Uncrewed Systems Technology 049 - April/May 2023

98 I n the world of autonomous vehicles, demand has arguably grown faster for marine systems than for any other vehicle type. Industries such as maritime asset security, ocean environmental research and offshore energy have become enthusiastic customers of USVs and UUVs, and with that has emerged a detailed understanding of what they want from their systems. The bulk of their requirements can be summed up as ‘data’, in huge quantities and extremely fine resolutions. And although advances in underwater cameras and Lidars continue, there remains little real substitute for sonars when it comes to subsea mapping, monitoring and inspections. Although the use of USVs along our coasts and rivers, as well as the more remote regions of the ocean, has become widespread for gathering data using sonar, the missions are usually straightforward, involving autonomous navigation along pre-planned routes and emitting pulses from their sonar payloads at a fairly constant rate throughout. UUVs by contrast increasingly use their sonars in more active ways, given their innately autonomous nature by virtue of the fact that RF data links cannot effectively penetrate water. While UUVs can integrate many of the same subsea mapping and inspection solutions as USVs, there is a growing trend to deploy sonar for obstacle detection and avoidance, and in some cases even to achieve SLAM navigation. Advances in forward-looking and imaging sonars are contributing hugely to this jump in UUVs’ AI capabilities, leading in turn to more USVs being developed to operate reactively to their sonar findings, such as backtracking to re-map an area where data lacked clarity or complete area coverage. For both types of vehicle, there has been a huge growth in the range of sonar systems available, with considerable effort going into SWaP-C optimisation. This has been accompanied by a fast- growing availability of small, cost- effective UUVs (particularly micro- AUVs), as well as easily deployed USVs designed to integrate one small sonar payload, and very large USVs intended to travel for weeks or months at a time while packing as many survey instruments as possible into their hulls. Data gathered by sonar remains paramount for operators in the marine realm, and advances in the technology are offering new capabilities, writes Rory Jackson Returns on investment April/May 2023 | Uncrewed Systems Technology High-resolution scanning and advanced stabilisation techniques are increasingly vital for multi-beam echo sounders used in gathering ocean data on objects such as these wrecked vehicles (Courtesy of Norbit)