The invention relates to a navigation system for navigating a catheter (3) in a vascular system (10), in which the current spatial position of the catheter (3) is continually measured by a locating device (2). The temporal sequence of the position signals obtained in this way is subjected to a filtering operation in order to compensate for cyclic intrinsic movements of the vascular system which are caused for example by the heartbeat. The filtering may comprise the suppression of amplitude maxima in the frequency spectrum at the heartbeat frequency. Furthermore, the filtering may comprise the calculation of a center of the trajectory in time windows of the length of the heartbeat.
