A remote sensor based on speckle tracking which uses an inertial-optical accelerometer is provided. The remote sensor makes it possible to correct the speckle pattern correlation centroid value in the presence of displacements due to vibrational noise. The inertial-optical accelerometer instantaneously highlights displacements of the sensor relative to an inertial reference, that is of a mass immovable with respect to the fixed stars, installed in the optical axis of the remote sensor.

An accelerometer comprising: a frame; one or more proof masses suspended from the frame by one or more flexures and movable relative to the frame along a sensing axis; a resonant element assembly, the resonant element assembly comprising a first resonant element and a second resonant element coupled to one another, the first resonant element connected between the one or more proof masses and the frame, the second resonant element connected between the one or more proof masses and the frame, such that movement of the one or more proof masses relative to the frame along the sensing axis results in one of the first and second resonant elements undergoing compression and the other of the first and second resonant elements undergoing tension; and drive circuitry configured to drive the resonant element assembly and a sensing circuit configured to determine a measure of acceleration.

An accelerometer comprising: a frame; one or more proof masses suspended from the frame by one or more flexures and movable relative to the frame along a sensing axis; a resonant element assembly, the resonant element assembly comprising a first resonant element and a second resonant element coupled to one another, the first resonant element connected between the one or more proof masses and the frame, the second resonant element connected between the one or more proof masses and the frame, such that movement of the one or more proof masses relative to the frame along the sensing axis results in one of the first and second resonant elements undergoing compression and the other of the first and second resonant elements undergoing tension; and drive circuitry configured to drive the resonant element assembly and a sensing circuit configured to determine a measure of acceleration.

The present disclosure provides a jump detection system for inertial measurement unit (IMU) integrated with a barometric altimeter in the same device (IMU-baro). The processor is configured to record time-series data of both a vertical component of the measured IMU-baro acceleration and the estimated vertical velocity of the IMU-baro, detect a potential jump by comparing the vertical component of the measured IMU-baro acceleration to one or more acceleration thresholds, and, validate the potential jump by comparing a difference between a maximum velocity and a minimum velocity within a vicinity of the potential jump in the time-series data of the estimated vertical velocity of the IMU-baro to a velocity threshold.

Embodiments of the present disclosure are directed towards a micro-electromechanical system (MEMS) sensing apparatus, including a laser arrangement configured to generate a light beam, a first waveguide configured to receive and output the light beam, and a second waveguide aligned endface to endface with the first waveguide. The second waveguide may be configured to receive at least a portion of the light beam from the first waveguide via optical coupling through the aligned endfaces. Either the first or second waveguide may be configured to be moveable in response to an inertial change of the apparatus, wherein movement of the first or second waveguide causes a corresponding change in light intensity of the portion of the light beam, the change in light intensity indicating a measure of the inertial change. Other embodiments may be described and/or claimed.

An acceleration measuring device is disclosed, for use as a gravimeter or gradiometer for example. The device has a support and a proof mass, connected to each other by at flexures allowing displacement of the proof mass relative to the support. The support defines a space for displacement of the proof mass. The device is configured so that the modulus of the gradient of the force-displacement curve of the proof mass decreases with increasing displacement, for at least part of the force-displacement curve. This is the so-called anti-spring effect. The resonant frequency of oscillation of the proof mass is determined at least in part by the orientation of the device relative to the direction of the force due to gravity. The proof mass is capable of oscillating with a resonant frequency of 10 Hz or less. The proof mass has a mass of less than 1 gram.

An acceleration measuring device is disclosed, for use as a gravimeter or gradiometer for example. The device has a support and a proof mass, connected to each other by at flexures allowing displacement of the proof mass relative to the support. The support defines a space for displacement of the proof mass. The device is configured so that the modulus of the gradient of the force-displacement curve of the proof mass decreases with increasing displacement, for at least part of the force-displacement curve. This is the so-called anti-spring effect. The resonant frequency of oscillation of the proof mass is determined at least in part by the orientation of the device relative to the direction of the force due to gravity. The proof mass is capable of oscillating with a resonant frequency of 10 Hz or less. The proof mass has a mass of less than 1 gram.

Embodiments of the invention include an accelerometer system. The system includes an accelerometer sensor comprising first and second electrode configurations and an inertial mass between the first and second electrode configurations. In one example, the accelerometer sensor being fabricated as symmetrically arranged about each of three orthogonal mid-planes. The system also includes an accelerometer controller configured to apply control signals to each of the first and second electrode configurations to provide respective forces to maintain the inertial mass at a null position between the first and second electrode configurations. The accelerometer controller can measure a first pickoff signal and a second pickoff signal associated with the respective first and second electrode configurations. The first and second pickoff signals can be indicative of a displacement of the inertial mass relative to the null position. The accelerometer controller can calculate an acceleration based on the first and second pickoff signals.

A high-precision magnetic suspension accelerometer for measuring the linear acceleration of a spacecraft is provided, comprising a magnetically shielded vacuum chamber system, a magnetic displacement sensing system, a magnetic suspension control system and a small magnetic proof mass. A optical coherence displacement detection technique is utilized for precisely measuring the position and the posture of the small magnetic proof mass in real time, and a magnetic suspension control technique is utilized for precisely controlling the position and the posture of the small magnetic proof mass to be brought back to the origin, so as to keep the small magnetic proof mass in the center of the systemic inner chamber. When the spacecraft is subject to a non-conservative force, the magnitude and direction of the acceleration can be precisely measured via the measurement of currents in the position control coils due to the acceleration of the spacecraft proportional to the currents of the position control coils. The accelerometer of the invention can avoid the technical bottleneck of high-precision machining, is easy to be produced and can achieve more high-precision measurement of the acceleration vector.

A moisture detector includes a sensor chip and a moisture determining unit. The sensor chip includes a humidity detector having a detection surface on which to measure humidity, and also includes a heater heating the detection surface, and the moisture determining unit is configured to, after causing the heater to start heating, determine whether moisture is present on the detection surface based on a difference in changes in the humidity measured by the humidity detector.