- •Textbook Series
- •Contents
- •1 Properties of Radio Waves
- •Introduction
- •The Radio Navigation Syllabus
- •Electromagnetic (EM) Radiation
- •Polarization
- •Radio Waves
- •Wavelength
- •Frequency Bands
- •Phase Comparison
- •Practice Frequency (
- •Answers to Practice Frequency (
- •Questions
- •Answers
- •2 Radio Propagation Theory
- •Introduction
- •Factors Affecting Propagation
- •Propagation Paths
- •Non-ionospheric Propagation
- •Ionospheric Propagation
- •Sky Wave
- •HF Communications
- •Propagation Summary
- •Super-refraction
- •Sub-refraction
- •Questions
- •Answers
- •3 Modulation
- •Introduction
- •Keyed Modulation
- •Amplitude Modulation (AM)
- •Single Sideband (SSB)
- •Frequency Modulation (FM)
- •Phase Modulation
- •Pulse Modulation
- •Emission Designators
- •Questions
- •Answers
- •4 Antennae
- •Introduction
- •Basic Principles
- •Aerial Feeders
- •Polar Diagrams
- •Directivity
- •Radar Aerials
- •Modern Radar Antennae
- •Questions
- •Answers
- •5 Doppler Radar Systems
- •Introduction
- •The Doppler Principle
- •Airborne Doppler
- •Janus Array System
- •Doppler Operation
- •Doppler Navigation Systems
- •Questions
- •Answers
- •6 VHF Direction Finder (VDF)
- •Introduction
- •Procedures
- •Principle of Operation
- •Range of VDF
- •Factors Affecting Accuracy
- •Determination of Position
- •VDF Summary
- •Questions
- •Answers
- •7 Automatic Direction Finder (ADF)
- •Introduction
- •Non-directional Beacon (NDB)
- •Principle of Operation
- •Frequencies and Types of NDB
- •Aircraft Equipment
- •Emission Characteristics and Beat Frequency Oscillator (BFO)
- •Presentation of Information
- •Uses of the Non-directional Beacon
- •Plotting ADF Bearings
- •Track Maintenance Using the RBI
- •Homing
- •Tracking Inbound
- •Tracking Outbound
- •Drift Assessment and Regaining Inbound Track
- •Drift Assessment and Outbound Track Maintenance
- •Holding
- •Runway Instrument Approach Procedures
- •Factors Affecting ADF Accuracy
- •Factors Affecting ADF Range
- •Accuracy
- •ADF Summary
- •Questions
- •Answers
- •8 VHF Omni-directional Range (VOR)
- •Introduction
- •The Principle of Operation
- •Terminology
- •Transmission Details
- •Identification
- •Monitoring
- •Types of VOR
- •The Factors Affecting Operational Range of VOR
- •Factors Affecting VOR Beacon Accuracy
- •The Cone of Ambiguity
- •Doppler VOR (DVOR)
- •VOR Airborne Equipment
- •VOR Deviation Indicator
- •Radio Magnetic Indicator (RMI)
- •Questions
- •In-flight Procedures
- •VOR Summary
- •Questions
- •Annex A
- •Annex B
- •Annex C
- •Answers
- •Answers to Page 128
- •9 Instrument Landing System (ILS)
- •Introduction
- •ILS Components
- •ILS Frequencies
- •DME Paired with ILS Channels
- •ILS Identification
- •Marker Beacons
- •Ground Monitoring of ILS Transmissions
- •ILS Coverage
- •ILS Principle of Operation
- •ILS Presentation and Interpretation
- •ILS Categories (ICAO)
- •Errors and Accuracy
- •Factors Affecting Range and Accuracy
- •ILS Approach Chart
- •ILS Calculations
- •ILS Summary
- •Questions
- •Answers
- •10 Microwave Landing System (MLS)
- •Introduction
- •ILS Disadvantages
- •The MLS System
- •Principle of Operation
- •Airborne Equipment
- •Question
- •Answer
- •11 Radar Principles
- •Introduction
- •Types of Pulsed Radars
- •Radar Applications
- •Radar Frequencies
- •Pulse Technique
- •Theoretical Maximum Range
- •Primary Radars
- •The Range of Primary Radar
- •Radar Measurements
- •Radar Resolution
- •Moving Target Indication (MTI)
- •Radar Antennae
- •Questions
- •Answers
- •12 Ground Radar
- •Introduction
- •Area Surveillance Radars (ASR)
- •Terminal Surveillance Area Radars
- •Aerodrome Surveillance Approach Radars
- •Airport Surface Movement Radar (ASMR)
- •Questions
- •Answers
- •13 Airborne Weather Radar
- •Introduction
- •Component Parts
- •AWR Functions
- •Principle of Operation
- •Weather Depiction
- •Control Unit
- •Function Switch
- •Mapping Operation
- •Pre-flight Checks
- •Weather Operation
- •Colour AWR Controls
- •AWR Summary
- •Questions
- •Answers
- •14 Secondary Surveillance Radar (SSR)
- •Introduction
- •Advantages of SSR
- •SSR Display
- •SSR Frequencies and Transmissions
- •Modes
- •Mode C
- •SSR Operating Procedure
- •Special Codes
- •Disadvantages of SSR
- •Mode S
- •Pulses
- •Benefits of Mode S
- •Communication Protocols
- •Levels of Mode S Transponders
- •Downlink Aircraft Parameters (DAPS)
- •Future Expansion of Mode S Surveillance Services
- •SSR Summary
- •Questions
- •Answers
- •15 Distance Measuring Equipment (DME)
- •Introduction
- •Frequencies
- •Uses of DME
- •Principle of Operation
- •Twin Pulses
- •Range Search
- •Beacon Saturation
- •Station Identification
- •VOR/DME Frequency Pairing
- •DME Range Measurement for ILS
- •Range and Coverage
- •Accuracy
- •DME Summary
- •Questions
- •Answers
- •16 Area Navigation Systems (RNAV)
