P4d Practical Aspects of Wideband Reception and Processing in Dual-polarized Weather Radars

In conventional radar systems the receiver bandwidth is designed to be similar to be bandwidth of the transmit pulse. For a given range sample estimates are averaged over time to improve the estimation accuracy. A number of methods have been proposed in the past for improving the quality of estimates without sacrificing range resolution (Mudukutore et al, 1998). Schemes using shorter pulsewidth or pulse compression techniques require opening up the system bandwidth. Recently Torres and Zrnic (2001) have suggested oversampling the radar signals in range and whitening the range samples as a potential way to decrease the measured standard deviation of various radar signal parameters. This process requires increasing only the receiver bandwidth. For the whitening of the received waveform to be accurate, numerous details have to be addressed such as full knowledge of amplitude and phase of the transmitted pulse. This paper presents a theoretical and experimental investigation of the procedure of oversampling in range (at a resolution smaller than normal pulse width). It is shown that use of oversampling and whitening improves the quality of reflectivity and velocity estimates nearly in agreement with the theory, however improvement is not so obvious for the polarimetric variables.