AUTOMATIC GAIN CONTROL OF A CLOSED LOOP FIBER OPTIC GYROSCOPE USING NON-LINEAR CONTROL LAWS

摘要

The gain of a variable gain amplifier (20) is arranged to amplify electrical signals output from a fiber optic gyroscope (12) is controlled to provides a stable AGC response irrespective of the actual gain level. A perturbation injection circuit (14) provides a perturbation signal +/-d to a phase modulator (16) connected to the fiber optic gyro (12). A perturbation compensation circuit (24) applies perturbation compensation signals to signals output from the variable gain amplifier (20) and produces a compensated signal by reducing the magnitude of the perturbation in the amplified signal output from the variable gain amplifier (20). A gain error circuit (28) connected to the perturbation signal remaining in the amplified signal after perturbation compensation. A feedback system (32, 34) provides a gain control signal to the variable gain amplifier (20) to reduce the magnitude of the gain error signal.