Method and arrangement for determining movement

To determine the movement of a device, a three-dimensional measurement of the device's acceleration is provided in known directions with regard to the device, and average signals (x, y, z) of acceleration signals (x, y, z) parallel to different axes are formed to allow tilt angles (&thetas;, ϕ, gamma ) of the device with respect to gravity to be defined. Acceleration change signals (xc, yc, zc) are formed by removing the average signals (x, y, z) from their respective acceleration signals (x, y, z) parallel to the different axes. The acceleration change signals (xc, yc, zc) and the tilt angles (&thetas;, ϕ, gamma ) of the device are used for forming a component (Zztot) of the acceleration change of the device, which component is parallel to gravity and independent of the position of the device.