Infill radar to supress clutter - how good is it?

[siftydog]

A question for the tech boffins;
I've heard of a second 'infill' primary radar being used in some circumstances to supress unwanted clutter - like from a windfarm for example.

How does another primary sensor not display the same clutter on the display, or is the lower lobe of the antenna suppressed thus helping it to 'see over' the interference. Or other means used, a simple earth bund for example?

I know certain sectors can be blanked from this sort of interference, but it renders that sector completely useless in a primary sense.

regards, Sifty

[Evil Lord Ham]

The in-fill radar uses terrain shielding to avoid detecting the windfarm (i.e it is behind a hill). The trick is to ensure that there is sufficient low level coverage of aircraft flying over the windfarm, but the turbines themselves are beneath detection.

[siftydog]

Thanks for that, it seems a little hit and miss as a workaround.
Has this technology been applied successfully anywhere in the UK yet, and for what applications would you want it? Windfarms are the only one that spring to mind, are there others?

Sift.

[Glamdring]

I believe there is a small radar head just next to the Kincardine bridge that is to help with windfarm clutter on Glasgow's radar. Not sure how successful it is, a Glasgow controller may wish to comment.

[siftydog]

Any takers from Glasgee?

[BDiONU]

I believe there is a small radar head just next to the Kincardine bridge that is to help with windfarm clutter on Glasgow's radar. Not sure how successful it is, a Glasgow controller may wish to comment.
That was built (at the power companies expense) in order to provide coverage over the Whitelees windfarm on Eaglesham moor which was being picked up nicely on the Lowther radar. Lowther displayed at Prestwick Centre has had a chunk cut out of it which encompasses phase 1, 2 and the planned phase 3 which is infilled by Kincardine Bridge.
I doubt Glasgow airport uses it but Prestwick Centre does.

BD

[Radarspod]

Glasgow do indeed make use of the Kincardine radar, or at least did when it was orginally put in while the Glasgow PSR was replaced.

Has this technology been applied successfully anywhere in the UK yet

This isn't "technology" as such, its just putting down more radars to fill in the gaps where blanking has to be put in over windfarms. There are at least 2 other examples in the UK being worked on where a new radar is being put in place to fill the gaps.

RS

[siftydog]

Back to the top with this,

would any users of an infill radar anywhere in the UK care to commment on whether there is a loss of primary returns at low level over the original source of clutter, or is it more exacting than that?

[NorthSouth]

Yes there's a (theoretical) loss of returns over the source of the clutter, because by definition the infill radar has to have a higher base of cover, so that it doesn't see the wind farm (or whatever's causing the clutter). But the loss is only a few hundred feet, and if that few hundred feet contains wind turbines several hundred feet high, there aren't many pilots who would want to fly in there anyway so in practice there's probably little or no loss of returns from aircraft that you'd want to see.

Don't forget it's been standard practice for yonks to simply blank out all cover over persistent areas of clutter e.g. road traffic, causing all genuine targets at all altitudes to disappear.

The difficulties with infill are less to do with lost returns than plots jumping as they cross the boundary of the patch, due to slant range errors between the two radars.

NS

[Downwind.Maddl-Land]

I don’t want to be accused of advertising or spamming but the problems alluded to by NorthSouth above have been resolved and demonstrated at UK Airport last year. Other problems that were solved were that of:

Orientating the axis of the aircraft return to appear as though it was originating from the wind turbine affected PSR;

Integrating differing turn rates of different PSRs;

If anyone would like to PM me, I can refer you to a video recording on a company website that clearly demonstrates this.

I trust that the content of this reply is within the rules of PPRUNE; if not, moderators please accept my apologies and delete this post.

[Impregelia]

Interesting topic. I believe the problems referred to by NS have been resolved by a company called Throughput at a couple of airports in the UK.

[mr grumpy]

There are various solutions being touted, as unique infill radars, to integrate infill radar and also as alternatives to infill radar. I believe that at this stage they are unproven or there are question marks as to just how workable they will be as solutions. Time will tell.

[Pronto_1]

Worked on looking at the effects of windfarms on ATC operations in the UK for several years (but by no means an expert :O).
At this present moment in time the only mitagation "proven" to work is infill radars with terrain shielding however the loss of low level coverage can be a major concern.
There are a couple of current sensor manufactuers who believe that they have deveoped/ improved their current radar technologies enough to differentiate between moving targets and turbine blades with good results(and have currently installed this at at least three locations,i can think of off hand).
There are also some new companies who are developing new infill technoligies which can be placed virtually anywhere without receiving windfarm interference. These systems have been demonstrated with good results however it is fairly new technology and requires some robust work to get it to full approval status

Windfarm issues not only cause unwanted clutter in traffic area they can also cause track suppression and track deviation (to name two other issues) as signals are suppressed in and around windfarms and ac returns are picked up from multipath results caused by turbine blades.

Not too sure if that helps, hopefully it should

[CGA]

I'm new here, and interested in wind turbine clutter solutions. Ive been told by ATC people that infill may not be possible where the radar turn rates are too low, and that the Glasgow/Kincardine solution may not be generally applicable to other airport sites. But I am very interested to hear more about the techniques (and demo video) referred to by Downwind.

[bitsink]

Believe me it is possible to mitigate the effects of wind turbine blades on PSR without the expense of infill radars. This has been demonstrated and independently verified by ANSPs and scientific bodies. The only reason this is not more widespread is the ANSPs want the energy companies to pay for the upgrade to existing radars.