Aircraft Navigation Basics1/C MQS

Two Schools of Air Nav Visual Flight Rules (VFR)

Navigation accomplished primarily by visual reference to the ground (charts, DR)

Requires at least 1000 ft. cloud ceiling and 3 miles of visibility (must be able to see where you’re going!)

Basic pilot training/certification

Instrument Flight Rules (IFR) Navigation accomplished primarily by reference to onboard

instruments, electronic navigation aids, and Air Traffic Control No weather minimums More advanced pilot training/certification required

Methods of AirNav Visual (“Pilotage’)

Dead Reckoning “Course Rules” (preplanned routes based on major landmarks) Charts

Global Navigation Satellite System GPS GLONASS

Radio Beacons Automatic Direction Finder (ADF)/Non-Directional Beacon (NDB) Very-High Frequency Omnidirectional Range (VOR) Tactical Air Navigation (TACAN)

RADAR Surveillance Air Traffic Control Airborne/Shipboard RADAR

Visual Flight Rules

VFR Charts Display Major landmarks/obstacles Airports and relevant information Population centers Major roads Airspace dimensions

Global Positioning System (GPS)

Primary navigation method for modern aircraft

Minimal error

Can be used for precision landings

Worldwide coverage

Non-Directional Beacon (NDB) Fixed ground station provides basic “bearing

to” information

Greater range but less precision than other methods

Aircraft can use signal to “home” on the station

Radio NavigationVHF Omnidirectional Range (VOR)

Ground station emits directional radio signals 360° around station

Offers more precise course guidance

Line-of-Sight (LOS) dependent

Provides aircraft with a line of position to/from the station (“radial”)

Multiple station fixes can be used to triangulate position

TACAN (TACtical Air Navigation) Available to military users only

Ground or ship-based

Provides bearing AND range information

Distance Measuring Equipment (DME) onboard aircraft sends and receives signals to ground station to determine range (similar to active SONAR).

Distance provided is “slant range” distance, which is not the same as distance over the ground!

RADAR Surveillance

Navigation function performed by RADAR stations Ground facilities

Airport towers Approach/Departure Control Air Route Traffic Control Centers (ARTCC)

Ships CIC ASW/ASUC Tactical Air Controller (ASTAC)

Aircraft E-2 Hawkeye E-3 AWACS

Primary function is aircraft separation and airspace management

Requires two-way communication

Severe weather avoidance available

Signals Degradation Navigational data is typically provided simultaneously,

providing redundancy and enhanced reliability.

Any of the navigational aids utilized by aircraft are vulnerable to attack/jamming/compromise.

In a degraded signals environment, aircraft navigation and operational performance will suffer as data inputs are reduced or eliminated altogether.

Many modern weapon systems – such as the GPS guided JDAM – are similarly vulnerable to a degraded environment.

ReviewTwo categories of aircraft navigation

Visual Flight Rules (VFR) Instrument Flight Rules (IFR)

Methods of aircraft navigation Dead reckoning, visual orientation, “pilotage” GNSS (GPS) Radio beacon (NDB, VOR, TACAN) RADAR Surveillance

Signals degradation Navigational accuracy and operational performance are degraded

when input signals are jammed or compromised