Electromagnetic tracking

Magnetic tracking is 3D tracking technology that uses magnetic fields to track an object in 6 degrees of freedom. It can be extremely precise if done right.

One company that makes electromagnetic tracking devices is Polhemus. Another company is Ascension Technologies.

The Magic Leap 1 used magnetic tracking for its handheld controller, but in a poor form.

Magnetic tracking at 240hz was researched by Neuralink for the purposes of tracking monkeys' body movements.

AC magnetic tracking

AC magnetic tracking means "alternating current magnetic tracking". It uses an AC electric current to generate alternating magnetic fields, which are picked up by a tracking sensor.

The fastest electromagnetic tracking system in the world is the Polhemus Viper 16, which tracks up to 960hz. This is much faster than the kalman filtered 100hz or 150hz of all existing consumer VR systems like SteamVR. Magnetic tracking feels better and more natural because it has a higher update rate and preserves high frequency transients in the movement, like a flick of a finger.