USE Network launch I UAV Works VALAQ l Cable harnesses l USVs insight l Xponential 2020 update l MARIN AUV l Suter Industries TOA 288 l Vitirover l AI systems l Vtrus ABI

51 USVs | Insight as target USV systems it is supplying to the Spanish navy. “Some might think that USV autopilots are much easier to develop than those for UAVs because you’re dealing with only two axes of movement rather than three, but the fluid dynamics of water and waves can be far more challenging to model around than air,” says UAV Navigation’s CTO Miguel Angel de Frutos. “The forces and movements from waves are powerful, and occasionally the USV leaves the water entirely, so it has no control. The Spanish Atlantic region is especially problematic in that regard, so we needed to program specific algorithms and logic to control the testbed vessels in very rough sea states.” The company chose to re-program its existing Vector rather than start from a blank sheet, as it was already certified to Mil-Std 810F and 461F for environmental and shock protection. It then integrated a suitable GNSS, IMU and dual CPUs. Also, the hardware design includes five serial ports, two CAN ports and several other I/Os to accommodate the number of mission sensors the new target USVs would carry, such as radars and cameras. The control mode algorithms for the USV version of the Vector are similar to those in the UAV version, but they have been reconfigured to include manoeuvring and logic similar to how humans might operate a boat, and to prevent overshooting waypoints and skipping over waves. The mode blocks include ‘Auto’ for following a pre-programmed route of waypoints, ‘Nav-To’ (navigate to) in which the USV sets and holds a heading towards a newly selected waypoint, and ‘Hold’ and ‘Loiter’ modes that can be set to activate upon reaching the final waypoint. Throughout the trials with the Spanish navy, the new SCR vessels – the Spayk I and Spayk II – were controlled using UAV Navigation’s Visionair GCS software, which enabled simultaneous control and monitoring of both craft (as well as UAVs as and when the operators needed). Angel says the software also allowed the integration of maritime charts, recovery positions and geo-fenced zones relative to manned naval ships to be established, as well as detect a capsize. Other USV-relevant features, such as representation of maritime traffic and predicted paths (amid traffic and currents) are under development. Oil & gas Maritime Robotics has announced the sale of one of its Mariner USVs to an unnamed customer in the Middle East, which intends to use the vehicle to conduct seismic surveys for oil & gas analytics. It has been equipped with a Sonardyne transition zone transceiver (TZT) and a Knudsen Engineering mini- sounder, to help position seismic nodes on the seafloor. “There are typically two kinds of offshore seismic surveys,” says Joel Pederick, operations manager at Maritime Robotics. “There’s towed marine seismic, in which a ship tows a spread of cables [filled with hydrophones] measuring about 1 km across and 8 km back, where a seismic source is intermittently triggered for the cables to receive the reflections and generate a sub-bottom geophysical map based on those. “The second kind, node seismic survey, uses geophones laid in patterns on the seafloor, and is becoming more popular. A mother ship (or ‘source ship’) triggers the seismic source at waypoints over the geophones, to create a map of where any faults lie, so the customer can work out where to drill or where the oil and gas reserves are migrating within the reservoir.” Judicious placement of geophone nodes is key to accurate geophysical maps, but in shallow waters this accuracy is hampered by dense acoustic reverberations. The TZT, however, is designed to collect hundreds of acoustically transmitted signals from transponders attached directly to either each seismic node or a nearby deployment cable. These signals will then be fused with the Mariner’s GNSS readings to calculate an accurate position of each node, both during and after placement (as Unmanned Systems Technology | June/July 2020 A Mariner USV has been supplied to a customer in the Middle East for conducting node seismic surveys in the oil & gas industry (Courtesy of Maritime Robotics)