Raytheon, NATS Work To Develop New Hardware, Processing

Several times over the past year, ANN has reported on stories in which proposed windfarms have come into conflict with the nation's air traffic system. One of the most common problems is radar interference caused by the giant, spinning blades of the wind turbines which are, in some cases, indistinguishable from aircraft. Some claim that air traffic concerns are stunting the growth of wind power in the United States.

Putting a set of turbines across an area can look like a "great field of moving objects," according to Raytheon Digital Airport Surveillance Radar technical director Peter Drake. "It's a very real problem." He said that in addition to the spinning blades appearing to be aircraft on radar screens, the interference can cause a legitimate target to suddenly shift its position.

The online technology magazine CNET reports that Raytheon and Europe's National Air Traffic Services have been collaborating on potential mitigations of the interference for the past two years. Raytheon Canada general manager Brian Smith said some of the same techniques being developed overseas could be applicable to the U.S. as well. One such solution is called concurrent beam processing, which allows radar systems to differentiate between targets in the air and ground clutter. Another involves more detailed terrain maps that allow stationary turbines to be screened out, leaving only the moving objects.

But these and other potential solutions to the problem require upgrading the radar hardware to allow it to process more data along with software updates. Smith says he is confident that the partners have come up with workable fixes.

Turbine manufacturers are reportedly doing their part as well, working on "stealth" technology that would reduce the radar signature of the devices. But Gary Siefert at the Idaho National Laboratories, a recognized expert on wind-radar conflicts, says most of the windfarms will have to be addressed on a case-by-case basis. "Anybody who says they can solve all the problems is probably overstating," he said.

FMI: www.raytheon.com