Radio navigation Flashcards
What is Radio Navigation?
Navigating or piloting the aircraft using only the instruments and the navigational systems installed such as VHF Omni directional Range (VOR) and Automatic Direction Finder (ADF)
Factors affecting Radio Waves
Diffraction
Reflection
Refraction
Attenuation
Diffraction
bending of radio waves when it hits an obstacle
Reflection
wave bounces back as it hits an impenetrable object
Refraction
bending of radio waves when passing through a medium
Attenuation
Complete or total loss of energy due to friction
Wave Propagation
- Omni Directional
- Directional
- Pulse / Echo
Omni Directional
Radio waves in all direction
Ex: VOR, NDB
Directional
Radio waves in a straight direction
Ex. ILS, localizer
Pulse/Echo
transmitting short bursts of radio waves (pulses) and analyzing the reflected signals (echoes) to determine the distance and characteristics of objects.
Ex. PSR/SSR
Types of Radio Waves
- Ground Waves
- Sky Waves
- Space Waves
Ground Waves
ground adding waves. travels parallel to and adjacent to the surface of the Earth. Long range but has poor quality (Low energy)
Sky Waves
enough energy to counteract the gravity. As energy Interacts with the ionosphere it goes back to the ground creating radio waves
Space Waves
waves that are not refracted which does not go back to the ionosphere. Line of sight are the common problems with theses because it does not refract
Very high frequency omni-directional range (VOR)
VOR station transmit radio beams, called radial, outward in every direction, based on Magnetic North
How does the VOR work
Start Time - Omni Directional
* Reference phase
End Time - Directional
* Variable phase
Classes of VOR
Terminal VOR
Low Altitude VOR
High Altitude VOR
VOR Airborne Equipment
Antenna
VHF-NAV Receiver
Indicator
Going away FROM the station
- Twist OBS until ‘FR’ appears
- Continue twisting OBS until CDI centers
- Once CDI is centered, your RADIAL or LINE OF POSITION reads under Course Index
Going TO the station
- Twist OBS until ‘TO’ appears
- Continue twisting OBS until CDI centers
- Once CDI is center, your RADIAL or LINE OF POSITION reads under Reciprocal Course Index
Things to remember before using the VOR
T – Tune (To the VOR station)
I – Identify (Through morse code)
T - Test
Testing the VOR
A – Accuracy
S – Sensitivity
A - Ambiguity
A – Accuracy
- VOR ground checkpoints – predetermined area in the airport with a known radial. +/- 4ᵒ allowable error
- VOR airborne checkpoints – a known landmark associated with a published radial. +/- 6ᵒ allowable error
- VOR Testing facility that broadcasts signal for radial 360 regardless of position
S – Sensitivity
- Twist OBS 10ᵒ left and right from the selected radial and there must be a full deflection of the CDI needle
