Fibre optic gyroscope

A fiber-optic gyroscope (English Interferometer Fiber-Optic Gyroscope, short IFOG ) is a gyroscope, which is based on the interference of two light beams that rotate in opposite directions in a coiled fiber. It is used to measure angular velocities.

The structure and operation of the fiber gyro based on the principle of Sagnac interferometer. A major difference is that the beam is not passed over the mirror circuit, but via a fiber optic. The glass fiber is not only once circulated, but there will be many turns wound (up to 5 km long). This provides a relatively small area, a much larger area than in an enclosed circulation and thus a much better measurable phase shift or difference frequency in the interference.

Related to the fiber-optic gyro, the laser gyro, the function of which is also based on the Sagnac effect. During the laser gyro using a ring laser with the underlying, the fiber optic gyroscope, an external source of radiation, for example radiation from a laser diode to be coupled.

Accuracy

The stability of the fiber-optic gyroscopes is typically lower than that of the laser gyro. Fibre gyro show drifts of about 0.003 ° / h and 100 ° / h, while laser gyros are in the range of 0.001 ° / hr to 10 ° / h. But in general, fiber-optic gyroscope show a higher angular resolution (up to 0.01 arc seconds ), while commercial laser gyro show about 1 arcsecond angular resolution. In contrast, laser gyroscopes typically better linearity than fiber-optic gyroscope and are thermally stable at correspondingly stable structure.

The Random Walk (noise) is fiber-optic gyroscopes, depending on the technology between 0.0001 ° / h0.5 and 0.5 ° / h0.5. It describes the random drift angle.

As a north-seeking systems mechanical gyros are now in quasi- static environment considerably cheaper than the fiber-optic gyroscope to be initialized (for example, for applications on merchant ships ). The alignment accuracy is slightly better than 1 °.

Applications

Fiber-optic gyroscope, in contrast to laser gyros relatively compact and cheaper than those. Unlike gyros they contain no moving parts and no wear parts. However, the costs are still so high that they have to date not found in consumer input. With increasing stability and production figures, however, they have the potential to replace mechanical systems, since they do not require run- time. A disadvantage is the loss of orientation upon failure of the power supply.

They are used as inertial navigation aid. They will be used in navigation systems for aircraft, ships and underwater vehicles are used. They are further along with GPS for the analysis of dynamic driving behavior used for example in the development departments of automobile manufacturers and automotive component suppliers (so-called elk test ), and for the attitude control of satellites.

  • Navigation
  • Laser application
  • Fiber optics
  • Optical measuring device
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