Simulation of Spaced-Antenna retrivals for an X-band active phased-array weather radar

Single radar based wind-vector retrieval methods offer the advantage of self-consistent spatial registration of estimated wind-fields. However, most such single-radar based wind vector retrieval methods available to the weather radar community, such as the Velocity-Azimuth-Display (VAD), sacrifice angular resolution to retrieve the wind-field. The lack of successful high-angular-resolution Spaced-Antenna (SA) weather radar demonstrations up until this point can, in part, be attributed to difficulties in synthesizing appropriate antenna systems. Active Phased-array antenna systems offer the possibility of synthesizing overlapping effective apertures - a necessity for weather radar SA retrievals.

Here, we present Monte-Carlo simulations of X-band spaced-antenna retrievals for an active phased-array radar system. This allows comparison of the robustness of parametric time and frequency domain SA baseline-wind estimators – showing that parametric time-domain SA estimation is preferred. Based on these simulations, we investigate the tradeoffs between aperture size and spacing on the SD of retrievals in the presence of turbulent decorrelation. Quantitative design choices are made to strike the balance between beam-broadening decorrelation and turbulent decorrelation. Owing to the tolerance of parametric SA baseline-wind estimation to thermal noise, we find that trading antenna-gain for the SD of the retrieved SA baseline wind is feasible, in spite of the lost SNR, as long as the SA baseline is appropriately chosen.