sensor information, and grades each individual packet of data with a probability score before fusing that probability data, and outputting what it feels to be the best assessment and decision for the operational situation it is being presented with,” Ratsey says. “Say you pick up an AIS target, but neither the camera nor radars see it, the autonomy system will almost certainly judge ‘that AIS signal is old and therefore not something we should worry about’. “Conversely, if the AIS doesn’t pick up a target, but the radars and camera all clearly see something at a given position, the main computer will judge that as a target with maybe 98% probability, and start taking its heading, velocity and so forth into account.” The system has been designed to track multiple targets at once, as vessels rarely encounter one at a time, especially in ports. When one target is within range of the USV, there will almost always be at least two to four others on the water nearby. Marine AI (headed by Ratsey and Phaneuf) supplies the autopilot computer, which was developed from the ground up to suit the Oceanus12, with capabilities such as low-level PLC access, and fine control over the motor steering and throttle. “We don’t need constant monitoring or comms; nor do we rely on an unreliable and costly always-on satellite connection to operate, as many USVs do,” Ratsey says. “That said, we do have an Iridiumbased system, which we’ve found very reliable, even with low bandwidths. While things like Starlink have only come along in the last two years or so, we’ll leverage that for live streams of camera, radar and survey payload data at some point in the future.” Powertrain The main tanks are built into the Oceanus12’s aluminium structure, while the day tanks are COTS plastic vessels, and a further bladder tank may be installed within the USV’s payload space. Two pumps, one on each side, deliver fuel to the day tank (then it is gravity fed to the generators), both pumps being COTS. For onboard fuel security, multiple redundant fuel lines and a PLC-managed valving system enable the port main tank to feed the starboard day tank, and vice versa, so operations can continue safely if a hose, connector or tank show signs of a fault. Identical pairs of generators, inverters, chargers and drives follow, and much like the fuel tanks, they are arranged in portstarboard configurations, and each one can be isolated via the control software in the event of a malfunction. “Regulators think that advanced software and other new tech is full of bugs or untested functions, and those are the problems they need to regulate for,” Ratsey says. “In reality, it’s the engineering and mechanical parts that need to catch up with the level of reliability needed for fully and persistently uncrewed systems. Before Mayflower went off on its first attempt at a transatlantic crossing, I said, ‘It’s going to be a $20 part that causes us to fail’ and that turned out to be true. “That first attempt came to a halt off the Azores for two reasons. First, a battery isolation switch had been mis-specified by that USV’s generator supplier and, second, the raw watercooling pump died. “An onboard engineer could fix either problem in an hour, but, for a USV, it means a five-day boat-recovery operation, thanks to less than $150 of equipment, all because they’d been used in a vehicle design that contained single points of failure. That’s why redundancy is so critical for industrial USVs.” The generators are three-phase, 480 V systems, outputting 23 kW each, with Zero forgoing higher voltages to prevent the need for huge cables onboard. Beta Marine’s generators were chosen for their compactness, cost-effectiveness and strong fuel economy, while the alternators were purchased from Mecc Alte in Italy. The batteries through to the motor drives are 400 V systems, provided by RAD Propulsion. Each of the two packs stores up to 21 kWh, with one designated October/November 2024 | Uncrewed Systems Technology The boat’s energy efficiency is aided by the soft, hydrodynamic curves of the shell plating, enabled via Snijtech’s very large metal-forming and bending machinery
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