Litef Gmbh

Werner Schroder

Eberhard Handrich

A method and device for reading out a fiber gyroscope based on the concept of determining, by gating the light signal for particular time intervals, only one particular phase section of the read-out signal of a photodetector of the fiber optic gyroscope modulated with a periodic function. Further phase sections are determined in sequence and cyclically in the same manner so that the entire photodetector signal is detected after one full cycle. Signals associated with individual phase sections are averaged separately and processed to obtain a rotation rate-proportional signal. The read-out signals can also be processed so that a control signal for deviation of the phase modulator is obtained and/or the gyroscope scale factor is stabilized.

Method and apparatus for demodulating the rotation rate signal of a

A method and apparatus for reading out angular rates by means of a passive optical resonator provides for the generation of three component light beams individually tuned to distinct resonator modes. One component light beam is radiated into the resonator in the opposite direction to the two other component light beams. By means of an evaluating logic, differences are formed between the counterrotating light beams and the differences weighted and subtracted from each other to provide angular rate. The optical length of the resonator, and, thus, temperature are available as a weighted sum of the differences. Temperature drift may be eliminated from angular rate measurements by compensation according to the invention.

Method and apparatus for measuring angular rate with a passive optical

Method and apparatus for angular rate measurement and digital angular rate readout by means of a fiber interferometer using the Sagnac effect. Three component light beams are generated by means of an acousto-optical modulator which is operated in the Raman-Nath region. One component light beam is introduced unmodulated in a first direction into a fiber coil while the second and third component light beams are introduced with raised and lowered frequencies, respectively in the opposite direction. After passing through the coil, the component light beams are received by a photodetector and fed to controllers for generating the differential frequencies. Weighted, the differential frequencies are subtracted from each other or summed and evaluated as the angular rate and/or measures of the temperature of the fiber coil.

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Werner Schroder