The gravimeter is a particular type of accelerometer specifically designed to measure the acceleration of gravity. According to the equivalence principle of general relativity, the effects of gravity and acceleration are the same; therefore, an accelerometer cannot distinguish between the two cases.
As gravimeters, it is possible to use improved versions of accelerometers for static measurements, in which sensitivity, precision, and stability characteristics have been uniquely appointed. In fact, in this application, it needs to detect extremely small acceleration variations.
Where, for scientific purposes, it is necessary to carry out extremely precise measurements, an instrument is used that works with the same principle as the laser accelerometer: in this case, the acceleration of the fall of a grave is detected in a vacuum chamber, using a laser interferometer for measuring displacement, and an atomic clock for measuring fall time.
The detection of gravitational acceleration, besides being of interest in the scientific field (especially in physics and geology), is a practice of the mining industry (especially for the search of oil fields).
Learn more about gravimeter here: http://www.ecgs.lu/wulg/gravimeters/