RAF opposition to wind farms make The Times front page!

[AonP]

http://www.timesonline.co.uk/tol/news/environment/article3300814.ece

http://www.timesonline.co.uk/tol/news/uk/article3300737.ece

http://www.timesonline.co.uk/tol/news/uk/article3300736.ece

Fairly accurate, apart from the graphic showing Faeroes and Saxa Vord as radar installations! Also the great Type 102 gets a mention but not its in service date or what is going to replace the 3rd Type 93 at Staxton Wold.

[Whenurhappy]

Your links don't work...

[c-bert]

http://www.timesonline.co.uk/tol/news/environment/article3300814.ece

[SoundByDesign]

neither will protests against wind farms!

[c-bert]

Protests may not work, but Typhoons crashing into 777s will catch politicians attention...

[ORAC]

Well if they'd get rid of these poofy little electric fire output radars like the T101 and get some real radars like the T85 back in service they wouldn't have a problem.

Mind you, they might need a few thousand turbines to generate the required 60Mw output.... :p

[SoundByDesign]

"Protests may not work, but Typhoons crashing into 777s will catch politicians attention..."

Especially the Chancellors.

[Wader2]

You want to read all the comments that follow the article.

A supposedly experienced ex-RAF sqn ldr says the interference is nonsense.

"As a retired RAF officer this statement is crap, any "radar" that is interferred with by wind turbined would be swamped by ground returns in any case.
. . .
Any aircraft low flying these days fly routes or something like helo's have published information about TV masts , and wind turbines. Anyone not using them should not be flying."

Someone else says that you can see the moving Boeing against the static wind turbines etc

"Spotting a Boeing is not the same as spotting an aircraft flying 20ft off the deck."

And another firmly grasping the wrong end of the stick;

"But there must be a diameter size of wind turbine that does not affect radar,"

"Surely it can’t be that hard to spot a moving object amongst stationary ones even if they do have moving parts? And what have we got billion pound satellites for?"

Or the really intelligent and well thought out:

"whay can't we put radars on the wind farms looking east, presumably they will be many miles further eastwards and so could see that many miles further? "

Or

"Aren't the turbines and masts made mostly of composites, which reduces their radar footprint?. But then why can't the MoD tune the known obstructions out of their systems with an alogorithm just before displaying on their radar screens?


This is absurd. The MOD needs to find a technical solution to the wind farm problem

MOd are paranoid about their blastd radar. Whom are they detecting? The Russians? The French? The Chinese? Anyone launching a sneak attack would do so with missiles. Ordinary radar - useless. "

Unless of course it is that Boeing driven by terrorists!:\

From the article:

"Giving evidence to a planning inquiry last October, a senior MoD expert said that the turbines create a hole in radar coverage so that aircraft flying overhead are not detectable. . . . This obscuration occurs regardless of the height of the aircraft, of the radar and of the turbine.”

The only sensible comment comes from Exasperated of Bristol:

