Doppler Velocity De-Aliasing Based on Lag-1 Cross-Correlation for Dual-Polarization Weather Radar

Alternate transmission and alternate reception (ATAR) mode, as a crucial polarization mode, enables a single channel to be utilized in dual-polarization weather radars, which reduces the weight, power, and cost of the radar. The ATAR mode has a broad application based on high-altitude platforms with limited load and power. The interval between co-polarization signals is twice the pulse repetition time (PRT) in the ATAR mode. Thus, the Nyquist velocity interval is half of the one existing in the traditional radars. This hampers the application of the ATAR mode in severe weather observations. In this letter, a velocity de-aliasing algorithm is proposed, where lag-1 cross-correlations between adjacent radials are utilized to calculate the velocity estimates. This extends the Nyquist velocity interval of the ATAR model twofold compared to that of the traditional algorithm, which uses lag-1 autocorrelations between adjacent radials. In addition, the constraints of the proposed algorithm are analyzed. The proposed algorithm is validated via X-band PWR data, and the results show that compared to the true value, the biases of the de-aliased velocities in the ATAR mode are within ±1 m/s for 96.9% of the range bins. This method is also suitable for use with the alternate transmission and simultaneous reception (ATSR) mode.