A coordinate system registration module (62), including radiopaque elements (102) arranged in a fixed predetermined pattern and configured, in response to the radiopaque elements generating a fluoroscopic image, to define a position of the module in a fluoroscopic coordinate system of reference. The module further includes one or more connections configured to fixedly connect the module to a magnetic field transmission pad (50) at a predetermined location and orientation with respect to the pad, so as to characterize the position of the registration module in a magnetic coordinate system of reference defined by the magnetic field transmission pad.