USV Performs Lidar and Multibeam Survey at Trondheim Fjord in Norway

In this case study, we highlight the benefits of using the NORBIT WINGHEAD and iLiDAR integrated survey system on unmanned surface vehicles for shallow water surveys.

Used Sensors

NORBIT WINGHEAD® i77h, featuring integrated Applanix OceanMaster GNSS/INS system
NORBIT iLiDAR
NORBIT Sound Velocity Profiler
Maritime Robotics Otter USV

WINGHEAD benefits:

First cylindrical ultra-high resolution bathymetry sonar on the market
0.5 x 0.9°beam widths at 400kHz
HD beamformer providing 1024 beams per ping
High performance integrated GNSS/INS systems
Integrated sound velocity probe
Small form factor and low power consumption
Designed for rapid mobilization on any platform
Available with optional Lidar

The Otter is a versatile USV designed for seabed mapping and monitoring applications in sheltered waters, harbours, lakes and rivers.

Best-in-class endurance for its size, operating up to 20 hours at 2 knots
Max speed of 6 knots
A payload capacity of up to 40 kg
The modular solution easily split up into lightweight parts for easy transportation (smaller vans, boats, helicopters etc.), launch and recovery from cranes on ships or quayside
Built-in AutoCast winch for SVP casts and planning functionality for automated deployment

The highly integrated solution enables small form-factor and rapid deployment

All sensors are interfaced to a small topside unit, where data is time-stamped by the integrated GNSS
The sonar and surface SVP are interfaced to the topside unit via a single deck cable
The GUI features an integrated INS setup wizard, as well as monitoring functions, to simplify the setup
The survey system interfaces to an on-board computer via Ethernet connection for data acquisition

Skansen is a historic area in the city of Trondheim, Norway. A fortification in older days, it is now well known for its marina, train station and the Skansen Bridge, a 52m span bascule railway bridge that can open for marine traffic to access the Trondheim Fjord. The Skansen Bridge was designed by structural engineer Joseph Strauss, who also designed the Golden Gate Bridge in San Francisco. The main goal of the survey was to perform the inspection of the jetty and investigate if there has been any displacement of rocks forming the jetty. The survey was controlled remotely from the Skansen Bridge.

The entire system is designed for rapid mobilization and deployment.

The USV is lightweight and can be transported in a van
Easily deployed from a slipway, with all sensors pre-mounted on the USV
Survey offsets are fixed and known, thus no measurements are required

The entire system is controlled remotely from the quayside.

The Otter USV is manoeuvred using a mobile device
Easy-to-use control software is used to plan the survey and collect data
All data is time-synchronized internally
RTK GNSS positioning using Internet-based corrections (no cables, base stations or radios)

Combining NORBIT WINGHEAD and Lidar with the Otter USV enables a surveyor to get high-resolution data while drastically minimizing the mobilization time. The combination of NORBIT Multibeam and Lidar technology enables surveyors to collect point cloud data above and below the waterline from a portable, unmanned platform.

NORBIT’s curved array technology allows the beams to be steered electronically up to the waterline without having to physically rotate the sonar, which is ideal for combined Multibeam and Lidar surveys and allows the seamless transition between the two data types. Curved arrays produce narrower beams (higher resolution) across the entire swath compared to an equivalent flat array system. The combination of 1024 beams and 0.5°beam widths provides ultra-high-resolution point cloud data and facilitates the detection of small targets such as rocks, ropes, chains, anchors, etc. which may be hazardous to navigation in shallow harbours. The USV can operate in shallow, difficult-to-reach areas where it is difficult for conventional survey vessels to navigate.