Scaling up gyroscopes: From navigation to measuring the Earth's rotation

May 06, 2013

Accurately sensing rotation is important to a variety of technologies, from today's smartphones to navigational instruments that help keep submarines, planes, and satellites on course. In a paper accepted for publication in the American Institute of Physics' journal Review of Scientific Instruments, researchers from the Technical University of Munich and New Zealand's University of Canterbury discuss what are called "large ring laser gyroscopes" that are six orders of magnitude more sensitive than gyroscopes commercially available.

In part, the increased sensitivity comes from the scaled-up size – the largest of these gyroscopes encloses an area of 834 square meters – meaning these instruments are no longer compatible with navigation applications. In addition, a very involved series of corrections must be made when using these instruments to account for a variety of factors, including the gravitational attraction of the moon. According to the researchers, however, the progress in these devices has made possible entirely new applications in geodesy, geophysics, seismology, and testing theories in such as the effects of .

Ring laser gyroscopes rely on propagating in opposite directions along the same closed loop or "ring." The beams interfere with one another forming a stable pattern, but that pattern shifts in direct proportion to the rotation rate of the whole laser-ring system (called the "Sagnac effect"). Large ring laser gyroscopes are attached to the Earth's crust so that a shift in that pattern (seen as an observed beat note in an actively lasing device) is directly proportional to the rotation rate of the Earth.

Perturbations in that rotation rate capture the momentum exchange between the atmosphere, hydrosphere, and lithosphere, and so large ring laser gyroscopes could be used to indirectly monitor the combined effects of variations in global air and , for example. They may also be used both to supplement and improve calculations currently made with Very Long Baseline Interferometry (VLBI) techniques for measuring the orientation of the instantaneous rotation axis of the Earth and the length of day.

Additionally, changes in the ring's orientation also shifts the beat note of the interferometer, making the large ring laser gyroscope useful for detecting tilts in the Earth's crust, which current seismometers cannot distinguish from horizontal acceleration.

Explore further: Researchers demonstrate ultra low-field nuclear magnetic resonance using Earth's magnetic field

More information: "Large Ring Lasers for Rotation Sensing" is accepted for publication in the journal Review of Scientific Instruments.

add to favorites email to friend print save as pdf

Related Stories

First ever direct measurement of the Earth's rotation

Dec 22, 2011

A group with researchers of the Technical University of Munich, Germany, are the first to plot changes in the Earth's axis through laboratory measurements. To do this, they constructed the world's most stable ...

A tracking device that fits on the head of a pin

Oct 05, 2010

( -- Optical gyroscopes, also known as rotation sensors, are widely used as a navigational tool in vehicles from ships to airplanes, measuring the rotation rates of a vehicle on three axes to evaluate ...

The first controllable atom SQUID

Nov 07, 2012

(—Scientists have created the first controllable atomic circuit that functions analogously to a superconducting quantum interference device (SQUID) and allows operators to select a particular quantum ...

Recommended for you

User comments : 0