- •Introduction
- •Benefits of RNAV
- •Types and Levels of RNAV
- •A Simple 2D RNAV System
- •Operation of a Simple 2D RNAV System
- •Principle of Operation of a Simple 2D RNAV System
- •Limitations and Accuracy of Simple RNAV Systems
- •Level 4 RNAV Systems
- •Requirements for a 4D RNAV System
- •Control and Display Unit (CDU)
- •Climb
- •Cruise
- •Descent
- •Kalman Filtering
- •Questions
- •Appendix A
- •Answers
- •17 Electronic Flight Information System (EFIS)
- •Introduction
- •EHSI Controller
- •Full Rose VOR Mode
- •Expanded ILS Mode
- •Full Rose ILS Mode
- •Map Mode
- •Plan Mode
- •EHSI Colour Coding
- •EHSI Symbology
- •Questions
- •Appendix A
- •Answers
- •18 Global Navigation Satellite System (GNSS)
- •Introduction
- •Satellite Orbits
- •Position Reference System
- •The GPS Segments
- •The Space Segment
- •The Control Segment
- •The User Segment
- •Principle Of Operation
- •GPS Errors
- •System Accuracy
- •Integrity Monitoring
- •Differential GPS (DGPS)
- •Combined GPS and GLONASS Systems
- •Questions
- •Answers
- •19 Revision Questions
- •Questions
- •Answers
- •Specimen Examination Paper
- •Appendix A
- •Answers to Specimen Examination Paper
- •Explanation of Selected Questions
- •20 Index
Chapter
13
Airborne Weather Radar
Introduction |
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207 |
Component Parts . . . . . . . . . . . . . . . . . . |
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207 |
AWR Functions . . . . . . . . . . . . . . . . . . |
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Principle of Operation . . . . . . . . . . . . . . . . |
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211 |
Weather Depiction . . . . . . . . . . . . . . . . . |
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213 |
Monochrome Control Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215 |
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Function Switch . . . . . . . . . . . . . . . . . . |
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Mapping Operation |
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218 |
Pre-flight Checks . . . . . . . . . . . . . . . . . . |
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218 |
Weather Operation |
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219 |
Colour AWR Controls . . . . . . . . . . . . . . . . |
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.219 |
AWR Summary . . . . . . . . . . . . . . . . . . |
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.221 |
Questions . . . . . . . . . . . . . . . . . . . . |
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Answers . . . . . . . . . . . . . . . . . . . . . |
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224 |
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13 AirborneWeather Radar
Radar Weather Airborne 13
206
AirborneWeather Radar 13
Introduction
Airborne weather radar (AWR) is used to provide pilots with information regarding weather ahead as well as navigation. Unlike most other systems, it requires interpretation by the pilot and its use is enhanced by the skill of the user.
The radar information can be displayed on a dedicated unit or shown (on modern aircraft) in combination with the aircraft route on the EFIS navigation display (ND).
Information on cloud formations or terrain features is displayed on the indicator’s screen as a range from the aircraft and a bearing relative to its heading. The presentation can be monochrome or, on modern systems, in the colours green, yellow, red and/or magenta. In the weather mode the colours represent the increasing variations in rainfall rate from light to very strong returns; magenta usually indicates the presence of turbulence associated with intense rainfall. For ground mapping green indicates light ground returns, yellow medium ground returns and red heavy ground returns.
Component Parts
The airborne equipment comprises:
•Transmitter/receiver. (Figure 13.1)
•Antenna, which is stabilized in pitch and roll. (Figure 13.1)
•Indicator. (Figures 13.1, 13.2, 13.3 and 13.4)
•Control unit. (Figure 13.1)
AWR Functions
The main functions of an AWR are to:
•detect the size of water droplets and hence deduce where the areas of turbulence are within the cloud.
•determine the height of cloud tops by tilting the radar beam up or down.
•map the terrain below the aircraft to provide navigational information and high ground avoidance.
•provide a position fix (range and bearing) from a prominent feature.
Airborne Weather Radar 13
207
13 AirborneWeather Radar
Radar Weather Airborne 13
Figure 13.1 AWR Components
208
AirborneWeather Radar 13
Figure 13.2 Monochrome Cloud Display and Avoidance Courses
Airborne Weather Radar 13
Figure 13.3 Colour Weather Display
209
13 AirborneWeather Radar
Radar Weather Airborne 13
Figure 13.4 Terrain Mapping Display
210