Week 1-RADAR THEORY
Page 1: RADAR Fundamentals
Basic radar principles and general characteristics.
Various settings and measurements related to radar operation include:
Pulse frequency: 2 Hz
Range: 0.422 NM
Various true bearing and speed indicators.
Main components of the radar system, including:
AUTO TUNE
Different antennas and their configurations
Display information on targets, showing various parameters like heading (HDG), speed, and distance.
Page 2: Introduction to RADAR
Definition: RADAR stands for "RAdio Detection And Ranging."
Purpose: Designed for detecting and tracking objects at significant distances.
Practical benefits for navigators include:
Locating navigational aids.
Performing radar navigation.
Tracking nearby vessels to avoid collisions.
Page 3: RADAR Technology
Frequencies:
X-band and S-band, essential for various RADAR applications.
Basic operating principles include transmitting a wave and receiving the echoed wave.
Page 4: Fundamental Principles of RADAR
Main tasks of RADAR on board ships:
Prevent collision (visibility in fog/dark).
Assist in navigation during coastal and landfall voyages.
Page 5: Radar Functionality
Radar emits radio waves that bounce off objects.
Analysis of time taken for waves to return helps determine:
Distance
Direction
Speed of detected objects.
Page 6: Characteristics of Radio Waves
Radio wave cycle:
Frequency: number of cycles per second (measured in Hertz).
Wavelength: distance between successive crests.
Amplitude: height of the wave from the crest to the centerline.
Page 7: Radar Transmission Method
Marine RADAR uses pulsed transmission instead of a continuous wave.
Pulses travel outward at a speed of 300 million meters per second (161,987 nautical miles).
Page 8: Reflective Waves in Radar
When a radar pulse strikes a reflective surface, it creates an echo.
The range calculation formula: Range = (T x S) / 2, with:
T = elapsed time
S = speed of radar wave.
Page 9: Operational Characteristics of RADAR
Regulatory context: SOLAS Chapter 5, Regulation 19, requires specific radar technology for ships of 300 gross tonnages and upwards.
Page 10: S-Band and X-Band Antennas
Breakdown of antenna types:
S-band antenna (12 ft) for FAR-2137S.
X-band antenna (various sizes) for FAR-2117, 2127.
Pulse rates described in cycles per second.
Page 11: X-Band Characteristics
X-band (3 cm) offers:
Higher resolution and finer detail—ideal for small target detection (e.g., raindrops, birds, small aircraft).
Page 12: S-Band Characteristics
S-band (10 cm) is reliable in adverse weather conditions for navigation and tracking.
Often two radar systems are used for navigation purposes.
Page 13: Vertical Beam Width (VBW)
Definition: The vertical angle between upper and lower radar beam edges.
Caveats:
Narrow VBW may miss targets in roll/pitch.
Wide VBW could spread energy too thinly.
Page 14: Horizontal Beam Width (HBW)
Definition: The angle between leading and trailing edges of the radar beam.
Page 15: Pulse Length
The duration for which a pulse is emitted from the scanner.
Page 16: Components of RADAR
Breakdown of components include:
Antenna Unit
Transceiver
Modulator
Signal Processing Unit
Display Unit
Page 17: Radar Antenna Components
Antenna unit rotates and emits waves, while the transceiver handles wave generation and signal processing.
Display unit provides sensor data visualization.
Page 18: Radar System Interaction
Overview of components including:
Duplexer
Modulator
Processor and display technologies.
Page 19: Advantages of RADAR
Real-time information updates for obstacles and vessels.
Performs well under adverse weather conditions.
Enhances collision avoidance through timely actions.
Page 20: Limitations of RADAR
Limited resolution leading to difficulties in differentiating small or closely spaced vessels.
Potential for false echoes caused by environmental factors.
Effective range affected by antenna height and Earth's curvature.
Page 21: Basic Principles of RADAR
Core principle: Determine object range by measuring pulse travel time from ship to target and back.
