A gyroscopic device comprising a beam, column or other continuous unitary structure of consistent vibratory characteristics along its full length and including piezoelectric material. The piezoelectric effect is used both excite the structure into resonant vibrations along a first axis and then, when a rate of turn is applied along a second axis at right angles to the first, to detect that rate of turn by sensing vibrations set up in the beam in a direction parallel to a third, orthogonal axis due to Coriolis forces resulting from the applied rate of turn. The beam may be held at both ends, or may be supported at one end only with the other end free. The vibrations applied to and sensed within the beam by means of the piezoelectric effect may be parallel, transverse and radial relative to the beam axis, or may be in a rotary sense around that axis. A mode of vibration in which opposite faces of the beam oscillate in parallel directions but out-of-phase is also disclosed.

This invention relates to a single axis solid state attitude sensor in which, the spatial orientation of a resonant rode on a resonant body is maintained in alignment with the inertial angle K8 of the resonant body.

A method of and apparatus for scale factor compensation for piezo-electric rate sensors maintains the magnitude of vibration at a primary pick-off point substantially constant to enable one of the variables of a vibrating structure--the piezo-electric charge coefficient .beta. to be determined, and thereby enables variation of the scale factor of the sensor from a calibrated value to be determined. This enables correction of the sensor output by a computational scale factor control unit to ensure that the output therefrom allows for a more accurate sensor. Thus, sensors are provided for applications requiring a higher degree of accuracy than they were previously able to provide for.

A gyroscopic device comprising a resonator in the form of a disc, cylinder or like structure of circular outline, of a composition containing piezo-electric material and preferably made of a an integral mass of such material. The resonator is excited into dilatation-type vibration by electric currents applied to exciting electrodes electro-deposited in a regular pattern around the circumference of the structure, and these vibrations are sensed by detecting electrodes similarly deposited around the wall in a similar but angularly displaced pattern. A measure of any rate of turn which the structure is undergoing about its axis can be derived from the resulting phase shift of the electrical output from the detecting electrodes.

The present invention is an inertial rate of turn sensor of the vibratory type employing force feed back techniques for maintaining the free end of a cantilever in a nulled lineal path, constant with respect to the casing of the instrument. The current required to maintain the constant lineal path is then a measure of the amplitude of the rate of turn of the case and the phase sense of that current defines the sense of rotation of the case and therefor of the craft.