US Patent 8718930 Acoustic navigation method

An information processing apparatus that detects a current location of the information processing apparatus; obtains a direction of a destination from the detected current location as a target direction; detects a facial orientation of a user wearing a headphone unit connected to the information processing apparatus via a wired or wireless connection in relation to a reference orientation based on outputs of a geomagnetic sensor and an acceleration sensor connected to the headphone unit; obtains a relative target angle based on a difference between the target direction and the user's facial orientation; and generates sound to be output by the headphone unit based on the obtained relative target angle.