Aircraft, spacecraft and ships have long benefitted from using gyroscopes to help them navigate, and recently advances in photonic gyroscopes have brought this technology into the mainstream. These improved gyroscopes -- based on fiber optic tehchnology -- are solving navigational problems in automobiles, construction and industrial vehicles, antenna systems and agriculture.The gyroscope is a sensor that can measure rotation rates with respect to an inertial plane. Mechanical spinning-mass gyroscopes are not easy to handle and require a lot of maintenance. Ring laser gyroscopes produce lock-in phenomena and so require mechanical dithering if they are to retain sensitivity at small rotation rates. Fiber optic gyroscopes are more accurate and easier to use and so have prompted widespread advances in traditional gyroscope applications and developments in entirely new fields. Continuing advances in the areas of interferometric fiber guros, resonator fiber gyros and Brillouin fiber gyros may reduce device costs without sacrificing sensitivity, thus enabling still more applications…