1. A method for determining a velocity of an object in a printing system, the printing system comprising an fixed reference point, a reference pattern, independently movable with respect to said fixed reference point, wherein the object is independently movable with respect to said fixed reference point and with respect to the reference pattern, a first sensor, configured to have substantially the same velocity as said object with respect to said reference pattern and configured such that in operation the reference pattern is sensed by said sensor, comprising the steps of: a) moving said reference pattern relative to said fixed reference point independent of said object, b) determining the velocity of said reference pattern with respect to said fixed reference point, c) sensing said reference pattern using said first sensor, d) providing a sensor signal based on said sensed reference pattern, and e) determining the velocity of said object relative to said fixed reference point based on the determined velocity of said reference pattern with respect to said fixed reference point, and based on said sensor signal.