title: How to detect magnetic north / azimuth without Magnetometer
body: <p>I'm working on an Android device which does not have a Magnetometer but has a Rotation Sensor (Gyro) and Gravity Sensor and GPS. I would like to determine <strong>True North / Azimuth</strong> from these sensors but can't figure out how. Without a Magnetometer, how do I determine the orientation of this device? Clearly somehow it knows where North is given the Maps app works just fine. </p>