A method for generating a movement signal of an object such as a body part of a human or animal is provided. The movement signal provides quantitative information on a movement of the object. The method includes acquiring an electromagnetic navigation signal such as a Pilot Tone signal from the object. The electromagnetic navigation signal is modulated by movements of the object. A reference signal is extracted from the navigation signal, and a parameter having a known time-dependency is determined from the reference signal. The navigation signal is corrected based on the parameter or a time-average of the parameter to reduce a signal drift in the navigation signal. The movement signal is extracted from the corrected navigation signal.
