The Goal Line Technology (GLT) has proved itself to be one of the most important innovations of the decade in the field of football. The main use of this technology is to instantly determine if the ball had crossed the entire goal line or not. This technology is not supposed to replace the role of the referee from the game but rather to aid in the decision-making capability of the referee.

Hawk-Eye In this method of Goal Line Technology, Fourteen high-speed cameras are placed at different locations of the stadium. Seven cameras are pointed towards each of the goal posts. These cameras track the ball using the technique called triangulation to get the accurate position of the ball relative to the goal line. In triangulation, the distance and position to or of an unknown point is calculated with the help of two known points.
Triangle is formed between these three points and uses the angle between them to determine the whereabouts of the third unknown point which is the ball itself. This technology can give a reliable result if at least three cameras have a line of sight to the ball. Once a goal is detected, an encrypted radio signal is sent to the wristwatch worn by the referee which vibrates and displays a message that a goal was scored.

Goalref This method of Goal Line Technology depends on the principle of electromagnetic induction. Here a low-frequency magnetic field is generated in the goal post. The ball is designed to integrate a passive electromagnetic circuit embedded between different layers of the ball.
A software system continuously monitors the condition of the magnetic field in the goal post. Any change in the magnetic field caused by the passage of the coils in the ball over the line is considered to be the goal. Once a goal is detected, an encrypted radio signal is sent to the wristwatch worn by the referee which vibrates and displays a message that a goal was scored. Goalref is inexpensive compared to Hawk-Eye technology so it is more affordable for low budget tournaments.

Although a stable state of Goal Line Technology is achieved using these two methods, more innovative ideas are always welcomed in this everyday evolving world. Everyone would love more economic, precise, and smart Goal Line Technology. More research is still required.