Airborne Polarimetric Doppler Phased Array Weather Radar: Digital Twin of the Active Electronically Scanned Array

A weather radar using an active electronically scanned array (AESA) enables rapid scanning of the antenna beam for Doppler and polarimetric radar observation measurements. An AESA consists of radiating elements, power amplifiers, attenuators, phase shifters, array controllers, and digital converters. This paper describes a digital twin, the AESA Simulator, which models both the AESA and weather radar returns, developed to explore and validate the optimal configuration of the APAR subsystems. Using a hybrid digital beamforming architecture, multiple, simultaneous receive beams are realized upon reception. Traditional analog beamforming will be performed along each row, while digital beamforming will be performed across the per-row outputs of the AESA. The simulator sums over a spatial grid, rather than using a prescribed antenna pattern, in order to support testing of multiple receive beams, clutter mitigation algorithms, and other developments that require accurate modeling of spatial diversity. The digital twin allowed NCAR/EOL to accelerate the timeline for engineering development of the APAR radar back end (RBE) and provides the necessary configurability to conform to the eventual AESA digital data acquisition and control interfaces as AESA and RBE development converge. Together the simulator and RBE are used to evaluate/validate the radar at the system level.