Navigation Lecture Notes

Introduction to Navigation

• Navigation is divided into three parts:
  • General Navigation
  • Radio Navigation
  • Instrument Navigation
• DGCA CPL exam consists of 100 questions, with approximately 35 questions from General Navigation.
• Understanding navigation is crucial for pilots, especially when flying solo.
• Safety of passengers depends on the pilot’s knowledge.

Importance of the Basics

• Clear understanding of basics is essential for grasping advanced topics.
• The first three days of navigation training are critical.

The Shape of the Earth

• Options for the shape of the Earth:
  • Circle
  • Sphere
  • Ellipse
  • Ellipsoidal
  • Oval
  • Oblate Spheroid
  • Geoid
• Correct Answer: Oblate Spheroid (Earth is slightly compressed at the poles).
• Key Terms:
  • Cardiology: Study of the heart.
  • Cardioid: Diagram resembling a heart shape.
  • Geoid: Shape similar to Earth.

Earth’s Dimensions

• Equatorial Diameter (ED) vs. Polar Diameter (PD):
  • ED > PD by 23 nautical miles.
  • Polar Diameter = 6,886 nautical miles.
• Compression of Earth: 0.3%; can be ignored for practical purposes in aviation.

Earth’s Rotation and Revolution

• Rotation: Movement around its own axis (West to East).
• Revolution: Movement around the Sun.
• The inclination of Earth’s axis is 23.5 degrees.

Cardinal and Quadrantal Directions

• Cardinal Directions: North, East, South, West.
• Quadrantal Directions: Northeast, Southeast, Southwest, Northwest.

Why is the Earth Inclined?

• The inclination allows for seasonal changes and distribution of temperature.
• Earth's axial tilt is crucial for sustaining life on the planet.

Great Circles and Latitudes

• Equator: A great circle, plane perpendicular to the axis of rotation.
• Latitudes: Parallel to the equator, ranging from 0° at the equator to 90° at the poles.
• *Significant Latitudes:
  • Tropic of Cancer: 23.5° North
  • Tropic of Capricorn: 23.5° South
  • Arctic Circle: 66.5° North
  • Antarctic Circle: 66.5° South

Longitudes

• Longitudes (Meridians): Semi-great circles joining the North and South Poles, measured from the Prime Meridian (0°).
• Anti-Meridian: The opposite meridian to any given meridian at 180°.
• Total number of longitudes: Infinite.

Calculation of Change in Latitude and Longitude

• Change in Latitude (ΔLat): Difference between two latitude points.
• Change in Longitude (ΔLong): Difference between two longitude points.
• Directions matter when calculating changes in latitude and longitude.

Graticule

• Definition: The network of latitudes and longitudes on a map or chart.
• Important for navigation and chart reading.

Conclusion and Preparation for Next Class

• Tomorrow's class will focus on calculating changes in latitude and longitude in minutes and seconds.
• Students are advised to bring scientific calculators for practical exercises.