The invention provides a closed-loop detection method of an atomic
gyroscope on the basis of photoelastic modulation. The closed-loop detection method comprises the following steps: a Faraday
actuator is placed in front of a 1 / 4 wave plate and a
photoelastic modulator; detection
laser passes through a
polarizer, a Faraday modulator, an alkali-
metal gas chamber, the 1 / 4 wave plate, the
photoelastic modulator and an analyzer in sequence, a
fast axis of the 1 / 4 wave plate and an
optical axis of the
polarizer are in the same direction, a
fast axis of the
photoelastic modulator and the
optical axis of the
polarizer form a 45-degree angle, and the analyzer and the
optical axis of the polarizer form a 90-degree angle; a
deflection angle of the closed-loop Faraday
actuator is controlled by a PID (
Proportion Integration Differentiation) controller, the output of a lock-phase
amplifier is kept to be zero, and at the same time, the rotating angle to be detected is read out by an output angle of the closed-loop Faraday
actuator. The closed-loop detection method provided by the invention has the advantages that the rotating angle to be detected is only related to the rotating angle of the closed-loop Faraday actuator and is not related to the
light intensity and the photoelastic modulation amplitude, so that the influence of parameter fluctuation on a detection
system is isolated on the principle, a scale factor of the closed-loop photoelastic modulation detection is easily stabilized, and the detection accuracy of the atomic
gyroscope is improved.