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In this paper, we review recent developments in interferometric fiber-optic gyroscopes for industrial applications. These gyroscopes use only elliptical-jacket or elliptical-core polarization-maintaining-fibers to make their optical systems immune to environmental effects, and they use open-loop or closed-loop signal processing circuitry. We have begun mass production of a gyroscope for automotive navigation and location systems. The more accurate gyroscopes have been applied to a number of consumer applications such as attitude control systems of unmanned agricultural helicopter, pipe-mapping and north-finding systems. For further enhancement in terms of size, cost, and accuracy, we have developed an application specific integrated circuit and an integrated optical circuit.
Shigeru OHO Hisao SONOBE Jun-ichi MAKINO Hiroshi KAJIOKA Tatsuya KUMAGAI
The phase-modulated optical fiber gyroscope signal was analyzed in a time-domain. The rotation rate detected by the gyroscope optics was extracted from the gyroscope signal as time-domain characteristics at the maximum sensitivity.
Shigeru OHO Hisao SONOBE Jun-ichi MAKINO Hiroshi KAJIOKA Tatsuya KUMAGAI
A down sampling technique was applied to signal processing for optical fiber gyroscopes. It lowered the higher speed requirement for the sampling system and numerical operations. Utilizing the technique, a digital signal processing circuit extracted rotational information from the gyroscope signal.
Shigeru OHO Hisao SONOBE Jun-ichi MAKINO Hiroshi KAJIOKA Tatsuya KUMAGAI
Secondary phase modulation was proposed for lowering the signal frequency band of open-loop optical fiber gyroscopes. Extracting the lowered frequency spectra, the rotation rate was derived from the gyroscope signal and the drift in the optical parameters were compensated.