# Fibre-optic Gyroscope > [[PORTAL_Avionics|Avionics]] spine. ## Microsims — three.js <div class="microsim-player"> <iframe src="https://wikitube-3d-microsims.netlify.app/Fibre-optic_gyroscope.html" width="100%" height="520" frameborder="0" loading="lazy" sandbox="allow-scripts allow-same-origin" title="Fibre-optic gyroscope — three.js microsim"></iframe> </div> ## Overview A fiber-optic gyroscope (FOG) detects rotational changes using the Sagnac effect, functioning as a non-mechanical alternative to traditional gyroscopes. The device operates by injecting two laser beams into optical fiber travelling in opposite directions around a coil that can extend several kilometres in length; rotation of the coil causes a differential phase shift between the counter-propagating beams, which is measured through interferometry and converted into angular velocity. FOGs contain no moving parts, giving exceptional precision and reliability, and are extensively deployed in [[Inertial_navigation_system|inertial navigation systems]] aboard military aircraft, spacecraft, and ships — particularly valuable where GPS jamming or denial makes autonomous sensing essential. **On the spine:** [[Radar]] · [[Autopilot]] · [[Fly-by-wire]] · [[Inertial_navigation_system]] · [[Ring_laser_gyroscope]] · [[Aviation]] · [[Aircraft]]. ## Wikipedia : Wikitube **Strict pair:** [Wikipedia](https://en.wikipedia.org/wiki/Fibre-optic_gyroscope) : [Wikitube](https://en.wikitube.io/wiki/Fibre-optic_gyroscope) --- *Repopulated 2026-08-05 · text transfer · 0 deletions.*