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  • Navigating
    at Sea
    • Challenges of Sea Navigation
    • Navigating Without a Clock
    • The Longitude Problem
    • The U.S. Goes to Sea
    • Navigate at Sea! Activity
  • Navigating
    in the Air
    • Challenges of Air Navigation
    • Early Air Navigators
    • Navigation at War
    • Navigate the Skies! Activity
  • Navigating
    in Space
    • Challenges of Space Navigation
    • Reaching for the Moon
    • Navigating in Deep Space
    • Navigate in Space! Activity
  • Satellite Navigation
    • Challenges of Satellite Navigation
    • Reliable Global Navigation
    • Global Positioning System (GPS)
    • Who Uses Satellite Navigation
  • Navigation
    for Everyone
    • Meet a Professional Navigator
    • Personal Navigation Stories
  • Timeline of Innovation
  • Artifacts
  • Learning Resources
  • Multimedia Gallery
  • Research
  • Visit the Exhibition

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Time and Navigation
The untold story of getting from here to there.
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  • Navigating at Sea
  • Navigating in the Air
  • Navigating in Space
  • Satellite Navigation
  • Navigation for Everyone
  • Timeline of Innovation
  • Artifacts
  • Learning Resources
  • Multimedia Gallery
  • Research Journal
  • Visit the Exhibition
  • Challenges of Air Navigation
    • Flying Boats Cross the Seas
    • Overcoming the Challenges
      • Celestial Navigation
      • Radio Navigation
      • Dead Reckoning
    • Navigate the Skies! Activity
  • Early Air Navigators
    • Dying to Set Records
    • Charles Lindbergh's Calculated Risk
    • The Business of Air Navigation
      • The Teacher: P. V. H. Weems
      • The Air Navigation Community
      • Radio Time for Aviation
    • Lindbergh's New Tools
    • Two Men in a Hurry
      • The Winnie Mae
      • Meet the Navigator: Harold Gatty
    • Navigation Gone Wrong: Amelia Earhart
  • Navigation at War
    • The Wartime Navigator
      • Harry Crosby
      • Tools of the Trade
    • Naval Aviation
      • Meet the Navigators: WAVES
    • A New Era in Time and Navigation
      • Hyperbolic Systems
      • LORAN
      • Meet the Clockmaker: Alfred Loomis
  • Navigate the Skies! Activity

Explore More

Lockheed Model 10E Electra »
Radio Time Signals »
Fred Noonan navigating a Pan Am Sikorsky S-42 »
Radio Navigation »
LORAN Day and Night Coverage, 1945 »

A New Era in Time and Navigation

In World War II, navigators began switching from mechanical time to frequency-based time systems.

In 1940, British scientists and engineers developed GEE—a practical medium-range (up to several hundred miles) system of radio navigation based on measuring the time-delay between sets of radio signals. The United States built on this effort and created a longer-range system called LORAN (LOng-RAnge Navigation) to provide oceanic coverage for ships and aircraft.

Although initially no more accurate than celestial navigation, LORAN had a big advantage: it worked when the sky was clouded over. And during the day, when sextant Sun “shots” could only provide a line of position, LORAN gave a precise fix. GEE and LORAN were essential tools for American and British forces in World War II.

loran_map_2.jpg

LORAN Day and Night Coverage, 1945
By the end of World War II, the LORAN system could be used over 30 percent of the globe.
Credit: National Air and Space Museum, Smithsonian Institution.

nasm-1a23048p.jpg

Consolidated PB4Y-2 Privateer
Long-range Navy patrol aircraft required better all-weather navigation systems like LORAN.
Credit: National Air and Space Museum, Smithsonian Institution

untitled-1_-_small.jpg

C-1 Timing Unit
It contained a crystal ocillator and was key to the LORAN system.
Credit: National Archives and Records Administration
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  • Hyperbolic Systems »

    In a hyperbolic system, a receiver on an aircraft or ship picks up radio signals.

  • LORAN »

    Navigators went from using mechanical-based time measured in seconds to using radio frequency-based time measured in microseconds.

  • Meet the Clockmaker: Alfred Loomis »

    Alfred Loomis’s fascination with timekeeping precision led to the invention of LORAN.

  • Navigating at Sea
    • Challenges of Sea Navigation
    • Navigating Without a Clock
    • The Longitude Problem
    • The U.S. Goes to Sea
    • Navigate at Sea! Activity
  • Navigating in the Air
    • Challenges of Air Navigation
    • Early Air Navigators
    • Navigation at War
      • The Wartime Navigator
      • Naval Aviation
      • A New Era in Time and Navigation
        • Hyperbolic Systems
        • LORAN
        • Meet the Clockmaker: Alfred Loomis
    • Navigate the Skies! Activity
  • Navigating in Space
    • Challenges of Space Navigation
    • Reaching for the Moon
    • Navigating in Deep Space
    • Navigate in Space! Activity
  • Satellite Navigation
    • Challenges of Satellite Navigation
    • Reliable Global Navigation
    • Global Positioning System (GPS)
    • Who Uses Satellite Navigation
  • Navigation for Everyone
    • Meet a Professional Navigator
    • Personal Navigation Stories
  • Timeline of Innovation
  • Artifacts
  • Learning Resources
  • Multimedia Gallery
  • Research
  • Visit the Exhibition
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  • Privacy
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  • Press
  • Donate
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