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GPS tracking wouldn't work. The military grade reception only gets you down to a few meters. The civilian band is multiples larger. It's fine for a lot of things especially when you can extrapolate due to roadways and add in cell data, but the accuracy needed for football placement would be impossible.
that might have been true 15 years ago but current GPS tech is way more accurate than that...but the tech for that is pretty expensive and requires near perfect conditions....also positions need to be observed for longer periods of time...it's basically too cumbersome for a 3 hour football game where the ball is constantly being moved...playing indoors only adds to the problems for recording data