Orthogonal waveform separation based on echo compression for airborne MIMO-SAR systems

摘要

Attention has been devoted to multi-input multi-output (MIMO) synthetic aperture radar (SAR) systems in recent years. The applications of MIMO-SAR systems which involve high-resolution wide-swath remote sensing, three-dimensional imaging, and multi-baseline interferometry are seriously limited, because the superposed echoes of the multiple transmitted orthogonal waveforms cannot be separated perfectly. The imperfect separation will introduce ambiguous energy and degrade SAR images dramatically. Here, a novel orthogonal waveform separation scheme based on echo compression is proposed for airborne MIMO-SAR systems. Specifically, apart from simultaneously transmissions, the transmitters are required to radiate alone several times in a synthetic aperture to acquire their private inner-aperture channels. For the relevant scene, the energy of the solely radiated orthogonal waveforms can be concentrated by matched-filtering the superposed echoes with the sensed echoes. To this extent, the orthogonal waveforms can be perfectly separated through extracting the peaks from the echo-compressed results. The proposed scheme is validated by simulation results.