New tech lets air traffic systems tell the difference between airplanes and wind turbines
By Ben Coxworth
November 30, 2012
Wind farms and airports don’t mix. Unfortunately, when the blades are turning on wind turbines, the motion can interpreted as aircraft on air traffic control radar screens. Needless to say, the results of such confusion could potentially be catastrophic – or at the very least, they could make things much more stressful for already-frazzled air traffic controllers. UK tech firm Aveillant, however, claims that its Holographic Radar system is the solution to the problem.
According to Aveillant CEO David Crisp, the problem of “wind turbine clutter” has so far not been sufficiently addressed by anyone else.
“For the most part, airports are lodging planning objections to wind farm development in their vicinity on safety grounds,” he told us. “A handful of organizations are using blanking technologies, crude techniques to remove the wind farm returns, such as placing the radar behind a hill so that the wind turbines are out of sight. But such techniques are imprecise and leave unmonitored airspace so are not a long term solution to the problem.”
Conventional radar systems commonly used at airports rely on a rotating antenna, that sweeps a focused radar beam in a complete horizontal circle once every few seconds. By contrast, the Holographic Radar system utilizes a stationary array that receives radar signals from all directions, all the time.
Using those signals, it analyzes what is known as the Doppler phase shift, which relates to how moving objects reflect radio waves depending on their direction and velocity. By doing so, it is reportedly able to easily tell the difference between turbines and airplanes, and can pinpoint any turbines within 20 nautical miles (37 km) of the airport.
The idea is that Holographic Radar would be integrated into an airport’s existing radar system – not replace it. Since it would “know” where all the turbines in the area were, it could simply remove their radar returns from the air traffic control screens.
A development unit is currently reported to be performing well in a field trial, with more trials of a pre-production unit planned for the second quarter of next year.
Of course, some people might just suggest not building wind farms near airports. Crisp, however, thinks that won’t always be an option. “Until now we have coped, but we are now getting to the stage where wind farm developers are running out of areas to build away from airports,” he said. “If we are to meet renewables targets, we will need to see wind farms built in the vicinity of airports over the next few years. Then we will have to deal with the problem.”