Localization of A Omni-Directional Robot

[Ether]

Originally Posted by cad321

What about 2 omni wheels placed perpendicular to each other that drag along the floor. As the one in the y axis moves, it gives you your position in the y axis

That's true only if there is no vehicle rotation. If there is going to be vehicle rotation, you need either a) a gyro, or b) a third follower wheel... and you'll need to integrate (vector sum) the vehicle movements.

You might find this post of interest (and also the rest of the post in that thread).