Sensitivity of a fiber-optic gyroscope to environmental magnetic fields.

It is shown that environmental magnetic fields may cause a considerable error for the detected rotation rate even though the line integral of the magnetic field along the fiber vanishes. Experimentally, it has been shown that the earth's magnetic field yields a bias uncertainty of about 10 degrees /h, which can be reduced by at least 1 order of magnitude if the fiber coil is protected against environmental magnetic fields.