Unmanned Systems Technology 036

58 and turbidity profiling [SVP Tu], CTD [conductivity, temperature and depth] and SVCTD [sound velocity, conductivity, temperature and depth].” The AML-6 is rated to 500 or 6000 m, and like the AML-3 it can output data in real time, log data for later processing or both. With the option of integrating six X2change sensors, the AML-6 is geared for multi-parameter applications such as those found in environmental and research operations. AML can also incorporate two additional digital or analogue third-party cabled sensors with the AML-6 if requested. Both the AML-3 and AML-6 incorporate ‘hot spot’ wi-fi for uploading data and bidirectional comms when surfaced. The 500 m versions incorporate AML’s ‘streetlamp UV’ for biofouling protection. Both also feature USB-C ports for quick battery charging, as well as another option for data uploads. Vestdavit unveiled its SOLUS launch & recovery system (LARS), which has been co-developed with H Henriksen, to make it easier to deploy and retrieve USVs between the water’s surface and ships’ decks. “Traditional LARSs use either cages lowered by davits, which work well but can be as heavy as the USV itself, or slipways, which are limited in their usefulness to sea states below 3,” explained William Goodall. “Our system does away with the cage, still using a ship-mounted davit but combining it with a USV-mounted offload hook attached to a Dyneema rope that hangs from the davit. The davit lowers the USV, and when it hits the water, the offload hook releases the USV so it can start its mission.” Recovery is by a winch (also with a Dyneema rope). The USV steers next to the mother vessel, the winch spools out its rope onto a telescopic pole that extends down from the ship’s deck towards the unmanned vessel, and the operator handling the pole catches the USV’s rope and feeds it into the davit, which can then be used to lift the USV out of the water. “This equipment is small and lightweight compared with a cage, taking far less space and effort to use, and it can be used in a far wider range of sea states than cages or slipways,” Goodall added. “That hugely widens the operational window for USVs, making it easier to conduct mine countermeasures, maritime surveys and other missions.” iMEMS Technology showcased the Aurora and Aurora+, its next-generation IMUs for marine and offshore applications. Linda de Luca told us, “All our motion sensors use the combination of a FPGA and DSPs, with the FPGA offering a higher level of real-time performance and filtering. This arrangement allows extremely low latency measurements and estimation.” By delegating mathematical functions from the instruction-based DSP to the clock-based FPGA, the Aurora and Aurora+ can perform calculations at speeds of at least 1 kHz, and measurements and estimates of data at a minimum of 3 kHz. The IMUs’ architecture also enables significant SWaP-C optimisation, with both products weighing 500 g, measuring 75 x 75 x 65 mm and consuming up to 2.5 W (at a voltage input of 6.5-36 V). The Aurora outputs roll, pitch and yaw data accurate to 0.05 º (RMSE) with heave accurate to 5 cm, while the Aurora+’s roll, pitch and yaw measurements are accurate to 0.01 º , and its heave is accurate to ±10 m. “We have also introduced an IoT system for all our motion sensors,” de Luca added. “That allows for smart remote data analysis and monitoring over the cloud, using the MQTT protocol to allow real-time data transmission.” SubC Imaging discussed its Rayfin series of underwater cameras, which are used by marine research organisations in various applications around the world. “The Rayfin product line can record HD video or at 4K resolution while capturing ultra-high resolution digital stills,” explained Mitch Colbourne. February/March 2021 | Unmanned Systems Technology Vestdavit’s SOLUS launch & recovery system iMEMS Technology’s Aurora IMU