Mixed near- and far-field 2D imaging with sparse arrays

The advent of a new generation of radar arrays, topologically sparse and with wide apertures, has emerged in the field of automotive sensors to enable autonomous driving. These wide and coherent radar sensors aim at providing a high angular resolution to perform accurate imaging frontwards. However, a larger aperture increases the near-field region boundary to tens of meters. A region, where imaging methods are more demanding than in the far-field. Here, we introduce a mixed near- and far-field processing approach that preserves a high imaging capacity across the field of view. To this end, the signal space is separated and processed adequately and efficiently on each subspace. This mixed imaging approach is illustrated in a 2D range-azimuth configuration and paves the way to real-time imaging capabilities for wide radar apertures.