Positional tracking

Position and rotation tracking is the tracking of something's position and rotation in space, such as a headset or a controller.

It is also known as 6DOF tracking, for the 6 degrees of freedom (DOF): horizontal, vertical, depthwise, pitch, roll, and yaw. It is used in an absolute positioning system. It can be done using a number of different hardware technologies, such as electromagnetic tracking or camera-based tracking.

Methods of camera-based tracking include methods using SLAM or VIO.

Position can be represented in a computer system using a 3D vector. Rotation can be represented using a quaternion.

PnO tracking is related to rotation tracking, which uses 3DOF of space.

Methods

• Markerless inside-out tracking, which is camera-based tracking (SLAM/VIO)- This is used on headsets such as Meta Quest headsets and the Project North Star. An open source method is Basalt. It can use visible light or infrared light, which can be artificially emitted.
• Marker-based tracking - Camera based tracking that uses markers in the environment, which is simpler to implement.
• Electromagnetic tracking. Electromagnetic tracking requires an external source. It gets jittery when there is metal around, like a metal laptop computer. Magnetic tracking is typically wired, but it does not have to be.
• UWB tracking
• Mechanical tracking
• Acoustic tracking
• Visible light-based tracking
• Infra-red based tracking

Magnetic tracking

240Hz is generally sufficient if using magnetic tracking with no filtering.

History

3D tracking has been used for motion capture for 3D animated movies.

The 3DOF regime of cheap tracking was embraced by Oculus VR with the original Oculus Rift. The CV1 of the Oculus Rift used (and the DK2) constellation tracking, which is a complex method of 6DOF tracking added on to a robust 3DOF system.