Interactions of Wind Turbines with Aviation Radio and Radar Systems

Cover
Contents
List of figures
List of tables
About the author
Preface
	References
1 Introduction
	1.1 Wind turbines and aviation radio and radar systems
	1.2 Climate change and renewable energy
	1.3 International events and energy
	1.4 On-shore wind farm siting problems
	1.5 Pre-feasibility
	1.6 Off-shore
	1.7 Increasing wind turbine footprint
	1.8 Aviation
	1.9 The aim of this book
	1.10 The composition of the book
	References
2 A brief history of windmills, electricity generation and radar
	2.1 Problems are reported
	2.2 Approach
	2.3 Machines for extracting energy from wind
		2.3.1 Sails
		2.3.2 Rotating machines
		2.3.3 The influence of wind direction
		2.3.4 The first horizontal axis machine?
		2.3.5 Increasing complexity
		2.3.6 Windmill proliferation
		2.3.7 European winds of change
		2.3.8 Cap Mills
		2.3.9 Evolution towards the modern wind turbine design
		2.3.10 Options and understanding
	2.4 Machines for generating electricity
		2.4.1 Electricity and magnetism: Oersted
		2.4.2 Faraday, motors and generators
		2.4.3 Commercialisation of power generation
		2.4.4 James Blyth – the first electricity-generating wind turbine
		2.4.5 US wind turbines – the first horizontal axis machines
		2.4.6 Danish and German wind turbines – appliances of science
		2.4.7 Turbine development during the 20th century
	2.5 Radar
		2.5.1 Getting over the influence of Aether
		2.5.2 Faraday and Maxwell
		2.5.3 Proving Maxwell’s theories
		2.5.4 Propagation and Marconi
		2.5.5 Hülsmeyer and the Telemobiloskop
		2.5.6 Improving the early systems
		2.5.7 Non-metallic objects and the Naval Research Laboratory
		2.5.8 Other nations
		2.5.9 Secondary surveillance radar
		2.5.10 Development of PSR
		2.5.11 Computerisation
		2.5.12 Networking
	2.6 Summary
	References
3 Aviation and aviation radio systems
	3.1 Introduction
	3.2 Regulation
	3.3 Aviation’s ground environment
		3.3.1 Introduction
		3.3.2 Ground terminology
		3.3.3 Aerodrome or airport location
		3.3.4 Runways
		3.3.5 Take off, take-off or departure?
	3.4 The air environment
		3.4.1 FIRs
		3.4.2 Airspace class
		3.4.3 Airspace types
		3.4.4 The role of AGA communications
		3.4.5 Altitude measurement
		3.4.6 Reference pressures
		3.4.7 Accommodating variations in air pressure
	3.5 The rules of flight
		3.5.1 Visual flight rules
		3.5.2 IFRs
		3.5.3 Control of flight
		3.5.4 Navigation
		3.5.5 Flying using instruments
	3.6 AGA communications
		3.6.1 The importance of AGA communications
		3.6.2 Spectrum use
		3.6.3 Additional military spectrum use
		3.6.4 Modulation method
		3.6.5 AGA protocols
		3.6.6 Equipment considerations
		3.6.7 Calculating the distance to the radio horizon (constraining mitigation of effects)
		3.6.8 Radio horizon implications
		3.6.9 Long-range communications
	3.7 Aeronautical Navigation Aids (Navaids)
		3.7.1 Non-Directional Beacon
		3.7.2 VOR/DME
		3.7.3 DME
		3.7.4 TACAN
	3.8 Precision landing aids
		3.8.1 The development of ILS
		3.8.2 ILS
	3.9 Primary radar
		3.9.1 ATC
		3.9.2 Nomenclature
		3.9.3 Primary radar characteristics
		3.9.4 Detecting the presence of targets in noise
		3.9.5 The Neyman and Pearson Theorem
		3.9.6 A practical target detector
	3.10 Secondary radar
		3.10.1 SSR development
		3.10.2 Operating concepts
		3.10.3 Equipment
		3.10.4 Mode S
		3.10.5 Mode S message sets
		3.10.6 Advantages of SSR/IFF
		3.10.7 Disadvantages of SSR/IFF
		3.10.8 Why cannot wind turbines carry SSR like aircraft?
	3.11 SSR derivatives
		3.11.1 Automatic dependent surveillance – broadcast
		3.11.2 Multilateration (M-Lat) and wide area multilateration (WAM)
	3.12 Air defence radar
