Patent ID: 8248209

Claim:
A device (D) for communicating between a mobile element and a fixed element, comprising: an electromagnetic field-based reader (L) comprising a transmitter with a transmitting antenna and a receiver with a first antenna placed in a housing ( 1 ); and a beacon (B) comprising a receiver able to receive a signal originating from the transmitter of the reader (L) so as to provide energy to a transmitter able to dispatch a signal received by the receiver of the reader (L), wherein, characterized in that the receiver of the reader (L) comprises i) at least one second antenna formed by windings around horizontal ferrite bars, and ii) signal comparison means able to compare the signal received by the first antenna ( 3 ) of the receiver with the signal received by the second antenna ( 4 ) so as to determine the moment at which the reader (L) passes vertically in line with the beacon (B), and each of the first antenna ( 3 ) and the second antenna ( 4 ) comprises two windings ( 5 , 6 , 7 , 8 ), for each of the first antenna ( 3 ) and the second antenna ( 4 ), one of the two windings ( 6 , 8 ) is configured to determine the phase of the signal gathered by the corresponding antenna, and for each of the first antenna 3 ) and the second antenna ( 4 ), one of the two windings is used to receive a signal, one or more arithmetic operations being carried out thereafter on at least one of the signals obtained, wherein said mobile element is a train, the reader is configured to be mounted horizontally underneath the train, and the first antenna and the second antenna are located in a bottom part of the housing.