In this paper, we propose a collaborative sensing scheme for source localization and imaging in an unmanned aerial vehicle (UAV) network. A two-stage image formation approach, which combines the robust adaptive beamforming technique and sparsity-based reconstruction strategy, is proposed to achieve accurate multi-source localization. In order to minimize the communication traffic in the UAV network, each UAV node only transmits the coarse-resolution image, in lieu of the large volume of raw sampled data. The proposed method maintains the robustness in the presence of model mismatch while providing a high-resolution image.
Modern radio telescopes commonly use antenna arrays, and high-resolution imaging techniques exploiting radio astronomical signals collected at these antenna arrays play a critical role to achieve their missions. Beamforming techniques have been developed in radio astronomy to generate dirty images with limited image resolutions for many years. Because the manifold of a radio telescope array varies over time due to the Earth rotation, beamformers are separately designed and implemented at each time epoch, and the resulting images are averaged to form enhanced dirty images. Considering the fact that astronomical scenes are typically sparse, we present a new method through sparse reconstruction to obtain clean astronomical images. Sparse reconstruction methods that fuse the measured data observed at multiple time epochs are examined and compared. Unlike beamforming techniques which require an additional deconvolution procedure for clean image formation, the proposed technique provides clean astronomical images with accurate estimation of the source position and a high dynamic range.