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1. VERIFEYETM:
Mitigating the effects of wind farms on radar
Increased detection, highly configurable, easy to integrate, and low cost
Challenge
Eliminate the effects of wind
turbines on radar:
• Assist the UK Government in
attaining renewable energy
targets
• Remove interference for ATC
and AD operations
• Maintain radar operator
confidence
• Provide zero degradation to
existing radar services
• Provide cost effective solutions
Solution
VERIFEYE is a novel patch-in
solution using multiple navigation
radars aimed at providing a zero
degradation mitigation technique.
Other benefits include:
• Low cost compared to a new
radar patch-in solution
• Increased detection confidence
of aircraft
• Highly configurable system to
meet the needs of any size
development
• High redundancy system
• Readily integrated with existing
radar set-ups
Results
Initial trials for VERIFEYE have
shown that:
• Aircraft can be tracked within the
Civil Aviation Authority
specifications, CAP 670
• In many cases, the quality of air
surveillance can be improved
• Quick and easy to implement,
and can be patched in to any
type of affected radar system
Due to their sheer size and
reflectivity, wind turbines can have
a detrimental impact on radar and
navigation systems. The UK has
many airports and military sites
spread across the country that
provide air traffic control (ATC) and
air defence (AD) services, which
the wind turbines can interfere with.
The radar interference from
turbines can lead to a number of
issues, including:
• False aircraft like tracks
• Loss of detection of aircraft over
and around the wind farm area
• Increased clutter levels
• Distraction to radar operators
These issues have led to a
significant increase in objections to
wind farm developments from the
aviation and defence stakeholders.
This is a major reason why the
development of wind energy is held
up in the planning process, thus,
causing the UK to fall short of its
energy targets.
Technical mitigation solutions have
so far either fallen short of the
industry requirements, or do not
solve enough issues to be
considered useful.
VERIFEYETM is a mitigation technique
that aims to eliminate the impact that
wind farms can have on any type of
radar. The solution utilises low cost
navigation radars, which can be
modified for air surveillance, to
mitigate the effects of wind farms.
Multiple navigation radars, along with
a centrally located high elevation
scanning radar, sited within the wind
farm, can provide improved elevation
coverage above and around the wind
farm itself, ensuring excellent radar
coverage for all areas.
The information from the navigation
radars is combined using advanced
plot fusion techniques to form an
accurate surveillance picture of any
object, e.g. aircraft, which are flying
over or around a wind farm.
This information is fed back into the
affected radar to 'fill in' to the display
as a patch-in solution. Alternatively, if
the currently affected radar cannot
accept patch-in solutions, a separate
VERIFEYE display could be set up, to
accept and display the patch-in feed.
VERIFEYE aims to be the first zero
degradation mitigation solution on the
market, and in many cases, could
provide improved radar coverage
around the wind farm area.

2. Why QinetiQ?
• Provision of bespoke solutions
based on decades of
experience
• Over 20 years of research and
understanding into the effects
of turbines on radar, including:
Real life measurements
In-depth modelling
capabilities
Complex materials
analysis, including radar
absorbent materials
• Wealth of experience in the
wind energy and radar
industry, and a high level of
understanding of all the
technical issues, which
uniquely places QinetiQ to
develop mitigation solutions
• VERIFEYE is a solution for any
type of radar, for any size of
wind farm
Current patch-in solutions
Patch-in solutions are limited but can
take one of two approaches. Firstly, a
nearby radar is required that is
unaffected by the wind farm, e.g. due to
terrain shielding. A second approach is
to purchase an additional radar, sited at
a different location that is again
unaffected by the proposed wind farm.
These approaches are often not an
option to proposed developments due
to the need for an unaffected radar, let
alone the cost and implementation of a
new radar. Additionally, there is usually
some level of radar coverage loss over
the turbines with the patch-in option.
The VERIFEYE approach is different,
and provides a number of benefits:
• Low cost compared to a new radar
• Not limited to a single wind farm
• Not reliant on terrain shielding
• No loss of coverage
• Improved redundancy
Improved radar coverage over a wind farm
Multi-sensor enhancements
By utilising more than one radar to
view an approaching aircraft at any
one time, along with advanced signal
processing techniques (developed by
QinetiQ), three dimensional (3D)
information can be achieved, rather
than the conventional two dimensional
(2D), which is imperative for AD
operations. This information,
combined with a much higher update
rate, compared to many ATC and AD
units, allows the exact position and
velocity of the aircraft to be accurately
determined, despite the presence of
the turbines.
Tracking of aircraft on a radar screen
The benefit of using navigation-like
radars is that they are much less
susceptible to strong sources of radar
interference than their ATC and AD
counterparts. The use of the high
elevation scanning radar, placed
within the wind farm, to survey the
region of the sky directly above the
wind turbines reduces the problems of
the turbines blocking the radar’s view
of any aircraft traversing the site.
There is also a potential for the ATC
or AD radar plots to be added into the
VERIFEYE plot fusion software. This
reduces the problems of known
boundary issues by seamlessly
integrating aircraft tracks.
Trial results
In July 2008, a proof of principal trial
was carried out for VERIFEYE at
QinetiQ’s Funtington radar test facility.
The trial showed that a two radar
system could track aircraft to within
the Civil Aviation Authority guidelines,
CAP 670. The accuracy of the tracks
was shown to be better than 193
metres in range, and 0.81 degrees in
azimuth. Adding more radars will
further increase the accuracy.
VERIFEYE was also shown to
members of the Aviation Advisory
Panel in June of 2009, where the
benefits of the system were
demonstrated.
Modelling Capabilities
To support and complement the
VERIFEYE mitigation solution,
QinetiQ has extensive radar
modelling capabilities, which can
assess the suitability of VERIFEYE,
and provide evidence to aviation
stakeholders of how effective the
solution is likely to be before
installation.
Tracking of aircraft on a radar screen
The modelling of mitigation
solutions, not just limited to
VERIFEYE, is an excellent method
of reducing risk in the
implementation of solutions.
Examples of modelling include:
• Radar line of sight
• Advance propagation analysis
• Full ATC/AD simulations
• Before/after comparisons
ATC simulation of wind farm effects
VERIFEYE™ and QINETIQ are
trade marks of QinetiQ Limited
For more information please contact:
Customer Contact Team
QinetiQ
Cody Technology Park
Ively Road Farnborough
Hampshire GU14 0LX
United Kingdom
Tel +44 (0) 8700 100942
www.QinetiQ.com
Copyright © QinetiQ ltd 2009
QINETIQ/09/02645