The underlying technology and mode of operation behind Hawkeye GLT is remarkably similar to that of GoalControl-4D. One of the reasons eyebrows were raised when the German company was chosen for the World Cup in Brazil is because the British group already has a great track record and has become a familiar visual aid to umpires and fans in tennis and cricket for many years. Hawk-Eye's first GLT system was already tested by the English Premier League in a match in 2007 and was used for the first time the season just ended by the PL.
Its use has only increased the chatter amongst fans and has hardly impacted the speed and continuity of the game, as many had feared it would.
The officials' watch used with the Hawk-Eye system was developed in an exclusive deal with French company Adeunis RF, but neither company is commenting on the frequencies deployed for sending the encrypted data to the match officials.