Patent ID: 8583215
Filing Date: 2013-11-12
Classification: A61B

Abstract:
1. A method for position sensing, comprising: inserting a probe comprising a first probe-electrode and a second probe-electrode into a body of a subject; coupling body-surface electrodes to a surface of the body; measuring, using first circuitry coupled to at least the first probe-electrode and having a first electrical ground, currents passing between the first probe-electrode and the body-surface electrodes, the probe and the plurality of body surface electrodes defining respective paths and an impedance along each respective path; determining position coordinates of the probe responsively to the measured currents using positioning circuitry, having a second electrical ground, coupled to at least the second probe-electrode; isolating the first electrical ground from the second electrical ground; and providing a predetermined inter-ground coupling impedance coupled between the first electrical ground and the second electrical ground, the inter-ground coupling impedance being higher than the impedance along each respective path; and maintaining accuracy of the position coordinates determination by reducing parasitic capacitance between the positioning circuitry and one or more of the first electrical ground and the second electrical ground.