Qinetiq Limited

Adrian Sean Coffey

Robin Jones

Martin Johnson

Michael Harris

David Arthur Smith

Selina A Ballantyne

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

An apparatus for producing a digital depiction of a signal ( ) which is adaptive to the signal itself. A constant rate sampling means, such as an analogue to digital converter ( ), samples the signal ( ) at a constant rate and produces a first digital depiction ( ) of a signal. A transformation means ( ) is responsive to the first digital depiction ( ) and produces a second digital depiction based on the evolution of the signal. The transformation means may be capable of determining when a predetermined threshold level has been crossed and measuring the time interval between predetermined threshold level crossings. The transformation means ( ) may include a logic arrangement and a timer counter and is run from a clock signal ( ) from the same clock ( ) as drives the sampling means. A method of adapting a conventional ADC ( ) to adaptively sample the signal ( ) by adding a transformation means ( ) run off the same clock ( ) as the ADC ( ) is also provided.

Method and apparatus of producing a digital depiction of a signal

An analogue to digital converter generating at least two threshold levels and a comparator for comparing each of the levels with the input signal and generating a primary digital output signal to provide an indication that the input signal has crossed one of the threshold levels. The converter comprises a timer for determining the elapsed period of time between the input signal crossing a first level and the input signal crossing a second level and for generating a secondary output signal representing the elapsed time, whereby the secondary digital output signal and the corresponding primary output signal are used to provide a digital representation of the analogue input signal. The converter may also comprise a receiver of the primary digital output signal from the comparator and for providing an UP/DOWN digital output signal to indicate in which direction the input signal crossed the threshold level.

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Malvern, United Kingdom

Adrian Sean Coffey