Unmanned Systems Technology 025 | iXblue DriX I Maintenance I UGVs I IDEX 2019 I Planck Aero Shearwater I Sky Power hybrid system I Delph Dynamics RH4 I GCSs I StreetDrone Twizy I Oceanology Americas 2019

93 being able to operate underwater for four days and the Navigator having an eight- day subsurface endurance. Water Linked has developed a new acoustic modem aimed at applications including AUV telemetry and ROV wireless control, for UUV manufacturers and operators seeking a less costly and maintenance-intensive alternative to tether cables and connectors. The Modem 64 (or M64) measures 112 x 30 mm and can operate at depths down to 300 m (with other depth ratings available on request). Power consumption is 216 mAh on a 12 V supply. “The M64 is deployed in pairs, and they will automatically establish a two- way data network between them,” said Oliver Skisland. “Data to be sent is placed into one modem’s data buffer using a standard serial interface; once there, that modem starts transmitting it to the other modem. A full-featured protocol for communication between the modems is included as standard.” The system transmits over 200 m in all directions, and gives a 64 bit/s data link with a latency of 500 ms. “A major issue with legacy acoustic modem products is stability, as well as very little focus on ease of use,” Skisland said. “By using the latest computer processor technology and our own internal design principles, we have sought to overcome these problems for anyone looking for a wireless data network for their subsea operations.” Surfbee showcased its eponymous USV for acoustic doppler current profiler (ADCP) integration and operations. “The system currently integrates Sontek, Teledyne and Rowe ADCPs,” said Jack Hurley. “It measures 1.3 m long, 60 cm wide, is 10 cm thick and can carry a 30 kg payload.” The vessel is built from a PVC rib-stitch hull similar to those in inflatable stand-up paddle boards to keep manufacturing costs as low as possible, and is powered by two underwater brushless DC thrusters installed beneath the stern. Applications include surveillance operations for law enforcement and environmental protection agencies, with the craft’s low profile being highlighted by the company as making it naturally hard to detect. As well as ADCPs, the vehicle comes integrated with BeeHive Lab operating software that enables plug- and-play integration of additional sensors including EO, radar, sonar, and NIR. The software also allows geo-tagging of survey data and live uploads to the company’s cloud server, for real-time assessment of fish stocks, glaciers and aquatic ecosystems. Preservation of the Great Barrier Reef was a key motivator behind the vessel’s development. Advanced Navigation was on hand to discuss the use of its Subsonus USBL acoustic positioning system in a recent project with Geosurvey Mexicana, a company providing marine survey and underwater research services for private and public organisations. Geosurvey Mexicana tested the performance of the Subsonus Oceanology International Americas 2019 | Show report Unmanned Systems Technology | April/May 2019 Ocean Aero has expanded its line of AUSVs Water Linked’s M64 acoustic modem The Surfbee acoustic doppler current profiler