GoalRef features a passive electronic circuit embedded in the ball and a low-frequency magnetic field around the goal. Any change in the field on or behind the goalline is detected by coils embedded in the goal frame, which determine the scoring of a goal. By producing low magnetic fields around the goals, GoalRef creates the radio equivalent of a light curtain. As soon as the ball has wholly crossed the goal line between the posts, a change in the magnetic field is detected. A goal alert is then instantaneously transmitted to the game officials using an encrypted radio signal, with a message displayed on their wristwatches.
The Hawk-Eye system was first developed in 1999. Hawk-Eye is an existing technology currently used in "cricket, "tennis, "snooker and Gaelic games being played in "Croke Park by the "Gaelic Athletic Association. It is based on the principle of "triangulation using the visual "images and timing data provided by high-speed video cameras at different locations around the area of play. The system uses high frame rate cameras to "triangulate and track the ball in flight. The software calculates the ball’s location in each frame by identifying the "pixels that correspond to the ball. The software can track the ball and predict the flight path, even if several cameras are being blocked. The system also records the ball's flight path and stores it in a database that is used to create a graphic image of the flight path, so the images can be shown to commentators, coaches and audiences. The data from the system can also be used to determine statistics for players and analyse trends. The proposal involves placing seven cameras for each goal mouth around the stadium. The system is near real-time and referees will be notified on their encrypted watch in less than one second from the ball crossing the line. Critics of the system claim the system will slow down the game and that the statistical margin of error is too large. Both "Roger Federer and "Rafael Nadal have criticised the accuracy of the system in tennis (though Roger Federer now supports the use of the system in football).
Second phase of testing
On 3 March 2012, "IFAB announced that 2 of the 9 proposed systems had proceeded to the second stage of testing. These were Hawk-Eye and GoalRef. In the second phase of testing, the manufacturer of the technology chose a stadium to test its technology in a number of imagined scenarios. Testing was also conducted in professional training sessions and in laboratories to account for different climatic conditions and other magnetic field distortions. Tests on the watch to be worn by referees were also be undertaken. The systems also each underwent testing in some competitive matches.
The German-Danish GoalRef technology underwent match testing in some "Danish Superliga matches in the first half of 2012. Following the second phase trials, on 5 July 2012 IFAB approved GoalRef in principle, making it available for use in professional matches under a set of revised "Laws of the Game. Each installation however would also require licensing approval for use in the individual stadium, on a 12-month basis. The "2012 FIFA Club World Cup was the first tournament where GoalRef was used by a match referee. Goal Ref was used for the first time on 6 December 2012 in the first match of the 2012 FIFA Club World Cup.
The first match to use the "Sony-owned Hawk-Eye goal-line technology was "Eastleigh F.C. versus "A.F.C. Totton in the "Hampshire Senior Cup final at "St Mary's Stadium, "Southampton in "England on 16 May 2012. Although it used Hawk-Eye, the system had no bearing on the referee's decisions and the system readings were only available to "FIFA's independent testing agency. The system was also in place for the technology's second test on 2 June for "England's "friendly match against "Belgium.
Following the success of the trials, in July 2012 IFAB voted unanimously to officially amend the Laws of the Game to permit (but not require) goal-line technology.
In December 2012, "FIFA announced it would introduce goal-line technology at the "2012 FIFA Club World Cup in "Japan. "Hawk-Eye technology was employed at "Toyota Stadium, while GoalRef was used at "International Stadium Yokohama.
In April 2013, FIFA announced that "GoalControl, a camera-based system, would be used at the "2013 Confederations Cup and, if successful, would be implemented at the "2014 FIFA World Cup (in October 2013, FIFA confirmed the use of "GoalControl at the "2014 FIFA World Cup.) Its system, GoalControl-4D, uses 14 high-speed cameras located around the pitch and directed at both goals.  Later in April "the Football Association announced that Hawk-Eye would be used in the "2013–14 Premier League season. On 16 December 2013, it was announced that Hawk-Eye would be used in three of the four quarter-finals and any subsequent matches in the "League Cup. The system was used when, on the very next day, the "Sunderland – "Chelsea quarter-final goal from Frank Lampard was allowed. The first goal to be decisively awarded using goal-line technology in the English Premier League was "Edin Džeko's goal for "Manchester City against "Cardiff City on 18 January 2014.
The first World Cup tournament to use goal-line technology was the "2014 FIFA World Cup. In a 15 June 2014 "group stage match between "France and "Honduras, the Honduran goalkeeper "Noel Valladares dropped a shot from "Karim Benzema into the goal for the first World Cup goal given by the technology.
In December 2014, the "Bundesliga clubs approved goal-line technology that will be introduced at the start of the "2015–16 Bundesliga season. The league picked the cheaper Hawk-Eye system over two German technologies. The technology was also introduced for "Ligue 1 for the start of the "2015–16 Ligue 1 season.
The technology was used in the "UEFA Europa League final, "UEFA Champions League, "European Championship and "Copa America for the first time in 2016.
