How Goal-Line Technology Works
Goal-line technology uses multiple high-speed cameras positioned around the goal to track the soccer ball's exact position. The cameras record footage at extremely fast speeds and create a three-dimensional image of where the ball is at all times. When the ball approaches or crosses the goal line, the system analyzes whether the entire ball has completely crossed the line. If a goal has been scored, the referee receives an instant alert on a special watch or device within about one second.
Approved Systems
FIFA has approved two main goal-line technology systems for professional soccer. Hawk-Eye is used in many European leagues and was the first system approved. GoalControl is FIFA's official system and is used in major tournaments like the World Cup and Champions League. Both systems must meet strict FIFA accuracy standards and be tested regularly to ensure they work properly.
When Goal-Line Technology Is Used
Goal-line technology is used only to make decisions about whether a goal has been scored. It cannot be used for other fouls or decisions in the game. The system automatically alerts the referee when it detects that a ball has crossed the goal line. The referee makes the final decision based on the technology's information, but the technology provides the evidence needed to make an accurate call.
Accuracy Requirements
FIFA requires goal-line technology systems to be accurate to within 5 millimeters. This extremely high level of accuracy ensures that no goals are incorrectly awarded or denied due to system errors. Both approved systems must pass regular testing and certification to continue being used in professional matches.
Implementation in Tournaments
Major soccer tournaments including the FIFA World Cup, European Championship, and club competitions like the Champions League use goal-line technology. However, not all professional leagues use the system due to cost. Leagues and teams must choose to implement goal-line technology, and many lower-level professional competitions do not have access to it.