Azimuth-frequency analysis for wind farm clutter identification and mitigation in Doppler weather radars

Concerns caused by wind turbine interference on weather, navigation and surveillance radars are well-documented, and to date a number of approaches to understanding the characteristics of the wind turbine clutter (WTC), the automatic detection of such structures, and possible mitigation of signal contamination have been proposed. The authors suggest a new approach based on the relative attributes of the evolutionary Doppler spectra of WTC and weather, using azimuth scans for each range gate. The data used in the course of the investigation consisted of NEXRAD Level 1 scanning and spotlight Doppler weather radar returns. Identification of WTC independent of weather is based on statistical analysis of the azimuth-Doppler spectral coefficients and cross-spectral analysis of successive azimuth frames. Mitigation of WTC-corrupted coefficients is carried out by nulling the affected coefficients, followed by bi-linear interpolation on planes in the azimuth-range-Doppler 3D data set. Promising results are demonstrated on the aforementioned measured and simulated data, and suggestions for continued research are included.

Acknowledgements

The authors express their appreciation to Dr. Tim Crum, NOAA, and Prof. Robert Palmer, University of Oklahoma, for providing the measured data used in this study. This work was supported by the US Department of Energy Grant # DE-EE0002980.