Page 22: Directional Capabilities of Radar
Directional antennae allow for bearing determination.
Requires precise antenna orientation for accurate measurements.
Page 23: Radar Target Display
Targets displayed on a Plan Position Indicator (PPI).
Earlier models featured less visual fidelity compared to modern displays.
Page 24: Directional Transmission Requirements
Importance of directional transmission and narrow horizontal beam production.
Short pulse intervals enhance radar performance.
Page 25: Comparison of X-Band and S-Band
Summary characteristics:
X-Band: Better directivity and detail but limited in weather conditions.
S-Band: Penetrates inclement weather effectively with long-range capabilities.
Page 26: Brief Historical Timeline
1865: Maxwell's electromagnetic theory proposed.
1886: Hertz discovers electromagnetic waves.
Page 27: Radar Attenuation
Definition of radar attenuation and effects on target detection.
Page 28: Historical Advances in Radar
1904: First practical radar (Hülsmeyer's "telemobilscope").
1922: Successful location of a wooden ship using radar.
Page 29: Radar Developments
Milestones in equipment development during WWII and post-war advancements.
Page 30: Radar System Block Diagram
Basic components and their functions in a pulse-modulated system.
Page 31: Breakdown of Radar System Components
Main components: power supply, modulator, transmitter, antenna system, receiver, and indicator.
Page 32: Detailed Component Functionality
Modulator produces triggering signals.
Transmitter generates short powerful radio-frequency pulses.
Page 33: Antenna Functions
Antenna's role in rotating, transmitting, and receiving echoes.
Page 34: Additional Radar Information
Features and configurations noted in the radar equipment display.
Page 35: Scanner Types
Discussion of slotted array antennas and their effects on target determination.
Page 36: Beamwidth Characteristics
Definitions and standard measurements for horizontal and vertical beamwidth.
Page 37: Basic Radar Operations
Overview of how radar emissions reflect off objects and calculate range.
Page 38: Range Determination
Formula for range calculation based on time taken for signal return and speed of light.
Page 39: Bearing Determination
Angular measurement of the target based on antenna orientation and directivity.
Page 40: True Bearing Measurement
Explanation of true bearing and relative bearing definitions.
Page 41: Radar Display Methodology
Overview of how targets are displayed on the PPI and associated features.
Page 42: Modern Radar Display Technology
Discussion of LCD and CRT screens in modern radar systems.
Page 43: Target Presentation
Description of the visual representation of objects as "pips" or "blips" on the radar display.
Page 44: Radar Data and Measurements
Details about headings, target data, and key constants regarding maritime conditions.
Page 45: Radar Range Factors
Atmospheric effects and object factors impacting radar range.
Page 46: Calculating Radar Range
Formulae for determining radar detection distance combining heights of scanner and targets.
Page 47: Unusual Propagation Conditions
Effects of atmospheric conditions on radar pulse propagation (super-refraction and sub-refraction).
Page 48: Radar Resolution Types
Differentiating between range and bearing resolution in radar displays.
Page 49: Display Capabilities
Capabilities of radar to distinguish between multiple target echoes close together.
Page 50: Range Resolution Dynamics
Influence of pulse length on range resolution capacity.
Page 51: Practical Usage of Pulse Length
Short pulse lengths enhance resolution at shorter ranges; longer lengths for longer detection.
Page 52: Understanding Beamwidth
Definition of beamwidth in context with radar technology.
Page 53: Pulse Repetition Rate Dynamics
Relationship between pulse length, detection range, and repetition rate.
Page 54: Output Power and Maximum Detection
Consideration of output power effects on detection range and optimizing radar setup.
Page 55: Conclusion
Summary of radar components and their significance in operational terminology.
Page 56: Basic Principles Recap
Recap of RADAR core principles and bearing measurement accuracy.
Page 57: Components Overview
Final encapsulation of the basic components for a radar system, including power supply and modulator details.
Page 58: Outro
Acknowledgment for attention and learning engagement.