Latest radar flight trial results

Further flight trials in Britain to assess new radar technology to overcome interference from wind farms on military and civil air traffic control radar have added to the understanding of mitigation methods. Results from the latest trials were presented last month in a well attended session at the 28th annual conference of the British Wind Energy Association (BWEA).

A variety of aircraft flew over four different wind farms in Wales in June to test two types of radar technology: BAE Systems' Advanced Digital Tracker (ADT), and the Sensis SPE-3000 processor developed by SELEX SI of Italy. Both systems allow radar operators to track the course of aircraft above wind farms by filtering out clutter from the movement of wind turbine blades on radar screens.

"Radar problems are very well understood now," said BAE's Mike Butler. "We have a range of technologies that we can use. Technologies are no longer the issue now, it is the acceptance of those technologies." Graham Biggs from SELEX added: "I do not believe you will get a magic bullet -- a 100% safety case. You will get a range of mitigation techniques."

Appraising the systems, aviation analyst Charles Morelli of Pager Power warned that there would be times when neither product would be suitable. This was illustrated by the oldest of the wind farms used for the trial where the 103 turbines are densely packed together. The technology worked best with the three later wind farms where turbines are larger but are spaced further apart.

The ADT might be more suitable for use with younger Watchman type radar, while the Sensis SPE might be more suited to older generation Watchman type radar, said Morelli. Mike Watson from Pure Power added that which system would be best would depend on the airport. "It's very much horses for courses," he said. "We have some solutions on the table. It is now up to developers to engage with air traffic controllers and find out which solution is best for them," said Chris Tomlinson from the BWEA.