Vital-SAR-Imaging With a Drone-Based Hybrid Radar System

Full-coverage synthetic-aperture radar (SAR) imaging and human target identification in complex scenes are very important for security and rescue applications. In this paper, a drone-based vital-SAR-imaging hybrid radar system is proposed to realize targets' imaging and human identification simultaneously. Carried by an operational custom-built drone with a designed S-shaped trajectory, 2-D SAR images of the entire region could be obtained through the frequency-modulated continuous-wave mode, and the “vital Doppler” effect of human target can be searched through the Doppler mode. Then, the vital-SAR-imaging could be achieved. Several experiments including cart-based SAR imaging with three trajectories, cart-based vital-SAR-imaging, and drone-based multitrajectory vital-SAR-imaging were carried out to reveal the capability and distinct operational features of the proposed system. Experimental results demonstrate that the system has the ability to obtain SAR imaging results in different scenes with multiple trajectories, and the human target could be effectively distinguished from other stationary objects. The results show that the lowest human target location error is 0.06 m in a 4 m × 9 m indoor region, which illustrates the great potential for search and rescue applications.