Navigation Technology

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

Vocabulary DME TACAN Situational awareness Chapter 4, Lesson 5

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

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

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

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

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

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

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.

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

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

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

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.

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

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

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

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

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

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