Patent ID: 7867113

Claim:
A system comprising: a movable object, a plurality of pairs of antennas arranged with a goal including two goal posts and a horizontal crossbar that delimit a periphery of a flat target plane, one antenna of each of said pairs being arranged and displaced from the other antenna of each of said pairs in a direction perpendicular to the flat target plane, radio wave emitter means arranged in the movable object and/or each antenna, and means for receiving radio waves from the radio wave emitter means and for providing an output accordingly arranged in each antenna and/or in the movable object, at least one stationary auto-calibration transmitter arranged in the flat target plane and configured to provide a calibration signal to the plurality of pairs of antennas, and processing means to receive and process said output together with a predetermined set of conditions and to provide a resulting output if the set of conditions are fulfilled so as to determine whether the movable object passes the flat target plane.