Methods and systems method for sensing a position of an ob-ject in a body include positioning a probe in the body, making measurements of mapping electrical currents passing between at least a first electrode on the probe and a plurality of second electrodes on a surface of the body, calibrating the measure-ments so as to compensate for one or more non-ideal features of the measurements including effects of system-dependent electri-cal coupling to one or more devices other than the first elec-trode and the second electrodes, and computing the position of the probe in the body using the calibrated measurements.
