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

82 In operation | Teledyne SeaRaptor and 6000 m depth rating,” Reynisson explains. “Rather than just detecting obstacles, it performs bottom-tracking, allowing the SeaRaptor to plot terrain up to 100 m ahead, and engage in terrain- following behaviour long before any obstacle can endanger the system.” In addition to programming a route and the sensors to be used, the operator must plan how to reach the survey site, both in terms of transporting the AUV to the correct part of the ocean and considering how to handle the dive down to 3000 or 6000 m. To transport the SeaRaptor to the location of a new deep-ocean survey mission, Teledyne has developed a special, 20 ft-long storage container. Initially, this enables easy ferrying such as by train and ship to whichever part of the ocean is above the survey site. However, the container was also designed according to the parameters of a manned mission vessel owned and operated by a Teledyne Gavia customer, so that it could sit on its operations deck and work within the existing infrastructure. “And given the vehicle’s dry weight of a tonne or more, it’s not something two people can haul out, so we installed a launch slipway of hydraulically driven wheels to ‘push’ the SeaRaptor out for deployment, after a side-door along the length of the container is opened,” Reynisson says. “Inside that container, the AUV has maybe 5 in of space on each side. We have more flexible storage solutions for other potential users, but this initial storage and launch solution was designed to sit permanently on that customer’s ship.” After the AUV is pushed out from the container, an A-frame hydraulic winch equipped with a Mermac D docking head (originally designed for launching and recovering ROVs and towed systems) is connected to the centre lift point of the vehicle and lowers it into the water. Given the safety concerns of working in the weather conditions and sea states of deep-ocean regions, this sequence of launch systems is automated, to ensure that personnel can stay off-deck as the SeaRaptor is deployed, to counter the risk of injury or damaging the craft. Diving and sensing Teledyne Gavia has integrated a release mechanism from Teledyne Benthos into the SeaRaptor that allows a weight to be attached temporarily to it. That allows it to descend to its required depth without having to use the drive thruster. Given that the operating speed of the vehicle is about 3 knots (5.5 kph), not having this option would mean consuming significant power to reach the seafloor, without generating any survey data along the way. The mechanism, the VR Series, can be triggered acoustically or by various commands. It can be released at a particular depth or after a certain time into the mission. The SeaRaptor actually has two of these releases, allowing it to release a second weight later in a mission to make the vehicle more positively buoyant and enable a thruster-free ascent. The VR Series release takes between 5 and 10 s to unlock, and the released weights are made from materials such as steel that will dissolve in the ocean, to prevent pollution. “A lot of that weight carry-and-release system is customisable depending on how the end-user might want their SeaRaptor to descend and surface, but the operator needs to be careful, because unlike other AUVs you’re starting with something that’s negatively buoyant,” Reynisson cautions. “So if you don’t have a good hold on the SeaRaptor it’ll drop down into the ocean depths.” Once it has reached the seafloor, it will begin the pre-programmed survey operation, autonomously following the user-commanded route using a combination of USBL updates (or LBL updates, mission duration and costs permitting) and dead reckoning. The greater payload capacity and power supply of the SeaRaptor compared with the Gavia enables the integration of more demanding systems, such as the recently launched SeaBat T-50S multi-beam echo sounder from Teledyne Reson, a sensor June/July 2019 | Unmanned Systems Technology The SeaRaptor is equipped with a pair of weights to make it negatively buoyant as its mission begins, enabling a thruster- free dive. One weight can be dropped upon reaching the sea bed and the other released later for a thrusterless ascent