Assessment of wind turbines generators influence in VOR aeronautical navigation systems

The main objective of this paper is to study and quantify the influence of wind turbine generators on the omnidirectional range systems of very high frequency (VOR), as well as to define exclusion regions around these systems. These goals were accomplished through the development of a model, and then taking flight routes into account. In order to verify the influence caused by wind turbines, calculations were performed for the flight levels 55 and 450, and for several previously defined flight routes, for Portugal. In Nisa, where there is a nearby wind farm (Serra da Amêndoa), the signal power coming from the turbines presents significant values compared to the receiver sensitivity, which may originate a carrier-to-interference ratio lower than the acceptable minimum. In this case, the minimum distance at which the nearest wind turbine should be installed is 10.3 km, in order to guarantee an acceptable interference (but this distance is very much geographically dependent).