Goal-line technology is headed for the big time.
FIFA announced Tuesday that GLT will be used at the 2014 World Cup and 2013 Confederations Cup after successful tests at the 2012 Club World Cup.
That's good news for fans of getting the call right, but no one yet knows for sure which form the technology will take in Brazil this summer and next.
With the big announcement out of the way, we've outlined FIFA's options for goal-line technology in the space below.
With different technologies on the market, FIFA has launched a tender today, setting out the technical requirements for the two forthcoming competitions in Brazil.
The two GLT providers already licensed under FIFA’s Quality Programme for GLT, and other GLT providers currently in the licensing process (that must have passed all relevant tests as of today) are invited to submit tenders.
Interested GLT companies will be invited to join an inspection visit to the Confederations Cup venues, currently scheduled for mid-March, with a final decision due to be confirmed in early April.
The technical requirements are listed in another article at FIFA.com. The four points come off as almost too simple.
First, the technology must be used only for goals. Second, it must be accurate. Third, the process must take less than a second. Fourth, the signal for a goal must be sent only to the match's officials.
Based on those parameters, FIFA already has two options. Tuesday's announcement indicated that others will be considered before a final decision in April.
Here are basics on the two existing contenders.
This is the system used in tennis and cricket. It employs six cameras and the principles of triangulation to determine where the ball is on the pitch.
If the ball crosses the goal line, the system sends a radio signal to the referee's wristwatch in less than a second (per BBC Sport).
A FIFA video illustrating the Hawk-Eye system can be seen here.
Instead of visual triangulation, GoalRef employs the principle of electromagnetic induction.
The system sets up a low-frequency magnetic field around the goal. An electronic microchip implanted in the ball causes a change in the field when the ball crosses the goal line.
Like Hawk-Eye, GoalRef takes less than a second to send a signal to the referee's watch (via Sky Sports).
A FIFA video illustrating the GoalRef system can be seen here.
FIFA has called for other GLT providers to submit new proposals before a final decision is made in April. When FIFA makes its decision, the chosen system will be used in both the Confederations Cup this year and the 2014 World Cup.
Which system would you choose? Let us know in the comments.