Random steerable arrays for synthetic aperture imaging

In classical spotlight-mode synthetic aperture radar (SAR), a mobile sensor array is steered to always focus on the same area (spot) as it moves, transmitting pulses to illuminate the spot and receiving and processing their reflections. The result is a high resolution image, covering a relatively small area. In this paper, we propose using a randomly steerable sensor array for synthetic aperture imaging, aiming to increase the coverage area without sacrificing the imaging resolution. This is realized by steering the beam of the array such that each transmitted pulse illuminates one of two or more spots, randomly selected with equal probability. Each of those spots has the same size as a single spot in a classical array, effectively doubling (or more) the total area illuminated. Using principles from compressive sensing (CS) we demonstrate that it is possible to reconstruct the images of all illuminated areas by exploiting the structure of the reconstructed images. Our experimental results demonstrate that our random steerable array can double coverage with almost the same imaging resolution.