Abstract: A high precision rotation sensor comprises an inertial mass suspended from a base wherein the mass is responsive to rotational inputs that apply loads to load-sensitive resonators whose changes in resonant frequency are related to the applied loads.

Abstract: A high precision rotation sensor comprises an inertial mass suspended from a base wherein the mass is responsive to rotational inputs that apply loads to load-sensitive resonators whose changes in resonant frequency are related to the applied loads.

Abstract: A device and method for improved geodetic and seismic measurements are disclosed. The device comprises a triaxial accelerometer assembly, mounted to a reference structure, having full scale ranges greater than +/?1 G on three orthogonal axes and a mechanism for rotating the triaxial accelerometer assembly on the reference structure. The triaxial acceleration assembly is calibrated with an internal alignment matrix such that measurements of Earth's gravity vector are rotationally invariant with respect to the direction of Earth's 1 G static gravity vector irrespective of the orientation of the triaxial assembly on the reference structure. In-situ calibrations are performed by rotating the axes of the triaxial acceleration assembly in the direction of Earth's static gravity vector. Drift of the triaxial accelerometer assembly is compensated for by measuring changes in the values of the invariant static gravity vector for each axis and correcting for the drift with new calibration coefficients.

Abstract: A device and method for improved geodetic and seismic measurements are disclosed. The device comprises a triaxial accelerometer assembly, mounted to a reference structure, having full scale ranges greater than +/?1 G on three orthogonal axes and a mechanism for rotating the triaxial accelerometer assembly on the reference structure. The triaxial acceleration assembly is calibrated with an internal alignment matrix such that measurements of Earth's gravity vector are rotationally invariant with respect to the direction of Earth's 1 G static gravity vector irrespective of the orientation of the triaxial assembly on the reference structure. In-situ calibrations are performed by rotating the axes of the triaxial acceleration assembly in the direction of Earth's static gravity vector. Drift of the triaxial accelerometer assembly is compensated for by measuring changes in the values of the invariant static gravity vector for each axis and correcting for the drift with new calibration coefficients.

Abstract: A high-resolution digital seismic and gravity sensor includes an inertial mass connected to one or more force-sensitive resonators. The weight of the inertial mass is substantially unloaded with a spring arrangement when exposed to the force of the static gravity field. Seismic accelerations applied to the base of the seismic and gravity sensor, or changes in the gravitational field, generate loads that are transmitted to force-sensitive resonators so that changes in resonant frequency are related to the applied load. The changes in resonant frequency are thus a measure of the seismic accelerations and gravitational field variations.

Abstract: A high-resolution digital seismic and gravity sensor includes an inertial mass connected to one or more force-sensitive resonators. The weight of the inertial mass is substantially unloaded with a spring arrangement when exposed to the force of the static gravity field. Seismic accelerations applied to the base of the seismic and gravity sensor, or changes in the gravitational field, generate loads that are transmitted to force-sensitive resonators so that changes in resonant frequency are related to the applied load. The changes in resonant frequency are thus a measure of the seismic accelerations and gravitational field variations.

Abstract: A triaxial acceleration sensor comprises an inertial mass suspended in three orthogonal directions by support members in a statically determinate structure. Acceleration applied to the inertial mass generates loading forces that stress the support members either in tension or in compression. The stress levels are thus a measure of the applied acceleration. In an embodiment of this invention, the support members are force-sensitive resonators whose resonant frequencies of oscillation are related to the stresses in the members. The resonant frequencies are thus a measure of the complete three-dimensional vector of the applied acceleration.

Abstract: A triaxial acceleration sensor comprises an inertial mass suspended in three orthogonal directions by support members in a statically determinate structure. Acceleration applied to the inertial mass generates loading forces that stress the support members either in tension or in compression. The stress levels are thus a measure of the applied acceleration. In an embodiment of this invention, the support members are force-sensitive resonators whose resonant frequencies of oscillation are related to the stresses in the members. The resonant frequencies are thus a measure of the complete three-dimensional vector of the applied acceleration.

Abstract: A digital angular rate and acceleration sensor is constructed with force-sensitive resonators positioned longitudinally on one or both sides of the neutral bending plane of a cantilevered structure. The cantilevered structure has an inertial proof mass at its free end with a periodic velocity applied sideways to the bending plane. Rotation about the longitudinal axis, which produces periodic Coriolis acceleration, as well as inertial acceleration applied perpendicular to the bending plane, generate tensile and compressive forces on the resonators thereby altering the resonant frequencies that are thus a measure of angular rate of rotation and acceleration.

