Unmanned Systems Technology 033 l SubSeaSail Gen6 USSV l Servo actuators focus l UAVs insight l Farnborough 2020 update l Transforma XDBOT l Strange Development REVolution l Radio telemetry focus

34 planning, loading, monitoring and remote operation using either wi-fi or Iridium comms. Once the mission has been uploaded and started, however, normal operation is completely hands-off. The operator does not have to be a qualified mariner, although maritime experience is useful, especially in mission planning. No maritime ‘rules of the road’ are programmed into the mission system, nor are any active collision avoidance systems, as the Gen6 vessel’s small size and low speed are sufficient to avoid causing damage to anything that it might hit or, more likely, hit it. Capable of managing several vessels simultaneously, the control system software is based on a Windows- compatible GUI, enabling waypoint and course navigation, and allowing the operator to create inclusion zones, holds and loops, and set up station-keeping at a selected target waypoint. It also supports comms functions including text and visual status indicators, SMS and email alerts. The wi-fi system is used for short- range, high-bandwidth comms directly between the operator’s laptop/tablet and the vessel, while the Iridium system uses the satcom provider’s Short Burst Data (SBD) service for anything beyond line of sight. Both are capable of supporting command & control (C2) functions and transmitting payload data. A third option under development is a cellular comms system packaged with a masthead camera and integral computer. The camera’s primary purpose is to capture high-resolution images of targets such as vessels fishing illegally, and the cellular comms will provide more bandwidth than Iridium SBD, and more range than wi-fi, while also supporting real-time C2 functions. It could also be used with the camera in a visual collision avoidance system under the control of the human operator. Together with the cellular comms, the additional computer packaged with the camera will provide a means of separating the data-handling and comms for the payloads from those that serve the C2 functionality. Under the current arrangements, however, payload data can be stored locally on an SD card and sent via Iridium or wi-fi, but relies on the vessel’s main computer. At the moment, the data interface for payloads follows the RS-232 standard, while the batteries supply 12 V DC power, stepped down to 5 V at the masthead, but others can be integrated as necessary. Payloads integrated so far include a conductivity, temperature and depth sensor, a chemical ‘sniffer’ and both fixed and towed hydrophone arrays. Multiple payloads can be accommodated simultaneously, limited only by their size, drag penalties and power requirements. Materials and manufacture The principal materials used in the Gen6 vehicle are fibre-reinforced plastics, wood and monolithic plastics. They have been chosen for their combination of August/September 2020 | Unmanned Systems Technology This drawing shows the relationship between the cam and the tensioner arm (top) and the symmetrical profile of the cam (above). With the arm on the dwell portion of the cam (600), the sail won’t generate thrust. Holes (614) reduce weight The white discs clipped to the Gen6’s submerged hull are elements of the POCIS system used to monitor traces of explosives released from unexploded ordnance on the seabed (Courtesy of the US Army Corps of Engineers)