Intertial navigation on android phone with Kalman filter
The quick answer is that its not really possible to get the position information from a phone IMU with gyroscope, compass and accelerometer. Even with a Kalman filter its too unreliable to get any linear acceleration signal that can be integrated to give position. I have looked at a lot of Kalman filter papers for IMUs and at best, the linear acceleration is treated as a nuisance term. The three sensor IMU with Kalman filter does however give pretty solid 3D rotation estimates.