Use of Coherency to Improve Signal Detection in Dual-Polarization Weather Radars

Currently the WSR-88D network of weather surveillance radars (i.e., NEXRAD) uses only power estimates for signal censoring. The planned network upgrade to dual polarization will result in 3dB SNR reduction per channel because transmitter output will be split between H and V channels. Therefore, radar sensitivity will diminish if the current power based censoring scheme is retained. In this paper, an alternative signal detection scheme is proposed which yields improved detection over the current approach. It mitigates the effects of SNR decrease by utilizing the weather signal coherency in sample-time and across channels. Choice of thresholds for specified false alarms and probability of detection are discussed.