ring laser gyro

A highly accurate way to measure change in an angular position or at an angular rate without the use of any mechanically spinning wheel. The ringed laser gyro principle is based on the small frequency difference produced between two laser beams traveling in opposite directions within the ring. When the gyro is rotated, the frequency difference is measured and the data are processed to determine the rotational velocity and the rate of its change with very high accuracy. The main advantages of the laser gyro are that it has no moving parts, does not require any warm-up time, and has a high long-term stability and rate capability. It is insensitive to linear acceleration and provides fine resolution over a full dynamic range. See laser gyro.