		3.12.1 Phased array radar
	3.13 PAR
		3.13.1 PAR requirements
		3.13.2 PAR coverage
	References
4 The wind, wind turbines and wind farms/wind parks
	4.1 Introduction
	4.2 The wind
		4.2.1 Causes of terrestrial wind
		4.2.2 Friction and wind
		4.2.3 Turbulence
		4.2.4 Wind speed classes
	4.3 Definitions
		4.3.1 The wind turbine
		4.3.2 Wind farm/wind park
		4.3.3 Combined energy farm
	4.4 Wind turbine construction
		4.4.1 The tower
		4.4.2 The nacelle
		4.4.3 The blades
		4.4.4 On-shore foundations
		4.4.5 Off-shore foundations
		4.4.6 Lightning protection
	4.5 Size of wind turbines
		4.5.1 Metrics
		4.5.2 Other factors
		4.5.3 Trends
	4.6 Wind farm layout and design factors
		4.6.1 Turbine layout – on-shore
		4.6.2 Turbine spacing off-shore
	4.7 Wind farm lifetime
	4.8 Wind farm operations – curtailment
		4.8.1 The emergency stop
		4.8.2 Slowing and stopping the turbine
		4.8.3 Acoustical noise
		4.8.4 Shadow flicker
		4.8.5 Ecology
		4.8.6 Grid capacity
		4.8.7 Ice accretion
		4.8.8 Aviation objections
		4.8.9 Trends
	4.9 Wind farm planning and construction considerations
		4.9.1 Introduction
		4.9.2 Finding an on-shore site to develop
		4.9.3 Finding an off-shore site to develop
		4.9.4 The planning process
		4.9.5 Preparation of a consent or planning application
		4.9.6 The EIA/EIS
		4.9.7 Planning submission
		4.9.8 Planning conditions
	4.10 Construction of a wind farm
		4.10.1 Ordering turbines
		4.10.2 Access works
		4.10.3 Turbine foundation works
		4.10.4 Cabling and the grid connection
		4.10.5 Coordination
	4.11 The impact of a wind turbine on the electromagnetic spectrum
		4.11.1 Scope
		4.11.2 General principles of RCS
		4.11.3 The RCS of wind turbines components, wind turbines and wind farms
	4.12 The problem space
		4.12.1 Radar technical interactions
		4.12.2 Saturation
		4.12.3 Clutter
		4.12.4 Pulse compression
		4.12.5 Processing overload
		4.12.6 Track data block obscuration
	4.13 Obscuration
		4.13.1 Region and scale of obscuration
		4.13.2 Tracking and track seduction
		4.13.3 Processing overload
		4.13.4 PSR shadow
		4.13.5 PSR mitigations
		4.13.6 SSR effects
		4.13.7 SSR mitigation
	4.14 Communications and navigation – fast fading and phase error
		4.14.1 Fading
	4.15 AGA safeguarding
		4.15.1 Principle
		4.15.2 Power level calculations
		4.15.3 Carrier power
		4.15.4 Interference power
		4.15.5 Significance of the power available
		4.15.6 Illustration
	4.16 VOR and bearing error
	4.17 ILS effects
	4.18 Doppler signature of a wind turbine
		4.18.1 Doppler
		4.18.2 Wind turbine Doppler signature
	4.19 Wind turbines and radio shadow
		4.19.1 Misconception
		4.19.2 Diffraction
		4.19.3 Aim
		4.19.4 Analysis
		4.19.5 Approximations/assumptions
		4.19.6 Signal amplitude results
		4.19.7 The effects of frequency on diffraction and shadow – signal amplitude
		4.19.8 Summary of amplitude results
		4.19.9 Shadow phase effects
		4.19.10 Effects of wavelength on shadow phase effects
		4.19.11 Interpretation of results
	4.20 Wider concerns
		4.20.1 Scope
		4.20.2 The greatest challenge
		4.20.3 Acceptable levels of confidence
		4.20.4 Precedent
		4.20.5 Digital twins
		4.20.6 Common concerns
	References
5 Analysis
	5.1 Introduction
	5.2 Conversion of useful units
		5.2.1 Nautical miles and kilometres
		5.2.2 Decibels
	5.3 Radar frequencies
		5.3.1 Radio spectrum
		5.3.2 Radar frequency selection factors
	5.4 Radar performance
		5.4.1 A model of radar performance
		5.4.2 The radar equation
		5.4.3 Incorporating noise factor
		5.4.4 Blake’s method
	5.5 Near-field/far-field calculation
		5.5.1 The reactive near-field
		5.5.2 The near-field
		5.5.3 The far-field
		5.5.4 The location of the near-field/far-field boundary
