Optimal Sparse Array Design for Airborne Weather Radar With Integrated Communications

A close and continuous observation of typhoon can be accomplished by a phased array weather radar mounted on an airborne ship platform. The precise typhoon inner structure can be assimilated from the data obervations, thus envisioning a significant accuracy improvement in the prediction of typhoon intensity and travelling path. The requirement of high-resolution meteorological observation, against the limited power supply and payload weight imposed by the airborne platform, renders the deployment of sparse phased arrays essential to achieve tangible solutions. Integrated communications in the weather radar enable conveying the information to the ground control station without impacting radar beam scanning. This is completed by embedding the information symbols via the complex transmit beampattern modulation. As typhoon is a volume target spanning multiple range gates and angular bins, the focus of this work is a joint design of the optimal sparse array and associated beamforming weights for a well-controlled beam scanning in a wide angular range with integrated downlink communications. The constant modulus constraint of beamforming weights are imposed to maximize the radar transmit power efficiency, and an extension to discrete weight amplitudes is further considered for performance improvement. The simulation results demonstrate that the proposed sparse phased array weather radar can achieve an improved meteorological observation and a satisfied communication quality, especially in the scenarios of interferences.