Radar Beampattern Design for a Drone Swarm

Abstract

The limited battery power of Unmanned Aerial Vehicles (UAVs) is a major challenge in equipping them with onboard radar. Low power results in short flight times, short ranges, and modest radar detection performance. These limitations are overcome by deploying an array of multiple drones. However, challenges due to interference from on-ground services, clutter echoes, and platform motion could distort the antenna radiation pattern. In this paper, we consider beampattern design for a two-dimensional array of multiple single-antenna drones operating in a multiple-input multiple-output (MIMO) radar configuration. The resulting optimization problem has a quartic objective function with constant modulus and discrete-phase constraints enforced to account for hardware limitations. We solve this non-convex problem using a variation of the coordinate-descent algorithm and obtain MIMO transmit waveforms that achieve the desired UAV-borne radar beampattern. Our extensive numerical experiments validate our methods.