EvoLogics Sonobot 5: Elevating Multibeam Sonar Capabilities

Photo credit: EvoLogics
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With a rich legacy as a high-tech provider of robotic solutions, sensor systems, and underwater data networks, EvoLogics has consistently demonstrated innovation in one of its flagship products, the Sonobot 5 uncrewed surface vehicle. The Sonobot is a well-established product with a remarkable track record in bathymetry, underwater object search, and reconnaissance.

In 2023, the vehicle underwent significant enhancements, reaffirming EvoLogics' commitment to cutting-edge technology. The focal point of this evolution was the introduction of the EvoLogics Multibeam for the Sonobot 5 platform.

The EvoLogics Sonobot 5 © EvoLogics 2023

Multibeam Sonar: A Technological Leap

Unlike single-beam echosounders, the multibeam sonar, featured in the 2023 release, offers superior coverage and 3D mapping. Releasing multiple sound waves concurrently, it efficiently maps extensive underwater areas, drastically reducing survey time.

The key strength lies in its ability to generate higher-resolution imagery by emitting a fan-shaped array of sound waves, capturing echoes from various angles to create detailed 3D representations of underwater features.

Multibeam sonar outperforms its single-beam counterparts in providing enhanced depth accuracy. With advanced algorithms, it compensates for seabed complexities, mitigating the impact of factors like slope, refraction, and interference.

The multibeam sonar for the Sonobot 5 leverages a Norbit OEM solution, an entry-class multibeam sonar with a professional approach. Featuring high-grade dual GNSS and INS positioning and motion control, standard across all Norbit echosounders, this system boasts 256 beams at 1.45°x1°, a range exceeding 200 m, and a 50 Hz ping rate. These specifications enable professional surveying in accordance with the IHO’s S-44 standard.

Seamless Integration and Streamlined Design

EvoLogics engineers meticulously integrated the Multibeam with the Sonobot 5 platform to ensure optimal performance. The compact Norbit sonar interface unit (SIU) is fully embedded in the submergeable pod of the Sonobot vehicle. A single cable for power and data link connects the sonar head, which is easily detachable with a slide-and-lock mechanism for convenient transportation and storage.

The Sonobot 5 Image © EvoLogics 2023

To optimize performance, a custom-molded streamlined cover was added to the sonar head before the production of the first serial orders. This streamlined cover not only enhances the hydrodynamics of the vehicle but also adds extra robustness, providing crucial protection to the sonar-pod assembly. Particularly advantageous for surveys against strong currents, the streamlined cover minimizes drag, ensuring efficient navigation through challenging conditions.

It enables better utilization of the Sonobot’s powerful thrusters and aids in maintaining a steady survey speed during data collection.

The mechanical connection between the submergeable pod and the sonar, through the slide-and-lock mechanism, also underwent refinement after the final pre-production trials.

Weighing under 32 kg, the Sonobot 5 with EvoLogics Multibeam measures L 1.29 x W 0.96 x H 1.04 m (with antennas), making it the smallest and easiest-to-handle autonomous vehicle equipped with a professional multibeam sonar.

Bathymetry at the mound site taken in 2017 with the Sonobot’s standard 200 Hz single-beam echosounder with the “cairn” clearly visible

© EvoLogics 2023

Multibeam sonar survey of the underwater mound, DCT data preview during the mission, November 2023

© EvoLogics 2023

Multibeam sonar survey of the underwater mound, processed with QPS Qimera, November 2023

© EvoLogics 2023

Real-world Testing at Plessow Lake

In November 2023, EvoLogics re-surveyed the Plessow Lake in Brandenburg, Germany, a regular testing site for the company since 2016. The Sonobot 5 with EvoLogics Multibeam platform was put to the test around a known cairn-like formation on the lake floor.

Initially thought to be an ancient burial mound, subsequent underwater archaeological prospection determined it to be a geological phenomenon from the last glacial period. The mound's elevation and shape create variations in the lake's bathymetry, providing a unique opportunity to evaluate the echosounder performance in measuring depths and generating detailed bathymetric data.

EvoLogics engineers strategically took the Sonobot 5 with the upgraded Multibeam sonar to the Plessow Lake site, capitalizing on the known mound feature and existing single-beam bathymetry data.

During the survey, the complete sonar dataset was stored onboard the vehicle, with a live preview displayed to the operator at the land station. EvoLogics Multibeam is compatible with Norbit data collection tools DCT and NORdredge, web-based utilities for real-time monitoring of multibeam sonar operations. Norbit DCT was used for the live multibeam data preview at Plessow Lake, showcasing a more detailed preview than the single-beam bathymetry of the area.

Multibeam sonar survey of the underwater mound, processed with QPS Qimera, November 2023 © EvoLogics 2023

Global Availability and Future Demonstrations

The Sonobot 5 with EvoLogics Multibeam is currently in serial production, catering to customers worldwide. EvoLogics remains committed to meeting diverse surveying needs by offering compact and easy-to-handle multibeam sonar technology for higher-quality data. The team is gearing up for upcoming demonstration events in 2024 to showcase the vehicle and its configurations.

December 2023