Yozo Nishiura

Phase-modulated fiber optic gyroscope with wide dynamic range and linear scale factor

An open-loop phase-modulated fiber optic gyroscope with a wide dynamic range and linear scale factor is described. The optical Sagnac phase shift is transposed into an electrical phase shift by introducing two phase sensitive detectors and two electronic amplitude modulators with independent carrier frequency from the optical phase modulation. Preliminary experiments show good linearity over a wide dynamic range up to 1000 degrees /s and verifies the theoretical prediction.

FIBER OPTIC GYROSCOPE FOR AN AUTOMOBILE NAVIGATION SYSTEM

Sumitomo Electric Ind., Ltd., was the first in the world to start mass-producing the fiber optic gyroscope for an atuomobile navigation system. The fiber optic gyroscope was installed in an automobile in order to improve position detection accuracy. However, mass-producing the fiber optic gyroscope for an automobile navigation system was not possible before because it was difficult to achieve the high performance required under many operating conditions, especially in wide temperature ranges between -20 deg C to about 70 deg C. In order to overcome these problems, a new signal processing for a fiber optic gyroscope having the compensation functions of cancelling the fluctuation of the optical signal has been developed. The navigation system using this gyroscope has been installed in the Nissan Motor Companys 1991 CEDRIC, GLORIA, and CIMA models.