Mitigation of Wind Turbine Clutter Using Adaptive Beamforming for Phased Array Radars

The growth of the wind power industry has led to a severe challenge of wind turbines interfering with radar operations, which has been referred to as wind turbine clutter (WTC). Due to the motion of the turbine blades, WTC is non-stationary and cannot be filtered effectively using conventional ground clutter filters. Recent studies have been conducted to develop a robust mitigation algorithm for WTC, but no operational algorithm currently exists. With the next generation of weather radars likely being based on phased array technology, new approaches for WTC mitigation using adaptive beamforming are possible and should be explored. With phased array radars, it becomes possible to adaptively change the beam pattern when interfering signals are present so that their detrimental effects are mitigated. The difficulties in filtering WTC in the time and frequency domains can be avoided altogether by having nulls in the beam pattern in the directions of the WTC returns. The Atmospheric Imaging Radar (AIR), which is a unique mobile X-band weather radar developed at the Advanced Radar Research Center at the University of Oklahoma, has collected simultaneous RHI data of severe storms and WTC, and these data will be used to demonstrate the capability of adaptive beamforming to mitigate WTC. A comparison between conventional and adaptive beamforming will be presented to illustrate the advantages and challenges of using the latter for weather observations.