An Experimental Study of Radar Tomographic Imaging in A Multi-Bistatic Scenario

We report on an experimental study of target imaging at X-band, based on narrowband radar tomography in an emulated multi-bistatic scenario. By exploiting the spatial diversity of multiple widely separated receivers we demonstrate that narrowband imaging of a rotating target with sub-wavelength resolution and low side lobes is achievable, assuming the point-scatterer representation of the target holds. The non-uniform fast Fourier transform (NUFFT) is used for its computational efficiency in the image inversion processing. The resulting images confirm that the theory of 2D radar tomography generally holds: the wider and more populated the measurement samples are in spatial frequency space, the better the image resolution and sidelobe performance. The possible degradation for the case of limited target rotational motion is illustrated. A simple method to estimate the bistatic angles and compensate for phase errors across the different bistatic channels is also presented.