A few possible scenarios today, as the authorities get down to deciding which is going to be adopted. Apart from the option that Michel Platini [and our Fran] wants, which is let's put it off for another time or not have it at all, it appears that the option to emerge as favourite is to have both systems..! Here's the reasoning.
Hawk-Eye: Not only tested for football, but tested in other sports combat too. Proven system. Expensive to install, but once in, totally reliable, Requires a sight of 25% of the ball for a 100% lock on its position. Signals the ref.
GoalRef: Tested for football, now good enough apparently. Less expensive to install. Possible problems with reliability, which would presumably be ironed out eventually. Merely requires a magnetic field between the posts. Signals the ref.
The thing is, Hawk-Eye provides dramatic confirmation evidence simply because it has cameras. GoalRef just provides the signal, and it appears that the Premier League, and other top leagues, find the dramatic evidence of Hawk-Eye to be very tempting indeed. So, at the moment, it looks like both systems will be adopted. For the top leagues in every country which wishes to adopt it, Hawk-Eye will probably be the system. For leagues that can't afford Hawk-Eye, GoalRef will be used. The minefield may have been walked through quite successfully.
Hawk-Eye: Not only tested for football, but tested in other sports combat too. Proven system. Expensive to install, but once in, totally reliable, Requires a sight of 25% of the ball for a 100% lock on its position. Signals the ref.
GoalRef: Tested for football, now good enough apparently. Less expensive to install. Possible problems with reliability, which would presumably be ironed out eventually. Merely requires a magnetic field between the posts. Signals the ref.
The thing is, Hawk-Eye provides dramatic confirmation evidence simply because it has cameras. GoalRef just provides the signal, and it appears that the Premier League, and other top leagues, find the dramatic evidence of Hawk-Eye to be very tempting indeed. So, at the moment, it looks like both systems will be adopted. For the top leagues in every country which wishes to adopt it, Hawk-Eye will probably be the system. For leagues that can't afford Hawk-Eye, GoalRef will be used. The minefield may have been walked through quite successfully.