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

81 do many iterations of the PCBs and parts like that, because you learn more at each iteration and can make improvements,” Reynisson says. “We had preliminary design reviews, critical design reviews and set-up reviews, and several sensors were changed during the process as new sensors would come along that fitted the mission of deep-sea search and recovery better.” Technical development predominantly took place in Iceland (where Teledyne Gavia’s main facilities are located), by an r&d team of 10 engineers headed by Dr Hordur Johannsson, chief engineer at Teledyne Gavia. The result is an AUV that is 5.5 m long, 630 mm in diameter and weighs 1-1.2 tonnes in air (depending on configuration). It is available in versions rated to 3000 or 6000 m, and has multiple payload bays along the hull. The main propulsion comes from a single thruster that can be actuated 25 º to port or starboard, with two dive planes on the AUV’s sides which are independently controlled for roll compensation and ascent and descent. The SeaRaptor’s standard battery module provides 13 kWh (with 16 kWh optional) and typically incorporates 16 independently pressure-tolerant lithium- polymer battery packs – four groups of four packs connected in series. Each pack weighs about 8 kg in air and uses a wet-pluggable connector to enable individual packs to be quickly unhooked and replaced between missions. “Each pack is nominally about 29 V, so we connect them in series to push them up to 116 V, to optimise for the propulsion system,” Reynisson notes. “We then have multiple DC-DC converters to provide different voltages for different sensor needs, to handle a varied sensor selection so long as buoyancy and internal volume constraints are adhered to.” The BMS has monitoring sensors for each cell to log for battery health and optimise charging, discharging and power balancing across the power module. A range of sensors and technologies from other Teledyne Marine subsidiaries (such as Teledyne Benthos, BlueView and Reson) have also been integrated to assist with different stages and circumstances of the AUV’s operations. Pre-survey steps Before the SeaRaptor can be deployed, it is programmed with its tasks using similar mission planning (and post- mission analysis) software to that developed for the Gavia AUV. It is operated via the Gavia AUV Control Center software, a chart-based interface program in which the vehicle operator plans out a mission based on sea charts, with inbuilt route-planning templates that allow the user to set up a ‘lawnmower’ type back-and-forth survey pattern or long-line surveys. The user’s selected or customised routes can also be copied or transplanted into other sea coordinates for mission repeatability. “Although we were able to leverage that software we needed to write new functionality for the Control Center, to account for some new sensors and mission parameters such as the descent mechanism,” Reynisson says. “We were lucky enough that, with the modularity of the Gavia, we’d also made the Control Center a bit modular, which made implementing the software changes easier.” As an example of the changes, Reynisson notes that the Gavia AUV typically uses a single-beam obstacle avoidance sonar to detect any obstructions in its path. Upon detection, the Gavia will either ‘fly’ over it or stop, if the former action is not feasible. For the SeaRaptor’s detect-and- avoid capability though, the company integrated a forward-looking multi- beam sonar Teledyne BlueView. “This is BlueView’s M450-130-D6, a 450 kHz 2D imaging sonar, with a 130° FOV Teledyne SeaRaptor | In operation Unmanned Systems Technology | June/July 2019 Teledyne has developed the SeaRaptor for surveying down to 6000 m below sea level, in applications such as search and recovery of wreckage on the seafloor Sensing equipment integrated into the hull includes a multi-beam sonar, a side-scan sonar, a black box pinger, a camera and strobe lights