Aeronautical Navigation An Introduction Materials: Beachball globe, Nav Radios, Omniheads, Mercator/Gnomonic Chart Example, Handheld Radio, 4 Sticks for GPS demonstration Written for the Notre Dame Pilot Initiative By the Pilots of the University of Notre Dame “Teaching the Science, Inspiring the Art, Producing Aviation Candidates!”

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

Navigation Navis—ship Agere—to direct

Roadmap Terrestrial coordinates Concepts of position Chart projections Concepts of position Piloting & dead reckoning Radio navigation systems Other electronic navigation systems Celestial navigation Foundations of Navigation

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

Terrestrial Coordinate System Small Circles-all other circles Parallels

Longitude/Latitude Parallels of latitude are small circles (with the exception of the equator) Meridians of longitude are great circles Latitude is 90 degrees Longitude is 180 degrees

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!

Mercator vs. Gnomonic Mercator Projection Gnomonic Projection This is the Great Circle Track that Charles Lindbergh flew Owl – Shortest distance between two points is a curve (great circle) Gnomonic Projection

Lambert Conformal Projection (Sectional Chart) Look at the front cover of a sectional chart to see how it unfolds curved

Sectional Charts

Airways Follow Great Circles Owl – Airways always 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.

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. Any questions on these concepts Note that a NM is 15% longer than a SM

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? Draw these on the blackboard

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

Navigational Elements Measurement Point Bearing Range 2 bearings 2 ranges Bearing & range Results Fix LOP LOP (arc) Aviation Example Over SBN GIJ 178°R GIJ 4.2 DME GSH 313°/GIJ 178° GSH 16.3/GIJ 4.2 GIJ 178°/4.2 GSH = Goshen GIJ = Gipper

How do we get there? Plot a course Steer a heading Make a good track What’s a course? path of intended motion Steer a heading What’s a heading? the direction the aircraft is pointed Make a good track What’s a track? the aircraft’s path over the ground

Course, Heading, & Track Big Bad Wind End of animation Plot a course, fly a heading, and make a track

Types of Navigation Systems Pilotage Dead Reckoning Radio Navigation ADF VOR/DME/RNAV Electronic Navigation Loran GPS Inertial Celestial Types of Navigation: - Pilotage (Coastal) Navigation: employs the use of visual bearings and/or radar information to know landmarks to establish the ship's position and provide the information needed to safely and efficiently "drive" the ship. -Deduced ("Dead") Reckoning: a method of estimating the ship's position using the courses and speeds steered. First used when early mariners ventured out of sight of land, to enable them to get back home.

Basic VFR Navigation Techniques: Pilotage Sectional chart Dead reckoning (DEDuced reckoning) Compass & watch

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 o’clock

Dead Reckoning DEN Big Bad Tower 1300 DR N E S W 1200 DR 1100 DR 070 ° Big Bad Mountain 1000 DR Note how we know our position at every point in time because we know how fast we are flying and in what direction and for how long. We can safely navigate between hazards (called the Rockies). We always use BOTH dead reckoning and pilotage. PHX 0900 DR 0800 Fix

Types of Navigation Systems Pilotage Dead Reckoning Radio Navigation ADF VOR/DME/RNAV Electronic Navigation Loran GPS Inertial Celestial Types of Navigation: -Radionavigation: Typically uses electromagnetic signals transmitted from ground stations to establish position.

The Radio Compass 1946 Stinson Voyager A Great 1 person airplane Geo Metro of the Air 1946 Stinson Voyager

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 NDB’s transmissions

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

NDB Operates on 190-535kHz Types Range is 190-1750kHz 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 AM Radio Station

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 Differences between fixed card and moveable card.

ADF Using relative bearing and magnetic heading, magnetic bearing can be found Actual heading to fly to the station MB = MH + RB Examples from Gleim (p. 272) – 13, 15, 16, 19, 25, 30

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 Diagram homing on board

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

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

Types of ADFs Fixed Card Moveable Card RMI – Radio Magnetic Indicator 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!

Types of ADFs Fixed Card Moveable Card RMI