Are all magnetic trackers about the same?

A. No, there are several generations of trackers on the market.

These range from 1st generation AC electromagnetic technology patented by Polhemus in the 1970s; 2nd generation pulsed DC magnetic technology patented by Ascension in the 1990s; and now 3rd generation magnetic technology patented by Ascension. The latter features the latest improvements and innovations in magnetic technology.

First generation trackers are notoriously susceptible to distorted measurements in the presence of environmental metals, such as carbon steel, aluminum, and even stainless steel.

Second generation DC trackers exhibit only 1/5 the sensitivity to conductive metal as their earlier counterparts. As a result their sensors can be attached to ultrasound scanheads, titanium instruments and non-magnetic stainless steel objects without discernable loss of accuracy.

Third generation trackers represent the state-of-the art in tracking. These include alarms to warn of any accuracy distortion, special transmitters that screen distortions emanating below the tracking volume, microminiaturized transducers for close-in operation, and advanced calibration techniques that yield sub-millimeter accuracies.