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54 Show update | Oceanology International 2020 laser scanner – with cooling air inlets and a connector panel installed on the top. The system measures points accurate to 20 mm, with a repetition precision of 15 mm and a maximum effective measurement rate of 200,000 points/s. “The VQ-840-G also has a full-waveform recording capability that enables the user to modify processing parameters after the flight and perform waveform stacking to improve performance further,” Pfennigbauer added. For large-scale mapping of coastlines and shallow waters, Riegl has also developed the VQ-880-G II and VQ-880- GH, which provide water penetration to 1.5 Secchi depths. The VQ-880s’ turnkey surveying systems includes a GNSS-IMU unit and a bay for installing an RGB or IR camera. Both systems also integrate an infrared laser scanner to complement the data from the (main) green laser scanner, which enables improved detection of the water surface and more accurate measurements of the water’s depth. The green and IR laser scanners have a net measurement rate of up to 700 kHz and 280 kHz, respectively. Typical operations for both VQ-880s consume around 370 W (while operating lasers, IMUs and cameras, for an overall system weight of 65 kg) on a supply input of 18-32 V DC. Hydromea, which makes the Vertex AUV (as examined in UST 16, Oct/Nov 2017), has developed two new products that are due for release soon. The first is the DiskDrive 80 (or DD80) rim-driven disc thruster. It has 80 mm diameter propeller blades and was developed as a result of customer requests for a larger version of the DD50 (which has 50 mm blades). “As rim-driven thrusters, these systems have no central hub, which makes them much more resistant to becoming entangled with water plants, fishing lines or other debris that can be sucked into conventional thrusters and disrupt UUV operations,” said Felix Schill. “The 50 mm thruster produces 25 N of thrust force, while the 80 mm version will output at least 50 N, possibly more – we’re currently in the prototyping phase with that. Schill added that the DiskDrive name comes from the very thin profile of the thrusters – about 16 mm. That serves to reduce drag significantly for AUVs and ROVs which operate using thrust in multiple axes of movement. The thrusters are based on a patented, internally flooded design that uses the surrounding water for lubrication as well as coolant. It therefore needs no O-rings, seals, or oil, which could present potential points of maintenance or mechanical failure. The DD50 is now in mass production, and the company expects the DD80 to be commercially available within the next few months. Hydromea’s second upcoming release is its next-generation Luma optical modem for data comms over short-to-medium ranges. Its development has also been spurred by customer requests, specifically for a higher-bandwidth method of offloading data from their UUVs. Its development is currently in its early stages, but it is expected to be available later this year. It is expected to transmit at speeds above 1 Mbit/s (possibly as high as 10 Mbit/s) over an operating range of at least 50 m. These capabilities will put the (as- yet unnamed) modem ahead of its predecessors – the Luma 250LP, which is capable of 250 kbit/s at up to 7 m; and the Luma 500ER, which transmits 500 kbit/s at up to 50 m. Both of these weigh 250 g and typically consume up to 5 W during data transmissions; the new solution will be a bit heavier and consume slightly more power. Sonardyne has produced three new product updates aimed at improving navigation and localisation data for UUVs. The first of these is the all-new Sprint- Nav Mini, a combined AHRS (attitude and heading reference system), DVL (doppler velocity log) and pressure sensor solution for acoustic and inertial navigation. It comes in a 700 g, 300 m depth-rated version and a heavier 4.2 kg version rated to 4 km. Both units measure 215 mm tall and 149 mm in diameter, including connectors. Performance specifications for the 4.2 kg version have not been released, but the 700 g outputs heading data accurate to 0.5° secant latitude and both pitch and roll to 0.1 º (consuming 10 W during normal operations on a 24 V DC input). The second update is an upgrade to the Syrinx DVL, to optionally use inertial velocity data to compensate for vehicle motion in its acoustic doppler current profiling velocities. This enables calculations of absolute velocities through the local water column without having to track the seafloor, improving UUV navigation accuracy when far from the seabed. Lastly, Sonardyne has unveiled its next- generation Gyro USBL, which is 30% shorter and 40% lighter than the previous version thanks to a more compact redesign of the sensor assembly, improving its ease of installation in USVs. The Gyro USBL will also be available in two versions, both pre-calibrated but differing in performance. There will April/May 2020 | Unmanned Systems Technology Hydromea’s new DD80 rim-driven thruster