Application of MIMO to IFSAR

Synthetic Aperture Radar (SAR) provides all day, all weather and long stand off range capability of imaging large areas of the Earth. Single pass Interferometric SAR (IFSAR) using a pair of vertically displaced phase centers can be effectively used to estimate height using SAR images corresponding to each phase center. In recent years, multiple input multiple output (MIMO) radar techniques have received considerable attention. In this paper, we discuss the application of MIMO radar techniques for improving IFSAR height estimation. Additionally, we discuss IFSAR height estimation using multiple SAR images. We present an approach for selecting transmit waveforms to facilitate the computation of multiple SAR images corresponding to the virtual phase centers inherent in MIMO processing. With minimal modifications to existing two phase center IFSAR systems height estimation accuracy can be improved using MIMO techniques. Specifically, if the separation distance of the two phase centers is D, then using MIMO techniques the two phase center IFSAR system is transformed into a virtual three phase center IFSAR system with antenna element separation D and antenna length 2D. Example results are presented to demonstrate the benefits of this approach.