Abstract: A self-calibrating three axis angular rate sensor in which a single proof mass is supported from an outer case by a set of spring elements having substantially equal mechanical translational spring rates in all directions. Each axis is electromechanically coupled such that each of three sets of electrical terminals acts as a combined electrical driving and electrical detection means with respect to motion of the proof mass. The proof mass motion in combination with a general three axis angular rate input results in coriolis forces acting upon the proof mass. When the electrical terminals are driven with a multiplicity of additive sinusoidal time function electrical voltages, measurements of these voltages and resulting electrical currents comprise observable data for a computed extraction of three axis angular rate inputs.

Abstract: Apparatus for reducing the twice spin frequency vibration sensitivity of tuned inertial sensors by providing a twice spin frequency rotating filter thereon is disclosed. In accordance with the invention a rotating filter is supported on the shaft assembly of a tuned inertial instrument so as to rotate therewith at the spin speed. By tuning the combination of the filter rotor and the spring support thereof so as to have a natural frequency of twice sin frequency about axes perpendicular to the spin axis, the filter rotor, operating uncaged and substantially undamped, will absorb a large part of the twice spin frequency angular vibration torques imposed on the shaft assembly through bearing noise and other sources.

Abstract: Spin coupled angular rate sensitive inertial sensors of the tuned suspension system type with mounting structure, and method of fabricating and mounting such sensors whereby the twice spin frequency linear and angular vibration sensitivity characteristic of tuned sensors may be eliminated. The twice spin frequency angular vibration sensitivity characteristic of other tuned inertial sensors is reduced by creating an equal and opposite torque component dependent on the same vibrational input by angularly offsetting the rotor suspension system from a plane orthogonal to the spin axis, and by providing the shaft assembly with an effective product of inertia of controlled magnitude and orientation.Compensation for twice spin frequency linear vibration caused primarily by the spin bearings is achieved either by mounting the spin bearings in a relatively soft mounting, or supporting the instrument case (non-rotating portion) on a suspension tuned to twice spin frequency in the translational mode.

Abstract: Spin coupled angular rate sensitive inertial sensors of the tuned suspension system type, and method of fabricating such sensors whereby the twice spin frequency linear and angular vibration sensitivity characteristic of tuned sensors may be eliminated. The twice spin frequency angular vibration sensitivity characteristic of other tuned inertial sensors is eliminated by creating an equal and opposite torque component dependent on the same vibrational input. This is done by angularly offsetting the rotor suspension system from a plane orthogonal to the spin axis, and by providing the shaft assembly with an effective product of inertia of controlled magnitude and orientation. The product of inertia modulates any twice spin frequency angular vibration of the shaft about an axis orthogonal to the spin axis with the spin frequency of the shaft to provide an angular disturbance of the shaft about the spin axis.