A method for location tracking, includes measuring one or more first impedance-magnitudes, between a probe located at a location in an organ of a patient and one or more body-surface electrodes, at a first electrical frequency. One or more second impedance-magnitudes, between the probe located at the location and the one or more body-surface electrodes, are measured at a second electrical frequency. Based on the measured first and second impedance-magnitudes, one or more probe zero-frequency impedance-magnitudes between the probe and the one or more body-surface electrodes are estimated. The location of the probe in the organ is estimated based on the one or more probe zero-frequency impedance-magnitudes.