Vibrating Beam MEMS Accelerometers

Description

This lecture covers the principles and historical development of gravimetry, oscillations of a pendulum, gravity anomalies on Earth, ground water storage monitoring, lunar gravity experiments, CO2/gas density contrast monitoring, gravimetry on Mars, seismic ground motion monitoring, limitations in seismic sensors, vibrating beam resonant accelerometers, historical context of vibrating beam gravimeters, frequency shift vs applied force, microlever suspensions, measurement of response in vertical direction, in-lab sensor calibration, oscillator circuit interface, non-linear effects and noise processing, mode-localized sensing, common mode rejection, mode-localized MEMS accelerometers for seismic measurements, prototype SMG GRAV10 specifications, and field tests for mobile gravimetry.

Official source

https://mediaspace.epfl.ch/media/0_qrfqic3e

About this result

This page is automatically generated and may contain information that is not correct, complete, up-to-date, or relevant to your search query. The same applies to every other page on this website. Please make sure to verify the information with EPFL's official sources.

Related lectures (14)

Related concepts (142)

Inertial navigation system

An inertial navigation system (INS) is a navigation device that uses motion sensors (accelerometers), rotation sensors (gyroscopes) and a computer to continuously calculate by dead reckoning the position, the orientation, and the velocity (direction and speed of movement) of a moving object without the need for external references. Often the inertial sensors are supplemented by a barometric altimeter and sometimes by magnetic sensors (magnetometers) and/or speed measuring devices.

Balanced line

In telecommunications and professional audio, a balanced line or balanced signal pair is an electrical circuit consisting of two conductors of the same type, both of which have equal impedances along their lengths, to ground, and to other circuits. The primary advantage of the balanced line format is good rejection of common-mode noise and interference when fed to a differential device such as a transformer or differential amplifier. As prevalent in sound recording and reproduction, balanced lines are referred to as balanced audio.

Differential signalling

Differential signalling is a method for electrically transmitting information using two complementary signals. The technique sends the same electrical signal as a differential pair of signals, each in its own conductor. The pair of conductors can be wires in a twisted-pair or ribbon cable or traces on a printed circuit board. Electrically, the two conductors carry voltage signals which are equal in magnitude, but of opposite polarity. The receiving circuit responds to the difference between the two signals, which results in a signal with a magnitude twice as large.

Accelerometer

An accelerometer is a tool that measures proper acceleration. Proper acceleration is the acceleration (the rate of change of velocity) of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is acceleration in a fixed coordinate system. For example, an accelerometer at rest on the surface of the Earth will measure an acceleration due to Earth's gravity, straight upwards (by definition) of g ≈ 9.81 m/s2. By contrast, accelerometers in free fall (falling toward the center of the Earth at a rate of about 9.

Differential amplifier

A differential amplifier is a type of electronic amplifier that amplifies the difference between two input voltages but suppresses any voltage common to the two inputs. It is an analog circuit with two inputs and and one output , in which the output is ideally proportional to the difference between the two voltages: where is the gain of the amplifier. Single amplifiers are usually implemented by either adding the appropriate feedback resistors to a standard op-amp, or with a dedicated integrated circuit containing internal feedback resistors.