Patent ID: 7605744

Claim:
A method in connection with a weather radar, the method comprising the following steps: sending electromagnetic radiation in a pulsed manner to atmosphere, detecting radiation reflected or backscattered from the particles of the atmosphere, and defining at least phase differences (Δp) between the sent and received signals, characterized by sending at least two different carrier frequencies (f 1 , f 2 ) with different pulse repetition times (PRT, (T+δ), (T−δ)), such that at least the pulse repetition time (PRT, (T+δ), (T−δ)) of one of the carrier frequencies (f 2 ) is continuously altered, defining the phase differences (Δp) between the sent and received signals at least at two different carrier frequencies (f 1 , f 2 ), subtracting the defined phase differences (Δp) from each other in order to solve range and velocity ambiguity of the measurement, and eliminating unknown phase difference caused by distributed atmospheric target.