Abstract: An inertial measurement unit using body dithered ring laser gyroscopes in which the individual ring laser gyroscopes are firmly attached to a common dithered structure and provisions made to cancel the reaction moment from the dithered structure by a passive resonator. The stable element, to which both the dithered structure and the passive resonator are attached with torsion springs, also serves as a non-vibrating foundation for strapped down accelerometers. The resulting structure contains fewer parts, has lower fabricating cost and permits a smaller package size than a conventional inertial measurement unit with individually body dithered ring laser gyroscopes.

Abstract: A ring laser gyroscope having a triangular block configuration is dithered about its center of gravity. An optical wedge attached to the output mirror allows the center of support to include the line of symmetry of the block, thereby reducing temperature gradients, which could cause output signals in the absence of an input angular rate across the instrument. The optical wedge, a mirror and a beamsplitter form an interferometer to compensate the output signal of the ring laser to produce an output free from influence of the dither motion. The mirror and beamsplitter are adjustable to allow for small corrections necessary to exactly compensate the dither-motion and to achieve 90.degree. phase shift between the outputs from photodetectors.

Abstract: The invention is concerned with angular rate sensors, and particularly with ring laser gyroscopes which includes means for compensating for the effects of temperature gradients and residual lock-in. A ring laser gyroscope is provided which has a triangular block configuration, and which incorporates a triangular-shaped laser resonant cavity defined by three corner mirrors, including an output mirror. The ring laser gyroscope of the invention includes an optical wedge and a prism attached to its output mirror which permit the center of support of the gyroscope to be located in the plane of symmetry of the block. The gyroscope is mechanically vibrated about its center of gravity to prevent lock-in effects at low angular input rates. The construction of the gyroscope reduces temperature gradients across the plane of symmetry of the instrument, which temperature gradients produce spurious output signals in the absence of an input angular rate.