Unmanned Systems Technology 023 I Milrem Multiscope I Wireless charging I Logistics insight I InterGeo, CUAV London & USA show reports I VideoRay Defender I OS Engines GR400U-FI I Ultrabeam Hydrographic Ultra-2 I IMUs

61 VideoRay Defender | Digest latter two are neutrally buoyant in fresh water because they have a specially designed foam jacket to provide the flotation element. The tether and controllers can be packaged in a separate case to travel with the Defender, and tethers can be linked together to increase its range. While larger conductors provide a higher power transmission capacity, they lead to thicker tethers, which results in greater drag. The Negative tether has the largest conductors, followed by Neutral and then Performance. The Negative and Performance tethers have the smallest diameter to give the least drag, while the Neutral tether has the largest diameter. The tether connectors can be connected while they are wet. One of the pins in the connector is offset to make correct connection simple. The power module operates at 48 V DC with full monitoring of input voltage, output current and temperature to ensure that the power systems in the Defender are fully protected. This data is fed into the Opensea software so that any potential problems can quickly be identified. Building a configurable, modular UUV system that is small enough to transport easily on an airliner is no mean feat. Dropping the battery is one way forward. Lithium batteries cannot easily be carried on aircraft because of their fire risks, but carrying a specialist tether allows a local power source such as a generator to be used. This also gives unlimited mission time, albeit at the expense of range, although as mentioned, multiple tethers can be used to increase that. As mentioned, attention to detail and close collaboration has been key to the Defender’s development, and the Opensea software is at the heart of this. It provides not only the core navigation and control functions by integrating the KVH gyro and DVL sensor, as well as the multi-beam sonar, but also the modular software interfaces to allow other sensors to be easily added. That has allowed VideoRay to offer sensors that meet the needs of specific missions, whether it be using SD or HD cameras or other specialist sensors. The Opensea software framework also allows for more autonomous operation without the need for control by the operator, who can concentrate on the video or data feedback from the craft. While collaborators have delivered the control, navigation and sensor fusion functions, the Defender’s thrust and manoeuvrability come from the specialist design of the thruster, providing a significant lift capability for an easily transportable underwater vehicle. The thrusters are also easy to maintain and replace without having to dismantle the frame of the vehicle, allowing users to operate for longer periods. The system is now being used around the world for applications such as aquaculture, oil and gas line monitoring. VideoRay is also applying the modular design techniques to its existing PRO line of ROVs. The latest, the three-thruster PRO 5, weighs 10 kg, travels at up to 4.4 knots and can be configured with the same sensor subsystems used by the Defender. For example, it also uses the 750D or 1200D Blueprint sonar, along with a USBL from Seatrac and a single- or dual-axis manipulator from TriTech.  Unmanned Systems Technology | December/January 2019 Inertial measurement unit: KVH       Doppler velocity log: Nortek Operating system software: Greensea Systems Sonar: Blueprint Subsea Camera: TriTech Imaging Ultra-short baseline comms: Seatrac Some key suppliers The power board for the Defender showing the connections to the tether (Courtesy of VideoRay)