I am thinking about the possibility to use the accelerometer to calculate the position, the orientation, the speed and the path.

If we give to a program the initial conditions (orientation, speed, position), it could be possible, by integrating accelerations, to know always the position, the speed and the orientation.

Such a program could replace the gps programs in some cases (for exemple, store the plan of a cave) or be used as a magetometer-like device.

I know planes use such a method (Inertial measurement unit) to estimate their position.

The question is to know if N900's accelerometers are precise enough to get some useful result after a while.