Aeronautical Navigation

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Aeronautical Navigation

• An Introduction

Written for the Notre Dame Pilot Initiative By
the Pilots of the University of Notre Dame
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Quote

• For the execution of the voyage to the Indies, I
  did not make use of intelligence, mathematics or
  maps.
• Christopher Columbus

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Navigation

• Navisship
• Agereto direct

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Roadmap

• Terrestrial coordinates
• Chart projections
• Concepts of position
• Piloting dead reckoning
• Radio navigation systems
• Other electronic navigation systems
• Celestial navigation

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Terrestrial Coordinate System

• Great Circles The largest circle that can be
  drawn on the surface of the earth all like it.
• Equator
• Meridians

Equator
Meridian
Great Circle
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Terrestrial Coordinate System

• Small Circles-all other circles
• Parallels

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Longitude/Latitude

• Parallels of latitude are small circles (with the
  exception of the equator)
• Meridians of longitude are great circles

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Desirable qualities of a chart projection

• Maintain true shape of physical features.
• Maintain correct proportions of features relative
  to one another.
• True scale, permitting accurate measurement of
  distance.
• Rhumb lines plot as straight lines.
• Great circles plot as straight lines.

No chart has all of these!
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Mercator vs. Gnomonic
Mercator Projection
Gnomonic Projection
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Lambert Conformal Projection (Sectional Chart)
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Sectional Charts
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Airways Follow Great Circles

• V-12 from HAR to JST departs HAR westbound on a
  heading of 281, and departs JST eastbound on a
  heading of 096.

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Navigational concepts

• A circle has 360 degrees
• A degree has 60 minutes
• 1 of latitude is the same distance anywhere on
  the earth.
• How many miles is one minute of latitude?
• Ans. 1 min lat. 1 nm 2000 yds.

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Where are we?

• At the ROTC Building -point
• On Juniper Road -LOP
• ½ mile from Golden Dome -LOP(circle)
• Near Meijer
• Ambiguous(which one?)
• Imprecise(how far?)
• We will be there in 5 minutes
• Answer to when will we arrive there?

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Line of Position (LOP)

• A line that defines our position in 1-D
• Not necessarily straight
• Arc, circle, hyperbola, intersection of spheres
• Need a second line to define a fix in 2-D
• Need a third to be sure

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Navigational Elements

• Measurement
• Point
• Bearing
• Range
• 2 bearings
• 2 ranges
• Bearing range

• Results
• Fix
• LOP
• LOP (arc)
• Fix
• Fix
• Fix

Aviation Example Over SBN GIJ 178R GIJ 4.2
DME GSH 313/GIJ 178 GSH 16.3/GIJ 4.2 GIJ
178/4.2

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How do we get there?

• Plot a course
• Whats a course?
• path of intended motion
• Steer a heading
• Whats a heading?
• the direction the aircraft is pointed
• Make a good track
• Whats a track?
• the aircrafts path over the ground

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Course, Heading, Track
Big Bad Wind
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Types of Navigation Systems

• Pilotage
• Dead Reckoning
• Radio Navigation
• ADF
• VOR/DME/RNAV
• Electronic Navigation
• Loran
• GPS
• Inertial
• Celestial

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Basic VFR Navigation Techniques

• Pilotage
• Sectional chart
• Dead reckoning
• (DEDuced reckoning)
• Compass watch

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Nomenclature

• True magnetic courses are given in 3 digits,
  e.g. 090
• Relative bearings are given in degrees or clock
  position, e.g. 10º left of the nose, or 11
  oclock

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Dead Reckoning
DEN
1300 DR
1200 DR
1100 DR
070
1000 DR
PHX
0900 DR
0800 Fix
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Types of Navigation Systems

• Pilotage
• Dead Reckoning
• Radio Navigation
• ADF
• VOR/DME/RNAV
• Electronic Navigation
• Loran
• GPS
• Inertial
• Celestial

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The Radio Compass

• 1946 Stinson Voyager

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ADF/NDB

• The ADF, or Automatic Direction Finder, is the
  receiver in the aircraft

• The NDB, or Nondirectional Radio Beacon, is the
  transmitting antenna on the ground

• The ADF is the receiver of the NDBs transmissions

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NDB

• The NDB is a ground-based radio transmitter that
  emits a signal in every direction
• Benefits
• Economic
• Easy to maintain
• Not line of sight
• Errors
• Susceptible to interference (T-Storms)
• Bounces around coastlines

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NDB

• Operates on 190-535kHz
• Range is 190-1750kHz
• Types
• HH 2000 watts 75nm range
• H 50-1999 watts 50nm range
• MH less than 50 watts 25nm range
• Compass Locator less than 25 watts 15 nm range

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ADF

• The ADF determines the bearing from the aircraft
  TO the station
• Needle ALWAYS points to the station
• Indicates relative bearing
• Bearing, measured clockwise, from the nose of the
  aircraft TO the station
• Card only indicates angle has nothing to do
  with direction aircraft is pointed

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ADF

• Using relative bearing and magnetic heading,
  magnetic bearing can be found
• Actual heading to fly to the station
• MB MH RB

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Homing the NDB

• Homing
• Flying the aircraft on any heading required to
  keep the needle pointed straight ahead (0 RB)
• Works great without wind
• Takes longer and not direct with wind

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Tracking the NDB

• Tracking flying on a heading that maintains a
  constant, desired track to/from a station
• Find heading/course that takes you to the station
• Once off by 10, double the deflection and turn
  towards station (head of the needle)
• Once deflection equals correction, you are back
  on course
• Turn 10 towards needle
• Repeat as necessary and become more precise with
  correction

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Intercepting the NDB

• Parallel course
• Note deflection
• Double it
• Turn towards needle
• Once deflection equals correction, you are on
  course
• Correct for wind (tracking)
• NOTE very similar to tracking

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Types of ADFs

• Fixed Card
• Always shows 0 at the top
• Moveable Card
• Can show magnetic heading at top
• Bad idea
• RMI Radio Magnetic Indicator
• Slaved to move with aircraft
• GREAT to have!

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Types of ADFs
Fixed Card
Moveable Card
RMI