Qinetiq Limited

David Arthur Smith

Michael Harris

Adrian Sean Coffey

A coherent laser radar or lidar device () for measuring wind speed is described that comprises a transmitter for transmitting a beam of light to a remote probe volume (), a receiver for detecting back-scattered light and an analyzer for calculating wind velocity at the remote probe volume from the Doppler shift in frequency of the detected back-scattered light. The analyzer is arranged to monitor for the presence of, and/or to ensure the calculated wind speed is corrected for, any Doppler frequency components of the detected back-scattered light that arise from back-scatter off cloud located at a range greater than the range of the remote probe volume. It is described how the lidar () may be scanned and wind velocity components calculated by fitting the scanned line of sight velocity values to a predetermined function. Furthermore, it is outlined how an initial fit may be performed to determine which points are to be used in this calculation. The incorporation of a back scatter profiling means, such as ceilometer (), is also described. A wind turbine () incorporating such a device () is also described.

Laser radar device and method

A buoyant platform apparatus, such as a buoy, is described that comprises a laser radar (lidar) wind speed measurement device. The lidar is arranged to make wind velocity measurements at one or more remote probe volumes of known position relative to said platform. The wind speed measurement apparatus may further comprise motion sensing means that, in use, monitor motion of the platform allowing wind speed at an absolute position in space to be measured. Wind velocity data may also be compensated for platform movement.

Wind speed measurement apparatus and method

A wind turbine is provided having a lidar wind speed measurement apparatus for achieving wind control. The lidar apparatus is arranged to scan the area in front of the wind turbine so as to generate a measurement of the wind speed across the wind field. The lidar apparatus may be located in the hub of the wind turbine and the look direction inclined away from the rotational axis so that rotation of the hub ensures scanning. Preferably the lidar apparatus has a plurality of look directions so as to increase the scanning rate. This may be achieved by having a number of dedicated lidar systems and/or by using multiplexed lidars. Measurement of the wind field allows improved control of the wind turbine giving efficiency and reduced wear benefits.

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Malvern, United Kingdom

David Arthur Smith