	5.6 Propagation
		5.6.1 The troposphere
		5.6.2 Refraction
		5.6.3 Huygens’ construction
		5.6.4 Fresnel zones
		5.6.5 Plotting the Fresnel zones
		5.6.6 The Cornu spiral
		5.6.7 Diffraction
		5.6.8 The knife-edge diffraction problem and the Fresnel–Kirchhoff parameter, a simplified method of calculating diffraction lo
		5.6.9 Analysing the geometry
		5.6.10 Approximating the diffraction loss
		5.6.11 Free space path losses
		5.6.12 Case study one
		5.6.13 Case study two
		5.6.14 Diffraction loss and multiple obstructions
	5.7 Mapping
		5.7.1 Good practice
		5.7.2 The terrain profile mapping
	References
6 Mitigation
	6.1 Definition and challenges
	6.2 Modification of the wind farm proposal
		6.2.1 Removal of wind turbines
		6.2.2 Reduced height of wind turbines
		6.2.3 Special coatings
		6.2.4 Turbine curtailment
	6.3 Modification of the aviation service being delivered
		6.3.1 Operational workarounds
		6.3.2 Changes to airspace
	6.4 Modification or replacement of affected systems
		6.4.1 Clutter removal
		6.4.2 Clutter removal with augmentation
		6.4.3 Clutter discrimination (wind farm tolerance)
		6.4.4 Performance metrics
		6.4.5 Integration of wind farm-tolerant radars
		6.4.6 Elevation sidelobe control
		6.4.7 Modified CFAR
		6.4.8 Feature extraction and classification
	6.5 What still needs to be done?
		6.5.1 The defence challenge
		6.5.2 Technical challenges
		6.5.3 Options and initiatives
	6.6 Technology readiness
		6.6.1 The problem
		6.6.2 Stakeholders
		6.6.3 Assessment techniques
	6.7 Technology readiness level
		6.7.1 Background
		6.7.2 NASA TRL
		6.7.3 Assessing the level
		6.7.4 Examples of TRL
	6.8 Observations on maturity
		6.8.1 Increasing maturity
		6.8.2 System/integration readiness level
		6.8.3 Definition of integration readiness levels
		6.8.4 TRL and IRL application to wind turbine mitigation
	6.9 Implementing mitigation
		6.9.1 Introduction
		6.9.2 Training
		6.9.3 Equipment or material
		6.9.4 Infrastructure
		6.9.5 Doctrine
		6.9.6 Organisation
		6.9.7 Information
		6.9.8 Logistics
	6.10 Putting to work
	6.11 Wind farm construction
	References
7 Future work
	7.1 Introduction
	7.2 Standardisation of turbine conspicuity
	7.3 Interactions between wind turbines and radio
		7.3.1 An uncertainty model
		7.3.2 Electromagnetic compatibility
		7.3.3 Submarine interactions
		7.3.4 Shadow effects
		7.3.5 3-D radar signatures
		7.3.6 A threshold for fast fading interference and cumulative effect
		7.3.7 Effects on modulation depth and thresholds
	7.4 Performance prediction
		7.4.1 Modelling granularity and scope
	7.5 Novel and enhanced signal processing techniques
		7.5.1 Non-traditional detection
		7.5.2 Tracking and data fusion
		7.5.3 Discrimination using cross-polarisation
	7.6 Artificial Intelligence
		7.6.1 Background publications
		7.6.2 Desirable functionality
		7.6.3 Critical behavioural characteristics
		7.6.4 System confidence
	References
Bibliography
	Introduction
	Chapter 1: Introduction
	Chapter 2: A brief history of windmills, electricity generation and radar
		On the history of windmills
		On the history of electricity generation
		On the history of radar
	Chapter 3: Aviation systems
		On aviation regulation
		On aviation
		On air–ground–communications
		On ILS
		On navigation systems
		On primary radar
		On radar tracking
		On secondary radar
	Chapter 4: Wind turbines and their effects
	Chapter 5: Analysis
		On the subject of radio propagation
		On the subject of mapping
		On the subject of radar performance
		On the general subject of radar cross section
		On the subject of the RCS of wind turbines
	Chapter 6: Mitigation
Glossary
Index
Back Cover