How to improve accuracy of accelerometer and compass sensors?

Question

i am creating an augmented reality app that simply visualices a textview when the phone is facing a Point of Interest (wich gps position is stored on the phone). The textview is

Answer 1

Integration of gyroscope sensor readings can give a huge improvement in the stability of the final estimation of the orientation. Have a look at the steady compass application if your device has a gyroscope, or just have a look at the video if you do not have a gyroscope.

The integration of gyroscope can be done in a rather simple way using a complementary filter.