This paper proposes two bias correction methods for the practical planar polarimetric phased array weather radar, namely, the boresight correction and the array pattern-based correction. As an extension of the projection matrix method developed in previous research, the performance of the boresight correction considering the measurement errors of element patterns and the impacts of entire array patterns on polarimetric variables is theoretically evaluated. It is shown that the measurement errors of element patterns are crucial for the polarimetric bias correction. Furthermore, for a planar electronically scanned antenna, the measurement performance of the linear depolarization ratio varies in the beam direction, while the measurement performance of the differential reflectivity remains almost the same within the beam scan area. In order to compensate the impacts of entire array patterns on polarimetric variables, the array pattern-based correction method is formulated, and its performance is theoretically analyzed. Assessments of the analysis and future research are discussed.

Due to the contradiction between the high sensitivity requirement and low transmission power of weather radars with solid-state transmitters, a pulse compression technique is necessary. For the purpose of range sidelobe suppression, methods based on amplitude modulation and a mismatched filter are commonly used for target detection radars, which are not applicable for weather observations because of its drawbacks such as main lobe expansion and power loss. This letter presents a nonlinear frequency modulation pulse compression waveform to achieve a very low range sidelobe level. A mathematical model for waveform design is established, in which the time-frequency relation is expressed as the combination of a linear function and a sine series. Thus, a set of parameters can fully characterize the time-frequency curve. By using a simulated annealing algorithm, the optimal parameter set can be obtained, which shows that a peak sidelobe level under -60 dB is achievable. Finally, this kind of waveform is implemented on hardware, and its performance is verified.