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In association football, goal-line technology is a method used to determine when the ball has completely crossed the goal line with the assistance of electronic devices and at the same time assisting the referee in calling a goal or not. The objective of goal-line technology (GLT) is not to replace the role of the officials, but rather to support them in their decision-making. The GLT must provide a clear indication as to whether the ball has fully crossed the line, and this information will serve to assist the referee in taking his final decision. In the wake of controversial calls made in the Premier League, 2010 World Cup and the Euro 2012, FIFA (previously against the technology) is testing potential candidates for goal-line technology. Nine systems were initially tested, but only two remain.
On 5 July 2012, IFAB officially approved the use of goal line technology. The two systems approved in principle were involved in test phase 2: GoalRef and Hawk-Eye. In December 2012, FIFA announced it would introduce goal-line technology in a competitive match for the first time at the 2012 FIFA Club World Cup in Japan.
The question of the inclusion of goal-line technology began to be raised in 2000 as a result of a penalty shootout during that year's Africa Cup of Nations final, when Victor Ikpeba's penalty for Nigeria against Cameroon was deemed by the referee not to have crossed the line after deflecting off the crossbar. To the contrary, television replays showed that it had. Cameroon went on to win the shootout and thus the Trophy of African Unity.
Interest was ignited in the United Kingdom after a game between Manchester United and Tottenham Hotspur in January 2005, in which Tottenham midfielder Pedro Mendes hit a shot 55 yards from goal. United goalkeeper Roy Carroll caught the ball and then dropped it at least a yard over the line before hitting it back out, but neither the referee nor the linesmen saw the ball cross the line. In response to this, FIFA decided to test a system by Adidas in which a football with an embedded microchip would send a signal to the referee if it crossed a sensor going through the goal. According to FIFA president Sepp Blatter, "We did different tests at the Under-17 World Cup in Peru but the evidence wasn't clear so we will carry out trials in junior competitions in 2007". However, those trials did not materialise and by 2008, Blatter had rejected the system outright, describing the technology as 'only 95% accurate'.
Another incident occurred in August 2009 in a league match between Crystal Palace and Bristol City. Striker Freddie Sears knocked the ball over the line from close range, but the ball bounced off the stanchion below the net and then came back out. The goal was not given and Palace manager Neil Warnock was furious. In March 2010, the International Football Association Board, which determines the laws of the game, voted 6-2 to permanently ditch the technology, with the Scotland and England football associations casting the dissenting votes. In a recent poll of 48 captains in the UEFA Europa League, 90% of respondents said that they wanted goal-line technology introduced. Following several refereeing errors at the 2010 FIFA World Cup – including the disallowed goal in Germany's 4–1 victory over England, when Frank Lampard hit a shot from outside of the penalty box that bounced off the crossbar and over the line; the ball came back out and the goal was disallowed because the assistant referee did not call for a goal – Blatter announced that FIFA would reopen the goal-line technology discussion.
Another instance of a controversial call was Chelsea’s 2–1 victory over Tottenham in 2011. Frank Lampard hit a shot just before halftime that slipped through the legs of Tottenham's goalkeeper Heurelho Gomes, and almost crossed the line before being tipped back into play, however the assistant called for a goal and Chelsea tied the game. Chelsea were credited with another goal that did not cross the line against the same opponents in the 2012 FA Cup semi-finals, leading again to calls for goal-line technology.
The role of IFAB 
As with all changes to the Laws of the Game, IFAB must sanction the use of goal-line technology. Six votes are required to make any changes. FIFA holds four votes and each of the world's first four football associations carries one vote. These are England's The Football Association, the Scottish Football Association, the Football Association of Wales and Northern Ireland's Irish Football Association.
Initial testing 
In July 2011, FIFA sanctioned tests on ten goal-line technology systems, requiring that the system notified the referee of the decision within one second of the incident happening. The message needed to be relayed via a visual signal and vibration. Tests were conducted by Empa between September and December 2011.
