Analytical method for monostatic radar cross section calculation of a perfectly conducting wind turbine model located over dielectric lossy half space

Abstract

Radar cross section (RCS) of a wind turbine has a key role for determining possible effects of wind farms on radar and navigation systems. Closed form expressions of the physical optics technique are applied to calculate monostatic radar cross section of an electrically large wind turbine model over a dielectric, lossy half space. The model is constructed with perfectly conducting canonical structures. First-order effects of the half space to the electromagnetic scattering mechanism are approximated with four-path model. Doppler spectrogram of the turbine model over lossy ground is obtained using short-time Fourier transform. The closed form expressions provide very-fast RCS calculations for different broadside directions and blade rotation speeds. Performance of this proposed method shows that it is suitable for real-time simulations that analyse the effects of the wind farms to the radar and navigation systems performance.

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

“…As it can be seen from equation (8), the amplitude of each frequency will depend in general on the physical parameters of the set-up. The curved shape introduces a complex dependence of these amplitudes on geometrical properties of the blade.…”

“…where is the integer of the Jacobi-Anger expansion (8). It is assumed that the radar provides Inphase and Quadrature (I/Q) outputs after mixing the received signal with the carrier frequency 0 , so the actual spectral lines are situated at 0 ± The amplitude of the frequencies in the spectrum depends on the Bessel functions ( ).…”

“…References [8]- [10] are examples of the work done in numerical modelling of turbines that analyse the effects of the wind farms to the radar and navigation systems performance. Investigations [11]- [18] use experimental data to study WTs radar cross-section (RCS) and investigate methods to mitigate it.…”

Influence of the wind turbine blade model on echo's Doppler characteristics

“…In order to obtain the Doppler characteristic of the radar echo of the wind turbines, the scholars at home and abroad have made a lot of research, mainly the field measurement [9, 10], the shrinkage ratio model experiment [11, 12], and the mathematical simulation [13–16] method. There are two kinds of methods involved in mathematical modelling of the wind turbine echo: one is to model the wind turbine echo based on the high‐frequency approximation algorithm [16] which is used in the field of electromagnetic scattering to compute the radar cross section (RCS) of wind turbine blades; and the other is, under the far field condition, to use the approximate equivalent relation to equal the wind turbine blade to the scattering points, and then to model the echo of the scattering points [15].…”

Solution of wind turbine blade Doppler and its characteristic analysis

“…In view of the simulation of the echo of the wind turbine, the point scattering model based on the wind turbine blade is proposed in the literature [11–13], but the model is obviously too rough; at present, it is only used for the qualitative analysis of the Doppler characteristic [14]. At the same time, the current study only considered the rotating motion of the blades, but lack of the actual motion of the wind turbine blades, such as torque and other movements [15–17].…”