"Turbines have been proven to exhibit the behaviour of real aircraft (due to moving blades imparting doppler shift onto returned signal). You can't just "invent an algorithm to filter them out" you risk filtering out aircraft too.

~~~~~~~~~~~

makes you weep doesn't it?

[ORAC]

due to moving blades imparting doppler shift onto returned signal Whatever happened to doppler compensated MTI...... :} Sorry, just a bit of banter.

I'd love to know a bit more but don't have the need to know any more. I am sure the problem is soluble and will involve MTI design and the threshold for signal returns on small radar cross-section relfections. The problem being that designing radars to solve the problem will take time, which the government doesn't have to meet it's EU targets for renewable power (don't even go there) and money, which the RAF doesn't have for what it really needs let alone new surveillance radars.......

This problem has been researched previously (http://www.bwea.com/pdf/Wind-Turbines-and-Radar-Operational-Experience-and-Mitigation-)with no major problems reported. One has to wonder if it might be more of a T101 problem rather than a wind turbine problem...... :E

[Wader2]

ORAC,

Correct me if I am wrong, but surely the purpose of MTI was to filter out PE and show moving targets free of airborne clutter.

To filter out the moving doppler returns from variable speed turbines so as to show only true moving returns is something else again and would involve speed gates etc.

Yes, airborne doppler radars can do magic (pun) but still have blind spots.

[Out Of Trim]

Well that's it then! - The ultimate stealth technology, we could put Wind Turbines on our Fighters and they would be invisible to Radar. We could call them propellors... eh, Oh! :}

Perhaps Not!

Oh dear; It appears the Wind Turbine Industry will have to think again!

[ORAC]

Correct me if I am wrong, but surely the purpose of MTI was to filter out PE and show moving targets free of airborne clutter. Doppler compensated MTI was designed to filter out slow moving returns such as flocks of birds etc. it does so my applying an appropriate doppler shift to the returned pulse frequency with a set range. It can also be set for small areas and for selected heading ranges. it can, of course, also remove aircraft such as helicopters or aircraft flying at multiples of the set doppler notch speed including slant range speeds. But all processing removes something. The problem of the aircraft above the sites vanishing would seem to relate to beam pattern or the same processing being used on multiple beams.

Knowing the position of the turbines and the normal rotation speed range, and perhaps even by monitoring them directly or my a microwave radar, I can't see why a suitable filter can't be set. OTH ground wave radars could fill in any resulting loss of low level cover - indeed considerably extend it.

It's not an insoluble technical problem, it's a cash and time problem.

[c-bert]

As an aside, could someone please explain what the purpose of the east coast radars is? What function do they perform that NATS cannot?

[Green Flash]

I think the Met Office weather radar southwest of Glasgow (Eaglesham Moor?) has had to be relocated due to the expanding turbine farm on it's doorstep.

[ORAC]

Wind Farms Impact on Radar Aviation Interests (http://www.bwea.com/aviation/radar.html)

Objectives

A study has been completed by QinetiQ to provide a detailed understanding of the interactions between wind farms and radar systems. The main objectives were as follows:

To determine the effects of siting wind turbines adjacent to primary air traffic control radar;

To determine the extent to which detailed design of wind turbines influences their effects on radar systems;

To determine the extent to which the design of the radar processing influences the effects of wind turbines on radar systems;

To provide text suitable for inclusion on the UK guidelines on Wind Energy and Aviation Interests..........

The following are some of the results generated by the project:

The design of the tower and nacelle should have the smallest Radar Cross Section (RCS) as possible. The RCS of these components can be effectively reduced though careful shaping and choice of construction materials;

Large turbines do not necessarily lead to large RCS (i.e. tower height does not greatly affect RCS);

Blade RCS returns can only be effectively controlled though the use of absorbing materials;

Spacing of wind turbines within a wind farm needs to be considered in the context of the radar cross range/down range resolutions.

Spacing the turbines such that only one turbine can appear in any range cell has advantages in identifying the wind farm, filtering out the turbines and in tracking aircraft over the farm area;

Single wind turbines do not create a significant ‘radar shadow’. Any shadow region is only dark to a distance of a few hundred metres behind the turbine. Beyond this there is some reduction of the radar power, and a time-variation, but these will not prevent detection except possibly for very small targets.

This study complements the recently the completed study by AMS which looked at the feasibility of modifying radars to remove the effects caused by wind turbines (report number W/14/00623/REP).

[Something witty]

A supposedly experienced ex-RAF sqn ldr says the interference is nonsense.

