Issue 45 | Uncrewed Systems Technology Aug/Sept 2022 Tidewie USV Tupan | Performance monitoring | Bayonet 350 | UAVs insight | Xponential 2022 | ULPower UL350i and UL350iHPS | Elroy Air Chaparral | Gimbals | Clogworks Dark Matter

54 Digest | Bayonet 350 against the waves, but what we’re trying to measure is the movement of the ground underneath it. “That means there’s about 10 in of distance between the DVL’s transducers and the ground, and if a particular DVL can’t handle that short a distance then it’s no good for our application. More and more models these days are able to achieve that in how they’re engineered though.” Dual RTK-processing for GNSS is also available for helping with survey and heading accuracy in real time, so long as a link through the water is available. As a final note on the OpenSea underwater navigation platform, Hartman comments that there are three levels to the software’s capabilities. The first is a basic tier for hands-on, joystick-based control. The second, ‘pro’ version, is geared more towards autonomous operations, with the setting of survey areas and routes, and the highest tier is called EOD Workspace, which encompasses modules and plug- ins for higher-level autonomy. “Those modules would be things like automatic target recognition, smart obstacle avoidance and other things that make use of much more heavy- duty sensors and processors, such as forward-looking sonar or HD video to ‘diagnose’ what objects might or might not be, such as a creature or a mine,” Farinella says. “That’s important, because we also offer three versions of the 350 – the basic version, the pro version and the EOD Workspace version – with payload sensors and software configurations often pre-packaged to fit what the end-user needs. We can put in Greensea’s most advanced offerings and capabilities with the required sensors, in navigation as well as payload terms, but we wouldn’t do that for a customer who just wants the basic version.” Data reception and storage Various data link options are available for end-users to receive mission and payload telemetry at their console in good order. In principle, wireless RF links can still work while the 350 is submerged, as the waters are often shallow enough that the data fidelity is not completely attenuated over the distances between the UGV and the surface. “Also, if someone just wants the basic version of the vehicle, by and large they’ll need only minimal radio frequency comms – they’re unlikely to attempt manual operations beyond dipping past the waves every now and then in a straight and predictable line,” Hartman says. “The pro version can also use that ‘wireless tether’, and if it goes too deep for the signal to reach the surface it can still navigate its path well enough until it gets back to a point where there’s a good signal again. “The EOD Workspace version comes with an added companion computer, which plugs and plays into the main electronics box for extra computational power to handle the extra autonomous decision-making that comes with it. And if that or the pro version need higher bandwidth comms so that the end-user can track what the vehicle is doing, we have some extra options there.” For instance, to perform higher fidelity subsea wireless comms, an acoustic modem with a range of up to 2000 m can be installed. The company cautions however that the actual practical range for reliable and consistent data is likely to be far less, and indeed the 350’s maximum depth is much less, making such ranges unnecessary in the first place. “Acoustic comms is really the August/September 2022 | Uncrewed Systems Technology GNSS localisation is used when the Bayonet 350 is above water, while USBL is an option for subsea localisation