Russian unmanned systems manufacturer Navis has demonstrated autonomous seabed mapping and underwater object surveys with its Sardine (Сардина; Sardina) unmanned surface vehicle (USV) during trials at Lahdenpokhya in the Republic of Karelia earlier this month.
The company said the six-metre-long prototype kept to its prescribed track with deviations of no more than three metres at four to six knots. Heading deviation was no more than 1° at 5.8 to six knots, and speed was held within 0.2 knots of the specified value.
The USV was controlled remotely from a pier across a water area of approximately two to three square kilometres. Demonstrated modes included manual remote control, automatic heading and speed keeping, automatic route following, and responses to equipment failures or departure from the permitted operating perimeter.
For seabed mapping, Sardine carried a HydroTech MS400U multibeam echosounder operating at 400 kHz, together with a sound-speed sensor and a satellite inertial navigation system. The USV transited autonomously to and between work areas, followed operator-prepared parallel survey lines and ran a separate set of lines for echosounder calibration.
Under a separate programme, the vessel was reconfigured with a HydroTech SS900 side-scan sonar and a BHQ-750d sector-scanning sonar, confirming its ability to carry out search and inspection work autonomously.
The main tasks were performed in relatively calm water with gusts of up to 12 m/s. Additional seakeeping checks took place in gusts of up to 18 m/s and wave heights of up to 1.5 metres.
The prototype now has a marine diesel engine driving a propeller, with a rudder and bow thruster, in place of the petrol engine and waterjet fitted in the earlier configuration.
Sardine has a beam of 1.2 metres, a composite wave-piercing hull, and a retractable bulb keel housing the survey payload. The full displacement is 1,300 kg, the payload capacity is up to 200 kg, the maximum speed is seven knots, and its endurance is up to 48 hours at cruising speed.
Navis plans to add sound-speed profiling from the craft itself and to develop launch-and-recovery equipment for deployment from research vessels.
A variant of the USV with greater autonomy and improved seakeeping is also planned.
