Originally Posted by
JessTheDog
Is there further information in the public domain? I think I grasp how the interference or spoofing would occur, but to what extent? How similar is the doppler shift from a rotating wind turbine blade to a fast moving jet aircraft, for exampe? How big are these blind spots? What is the position of the CAA? As I understand it they require consultation on windfarms within 30km of an aerodrome.
A raw doppler displayed on a radar screen displays the speed of the contact relative to the receiver. An F4 on an AWG12 radar would show as a largish and solid return (IIRC) but there would be a line of contacts on the same bearing in front and behind as each turbine blade as a given instant would have a higher or lower doppler shift in relation to the aircraft in which it was mounted.
Modern processing presents the doppler return as the correct range and as a single blip in the same way as the traditional image you might have of early pulse radars as beloved by film producers and the like.
The processing algorithyms can filter unwanted echoes, such as that from known windfarms, but also filter out wanted echoes that match the filter criteria.
The doppler return from a target flying tangential to a radar receiver will have exactly the same doppler value as a static target on the ground.
Doppler and filters are not, in thenselves, as complete answer.