Human element is lost
While advocates for goal-line technology maintain that it would significantly reduce refereeing errors during play, there are also criticisms of the technology. Much of the criticism came from within FIFA itself including former FIFA president "Sepp Blatter. Apart from the criticisms revolving around the technical aspects of the two proposed technologies, critics point out that such technology would impact on the human element of the game and remove the enjoyment of debating mistakes. Sepp Blatter has been quoted as saying "Other sports regularly change the laws of the game to react to the new technology. ... We don't do it and this makes the fascination and the popularity of football".
A study suggested that in the "2010–11 Premier League season "errors took place nearly 30% of the time that video replays could help prevent", but some people claim that instant replays would interrupt the flow of the game and take away possible plays.
Other critics believe it would be prohibitively expensive to implement the technology at all levels of the game and particularly for smaller/poorer football associations. FIFA officials have expressed a preference for 'better refereeing' as well as more match officials over implementing the technology. Advocates in turn cite the many examples of incorrect goal-line decisions deciding important games and point out that the technology has improved much since the initial trials carried out by FIFA. Advocates contend that any extra help for the referee should outweigh arguments that it would lead to non-uniform rules (since not all football associations would be able to implement it).
Blatter had been opposed to goal-line technology until "Frank Lampard's disallowed goal in the "2010 World Cup where the ball clearly crossed the line.
The introduction of the so-called ""fifth official", i.e. the extra "assistant referee standing beside the goal-line, was partly in order to facilitate in such situations.
In April 2013, "MLS commissioner Don Garber confirmed that MLS would not adopt goal-line technology for the 2014 season, citing cost as the overriding factor. "GoalControl installation would cost about $260,000 per stadium, and a further $3,900 for each game.
In early 2014, the vast majority of teams in the two divisions of the German "Bundesliga voted against introducing goal-line technology for financial reasons. The costs per club would have ranged from €250.000 for a chip inside the ball up to €500.000 for Hawk-Eye or GoalControl. The manager of "1. FC Köln, "Jörg Schmadtke, summarized the vote with "The cost is so exorbitant, that using this (technology) is not acceptable". World governing body FIFA are set to make £300,000 from the Premier League’s decision to install goal-line technology in all top-flight stadiums before the start of next season. Each of the 20 clubs will have to pay FIFA £15,000 to install, test and receive the ‘FIFA quality seal’ for Hawk-Eye’s camera-based system, which is expected to cost around £250,000 per ground in total. FIFA will also make an extra £15,000 from Wembley Stadium, which will have the technology installed for use in events such as the FA Cup semi-finals and final.
- "Wenger praise for Goal Decision System". PremierLeague.com. 8 August 2013. Retrieved 10 August 2013.
- FIFA (2012). "Testing Manual" (PDF). FIFA Quality Programme for Goal Line Technology.
- Thomas, K. (2014). "Keeping an eye on the ball". SPIE Newsroom. "doi:10.1117/2.2201406.01.
- FIFA.com (1 April 2014). "Goal-line technology set up ahead of FIFA World Cup".
- "Hawk-Eye confirmed as goal-line technology provider for Canada 2015". "FIFA. 31 March 2015. Retrieved 2 June 2015.]
- "Updated goal-line technology testing manual published - FIFA Quality Programme".
- "Final installation test - FIFA Quality Programme".
- "FIFA-accredited test institutes - FIFA Quality Programme".
- "Serie A approves goal-line technology for next season". ESPN FC. 13 February 2015. Retrieved 6 January 2016.
- "LFP adopts goal-line technology". Ligue1.com. 17 April 2015. Retrieved 6 January 2016.
- "Bundesliga to use goalline technology from 2015-16 season". BBC. 4 December 2014. Retrieved 6 January 2016.
- "Goal-line technology: Premier League votes in favour for 2013-14". BBC. 11 April 2013. Retrieved 6 January 2016.
- "FIFA certified GLT installations - FIFA Quality Programme".
- "FIFA licensed GLT providers - FIFA Quality Programme".
- "ChyronHego Partners With Fraunhofer IIS to Market and Develop GoalRef - ChyronHego".
- "Nigerian media bitter in defeat". BBC Sport. 14 February 2000. Retrieved 1 August 2012.
- "Manchester United 0-0 Tottenham". BBC News. 4 January 2005. Retrieved 28 June 2010.
- Miller, Herman (15 August 2009). "Neil Warnock furious as 'phantom goal' costs Crystal Palace". The Guardian. London.
- "Bristol City-Crystal Palace game will not be replayed". The Guardian. London. 17 August 2009.
- Emery, Daniel (28 June 2010). "PM and goal-line technology firms dispute Fifa claims". BBC. Retrieved 23 April 2015.
- McGrath, Liam (19 April 2010). "Goal-Line Technology: Crossing Too Many Lines For FIFA?". GeekWeek. Retrieved 28 June 2010.
- "Football's lawmakers reject goal-line technology". BBC. 6 March 2010. Retrieved 23 April 2015.
