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Navigation Systems That Changed Aviation

Gene Bush

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Early Navigation•No Navigational Aids

•Used Visual Aids (Rivers, Roads, Rail Road Tracks)

•Used Dead Reckoning

The process of estimating your position by advancing a known position using course, speed, time and distance to be traveled.

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Airmail Service•Ultimate goal was to establish transcontinental airmail service

•Pilots flew during the day time

•Mail was transferred to rail cars at night

•Airmail service lost money ever since its introduction, President Harding threatened to veto any additional money for the airmail service.

•Pilots demonstrated that it was possible to fly at night safely.

•Navigated using bonfires, torches, burning oil drums.

•Saved the airmail program

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Airmail Service

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Lighted Airways• Army Air Corps developed rotating beacons and fixed course lights.• Installed on the transcontinental route.• By 1927, over 4,000 miles of airways had lights.• Airmail could be delivered in 1/3 the time of a train.• Beacons were cost-effective, and an enormous aid for nighttime

navigation.• No value in bad weather

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Lighted Airways

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Lighted Airways

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Four Course Radio Range• Developed in 1929• Series of four towers set in a square that transmits Low

Frequency radio waves• Powerful 1,500 watt transmitters• 200 miles apart on the transcontinental airway• Enabled radio approach landings under adverse weather

conditions.• Signals easily distorted• Giant leap forward in navigation, pilots simply listened to a

radio receiver and followed these radio beams from station to station along the route.

• This system had a total of 378 stations before becoming phased out during the 1950s

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4-course radio range

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VOR• Developed after WWII (1950’s)• HF Radio beacon, transmits a signal that is divided into 360

degrees (radials)• Provides a long range (30nm-250nm)• Inexpensive to produce & operate• Allows for many users at once• Easy to use • Can be used for voice communication with associated FSS • Provides reliable signals day and night• Freed the pilot from strictly operating under VFR• Accurate and Predictable

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VOR• Combined with the glide slope allows super-accurate

precision approaches• Combined with DME tells the pilot how far they are from the

runway, also provides groundspeed

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VOR

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Global Positioning System (GPS)• Dates back to 1957 when the Soviets launched

Sputnik.• Sputnik used a radio beam to transmit telemetry • U.S. Scientists discovered that they could locate their

exact position on earth by listening and measuring Sputniks radio signal.

• U.S. Satellite navigation program began

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Global Positioning System (GPS)• 1960s – US Navy/AF/Army all had independent versions • 1973 – Combined to create one system operated by the AF• 1983 – KAL 007 is shot down by Russian fighters, President

Reagan declassifies GPS makes it available for civilian use.• 1994 – 29 Satellites in orbit, 24 for use and 5 spares

– FAA declares GPS operational for civil operations.

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Global Positioning System (GPS)• Offers highly accurate 3-D navigation• Enables more direct flight routes • Saves time and money!• Eventual replacement for VOR• Reduced separation minimums resulting in increased

system capabilities• All weather coverage

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Global Positioning System (GPS)

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Global Positioning System (GPS)

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Global Positioning System (GPS)

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VOR and GPS changed aviation• VOR: Allows very accurate, dependable all weather 3-D

navigation– Increased safety – Increased capacity

• GPS: Offers even more accuracy, flexibility, capacity and safety

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The End

Any Questions?