A fresh look at the range weighting function for modern weather radars

The range weighting function (RWF) is normally introduced in discussions of the radar resolution (or sample) volume due to the fact that the RWF and the two-way antenna pattern are the main determinants of the extent of such volume. The RWF determines how individual scatterer contributions are weighted as a function of their range to produce the meteorological data (e.g., reflectivity) associated with a single range gate. The RWF is commonly defined in terms of the transmitter pulse shape and the receiver filter impulse response and is used to determine the range resolution of the radar. However, the processing done to estimate the meteorological data from the time-series data can also modify the effective RWF. This is a third contributor to the RWF that has become more significant as new range processing techniques are introduced on modern radar systems (e.g., those that operate on range oversampled signals). The focus of this paper is the study of the impact of signal processing techniques on the RWF for weather radars. Following the new formulation, typical processing schemes are used to illustrate the variety of RWFs that can result with different signal processing techniques. Finally, an alternative way to measure range resolution is introduced that is more meaningful for weather radar applications.