Equivalent Circuit for Phase Delay in a Medium Frequency Antenna

The R(anging)-Mode is proposed as a maritime terrestrial backup system to Global Navigation Satellite Systems (GNSS) which are today the primary system for providing position, navigation and timing data onboard the ship. To enable accurate positioning with medium frequency R-Mode, a model is needed which describes the influence of the transmitter chain on the phase and amplitudes of the medium frequency R-Mode signal components. The paper depicts the influence of the transmitter chain, which is optimized for the transmission of a minimum shift keyed (MSK) modulated signal, with an equivalent circuit model with lumped elements that describes the transmitting antenna and the antenna tuning unit. Using this model, amplitude variations and signal delays are discussed.