Cairos GLT system 
Produced by a German company Carios Technologies AG, alongside Adidas, the GLT system used a magnetic field to track a ball with a sensor suspended inside. Thin cables with electrical current running through them are buried in the penalty box and behind the goal line to make a grid. The sensor measures the magnetic grids and relays the data to a computer which determines if the ball has crossed the line or not. If the ball does cross the line a radio signal is sent to the referee’s watch within a second. Adidas designed a ball that could suspend and keep a sensor safe and intact even when the ball is struck with great force. Cairos claims the process is practically instantaneous, addressing critics' concerns that the technology might slow down the game. An older system developed by Cairos was trialled at the 2005 FIFA U-17 World Championship, but was found not to be fast or accurate enough.
On February 25, 2013 FIFA granted a licence to Cairos Technologies AG, enabling them to provide goal-line technology for use in FIFA-sanctioned competitons.
The Goalminder system has two co-founders, Harry Barnes and Dave Parden, who first thought of the system after their favourite team, Bolton Wanderers, was relegated due to a wrongly disallowed goal. The technology was not picked up at the time, but after Frank Lampard’s disallowed goal in the 2010 World Cup, interest in goal-line technology spiked causing FIFA to investigate the possibility of sanctioning goal-line technology. The technology uses high-speed cameras built into the goal posts and cross bar to record images at 2000 frames per second and deliver visual evidence to the referee, in less than five seconds, to settle goal-line controversy. With this technology there is no calibration: just visual evidence. The system is thought to be cheaper because less expensive cameras will be needed and the field will not have to be dug into.
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 and snooker. 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).
IFAB discussion of candidate technologies 
Second phase of testing 
In the second phase of testing, the manufacturer of the technology will choose a stadium to test its technology in a number of imagined scenarios. Testing will also be 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 would also be undertaken. Tests must also undergo testing two competitive matches.
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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.
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. 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 used in the 2013-14 Premier League season.
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 comes from within FIFA itself including 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. He now says that the technology could be in place by the 2014 World Cup in Brazil. UEFA president, Michel Platini will likely oppose the plan, and instead propose additional referees beside each goal.
See also 
- FIFA (2012). "Testing Manual". FIFA Quality Programme for Goal Line Technology.
- "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.
- McGrath, Liam (19 April 2010). "Goal-Line Technology: Crossing Too Many Lines For FIFA?". GeekWeek. Retrieved 28 June 2010.
- Miller, Herman (15 August 2009). "Neil Warnock furious as 'phantom goal' costs Crystal Palace".
- "Bristol City-Crystal Palace game will not be replayed". 17 August 2009.
- "Football players push FIFA for goalline technology". CNN.com. 5 March 2010. Retrieved 28 June 2010.
- Wilson, Jonathan (28 June 2010). "Soccer could use instant replay, but not at expense of the sport's flow".
- Marcus, Jeffrey (29 June 2010). "FIFA President Apologizes for Refereeing Errors". NY Times. Retrieved 29 June 2010.
- "Premier League - Controversy as Chelsea beat Spurs". 30 April 2011.
- McNulty, Phil (15 April 2012). "Harry Redknapp says referee admitted Mata goal mistake". BBC Sport. Retrieved 16 April 2012.
- "Fifa to run tests on nine goal-line technology systems this autumn". The Guardian. 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".
- "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.
- "England friendly against Belgium to be big test of goalline technology". The Guardian. 24 May 2012.
- "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.
- "Nada 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.
- "Non-league final to be used for goal-line technology experiment". BBC Sport. 27 April 2012.
- "Goal-line tech gets green light". 3 News NZ. December 6, 2012.
- "GoalControl to provide goal-line system at World Cup in Brazil". BBC. April 02, 2013. Retrieved April 03, 2013.
- "Fifa snubs Hawk-Eye in favour of German goalline technology". Guardian. 2 April 2013. Retrieved 4 April 2013.
- "Goal-line technology: Premier League votes in favour for 2013-14". BBC. 2013-04-11. Retrieved 2013-04-11.
- 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.
- Michel Platini: goalline technology money would be better spent on grassroots – video