Automated real-time mitigation of ground clutter contamination for Dual-Polarization Doppler weather radars using the alternating transmission mode

The Office of the Federal Coordinator for Meteorological Services and Supporting Research (OFCM) is investigating the next replacement for the aging WSR-88D as part of a national interdepartmental collaboration to combine weather and air surveillance missions on a single platform. Promising is the multi-functional phased array radar (MPAR) which incorporates high temporal and spatial resolution needed for improved weather sensing. In addition, the MPAR design will surely include dual polarization since the integration of this technology into the WSR-88D is nearly complete and has shown significant improvements in rainfall estimation, precipitation classification, data quality and weather hazard detection. The requirement to incorporate dual polarization capabilities into an MPAR system requires that adequate cross-polar isolation exists between the horizontal and vertical channels of the antenna. Previous work in this area has shown that the cross-polar isolation required for simultaneous transmit and receive (STAR) is more stringent than with the alternate horizontal and vertical (AHV) transmission scheme. Use of STAR would allow much of the signal processing used on the WSR-88D system to be readily transferable into the MPAR; however, cross-polar isolation requirements may dictate AHV transmission with the need to consider signal processing techniques to decouple the Doppler phase shift from the differential phase shift between the horizontal and vertical receive channels.

This paper focuses on automated real-time mitigation of ground clutter for dual polarization Doppler weather radars using the Clutter Environment Analysis using Adaptive Processing (CLEAN-AP © 2009 Board of Regents of the University of Oklahoma) filter incorporated on National Weather Radar Testbed (NWRT) Phased Array Radar (PAR) and scheduled to be incorporated into the national network of weather radars (WSR-88D). In particular, the framework proposed by the authors for spectral processing of staggered-PRT waveforms is extended to mitigate ground-clutter contamination and to recover the spectral moments and polarimetric variables when the AHV mode of transmission is used. The performance of the proposed algorithm will be shown using simulations and archived WSR-88D polarimetric time-series data.