Wind power is becoming an important source of alternative energy as the world moves to drastically reduce greenhouse gas emissions in the next decade. While the number of wind farms is growing rapidly around the world, the detrimental effect of wind farms on existing radar systems is raising serious concerns. Wind farms create strong Doppler clutter and deep electromagnetic shadow that can lead to false alarms and missed detection of real targets of interest like aircraft and storms. A number of studies have been commissioned both in the US and abroad to assess the effect of wind farms on air defense, air traffic control and weather radars. Despite these efforts, the interfering effects of wind farms on radar are not well understood.
The objective of this research is to gain an in-depth understanding of electromagnetic scattering from wind farms. Our approach entails three steps: (i) develop and apply innovative simulation techniques to predict and analyze dynamic radar signatures of wind farm scattering, (ii) develop and apply measurement techniques to acquire scaled model and in-situ measurement data from wind farms to corroborate the simulation, and (iii) exploit the resulting knowledge by investigating radar interference mitigation techniques and wind turbine monitoring applications. The problem is challenging from both the simulation and measurement perspectives because of the unique shape of the structure, the time-varying nature of the scattering phenomenology and the very large physical as well as electrical size of the problem.
DOE-funded Study to Assess Offshore Wind Farm Effects on Radar, Sonar and Communications Systems
Radar Imaging of Wind Turbines
A. Naqvi, S.-T. Yang and H. Ling, "Investigation of Doppler features from wind turbine scattering," IEEE Antennas Wireless Propagat. Lett., vol. 9, pp. 485-488, 2010.
A. Naqvi, S.-T. Yang and H. Ling, "Investigation of Doppler features from wind turbine scattering," 2010 URSI North American Radio Science Meeting, Toronto, Canada, July 2010.
N. Whitelonis, S.-T. Yang and H. Ling, "Correction of Doppler features from wind turbine scattering using a near-field to far-field transformation," 2011 URSI National Radio Science Meeting, Spokane, WA, July 2011.
N. Whitelonis, S.-T. Yang and H. Ling, "Application of near-field to far-field transformation to Doppler features from wind turbine scattering," IEEE Trans. Antennas Propagat., vol. 60, pp. 1660-1665, March 2012.
A. Naqvi and H. Ling, "A signal filtering technique to remove Doppler clutter caused by wind turbines," Microwave Optical Tech. Lett., vol. 54, pp. 1455-1460, June 2012.
A. Naqvi, N. Whitelonis and H. Ling, "Doppler features from wind turbine scattering in the presence of ground," Progress in Electromag. Research Lett., vol. 35, pp. 1-10, 2012.
N. Whitelonis and H. Ling, "Application of a compressed sensing based time-frequency distribution for radar signature analysis," 2012 International IEEE AP-S Symposium, Chicago, IL, July 2012.
A. Naqvi, N. Whitelonis and H. Ling, "Doppler features from wind turbine scattering in the presence of ground," 2012 International IEEE AP-S Symposium, Chicago, IL, July 2012.
S.-T. Yang and H. Ling, "Electromagnetic simulation of the near-field distribution around a wind farm," Int. J. Antennas Propagat., special issue on Impact of Wind Farms on Radiocommunication Systems, vol. 2013, Article ID 105071, 9 pages, 2013.
A. Naqvi and H. Ling, "Time-frequency and ISAR characteristics of wind turbines with higher order motions," Progress in Electromag. Research, vol. 143, pp. 331-347, 2013.
A. Naqvi and H. Ling, "A study of radar features of wind turbines in the HF band," Progress in Electromag. Research, vol. 143, 605-621, 2013.
S.-T. Yang and H. Ling, "Investigation of the electromagnetic near field around an offshore wind farm," 2013 URSI National Radio Science Meeting, Orlando, FL, July 2013.
H. Ling, "On radar signatures of planes, vehicles, humans and wind turbines," ECE Department Seminar, Texas Tech University, Lubbock, TX, May 3, 2013.
H. Ling, "Computational electromagnetics of time-varying structures," 2013 Workshop on Electromagnetic Theory, Modeling and Simulations, Chengdu, China, invited speaker, June 9, 2013.
N. Whitelonis and H. Ling, "Radar signature analysis using a joint time-frequency distribution based on compressed sensing," accepted for publication in IEEE Trans. Antennas Propagat., August 2013.
C. Li, S. T. Yang and H. Ling, "ISAR imaging of a windmill - measurement and simulation," accepted for presentation in 2014 European Conference on Antennas and Propagation, The Hague, The Netherlands, April 2014.
R. Bhalla and H. Ling, "Effect of wind turbine microDoppler on SAR and GMTI signatures," accepted for presentation in 2014 Defense Security and Sensing Symposium, Baltimore, MD, May 2014.