With the previous example and access to GPS location, we can now update a user's location and be able to do a basic tracking in Augmented Reality. However, this tracking is only considering position of the user and not his or her orientation. If, for example, the user rotates the phone, nothing will happen, with changes being effective only if he is moving. For that we need to be able to detect changes in rotation for the user; this is where inertial sensors come in. The inertial sensors can be used to detect changes in orientation.
In the current generation of mobile phones, three types of sensors are available and useful for orientation: