Fiber optic gyroscope principle of operation in detail

Fiber optic gyroscope principle of operation in detail

First, the core principle: based on the Sagnac effect (Sagnac effect)

Relationship between optical range difference and angular velocity

Fiber optic gyroscope through the detection of the same closed optical path in the reverse propagation of the phase difference between the two beams of light to deduce the angular velocity.

When an optical fiber rotates around a coil with a carrier, the beam propagating in the direction of rotation undergoes a longer optical path than the beam propagating in the opposite direction, resulting in an optical range difference;

The optical range difference is proportional to the rotational angular velocity, and the angular velocity can be calculated by measuring the phase difference or the change of interference fringes.

Second, the key structure and workflow

Component Composition

Fiber optic coil: the core component, usually made of hundreds to thousands of meters of fiber optic winding, used to form a closed optical path;

Light source and detector: the laser light source emits light signals, and the detector captures the change of light intensity after interference;

Signal processing module: converts the phase difference into an electrical signal and outputs angular velocity data.

Working steps

The laser beam is divided into two beams by the beam splitter and propagates clockwise and counterclockwise along the fiber optic coil;

The optical signals converge and interfere at the detector, and the rotation causes the phase difference to change;

The angular velocity of the carrier is inverted by detecting the change in interference intensity.

Third. Technology Classification and Advantages

Technology evolution

The fourth generation of optical gyro: compared with mechanical gyro and laser gyro, fiber optic gyro has no moving parts, strong shock resistance and longer life;

High-precision type: navigation-grade fiber optic gyro achieves zero-bias stability better than 0.001°/h, suitable for spacecraft and precision guidance.

Unique advantages

High sensitivity: tiny angular velocity can be measured (e.g. the earth's rotation rate of 15°/h);

Environmental adaptability: high temperature resistance, anti-electromagnetic interference, suitable for extreme conditions;

Compact structure: miniaturized design is suitable for UAVs, robots and other miniaturized equipment.

Fourth:Typical applications

Military field: missile guidance, tank scope stabilization system;

Civilian field: UAV attitude control, high-speed train navigation, bridge health monitoring;

Aerospace: satellite attitude adjustment, spacecraft inertial navigation.

Through the above principle and structural design, the fiber optic gyroscope realizes high-precision and low-drift angular velocity measurement, and becomes one of the core components of the inertial navigation system.

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