Analysis of multiband monostatic and bistatic radar signatures of wind turbines

Abstract

This paper presents the results of recent measurements taken with two radar systems to measure the simultaneous monostatic and bistatic signature of wind turbines, at S-band and X-band. Coherent monostatic and bistatic data was collected with the University College London (UCL) NetRAD 2.4 GHz radar, and the Cranfield University CW radar operating at X-band. This initial analysis shows the bistatic Doppler signature of wind turbines and informs on the key differences seen at modest bistatic angles. Polarimetric variations are also analysed via data gathered using co-polarised VV and HH and cross-polarised VH components.

Experimental analysis of multistatic wind turbine radar clutter statistics

“…These systems have been mentioned as a possible mitigation approach for wind farm clutter, as multiple views on the area under surveillance as well as different deployment geometries can be beneficial to reduce the adverse clutter effects. In our previous work in [10,11] preliminary results were presented in terms of micro-Doppler signatures of wind turbines extracted from bistatic radar data, with limited bistatic angle of approximately 6.5°.…”

Wind Turbine Blade Radar Signatures in the Near Field: Modeling and Experimental Confirmation

“…The lower frequencies also exhibits intense level of power as predicted. In the experimental micro-Doppler, the trace of the tip present in the theoretical signature, can also be seen above the experimental results such as those in [12] and [17], as they are focused on monostatic and bistatic measurements in the far-field whereas our results focus on monostatic measurements in the nearfield. However, some comments could be made on qualitative aspects of the results obtained here.…”

Measurements and modelling of radar signatures of large wind turbine using multiple sensors

“…The turbine is a 7 MW Samsung model, with rotor diameter equal to 171.2 m, height of the hub 110.6 m and length of each of the 3 blades equal to approximately 85.6 m. The turbine is designed to operate with wind speed between 3.5 and 25 m/s, generating rotation speed of approximately 5.9 to 10.6 rpm, according to the information supplied by ORE-C, who maintains this turbine. It is important to notice that this model of turbine, designed for an offshore usage, is much larger than the onshore variants whose radar signatures were measured in previous work [6][7][8][9][10][11]. Groundtruth data from ORE-C (rotation velocity and yaw angle of the turbine over time) will allow correlating the passive and active radar signatures with the actual behavior of the turbine, enabling a step forward compared to previous work where this data was not made available by the wind farm management [10][11].…”

“…As an effect of this, the development of wind farmswhich is a priority to reduce reliance on fossil fuels -can be hindered by "radar objections" from defense or civil aviation authorities. Research within the radar community has been undertaken to characterize the radar signatures of wind turbine and farms, both from a modelling perspective [2][3][4][5] and from an experimental standpoint [6][7][8][9][10][11], as well as looking at improving signal processing and detection algorithms to make existing radar systems more resilient to wind farm clutter.…”

“…A wide range of different turbine sizes are considered, including one of roughly comparable dimensions (164 m diameter) to the one measured in this work (174 m), although the dimensions of the experimentally measured turbine are not stated. Multistatic/distributed radar systems have also been proposed to address this wind farm clutter issues, assuming that the additional spatial diversity from the network of radar sensors may be advantageous to reduce the clutter-to-target cross section and the spread in Doppler of the undesired clutter signal [10][11].…”