There has been a lot of technological advancements in the world of sports, be it in the method used to make a football, to how a player’s stats are measured & studied, to how a referee can now tell if a ball has completely crossed a line thanks to something buzzing on his wrist.
Here is a quick look at four goal-line technologies, all trying to help the referee call a goal, with completely different methods to arrive at the same conclusion.
GoalControl-4D was successfully tested at the Confederations Cup and the FIFA Club World Cup in 2013. After which the German company gained approval and certification ahead of Hawk-Eye to be used at the 2014 FIFA World Cup.
It uses 14 high-speed cameras mounted on the stadium roof or catwalk (7 per goal mouth) to capture the positioning of the ball in the air and on the pitch. When the ball passes the goal line, the referees receive a notification on their watches.
GoalRef was created by another German company, Fraunhofer IIS, who are specialists in wireless communications and tracking. They were the first of two (Hawk-Eye the other) to receive FIFA’s certification.
The third Germany company in the mix, CAIROS Technologies AG, also uses the magnetic field method of tracking the movement of the ball across the line. It was one of the earlier movers on goal-line technology, testing it’s system as early as December 2007 successfully at the FIFA Club World Cup in Japan.
Cable strands are installed underneath the playing field parallel to the goal line and in the goal frame and generate a magnetic field. The magnetic field sensor in the ball is located in a specially developed ball bladder. If the ball has crossed the goal line, a signal is sent to the referee’s watch.
Hawk-Eye install 7 cameras per goal, the most common location is on the roof of the stadium. Software combines the information from all cameras and is able to track the ball within the goal area. As soon as the system detects that the ball has crossed the goal line, it sends a signal to the official’s watch (pretty identical to GoalControl isn’t it?).