Airborne Polarimetric Doppler Phased Array Weather Radar: Performance Requirements and Design Specifications

Performance requirements for an airborne weather radar are more stringent than ground-based radar. Since the airborne radar has only a limited time for collecting measurements over a specified region, phased array radar with active electronic scanning array (AESA) enables rapid scanning of the antenna beam for collecting high-temporal and spatial resolution, research quality Doppler and polarimetric radar measurements. In the case of an AESA, when a beam is steered electronically away from the broadside, the gain and beamwidth change as a function of scan angle and cross-coupling between dual-polarization sources occur. For a specified aperture size and solid-state amplifier, pulse compression is used to enhance the received signal's sensitivity. To achieve reasonable along-track spatial resolution, the use of beam multiplexing (BMX) is essential. Beam multiplexing reduces errors in radar measurements while providing rapid updates of scan volumes. A beamforming architecture that supports BMX, and highspeed serial interconnect for front-end signal processing is essential for PAR's optimal performance. This paper describes the engineering design specifications of an antenna, transmit waveform, and weather radar signal processing subsystems.