Wind Power in the UK (PDF). - Sustainable Development Commission

sd.commission.org.uk

Wind Power in the UK (PDF). - Sustainable Development Commission

Annex C: Aviation and communicationClutter maps deal with clutter by storing thelocation and other characteristics of clutter in amemory circuit, which is then accessed on eachsweep to remove that clutter from the signal.Some radars have numerical limits on thenumber of cells which can be used for cluttermapping or RAG techniques. This may limit theapplicability to multiple wind farms.Track processing analyses radar returns andrejects any consecutive returns which do notconform to pre-set criteria for a moving aircraft.UK radar manufacturer AMS is currently triallingequipment known as ADT which uses a novelapproach to track processing which it is hopedwill eliminate wind turbine returns and also gainapproval from the CAA.Placing antennea at an elevation that raisesthe radar beam above the wind farm. In somecases it may be possible to eliminate windturbine returns from radars where the antennaelevation above the horizontal raises the radarbeam above the wind farm. The radar antennaat Belfast Airport, for example, is raised to avoidclutter from local high ground, which hasresulted in it avoiding returns from the nearestwind farm. However it is unlikely that raising ofan antenna specifically to avoid wind turbinereturns would be acceptable in most cases sinceit would cause reduced coverage of low levelairspace.Optimised antenna design for low elevationsidelobes, adjusting the tilt of the transmittedand received beams to minimise the number ofunwanted returns in the lowest elevation beam,changes to signal processing to reduce the preand post-compression limiting anddesensitising the background averager are asyet unproven and yet to be implemented.Ongoing trials and the DTI-funded AMSFeasibility Study which should be published inJune 2005 aim to specifically identify andevaluate technical software and hardwaremitigation techniques which will then beassessed by the MOD.Radio navigation aidsAeronautical radio navigation aids – beaconsto assist aircraft in determining their location –are also potentially vulnerable to interferencefrom wind turbines. Most aeronautical radionavigation aids in the UK are operated by NATS.All NATS technical sites have statutoryconsultation status for wind farm and otherdevelopments in close proximity. For all types ofbeacon – VOR, NDB, DME – the safeguardingzone for proposed wind energy developments isa 10km radius around the facility.Although there is some evidence fromelsewhere in Europe that safeguarding zonesaround radio navigation aids are smaller than inthe UK, there is no evidence of UK safeguardingpolicies around these types of facility restrictingwind farm development.Television interferenceBroadcast transmissions and the fixed radio linksare vulnerable to multi-path effects in the sameway as any radio. Television pictures and soundare fed to the transmitters by a network of fixedradio links, the higher capacity ones operating atmicrowave frequencies (3-30 GHz) while there-broadcast links (RBLs) from main to localtransmitters operate in the lower capacity UHFband (0.3-3 GHz).Three way split of responsibilityResponsibility for maintaining the quality oftelevision signals across the UK is splitgeographically between the BBC and what usedto be known as the Independent TelevisionCommission (ITC), now integrated into the Officeof Communications (Ofcom). Responsibility forthe integrity of the supporting network ofsustainable development commissionWind Power in the UK 143

More magazines by this user
Similar magazines