Radar constraints pose a significant barrier to wind developments in the UK. In particular, ‘primary surveillance radar’ are common reasons for objection because wind turbines can affect them in a variety of ways. The most significant issue is the presence of ‘clutter’ on the radar operator’s screen. Clutter is the term that describes unwanted targets that show up on the screen. This effect can cause a distraction and the targets could even be mistaken for an aircraft.
Goole Fields Wind Farm
The Goole Fields Wind Farm in East Riding of Yorkshire received an objection  from Robin Hood Airport Doncaster Sheffield due to potential clutter – the specific concern was that this could cause confusion when trying to distinguish between real aircraft and false targets.
The answer in the case of Goole Fields was a tried and tested solution based on utilisation of ‘in-fill’ radar coverage from an alternative source.
Radar In-Fill Mitigation
The affected area of the radar screen is ‘blanked’, meaning that no targets in the area are displayed (whether they are turbines or actual aircraft). This leaves a zone where there is no coverage, which is resolved by incorporating a feed from a different radar that covers the same area but is not affected by the turbines.
The principle of this solution is illustrated in the figure below.
Little John Radar
The Little John Radar was built specifically in order to mitigate the effects of wind turbines on radar, initially for Keadby and Tween Bridge. Another example of a radar that was built purely for wind farm mitigation purposes is the Kincardine PSR in Scotland, which was built to mitigate the impact of the Whitelee wind farm. More on the Kincardine radar solution can be read here.