There present description is directed to a method and a system for determining a time delay between a transmission and a reception of an RF signal in a noisy environment. The method comprises: transmitting the RF signal according to a transmit frequency pattern, the transmit frequency pattern comprising at least three pulses separated by a period of time, each one of the at least three pulses respectively being at each one of at least three different frequencies; receiving a received RF signal comprising the at least three pulses at the at least three different frequencies, each one of the at least three different frequencies associated to a receive phase change; comparing the receive phase change of one of the at least three different frequencies with the receive phase change of another one of the at least three different frequencies to obtain a dispersion phase difference; and calculating the time delay using the obtained dispersion phase difference.