Investigation of MIMO SAR for interferometry

In conventional interferometric synthetic aperture radar (SAR), the coherent combination of two SAR images reconstructed from two separated receive antennas is used for digital elevation model (DEM) or moving target indication (MTI), depending on the antenna constellations. In this paper we propose the novel system concept for interferometric SAR (InSAR) based on Multiple-Input Multiple-Output (MIMO) configuration. A digital beam forming (DBF) SAR system based on multiple receive antennas is extended to MIMO SAR concepts. We investigate its performance and processing features, particularly, associated with the received signal quality and the transmitter diversity. Using orthogonal linear frequency modulated (LFM) signal, it is shown that space-time coding scheme can be applied to SAR system in multiple-input single-output (MISO) configuration. A simple Alamouti scheme enhances the signal-to-noise ratio (SNR) and extracts a spatial diversity. Combining this transmitter spatial diversity and digital beam forming on receive, we introduce the potential of high resolution wide swath (HRWS) observation for Interferometry.