Where Am I ?

[Dave Shaffer]

Alternatively, depending on how you want to make your robot, you COULD use GPS. You just need to use differential GPS. See the wikipedia article on this.

And, if that's still not good enough (i.e. 10 centimeters claimed in the article), you could use interferometric GPS. That would give you one cm or better accuracy - in 3D, not just 2D. This is how much surveying is done nowadays.