Guidance Marine launch first local position reference sensor that does not use targets

May News

A new type of position reference sensor that does not use physical targets is changing the way that service operation vessels navigate in wind farms.

  Figure 1 -
RangeGuard Sensor.
Guidance Marine are experts in designing and manufacturing local position reference sensors and are the leading sensor supplier to vessels in the oil and gas industry. 2016 has seen the launch of a new type of sensor that is changing the way that vessels operate around wind farms. RangeGuard is the first sensor from Guidance Marine that does not use physical targets. It uses radar reflections from its surroundings to calculate precisely the vessel’s range to the nearest object in its field of view. Combining the information from two sensors allows range and bearing to be calculated and input into the dynamic positioning (DP) system of a vessel. The first targetless DP local position reference sensor (PRS).

Guidance Marine presented a paper at the Royal Institute of Naval Architects conference Design & Construction of Wind Farm Support Vessels, on 30th March titled “A New Era in Position Referencing”. Business Development Manager, Dr Sasha Heriot, described a collaboration between Bernhard Schulte Ship Management, Marine Technologies and Guidance Marine where two RangeGuard sensors were installed on the Bernhard Schulte managed vessel, the Ocean Zephyr.

Hendrick Busshoff, Offshore Marine Superintendent at Bernhard Schulte Ship Management trained as a Master mariner in the offshore oil and gas industry before moving to offshore wind. He recognised the differences in vessel operation in a wind farm compared to an oil field and identified the need for a new type of position reference sensor.

Figure 2- Installation of the Ocean Zephyr.                             
A vessel approaches a wind turbine on DP and typically uses DGPS and a laser PRS to obtain precise position. If poor quality reflector targets are installed on the wind turbine it can lead to the laser sensor detecting false reflections due to their proximity to other highly reflective surfaces, such as the high vis jackets of workmen on the landing platform and walk-to-work gangway. To overcome this problem, high quality reflective prism targets should replace low quality reflectors, but the cost of installing these on every single wind turbine in a wind farm can be prohibitive. Removing the need for physical targets altogether is a step change in wind farm navigation.

  Figure 3 - Sensor configuration. 
Relative position of vessel to wind
turbine is calculated using simple

Guidance Marine installed two RangeGuard sensors on the starboard side of the Ocean Zephyr. The 24GHz radar sensors send out a low power signal and the radar reflections from their field of view are detected. By combining information from two sensors, the location of the wind tower relative to the vessel can be calculated precisely.

Data was collected during a sea trial to the BARD 1 wind farm in August 2015. Although the sensors were not connected into the DP system, the sensors successfully recorded the movements of the vessel.  The next stage of the project is now underway at Marine Technologies to connect the sensors into the DP system of the ship.

Figure 4 - Approach to a wind turbine. The vessel keeps station
at 59m before moving to 50m. The vessel holds position for
around 15 minutes before moving to the final position at 26m.
A camera mounted adjacent to the sensors record the images of the
After the promising results obtained during the trials on the Ocean Zephyr, Bernhard Schulte decided to make full use of the potential of RangeGuard and install a fully DP integrated system on their SOV new build Windea La Cour. The technologically advanced vessel is scheduled to set sail in Q2 2016 and the RangeGuard system will ideally complement and expand the capabilities of the ship.


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