Bugged balls for tough calls [ball tracking systems]

This paper presents a soccer ball containing a transmitter that reveals the exact location of the ball on the pitch. It is a coin-size radio transmitter that broadcasts a pulsed signal in the 2.4 gigahertz band to a dozen receivers mounted on floodlight masts and near the sidelines. The receivers relay the pulses to a central computer, which then calculates the ball's exact location. The main goal of this transmitter is to help referees with tough calls, such as when a goalkeeper intercepts a ball on the fly after it has crossed the goal line. In such a case, the system would send a vibratory alert to a special wristwatch worn by the referee, signaling that the ball went over the goal.