A Cross Polar Interference Mitigation Technique for
Polarimetric Phased Array Weather Radar
Abstract: Polarimetric weather radar in simultaneous transmission mode requires high level
of cross pol isolation for acceptable data quality. Recently phased array technology is adopted
in this field due to its several advantages. But phased array suffers from poor cross pol
isolation. A signal processing technique is presented that simultaneously reduces its effect at
IQ data level and then additionally at the base product level. The transmission of long pulse
compression waveform (NLFM in this case) in the H and V channel with opposing direction
of frequency chirp is staggered by an amount larger than compressed mainlobe width. This
method uses the good cross correlation property of the two waveforms to offer suppression at
the intra-pulse level and benefits from naturally occurring random phase coding (since there
is zero correlation between signals belonging to different range bins) to give suppression at
the inter-pulse level.