Abstract: Digital pressure transducers employing force-sensitive resonators are designed according to a method that eliminates spurious mode resonances. The dimensional and geometrical relationships of the force-producing pressure elements and structures are chosen such that spurious modes of oscillation are not excited by the resonant modes of the force-sensitive resonators.

Abstract: A digital angular rate and acceleration sensor is constructed with force-sensitive resonators positioned longitudinally on one or both sides of the neutral bending plane of a cantilevered structure. The cantilevered structure has an inertial proof mass at its free end with a periodic velocity applied sideways to the bending plane. Rotation about the longitudinal axis, which produces periodic Coriolis acceleration, as well as inertial acceleration applied perpendicular to the bending plane, generate tensile and compressive forces on the resonators thereby altering the resonant frequencies that are thus a measure of angular rate of rotation and acceleration.

Abstract: Digital pressure transducers employing force-sensitive resonators are designed according to a method that eliminates spurious mode resonances. The dimensional and geometrical relationships of the force-producing pressure elements and structures are chosen such that spurious modes of oscillation are not excited by the resonant modes of the force-sensitive resonators.

Abstract: A load cell having single or multiple resonators arranged to receive a strain that is proportional to the strain in a beam to which the resonator(s) is attached. Arrangement of the multiple resonators with respect to a force-bearing beam of the cell determines whether the cell is a bending mode load cell or a shear mode load cell. Absolute and differential pressure sensors, accelerometers and weighing devices are disclosed which employ the multiple-resonators of the invention.

Abstract: Prior mounting systems for tuning fork temperature sensors have resulted in unpredictable activity dips within the sensor operating ranges. This problem is eliminated by the mounting and isolation system (32) of the present invention that is adapted to mount temperature sensitive tuning fork (20) to a support structure. The mounting system comprises a mounting member (34) adapted for rigid connection to the support structure, and support means (36) connecting the tuning fork base to the mounting member such that the tuning fork is supported solely by the support means. The support means comprises a low pass mechanical filter that transmits only vibration frequencies that are less than the operating range of frequencies of the tuning fork.

Abstract: A digital differential pressure sensor with relatively low sensitivity to common mode line pressure errors. The sensor includes an airtight enclosure having a pair of pressure ports through which pressures are coupled to opposite sides of a pressure-sensing diaphragm, bellows, or Bourdon tube. The pressure-sensing elements generate torques which are transmitted by a shaft to stress-sensitive resonators which are isolated from the torque-producing elements by a sealed, flexible tube.

Abstract: A transducer system for a weighing scale having a flexure mode crystal resonator includes a parallelogram linkage for supporting the load platform of the scale, a mounting structure for mounting the crystal resonator between two pivotally connected mounting arms, and a coupling assembly for coupling force from the parallelogram linkage to one arm of the mounting structure.

Abstract: A temperature sensor is formed by mounting a force-sensitive resonator on a resilient or non-resilient base structure, preferably in an enclosure such that thermally induced expansions or contractions of the base structure apply a stress to the resonator. The resonant frequency of the resonator is measured to provide an indication of the temperature of the base structure and resonator.

Abstract: A digital pressure transducer is formed by mounting a force-sensitive resonator to a structure of nonsymmetrical configuration which produces loads under applied pressure. The frequency of the resonator is measured to provide a digital indication of the applied pressure.

Abstract: A temperature sensor is formed by mounting a force-sensitive resonator on a resilient or non-resilient base structure, preferably in an enclosure such that thermally induced expansions or contractions of the base structure apply a stress to the resonator. The resonant frequency of the resonator is measured to provide an indication of the temperature of the base structure and resonator.

Abstract: A mounting structure for crystal resonators used as frequency standards and transducers which maximizes performance and reduces the sensitivity to environmental errors. In one embodiment, force sensitive crystal resonators having inherent unmounted temperature sensitivities are used in conjunction with reactive spring-like mounting arrangements having predetermined temperature stress characteristics such that the thermally induced mechanical stress of the mounting arrangements changes, compensates, and optimizes the overall combined temperature characteristics. In another embodiment crystal resonators are isolated from the external environment so that they are capable of sensing forces while operating in a vacuum or inert atmosphere. Environmental isolation is provided by bellows and/or diaphragm arrangements used alone or in conjunction with air-tight enclosures which enable forces to be applied to stress-sensitive crystals while isolating the crystals from the external force producing environment.