Choosing magnetometer/accelerometer for micro-mouse robot

[zazas321]

Hello. I am selecting components for my little hobby project (micro mouse to solve maze).

Which hardware component would be most suitable to be able to determine the robot direction (magnetometer?) and which component would allow me to calculate how far the robot was going in that particular direction?

Initially I was thinking about magnetometer+accelerometer. But I then realized that this may not be enough. I might be able to know the direction from the magnetometer and how fast the robot accelerated, but it wont tell me how much distance it covered since there is no way for me to know the speed.