Lemme try to paraphrase and remember what I was told in 8th grade science...
To determine how and where your moving to/towards there needs to be a reference point. If your in a car and you see a sign, the sign will pass by because you are moving and that will show you that you are moving. If the car is still and you see a sign, sitting there with you, you aren't moving.
So basically... Get a bg
