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Prestwick // Live Ops
// Surveillance

Radar displays and the ATM

Radar at Prestwick from No 12 GCA in the 1940s and the GCA caravan of the 1960s to the S511, the windfarm-tolerant Terma SCANTER and the 2026 replacement.

What it is

  • The Aerodrome Traffic Monitor (ATM) is a radar display in the tower (CAP 493 S2 Ch 1 para 21). The approach radar controller has a full radar display to vector and sequence arrivals.

How controllers use it

  • The ATM is used for landing order and spacing, departure separation, checking departure tracks and passing traffic information. It is not for approach radar services unless CAA-authorised.
  • Surface movement radar (SMR), where fitted, is used to monitor movements, confirm aircraft are lined up on the correct runway, confirm the runway is clear and the take-off roll has started, switch taxiway lighting and assist emergency vehicles.

UK rules and practice

  • SMR rules: CAP 493 S2 Ch 1 paras 10G/10H.

At Prestwick

  • No 12 GCA was at Prestwick after the war, its “almost the last RAF presence” on the airfield, until it was lent to London Airport in early 1947 (Aerodrome Engineering Group).
  • Around 1967 a controller was photographed “talking down” an aircraft in fog from a GCA caravan by the runway (atchistory).
  • Prestwick operated a Marconi S511 “Hybrid Watchman” primary radar (RWE, 2023) and procured a windfarm-tolerant Terma SCANTER 4002. In August 2026 the end-of-life EN4000 primary radar was cleared for replacement (Ayr Advertiser).
  • The replacement’s uses include locating non-cooperative traffic and observing surface and terminal movements.

// Through the eras

Radar displays and the ATM in each era of the Prestwick tower
EraStatusNotes
1930s–40sAt Prestwick (sourced)Radar approaches from the RAF No 12 GCA unit, working from trucks on the airfield, not from the tower.
1950s–60sAt Prestwick (sourced)GCA trucks and a caravan by the runway, photographed c.1967.
1980s–90sTypical UK practiceA radar monitor in the tower is typical; the S511 family dates from c.1980, but its Prestwick install date was not found.
ModernAt Prestwick (sourced)ATM in the tower; S511/EN4000 and Terma SCANTER 4002 primary radars; replacement cleared in 2026.
// Explainer

Radar and windfarms

Wind turbines show up as clutter on primary radar. A planning report on a windfarm under the RWY 30 approach rated its effect on Prestwick “Major, Significant”: the clutter sits under the approach, affects RWY 12 departures, and vectoring around it adds track miles. [RWE Enoch Hill 2 EIA Ch 8 (Aug 2023)]

  1. Jan 2015

    Tender for a “Windfarm Radar Mitigation System”

    Published 9 Jan 2015, deadline 10 Feb 2015 (ref. GPA_AENG_001, value not shown). The airport said it “is surrounded by land subject to significant planning applications for wind farm development”, that turbines would generate clutter on the ATC radar display, and that it “does not have a suitable means of mitigating or removing that clutter”. It wanted a “Regional Solution”: 360° to 20 nm, extending to 40 nm over time. Four lots: a wind-turbine-resilient primary radar; a 20 nm PSR expandable to windfarm tolerance at 40 nm by 2017; a Multi Radar Tracker fusing the mitigated data with the existing S511 PSR, SSR/WAM and future ADS-B; and a new radar display system. [PCS notice JAN196696 (2015)]

  2. S511

    The legacy primary radar

    An August 2023 planning report says Prestwick “currently operates a Marconi S511 Hybrid Watchman Model PSR” and has procured a Terma SCANTER 4002 as a potential mitigation, with the S511 continuing until replaced. [RWE Enoch Hill 2 EIA Ch 8 (Aug 2023)] A forum post (unverified) calls it an EN4000, S511 electronics with a Watchman antenna. [PPRuNe forum (unverified)] Its installation date at Prestwick isn’t in the sources we found.

  3. 2019–21

    Terma SCANTER 4002 trials, paid for by developers

    In August 2021 the Sunday Post reported a £5m turbine-tolerant “Scanter” radar, funded by windfarm developers, in final operational trials and due to enter service that summer. The same report said the airport had received more than £8m from windfarm firms over four years; ScottishPower Renewables’ lawyers put it at £8.2m, with £6m ring-fenced for radar upgrades, and accused the airport of unlawfully seeking annual payments, which the airport denied. [Sunday Post, 1 Aug 2021 (via wind-watch.org)] An official in-service date wasn’t found.

