Development of a space-use ring laser gyroscope in Japan

An account is given of the development history and current status of ring laser gyros for space applications in Japan. The first major design development effort employed mechanical dither and a 33-cm path length; the second design, based on an evaluation of the performance of the first, incorporated redesigned optics and dither-suspension system modifications. After testing and evaluation of the second design, a third mechanical dither system-based configuration was developed which changed the gyro's block shape and adopted lock-in control; scale factor characteristics and bias behavior were improved by these means.