- Abbreviation of laser gyroscope. A gyroscope in which two laser beams travel in opposite directions over a ring-shaped path utilizing multiple angled mirrors. During any movement of the aircraft, or other vehicle it is mounted on, the angular rotation rate is measured by determining the frequency shift in the beams, thus providing the angular position. Such a gyro is very rugged, and has no moving parts. Also called ring laser, or ring laser gyro.