Maybe I can get GPS data but I don't think it's accurate enough. A few feet wrong would show the wrong position of the drones. It is important to be able to see who is currently the number 1, 2, 3 in the race.
So in addition to finding the current position of the racers you'll also need some history to determine where they are on the track. You'll also need to define the path of the track in order to determine the rank.