Integrating accelerometer and velocity meter records

An accelerometer is an attractive instrument for measuring shock and vibration motions because it is small and rugged with little interaction effect on the base structure to which it is attached. It can also be located in many otherwisd inconvenient areas. However, there are some potentially serious problems when accelerometer signals are directly integrated to produce velocities and displacements. Throughout this page, a perfect accelerometer is assumed, i.e., the acceleration along its active axis is truly recorded while this recorded signal is unaffected by acceleration orthogonal to the active axis. Three potential problems are examined: the integration and double integration of a simple sinusoidal wave; the effect of shaking, i.e., rotations about some point or points during a shock motion; and, for some circuits, the effect of small imperfections in the callibration.