A processing scheme for LFM-based waveform MIMO SAR with digital beam-forming in elevation

Abstract

Multiple-input multiple-output synthetic aperture radar (MIMO-SAR) is of great potential for future high-resolution and wide swath imaging. However, its development is limited as the condition of orthogonality among the multiple waveforms received simultaneously is hard to satisfy. In this paper, a class of linear frequency modulation-based MIMO waveforms is introduced to settle this problem and correspondingly an effective processing scheme is proposed based on digital beam forming in elevation. In this scheme, for separating the mixed signals, null steering technique is employed to extract one waveform from the others. The main advantages of the proposed scheme include transmitting simultaneously, good inter-orthogonality between different waveforms with identical frequency range, separating them with mutual interference cancellation and good imaging quality. The main procedure of this scheme is derived and described in detail in the paper. Furthermore, an example MIMO-SAR system is provided for numerical simulation and the simulation results are obtained to validate the proposed scheme.