# Ring Laser Gyroscope > [[PORTAL_Avionics|Avionics]] spine. ## Microsims — three.js <div class="microsim-player"> <iframe src="https://wikitube-3d-microsims.netlify.app/Ring_laser_gyroscope.html" width="100%" height="520" frameborder="0" loading="lazy" sandbox="allow-scripts allow-same-origin" title="Ring laser gyroscope — three.js microsim"></iframe> </div> ## Overview A ring laser gyroscope (RLG) is an optical rotation-sensing device that employs two counter-propagating laser beams travelling the same path within a ring cavity, operating on the Sagnac effect, which shifts the nulls of the internal standing-wave pattern in response to angular rotation. Aside from a small dither-motor assembly used to avoid a low-rotation-rate lock-in effect, it has no moving parts, eliminating friction-related drift and enabling compact, durable designs. Tens of thousands operate today in [[Inertial_navigation_system|inertial navigation systems]] aboard military aircraft, commercial airliners, submarines, and spacecraft, typically achieving better than 0.01°/hour bias uncertainty and mean time between failures in excess of 60,000 hours — largely replacing the mechanical gyroscopes they superseded. **On the spine:** [[Radar]] · [[Autopilot]] · [[Fly-by-wire]] · [[Inertial_navigation_system]] · [[Fibre-optic_gyroscope]] · [[Aviation]] · [[Aircraft]]. ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Ring_laser_gyroscope) : [Wikitube](https://en.wikitube.io/wiki/Ring_laser_gyroscope) --- *Repopulated 2026-08-05 · text transfer · 0 deletions.*