1. Navigation Technology

2. Lesson Objectives
Identify why and when pilots use radio aids to navigation
Describe the operation of an Automatic Direction Finder (ADF)
Describe the operation of a Very high Frequency Omnidirectional Radio (VOR)
Identify the information provided by the Instrument Landing System (ILS)
Describe the operation of a GPS receiver
Identify the purpose of Automatic Dependent Surveillance-Broadcast (ADS-B)
Chapter 4, Lesson 5

3. Vocabulary
DME
TACAN
Situational awareness
Chapter 4, Lesson 5

4. Why and When to Use Radio Aids to Navigation
Radio aids help pilots navigate with precision to almost any point desired
Used when the weather isn’t clear, when altitudes are too great to follow landmarks on the ground, and to maintain safe distances between aircraft
Operating a radio aid requires: Installing a radio receiver in the aircraft, referring to air navigation charts, the ground stations themselves, and a flight deck with all of its flight instruments
Chapter 4, Lesson 5

5. Automatic Direction Finder
Determines the bearing from the aircraft to a selected ground station
On the ground a Non-directional AM radio beacon (NDB) station transmits radio signal energy in all directions
The station transmits a three-letter code at all times.
AM signals can curve with the Earth; they aren’t restricted to straight lines
Chapter 4, Lesson 5
Reproduced from US Department of Transportation/Federal Aviation Administration

6. Automatic Direction Finder
On the aircraft the ADF consists of a tuner, two antennas, and an indicator
To navigate, the pilot tunes the receiving equipment to an NDB ground station.
The ADF receives signals on both a loop and a sense antennae.
The loop antenna in common use today is a small flat antenna without moving parts.
Within the antenna are several coils spaced at various angles.
The loop antenna senses the direction of the station by the strength of the signal on each coil
The sense antenna provides whether the bearing is TO or FROM the station

7. Very high frequency Omnidirectional Radio (VOR)
A VOR ground station sends out an omnidirectional master signal and a highly directional second signal by a phased antenna array rotating clockwise in space 30 times a second.
By comparing the phase of the secondary signal with the master, the angle (bearing) to the aircraft from the station can be determined.
This line of position is called the "radial" from the VOR
Chapter 4, Lesson 5

8. Very high frequency Omnidirectional Radio (VOR)
VOR sends the pilot azimuth data — a measurement of distance in degrees
VOR ground stations broadcast at VHF in straight, unobstructed lines
Pilot tunes the VOR receiver to the selected VOR station’s frequency
VOR receiver finds the radial transmitting from a VOR station located on the ground
VOR receiver measures the radial in degrees clockwise from magnetic north
Tells the pilot the aircraft’s direction in degrees from a chosen station

9. VOR / DME
Together known as VOR/DME, some VORs include distance-measuring equipment (DME) — an electronic navigation system that determines the number of nautical miles between an aircraft and a ground station
The DME finds the slant range distance to or from a station.
Slant range distance is the direct distance between an aircraft and a station and so includes altitude
Chapter 4, Lesson 5

10. TACAN / VORTAC
The military also installs a piece of equipment called tactical air navigation, or TACAN.
This is an electronic navigation system used by military aircraft that provides distance and direction.
The military also uses TACAN when setting up
airfields in remote locations.
By dialing into the TACAN’s frequency, pilots can then find the airfields, figure out how far away they are, and orient themselves for landing.
When TACAN is installed with a VOR and DME, it is known as VORTAC.

11. Instrument Landing System
An instrument Landing System provides an approach path to a specific runway and provides three types of information:
Guidance comes from two transmitters on the ground:
The localizer lets the pilot know whether the aircraft is right or left of the runway
The glide slope indicator tells the pilot
whether the aircraft is above or below
the proper glide path
Range comes from marker beacons
An outer marker sits from four to seven miles from an airport.
A middle marker sits about 3,500 feet from the start of the runway.
An inner marker sits between the middle marker and the runway start, also known as the landing threshold.
Visual aids come from all approach lights and runway lights

12. Global Positioning System (GPS)
GPS is a satellite-based radio navigation system
The receiver measures distance from at least four satellites by counting the length of time it takes a radio signal to travel from the satellite to the GPS set
Then calculates position by using geometric equations and the four distances to the aircraft
Chapter 4, Lesson 5

13. Automatic Dependent Surveillance-Broadcast (ADS-B)
Device that repeatedly broadcasts a message that includes the aircraft’s ID, position, and velocity
ADS-B system broadcasts all of the
data it has collected to:
Air traffic control
nearby aircraft
and ADS-B ground stations
The FAA provides both traffic and weather reports free to pilots through its ADS-B broadcast services.
All aircraft will need to be able to communicate with the ADS-B system by 2020

14. Automatic Dependent Surveillance-Broadcast (ADS-B)
The service uses ADS-B ground stations to send the same radar-based information to the cockpit that air traffic controllers work with to track aircraft.
Pilots can track other aircraft flying inside a 15-mile radius and within 3,500 feet above and below their own aircraft
With this data they can keep enough separation between aircraft to avoid midair collisions.
So because of ADS-B, pilots have an improved situational awareness, a pilot’s understanding of where his or her aircraft is in relation to other aircraft, weather, location, and airspace regulations.

15. Lesson Objectives
Identify why and when pilots use radio aids to navigation
Describe the operation of an Automatic Direction Finder (ADF)
Describe the operation of a Very high Frequency Omnidirectional Radio (VOR)
Identify the information provided by the Instrument Landing System (ILS)
Describe the operation of a GPS receiver
Identify the purpose of Automatic Dependent Surveillance-Broadcast (ADS-B)
Chapter 4, Lesson 5

16. Activity 1: Contrasting Plotters and Dead Reckoning Computers
Use the Venn Diagram to identify the similarities and differences between plotters and dead reckoning computers as navigation tools
List their differences on each side of the diagram
List the similar uses and features where the two circles overlap
Chapter 4, Lesson 5

17. Activity 2: Radio Aids to Navigation
Review the textbook information on how and when to use radio aids to navigation
Read the information from NASA Virtual Skies on radio navigation aids
Complete the chart and describe how the aids work and when they are used in navigation
Chapter 4, Lesson 5

18. Activity 3: Current Developments in Navigation Technology
Create a presentation on one of the current developments in navigation technology
Conduct and investigate research using the sources identified
Chapter 4, Lesson 5

19. Activity 4: Features and Benefits of GPS and INS Guidance Systems
Fill in the chart using information from the textbook
Answer the analysis questions
Chapter 4, Lesson 5

20. Activity 5 Flight Simulator: Using VOR Stations to Navigate
Experience how to navigate an aircraft using VOR stations in Microsoft Flight Simulator
Chapter 4, Lesson 5