The gravimeter is a special type of accelerometer designed specifically to measure the acceleration of gravity. According to the equivalence principle of general relativity, the effects of gravity and acceleration are the same, so an accelerometer cannot distinguish between the two.
As gravimeters, it is possible to use improved versions of accelerometers for static measurements in which the sensitivity, accuracy and stability characteristics have been uniquely determined. In fact, in this application it is necessary to detect extremely small variations in acceleration.
When, for scientific purposes, it is necessary to carry out extremely precise measurements, an instrument is used that works on 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 to measure the displacement and an atomic clock to measure the fall time.
The detection of gravitational acceleration, besides being of interest in the scientific field (especially in physics and geology), is a practice in the mining industry (especially for the search of oil fields).