The Design of Orthogonal Waveform Suiting for Synthetic Aperture Radar Imaging

Abstract

Orthogonal waveform design is widely discussed in communication and radar fields. For synthetic aperture radar (SAR), the discussions of orthogonal waveform mainly focus on rang-ambiguity suppression and multiple-input multiple-output SAR (MIMO-SAR). And compared with other application areas, the design of orthogonal waveform for SAR is facing more challenges due to the distributed target characteristic. Nonlinear frequency modulation (NLFM) waveform can change the time-frequency relationship to adjust the energy distribution within the bandwidth to reduce the cross correlation energy (CCE), therefore, it is a promising candidate for orthogonal waveform designing. In this letter, a novel orthogonal NLFM waveform optimization framework is proposed. The proposed NLFM waveforms, which have a large time-bandwidth product, acceptable auto-correlation performance and low cross correlation energy (CCE), is suit for SAR imaging.