Abstract: Phase errors that occur when a dithered ring laser gyroscope enters its deadband are measured, and a correction is applied to the output of the ring laser gyroscope to compensate for these phase errors. The counterpropagating beams in a ring laser gyroscope are heterodyned to produce a pair of quadrature heterodyne signals that indicate the angular output of the laser ring laser gyroscope. The phase angle error between one of the heterodyne signals and either the sum or difference of the separate beam intensities is determined, The phase angle error signal is used to produce a control signal for adjusting the output of the ring laser gyroscope to correct for errors introduced at or near turnarounds in the dither cycle.

Abstract: A laser gyro for detecting rates of rotating the gyro having a primary dither means for eliminating lock-in at low rates of rotation and a secondary dither means for eliminating nonlinearities in the gyro output when the input rate is a harmonic of the primary dither frequency. The gyro includes a body having a polygonal shaped cavity therein with a mirror disposed at each of the corners thereof to form a closed loop path for two counter-rotating beams. The primary dither includes means for dithering two mirrors 180.degree. out of phase to maintain the cavity path length constant. The secondary dither includes a current dither for differentially modulating the current in each leg of the gyro to randomly null nonlinearities in the gyro output.

Abstract: A low Q ring laser gyro-dither motor assembly which is responsive to a wide range of frequency components of a drive signal having a randomly varying frequency such that the dither imparted to the gyro is frequency modulated by the drive. The frequency modulated dither varies the lock-in rate of the gyro as a function of the random drive signal to eliminate errors in the gyro output due to lock-in. The drive signal may be random in frequency only or random in both frequency and amplitude to provide the frequency modulation. Fixed frequency modulation may also be employed. The low Q assembly need not be driven at the natural frequency thereof so that a common drive circuit may be employed for a plurality of low Q gyro-dither motor assemblies forming an instrument cluster.