Issue 37 Unmanned Systems Technology April/May 2021 Einride next-gen Pod l Battery technology l Dive Technologies AUV-Kit l UGVs insight l Vanguard EFI/ETC vee twins l Icarus Swarms l Transponders l Sonobot 5 l IDEX 2021 report

48 for scripted autonomy, the AUV-Kit comprises a range of components from Sonardyne. For onboard inertial sensing, a Sonardyne Sprint-Nav is used, with the system housing containing an INS (built using ring laser gyros and accelerometers), a Doppler velocity log and a pressure sensor. “We were very much drawn to the fact that Sonardyne has products in its Sprint-Nav range that vary in navigational accuracy, from the Sprint-Nav300 to the -NavX, but they are all housed in the same packaging. That makes the navigation solution easily swappable to meet specification or cost priorities of various customers,” Lebo says. Sonardyne’s AvTrak 6 provides acoustic positioning and comms. It combines a transponder for USBL and LBL navigation, as well as a bidirectional acoustic modem with a data rate of up to 9000 bit/s for downloading survey data without having to recover the craft. The second part of the autonomy is referred to in-house as the “advanced autonomy”, which was developed in partnership with Metron to enable dynamic in-mission re-tasking and re-planning. “This is what enables success during long missions, where not every contingency can be planned for and mission failure would be costly,” Sgobbo says. “Capabilities such as dynamic re- planning and obstacle avoidance require advanced decision-making techniques such as look-ahead methods, which allow vehicles to play out multiple possible future scenarios in internal simulations. That enables them to choose the path that reflects a mission’s priorities and/or is most likely to lead to overall mission success.” Metron’s autonomy system is aimed at ensuring a ‘get home’ capability, to make sure the Dive-LD is always recovered safely, as well as ensuring that data quality meets a mission’s requirements. The system also decides if a fault that has been detected is worth responding to – by triggering an emergency return to the mission launch point, for example – and if the data is complete and of adequate quality, or if the AUV needs to go back to collect more data. For the most part, the Dive-LD can descend and surface using only its thrusters. However, if saving power or thruster damage are a concern, the standard AUV-Kit also includes a system of weights, similar to those on the Teledyne SeaRaptor (as discussed in UST 26, June/July 2019), which are installed near the nose and are released mechanically through downward-facing hatches. Before working with Dive, Metron’s system had been developed through projects with organisations such as the US Office of Naval Research and DARPA. It communicates with the Dive vehicle controller through a ‘backseat driver’ interface installed by Dive. The two programs are installed on separate computers within the Dive-LD, and are connected via a comms network architecture based on Ethernet and various serial protocols. Kit customisability As mentioned, Dive’s approach to manufacturing, component selection, and software and power interfaces ensures there are no constraints on hull shape, diameter or length, allowing adaptability to different mission requirements. The company notes that the default mode for launch & recovery is a pier- based crane system, but that too can be customised. For example, a future Dive AUV designed to be launched from a submarine might look rather different from one launched on the water’s surface by a vessel, but a complete redesign would not be needed for either craft. That would also apply for different payloads, which might have different requirements for space, weight, power and thermal management, as well as different impacts on vehicle speed, acoustic signatures and endurance. “The AUV-Kit’s subsystems remain constant between each vehicle variation,” Lebo explains. “Although the objective might sometimes be to swap out components such as the thruster or energy source, the core architecture remains largely constant. “If all the AUV-Kit’s components are readily available, and unexpectedly long lead times are not part of the equation, Dive can produce a unique AUV for a given customer in as little as 4 weeks from their initial request.” Key to this are in-house software April/May 2021 | Unmanned Systems Technology A sidescan synthetic aperture sonar is to be installed in the Dive-LD in the near future