An athermal open-loop hung mass accelerometer configures the CTE of the sensor heads such that any growth by the body in response to a body temperature gradient along the longitudinal axis is offset by the growth of the sensor heads in the equal and opposite direction to null the effects of the temperature gradient. In many configurations, the sensor head CTE is strictly less than the body CTE and typically between 60-80% of the body CTE to null the effects of the predicted body temperature gradient.

An athermal open-loop hung mass accelerometer configures the CTE of the sensor heads such that any growth by the body in response to a body temperature gradient along the longitudinal axis is offset by the growth of the sensor heads in the equal and opposite direction to null the effects of the temperature gradient. In many configurations, the sensor head CTE is strictly less than the body CTE and typically between 60-80% of the body CTE to null the effects of the predicted body temperature gradient.

An accelerometer closed loop control system comprising: a capacitive accelerometer comprising a proof mass moveable relative to first and second fixed capacitor electrodes; a PWM generator to generate in-phase and anti-phase PWM drive signals with an adjustable mark/space ratio, wherein said drive signals are applied to the first and second electrodes such that they are charged alternately; an output signal detector to detect a pick-off signal from the accelerometer representing a displacement of the proof mass from a null position to provide an error signal, wherein the null position is the position of the proof mass relative to the fixed electrodes when no acceleration is applied; a PWM servo operating in closed loop to vary the mark/space ratio of said PWM drive signals in response to the error signal so that mechanical inertial forces are balanced by electrostatic forces.

An accelerometer closed loop control system comprising: a capacitive accelerometer comprising a proof mass moveable relative to first and second fixed capacitor electrodes; a PWM generator to generate in-phase and anti-phase PWM drive signals with an adjustable mark/space ratio, wherein said drive signals are applied to the first and second electrodes such that they are charged alternately; an output signal detector to detect a pick-off signal from the accelerometer representing a displacement of the proof mass from a null position to provide an error signal, wherein the null position is the position of the proof mass relative to the fixed electrodes when no acceleration is applied; a PWM servo operating in closed loop to vary the mark/space ratio of said PWM drive signals in response to the error signal so that mechanical inertial forces are balanced by electrostatic forces.

A thermally insensitive open-loop hung mass accelerometer utilizes a transverse geometry to attach the body/flexures/proof mass so that thermal expansion effects due to thermal gradients across the accelerometer or bulk temperatures changes of one flexure relative to the other cause minimal or no axial displacement of the proof mass. In this geometry, multiple flexures may be stacked to achieve the required stiffness, thus reducing manufacturing costs and any tolerancing issues, without affecting thermal sensitivity. The accelerometer is suitably designed to exhibit a radial symmetry. The accelerometer is suitably designed to use low CTE materials for at least the proof mass and body and a low thermal expansion differential Eddy current sensor head.

A thermally insensitive open-loop hung mass accelerometer utilizes a transverse geometry to attach the body/flexures/proof mass so that thermal expansion effects due to thermal gradients across the accelerometer or bulk temperatures changes of one flexure relative to the other cause minimal or no axial displacement of the proof mass. In this geometry, multiple flexures may be stacked to achieve the required stiffness, thus reducing manufacturing costs and any tolerancing issues, without affecting thermal sensitivity. The accelerometer is suitably designed to exhibit a radial symmetry. The accelerometer is suitably designed to use low CTE materials for at least the proof mass and body and a low thermal expansion differential Eddy current sensor head.

A thermally insensitive open-loop hung mass accelerometer utilizes a transverse geometry to attach the body/flexures/proof mass so that thermal expansion effects due to thermal gradients across the accelerometer or bulk temperatures changes of one flexure relative to the other cause minimal or no axial displacement of the proof mass. In this geometry, multiple flexures may be stacked to achieve the required stiffness, thus reducing manufacturing costs and any tolerancing issues, without affecting thermal sensitivity. The accelerometer is suitably designed to exhibit a radial symmetry. The accelerometer is suitably designed to use low CTE materials for at least the proof mass and body and a low thermal expansion differential Eddy current sensor head.

A thermally insensitive open-loop hung mass accelerometer utilizes a transverse geometry to attach the body/flexures/proof mass so that thermal expansion effects due to thermal gradients across the accelerometer or bulk temperatures changes of one flexure relative to the other cause minimal or no axial displacement of the proof mass. In this geometry, multiple flexures may be stacked to achieve the required stiffness, thus reducing manufacturing costs and any tolerancing issues, without affecting thermal sensitivity. The accelerometer is suitably designed to exhibit a radial symmetry. The accelerometer is suitably designed to use low CTE materials for at least the proof mass and body and a low thermal expansion differential Eddy current sensor head.

An inertial sensor having a body with an excitation coil and a first sensing coil extending along a first axis. A suspended mass includes a magnetic-field concentrator, in a position corresponding to the excitation coil, and configured for displacing by inertia in a plane along the first axis. A supply and sensing circuit is electrically coupled to the excitation coil and to the first sensing coil, and is configured for generating a time-variable flow of electric current that flows in the excitation coil so as to generate a magnetic field that interacts with the magnetic-field concentrator to induce a voltage/current in the sensing coil. The integrated circuit is configured for measuring a value of the voltage/current induced in the first sensing coil so as to detect a quantity associated to the displacement of the suspended mass along the first axis.

An inertial sensor having a body with an excitation coil and a first sensing coil extending along a first axis. A suspended mass includes a magnetic-field concentrator, in a position corresponding to the excitation coil, and configured for displacing by inertia in a plane along the first axis. A supply and sensing circuit is electrically coupled to the excitation coil and to the first sensing coil, and is configured for generating a time-variable flow of electric current that flows in the excitation coil so as to generate a magnetic field that interacts with the magnetic-field concentrator to induce a voltage/current in the sensing coil. The integrated circuit is configured for measuring a value of the voltage/current induced in the first sensing coil so as to detect a quantity associated to the displacement of the suspended mass along the first axis.