We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Technology

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What Is a Ring Laser Gyroscope?

By Paul Reed
Updated: Feb 07, 2024
Views: 12,072
Share

A ring laser gyroscope is a precision instrument that uses a laser beam traveling in two directions to measure changes in angle, or a direction. Gyroscopes are used in navigation systems for aircraft and ships, and for guidance systems in missiles and precision weapons. The principle of using light to measure changes in direction are based on research by French scientist Georges Sagnac performed in 1913.

Gyroscopes use the principle of inertia to determine direction or changes in position. A spinning gyroscope wheel wants to remain in one position and will resist being turned. This can be demonstrated by a spinning top that will resist being pushed to one side, or attempting to turn a spinning bicycle wheel to one side.

A ring laser gyroscope makes use of the Doppler principle to measure differences in laser light beams. In 1842, Christian Doppler found that the frequency of sound appears different to a listener if the source of the sound is moving. Sounds moving toward a listener appear higher, and moving away appear lower in frequency. The effect also occurs with light, and a laser gyroscope utilizes this principle because the two beams travel at slightly different distances when the gyroscope is moved or tilted, as found by Sagnac.

The design of a ring laser gyroscope is normally a triangle with three equal sides, or an equal-sided box. A helium laser is placed on one side of the triangle or box, and laser beams are sent in opposite directions around the triangle. Using mirrors and prisms, the two beams are sent to a detector that looks at both the light and dark lines formed by the two beams, called interference patterns. The detector can look for changes in the interference patterns, which will move or shift position if the gyroscope is moved.

When the gyroscope is level, the two laser beams return to the detector at a known time difference, and the interference patterns are stationary. Tilting the ring laser gyroscope to one side causes the laser beams to return at slightly different times, and the interference patterns move at a rate consistent with the amount of tilt. The detector can be calibrated to show a tilt measurement for a turn-and-bank indicator on an aircraft used for precision turns, or to turn a compass dial used for navigation called a directional gyro.

Ring laser gyroscope technology began replacing mechanical gyroscopes in the late 20th century. Prior to that time, gyroscopes used wheels spun at very high speeds to create a stable gyroscope effect. These gyroscopes required compressed air or electricity for power, and were subject to performance losses due to mechanical friction. The ring laser gyroscope has no moving parts, and once calibrated can give excellent accuracy with minimal performance loss.

A problem with early laser gyroscopes was difficulty in measuring very small changes in direction or tilt. This effect is called lock-in, and the two laser beams appear at the detector at the same time increment as a non-moving gyroscope, which is incorrectly interpreted as being level. One method to prevent this error, called mechanical dithering, uses a vibrating spring to move the detector at a specific rate to prevent lock-in. Another method spins the gyroscope at a specific rate to prevent the false level measurements, though this unit is more expensive to produce.

Share
WiseGeek is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Editors' Picks

Discussion Comments
By anon995563 — On May 10, 2016

I do think ring laser gyroscope is very useful in navigation.

Share
https://www.wise-geek.com/what-is-a-ring-laser-gyroscope.htm
Copy this link
WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.

WiseGeek, in your inbox

Our latest articles, guides, and more, delivered daily.