A Method for Grating Lobe Suppression in Distributed Space-Based Coherent Aperture Radar Based on Randomized Angle Yaw

The distributed space-based coherent aperture radar (DSCAR) is a radar system that utilizes a space-based platform to form a formation of radar unit (RU) for joint target detection, inspired by the concept of distributed coherent radar. However, DSCAR based on uniform linear formation (ULF) suffers from numerous grating lobe which severely impair the beamforming performance. Due to the fact that conventional grating lobe suppression method based on non-uniform spacing is not suitable for uniform formation, this letter proposes a method based on randomized angle yaw to address the issue of grating lobe suppression in DSCAR. We present the formula for the DSCAR joint pattern and use particle swarm optimization (PSO) to optimize the peak side lobe level (PSLL). Simulation results demonstrate that randomized angle yaw method has better grating suppression effect than non-uniform spacing method, and increasing the number of RUs and the number of RU antenna elements will further improve the optimal PSLL.