A TIME-DOMAIN IMAGE FORMATION FOR HIGH FRAME RATE UAV SWARM SAR

Multistatic SAR based on unmanned aerial vehicles (UAV) swarm can simultaneously obtain the echo of the target from different perspectives. Thus it can synthesize a large aperture in a short time, realizing high resolution and high frame rate imaging of interested areas. But there is few imaging method for high frame rate UAV swarm SAR and the problem of overlapping apertures affecting imaging quality remains to be resolved. Therefore, this paper proposes a time-domain imaging method to solve the problems. Firstly, echo model of UAV swarm SAR is established and multistatic equivalent aperture distribution is analyzed. Then the echo is equalized to improve image quality. Next, coarse angular resolution images of each bistatic SAR pair in UAV swarm SAR is accurately formed. Finally, all bistatic images are recursively fused to get the final result. Simulation results verify the effectiveness and accuracy of the proposed method.