Development of LIDAR based wave measurement and reconstruction system for real time near field wave forecasting and floating system control*

Scanning LIDAR is investigated as a technique for measuring and reconstructing a local sea state that is propagated forward in time to predict sea surface elevations at another point in space and time. The technique is investigated for application in the real time control of a floating offshore wind turbine. Field experiments demonstrate the effect of weather conditions, grazing angle, and implementation on a floating platform on the accuracy of sea surface measurements. Time histories of sea surface elevation and wave statistics are derived from LIDAR point clouds and validated against wave gauge measurements. Point clouds are also used to develop a reconstruction and propagation of a directional irregular wave field based on previously developed methods in the literature. The technique is demonstrated for a proof-of-concept laboratory control of the motions of a floating body. The initial field measurements are used to derive design requirements for a field measurement platform to be deployed in the vicinity of a scale model floating wind turbine.