Implementation of a MIMO-SAR Imaging Mode Based on OFDM Chirp Waveforms

In this letter, a novel and low-cost echo separation technique for the multiple-input multiple-output (MIMO) synthetic aperture radar (SAR) is presented, based on the orthogonal frequency-division multiplexing (OFDM) chirp waveforms. The proposed scheme allows the generation of multiple OFDM chirp waveforms on common spectral support. In the new scheme, a series of simple time-domain operations including replica, T-shift, and superposition is applied to eliminate the interference waveform within a limited time. Then, a combination with a bandpass filter instead of a matched filter to focus signal power and digital beamforming (DBF) on receive in elevation enables the suppression of interference signals for a realistic spaceborne SAR scenario, where the swath width exceeds the spatial extension of the transmitted pulse. Furthermore, the distributed scene simulation results are presented to verify the practicability of the proposed scheme.

Automated summary

A novel and low-cost echo separation technique for MIMO synthetic aperture radar (SAR) based on OFDM chirp waveforms is proposed, allowing the generation of multiple waveforms on common spectral support. Simple time-domain operations are applied to eliminate interference, and a combination of bandpass filter and digital beamforming enables interference suppression in a spaceborne SAR scenario. Distributed scene simulation results validate the practicability of the proposed scheme.