How to determine relative position using accelerometer and gyro data

I am designing a robot, and need to track the distance and direction of the robot motion, Nothing in 3D, I only need x,y and angle in x y plane.

My question :

1. Is it possible to use gyro and accelerometer with kalman filtering or any other methods to track this? (I do not have motor encoders)

My constraints : I do not have space开发者_如何学JAVA to include a gps (due to power requirements) or motor encoders (due to motor support)

No, not really. If you integrate the accelerometer values twice you get position but the error is horrible. It is useless in practice.

Here is an explanation why (Google Tech Talk) at 23:20.

A related question is probably this.