Published online 6 November 2002 | Nature | doi:10.1038/news021104-6


Microwaves track football

Shin-pad transmitters could end controversial offside rulings.

Transmitters could give fans and pundits quick stats fixesTransmitters could give fans and pundits quick stats fixes© Cairos Technologies

A new system to monitor the positions of football players and the ball could make the game a lot less controversial. It can instantly alert referees, fans and coaches to whether a player is offside, or the ball has left the pitch or entered the goal.

Credit-card sized microwave transmitters are fitted in players' shin-pads. A peanut-sized transmitter goes inside the ball. Each produces a signature pattern several hundred times a second.

Up to 10 antennas around the pitch relay the information to a central computer, which pools the data to reconstruct the game. Within milliseconds referees receive information via a wrist receiver.

"The system can give information before the referee understands what's going on," says Sylvia Couronné of makers Cairos Technologies based in Karlsruhe, Germany. The computer sounding the alarm also collects statistics for coaches, pundits and fans. It can even recreate the game online, or control television cameras.

This winter, a full test will begin at a stadium in Nuremberg, Germany. Cairos hope to persuade FIFA, football's governing body, to use the technology in the next World Cup, to be held in Germany in 2006.

A computer pools the data to reconstruct the gameA computer pools the data to reconstruct the game© Cairos Technologies

Electronic monitoring of players will become the norm, at least on the training ground, says sports scientist Mark Williams of Liverpool John Moores University, UK. Information on movement could also be linked to data such as heart rate, he says.

But, Williams says, it's too early to say whether any monitoring can be accurate, quick and user-friendly enough to run a match. Referees who ignored an alert, or used them inconsistently, could also create arguments, he warns. This can happen with video umpires in cricket. "The uses for tactics and strategy are a lot clearer than those for officiating," Williams concludes.

Networks of video cameras and GPS transmitters on players can track a football game. But most monitoring technology cannot keep pace with play: asking it for advice would halt the game.