A tracking system in which radiofrequency signals emitted by an invasive device such as a catheter, are detected and used to measure the position and orientation of the invasive device. The invasive device has a transmit coil attached near its end and is driven by a low power RF source to produce a dipole...http://www.google.de/patents/US5377678?utm_source=gb-gplus-sharePatent US5377678 - Tracking system to follow the position and orientation of a device with radiofrequency fields
