Tennis Commander: A watch over your game by TENNIS COMMANDER LLC — Kickstarter
I was looking for something like this for Badminton, and I actually stumble onto this Kickstarter project. It looks too good to be true, especially the method / device to locate the player. From the research I have done so far, no bluetooth / wireless locating method is precise enough for badminton. So maybe with a bigger court, the precision is lesser significant?