== Working Principle ==
Internally the Location Managers uses an Extended Kalman Filter to combine and filter pose estimation systems, based on their probabilistic error levels. Each Pose Estimation System is therefore associated with a variance level (squared standard deviation), describing the expected uncertainty. Precise systems, such as [[AR-MarkersMarker]], are associated with a lower variance than inaccurate systems such as [[GPS]].
The Kalman Filter keeps track of the current device pose (= best estimate) and the associated uncerctainty. The operation is subdivided into two stages: Prediction and Correction.