A signal processing roadmap for NEXRAD

The WSR-88D, a modern Doppler meteorological radar developed by the Next Generation Weather Radar (NEXRAD) program, has been in operation since the early 1990's. The National Weather Service, through the Office of Science and Technology, and the WSR-88D Radar Operations Center (ROC), began updating the radar's signal processing capabilities within a few years after deployment of the last unit. These capability improvements include the successful Open Radar Data Acquisition (ORDA) System, and the forthcoming polarimetric upgrade currently under development.

The ORDA made it possible for project team members to significantly enhance meteorological data product quality. These recent enhancements were developed at the National Severe Storms Laboratory and the National Center for Atmospheric Research, and implemented by the ROC. Some of the enhancements include the Sachidananda-Zrnic (SZ2) range-velocity ambiguity mitigation technique, Super Resolution base moments, Clutter Mitigation Decision (CMD) for automatic clutter filter control, and an engineering test phase of Staggered Pulse Repetition Time (SPRT) mode processing. Many other capabilities are planned, and more are possible as the technology evolves. Some near term projects include operational SPRT, a hybrid spectrum width estimator, clutter recognition (CMD) enhancements including polarimetric parameter inputs, oversampling and whitening, advanced calibration methods, and improvements to clutter filters. Other advanced techniques such as pulse compression may soon be feasible. Developments in hardware and software technology may foster the practical application of advanced techniques as well. All of these planned and possible projects are addressed in a proposed “Signal Processing Roadmap” which is the subject of this paper. The roadmap document will address scientific relevance and technical feasibility only and is not intended to serve as program management direction.

In summary, this paper reviews the evolution of present capabilities and presents some possibilities for the future of radar signal processing for the WSR-88D.