"As a retired RAF officer this statement is crap, any "radar" that is interferred with by wind turbined would be swamped by ground returns in any case.
. . .
Any aircraft low flying these days fly routes or something like helo's have published information about TV masts , and wind turbines. Anyone not using them should not be flying."

Given the number of instances I have heard of new masts and entire windfarms 'appearing' without anything on the map, CALF or NOTAM I think this statement is a load of arrse!

Yes it should be 'up to date' legaly and the board will :mad: you if it isn't but its no good if the 'legal' information is inaccurrate in itself. As I understand it this deficiency is not entirely AIDU's fault, AFAIK there is a height AGL below which the obstruction does not need to be notified... and it is uncomfortably high :eek:

Given recent personal experience (unmarked extensive windfarm, fortunatly viewed from afar and ML, currently being looked at for inclusion) I would be reluctant to assume that my 'up to date' maps display all obstructions.

Not a comment on turbines and radar but...

[ORAC]

reference my comment that Knowing the position of the turbines and the normal rotation speed range See the following, which I presume is the AMS study mentioned above.

Resolving the Radar/Wind Farms Interaction (http://www.all-energy.co.uk/UserFiles/File/25Butler.pdf)

[c-bert]

Given that the people who did that study (BAE Insyte) are also the people supplying T102, one supposes it is lack of funding that prevents T102 overcoming wind farm issues.

[moggiee]

Will they not act like a kind of barrage baloon battery? After all, if they are big enough to present a hazard and clutter radar, maybe they'll be big enough to stop the nasty people in their bombers. :)

(NB: my cheek is not entirely tongue-free)

[Lurking123]

I'm not sure we even bother chasing them any more, with or without radar.;)

[JessTheDog]

There needs to be some sensible policy guidance on this, if objections are raised at the planning permission stage it is far too late.

There is likely to be a tolerable interference level which can be filtered out or localised, acceptable from the perspective of the air defence system.....multiple radars, E3 gap filling etc can cover when needed...add to that operator training, to watch for that suspicious plot entering the wind farm zone!

Of more concern would be interference in overland and low flying training areas. There is a case for keeping wind farms distant from these areas for very understandable flight safety reasons!

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.

[cwatters]

I thought the most interesting bit was...

"This obscuration occurs regardless of the height of the aircraft..."

Presumably this also applies to civilian radar ?

[ORAC]

Presumably this also applies to civilian radar ? Civilian radars predominantly work in a co-operative environment, namely the aircraft squawk mode 3A/mode S etc. The effects of wind turbines or other factors affecting primary radar are of supreme indifference to them.

Which is one reason why the AD system cannot solely rely on the ATC system - if you want to know why read the 911 report.

[Robert Cooper]

This issue is being looked at on this side of the pond too. Site below has some info and interesting links.

http://www.eere.energy.gov/windandhydro/windpoweringamerica/ne_issues_interference.asp

hope the link works. If not type it in :}

Cheers, Bob C

[LFFC]

The CAA have been working on this problem for quite some time, so it shouldn't be a surprise to government. The following document is dated July 06:

CAA Policy and Guidelines on Wind Turbines (http://www.caa.co.uk/docs/33/Cap764.pdf)

Chapter 2 spells out the impact of wind turbines on aviation and given the fact that civilian aviation is now more widespread than military aviation (even low level radar coverage over the sea for oil rig operations is important), it's strange that just military objections are being noted.

[cwatters]

Perhaps the problem for the military isn't detecting aircraft but also cruise misiles and the like.

I wonder if they've tried radar absorbing paint on the blades?

Edit: Seems the Americans are... "Coating equipment with absorbent or reflective materials to minimize the turbine's radar signature"

[themightyimp]

The CAA will not (generally) protest against windfarms; they will mitigate any potential risk by providing dispensation to allow aircraft to be controlled on SSR only. Fine for the UK military if the Queens enemys only operate in controlled airspace and cooperate by transmitting an SSR code.............. :}

[BigEndBob]

Whoever designs the first Stealth wind turbine will be quids in!

[Wader2]

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.

[GOLF_BRAVO_ZULU]

If turbine blades (is windmill too old fashioned?) didn't follow the wind around, the problem would be more containable. A turbine pointing axially at the RADAR head would return negligible doppler shift whereas one presented at 90 deg would return the maximum for the rotation rate.

Depending on spacing, do blades reflect and return from each other, thus multiplying shift values?

[AonP]

Looks like the wind farm developers have bought the RAF a new Air Defence radar for Trimmingham. Only another dozen needed!

BBC News - MoD drops opposition to Norfolk offshore wind farms (http://news.bbc.co.uk/1/hi/england/norfolk/8607471.stm)