Abstract: A method and system for determining the distance between two stations interconnected through a carrier wave connection for data transmission by frequency modulation (FM) or phase modulation (PM) and, if necessary, transferring the data concerning the distance determined. At least one of the two stations is movable and each station comprises a transmitter, a receiver and a transceiver antenna for said FM or PM data transmission. During operation the antennas are interlocked. The carrier wave transmitted by the first station and being normally FM or PM modulated by data signals is interrupted a number of times in this station. Upon detection of each one of these interruptions, the second station introduces a similar, corresponding interruption into the carrier wave transmitted by this second station. The carrier wave is normally also FM or PM modulated by data signals.