- Wilson, Jonathan (28 June 2010). "Soccer could use instant replay, but not at expense of the sport's flow". CNN.
- Marcus, Jeffrey (29 June 2010). "FIFA President Apologizes for Refereeing Errors". NY Times. Retrieved 29 June 2010.
- "Euro 2012: Ukraine's ghost goal against England another example of why we need goal-line technology, says Sepp Blatter". The Daily Telegrapgh. 20 June 2012.
- "Fifa to run tests on nine goal-line technology systems this autumn". "The Guardian. London. 21 July 2011.
- Conway, Richard (15 April 2012). "Goal-line technology edges closer". "BBC Sport. Retrieved 3 March 2012.
- "company". Cairos.com. Retrieved 13 March 2012.
- "Goal-line technology – Getting it right". "The WIPO Journal. August 2010. Retrieved 13 March 2012.
- "GLT System". Cairos.com. Retrieved 13 March 2012.
- "FIFA grants goalline technology licence to German firm Cairos". The Guardian. London. 25 February 2013.
- "About Goalminder - Goal Line Technology - Visually Informed". Retrieved 13 March 2012..
- "Goalminder aims to end goal-line errors". menmedia.co.uk. 11 October 2011. Retrieved 13 March 2012.
- Jackson, Jamie (24 May 2012). "England friendly against Belgium to be big test of goalline technology". "The Guardian. London.
- "GoalRef Goal-Line Technology Advances to Final". Fraunhofer. Retrieved 2012-12-12.
- Boothroyd, David (11 October 2011). "Sport technology enables improved decisions".
- Dickinson, Matt (17 August 2007). "Hawk-Eye set to extend its influence to contested goals". The Sunday Times. London. Retrieved 29 June 2010.
- "Why FIFA Refuses to Sanction Goal-Line Technology". Fast Company. 28 June 2010. Retrieved 29 June 2010.
- "Federer: Hawk-Eye must be scrapped". This is London. Retrieved 2010-06-28.
- "Nadal slams Hawkeye after losing to Youzhny". Rediff.com. 31 December 2004. Retrieved 28 June 2010.
- "Soccer needs technology, tennis does not: Federer". Reuters.com. 28 June 2010. Retrieved 29 June 2010.
- Berendt, Lars (16 May 2012). "FIFA tester teknologi i Silkeborg og Farum" (in Danish). "Danish Football Association. Retrieved 16 May 2012.
- "The ball tells you when it's in".
- "FIFA give debut to goal-line technology in World club curtain-raiser". Irish Independent. 6 December 2012. Retrieved 6 December 2012.
- "Non-league final to be used for goal-line technology experiment". "BBC Sport. 27 April 2012.
- "IFAB makes three unanimous historic decisions". FIFA.com. FIFA. Retrieved 23 April 2015.
- "Goal-line tech gets green light". 3 News NZ. 6 December 2012.
- "GoalControl to provide goal-line system at World Cup in Brazil". BBC. 2 April 2013. Retrieved 3 April 2013.
- Fifield, Dominic (2 April 2013). "Fifa snubs Hawk-Eye in favour of German goalline technology". Guardian. London. Retrieved 4 April 2013.
- "Goal-line technology: Premier League votes in favour for 2013-14". BBC. 2013-04-11. Retrieved 2013-04-11.
- BBC: Football League to use goal-line technology in Capital One Cup
- BBC: Sunderland 2-1 Chelsea
- Williams, Tom (19 January 2014). "Arsenal stay top, technology aids Manchester City". Sydney Morning Herald.
- "France 3-0 Honduras". "BBC Sport. 15 June 2014. Retrieved 15 June 2014.
- "Bundesliga approves Hawk-Eye goal-line technology for new season".
- "Goalline technology to be used in Champions League final".
- Association, Press (22 January 2016). "Uefa to use goal-line technology at Euro 2016 and in Champions League".
- "Copa America to use goal-line technology". 26 May 2016.
- Kelso, Paul (27 June 2010). "England v Germany: Frank Lampard's 'goal' reignites goal-line technology debate". The Telegraph. London. Retrieved 28 June 2010.
- CBC Sports (8 March 2008). "FIFA halts instant replay experiment". Cbc.ca. Retrieved 28 June 2010.
- "Sport technology enables improved decisions". newelectronics.co.uk. 11 October 2011. Retrieved 13 March 2012.
- Kelso, Paul (27 June 2010). "England v Germany: Fifa want 'better refereeing' not goal-line technology". The Telegraph. London. Retrieved 28 June 2010.
- "Soccer: No goal-line aids until 2013". London: ESPN. 5 October 2011. Retrieved 13 March 2012.
- theguardian.com (11 December 2012). "Michel Platini: goalline technology money would be better spent on grassroots – video".
- "mlssoccer.com - MLS Commissioner Don Garber says league won't adopt goal-line technology by 2014".
- Fußball: Bundesliga verzichtet auf Torlinientechnik, Spiegel Online, 2014-03-24.