Position tracking determine the position and orientation of one or more sensors for interaction, and control of computer processes. These position tracking systems need to not only provide accurate spatial and angular reference info, they must provide real-time analysis, and quick updates per second, at least 50 updates per second for most VR systems. They must also reduce lag or latency and improve accuracy in the systems. This allows for quick and accurate tracking of humans, peripheral devices, or even medical instruments. Active systems have at least one emitter which transmits a signal whose properties vary in space and at least one sensor which senses the emitted signal and permits calculation of spatial position based on the properties of the sensed signal.
Examples are magnetic, ultrasonic, or infrared signals that get emitted and sensed.
Passive systems don't use emitters, instead it's sensors detect features of objects or space the object takes up in order to determine their position. Passive systems use video and image processing technologies to calculate the position and orientation of marked or unmarked objects. Examples of this systems are mechanical BOOM systems. Outside-in configuration is when the object to be tracked has the emitter attach to it. This is similar to sonars and radars.