[yongkimleng]

Are you tracking 1 player or many players?

In a simple situation of tracking 1 player, you can use the abovementioned idea. You may need multiple receivers since the IR light can be blocked by the person's body, etc.

Where the person is can be calculated by the intensity of the IR received (since your IR transmit signal isn't pulsed)

IF your IR transmit signal IS pulsed, you can use time-difference in recieving the pulses to calculate the position.

However it gets more complicated if you have multiple players on the field. Mary have to result to using time-synchronised microprocessors on each IR transmitter on each player.