  4. Aug–Sep 2023

    Ministers rule out ongoing compensation

    ScottishPower Renewables’ 18-turbine Clauchrie scheme was refused on 31 Aug 2023. [Energy Consents Unit ECU00002001] In September 2023 ministers agreed with a public inquiry that mitigation costs “should be demonstrably incurred by Prestwick Airport and that there is no basis for ongoing compensatory payments”. The airport’s lawyers warned of “significant technical, operational and financial consequences”. It had received £5m in compensation from 2019 to 2021. [The Scotsman, 1 Oct 2023]

  5. Aug 2026

    Replacement radar cleared

    South Ayrshire Council granted a certificate of lawfulness to replace the end-of-life EN4000 primary surveillance radar with a modern equivalent on the same tower, next to the ATC tower and Apron E, as permitted development. Its stated uses: finding non-cooperative traffic, monitoring aircraft whose transponders fail, and watching surface and terminal movements. The make wasn’t named. [Ayr Advertiser, 15 Aug 2026]

How mitigation works

The CAA’s policy on wind turbines, CAP 764 (v7.1, Sept 2026), sets out the options, with detail in CAP 670 SUR 13. [CAA CAP 764 v7.1] [CAA CAP 670]

Blanking

Suppress radar returns in a sector over the windfarm. On most primary radars there is no height, so a blank is “a column at all altitudes”. Blanks must be small enough for aircraft to cross quickly. Micro-blanking uses high-resolution blanks, at the risk of scattered single-scan losses.

CAP 764 2.23, 2.48
Infill radar

A second radar with a clear view over the windfarm supplies data “stitched” into the main picture. If it fails, “the in-filled areas become simple blanks”. Glasgow Airport uses dual Terma SCANTER 4002 infill radars for Kype Muir windfarm.

CAP 764 2.24, 2.48; airport-technology.com, 4 Feb 2019
3D radar

Can provide information above windfarm-affected areas.

CAP 764 2.25
Doppler & spectrum filters

High-PRF/Doppler processing and spectrum filters tell turbines from aircraft by their Doppler signatures.

CAP 764 2.26–2.27
Turbine-tolerant radar

A radar like the Terma SCANTER 4002 maps turbine positions and suppresses their tracks while still tracking aircraft (Pager Power lists 6 m range cells and 1000+ tracks).

Pager Power; Clauchrie EIA snippet (unverified)
Transponder Mandatory Zone

A TMZ removes the need for primary radar in an area, but needs an airspace change under CAP 1616. In controlled airspace, SSR-only service is allowed for the minimum time after a temporary PSR failure.

CAP 764 2.28, 2.48 note
Holographic radar

Aveillant’s Theia 16A staring-array radar was deployed at East Midlands Airport in 2015 for the Spondon windfarm and received CAA operational approval.

airport-information.com, 23 Sep 2016
Planning conditions
A typical Prestwick suspensive condition: no blade fitted and no turbine operated until Scottish Ministers are told by the airport that every measure in the Radar Mitigation Scheme is in place and the CAA has approved it. The scheme covers “equipment, procedural or technological measures”, maintained for the life of the windfarm. [RWE Enoch Hill 2 EIA Ch 8 (Aug 2023)] Prestwick objected to Holy Isle because vectoring would avoid a 5 nm area, then withdrew after further assessment. [Pager Power: Holy Isle]
Beyond the airport
If the Terma is unserviceable, service continues on the NATS Lowther Hill SSR (Clauchrie EIA snippet, unverified). NATS has installed a replacement Indra radar at Lowther Hill, “stated to possess inherent windfarm mitigation”. [RWE Enoch Hill 2 EIA Ch 8 (Aug 2023)] Community Windpower’s consented 44-turbine Sanquhar scheme was shelved on cost after the 2023 decision. [The Scotsman, 1 Oct 2023]

Ownership and figures are as reported in the sources cited (the 2015 notice describes the airport as owned and operated by the Scottish Government). Sources that couldn’t be fully checked are marked unverified.

Radar displays and the ATM in the Prestwick tower · EGPK.info